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Group K GP1200 Triple Pipe Hammer Kits "70 mph on 92 octane gas"

Overview - In spring of 1998, Factory Pipe Products, of Ukia California, released their aluminum triple pipes for the GP 1200 Yamaha. These pipes are constructed as "completely water jacketed pipes". That means there are actually 6 complete pipe bodies...the 3 interior expansion chambers, and the 3 exterior water-jacket chambers. This complex construction is one of the reasons for the "attention getting" $2500 retail price tag.

Understandably, the FPP pipes were originally designed and intended for use on heavily modified IJSBA tour race machines. Given this, all the original testing and development was conducted only on such racing engines. When FPP decided to sell the triple pipes as part of their normal product line, their first order of business was to confirm the performance ability of the pipes on a completely stock machine (which is the standard goal for all their products). While the triple pipes certainly offered a noticeable performance gain on a stock machine, the increase was not on the order of what most customers would be expecting for a $2500 price tag.

It was at this time that FPP contacted Group K to help with the development of a "minimum modification" package that would allow the triple pipes to deliver a much bigger chunk of the potential power they had to offer. Since we already had considerable experience with the Yamaha 1100/1200 triple engines, we already had a pretty good idea of which modifications an FPP equipped GP 1200 might best respond to. This document will outline the modifications we found to be the most fundamental for FPP/1200 packages, and the technical reasoning behind those choices. 

Defining the Technical Differences - There is a long list of design and function differences between the way the stock singled bodied exhaust pipe and the FPP triple pipes do their job. With this in mind, we realized that "all" the same modifications that worked well on the single pipe format do not necessarily give the same ideal results on the triple pipe format. Our testing indicated that was often true.

The Stock Single Pipe - The stock single pipe actually can allow for some significant horsepower and rpm increases…within limits. The stock pipe is designed to yield it’s max power at about 6800 rpm, while the FPP pipes are tuned for max power at about 7300 rpm. This doesn’t mean that stock piped 1200's can’t spin past 6800rpm. Group K 1200's spin happily to 7000+, and many other shops have turned their stock pipe 1200's 7300 - 7600rpms. However if an engine builder wants to spin "a lot" beyond 6800 rpm, using the single pipe, he must make some undesirable modification choices to "force" the single piped motor to spin that high. These choices include (but are not limited too) excessive port timing, excessive compression ratio, excessive spark advance, excessive carb throat size, etc. These choices of excess would ordinarily make a recipe for very swift failures on any other high output engine. But the power increase afforded by these kinds of modifications is relatively small because they are having to work so hard against the mechanical "will" of the stock pipe. The result is that the extra rpm are certainly achieved, however the amount of sheer horsepower gained by this additional rpm becomes progressively less. In the real world this boils down to using a milder pitch impeller to allow the engine to "over-rev" more easily. The net result is a very small water speed gain that comes at the cost of a very large peak rpm gain. In time, the engine builder finds himself not just doing "two wrongs to make a right", but he is making a dozen wrongs trying to overcome the single big wrong of the stock pipe design. Over the last few years, the modifications needed to "force" the single piped motors into the high rpm range have become so "standard procedure" that they no longer seem extraordinary.

The FPP Triple Pipes - Because of the design of the FPP pipes, the Yamaha 1200 engine is a much more willing partner in the production of higher rpm horsepower. This being the case, most of the "extreme" tuning choices used on the old single pipe motors are simply no longer needed. The FPP pipes allow the engine builder to prepare a reliable high output 1200 without having to resort to all the "poor" technical choices of single pipe days. This was our approach and mind set with the development of our package for the FPP triples.

To maintain some perspective on our testing, we had to have a general riding application "aim"...that is, who will be riding this...and what is most important to them. There are already plenty of shops building intense accelerating, short fused, versions of this engine for closed course racing. However the majority of customers who have contacted us about FPP/1200 setups are interested in occasional local closed course, and informal "grudge racing" with their riding pals. The needs of this kind of setup are considerably different, and considerably less expensive, than what is needed for IJSBA pro tour racing.

Factory Pipe Products First Tests - We provided one of our GP 1200 Sleeper top end sets to FPP for their dyno testing. It became immediately apparent that the pipes, and the conservatively ported cylinders, performed very well together. However the biggest surprise was that they performed very well together with unusually low compression. In fact, our Sleeper cylinder yielded better "temperature control" at high rpm, using a stock volume head than with the milled Sleeper head that we had provided to FPP. This mirrored the results of our earlier on-water testing of the prototype triple pipes.

After this battery of dyno tests, FPP assembled their test boat with the Sleeper ported cylinder, their pipes, cdi box, and Solas impeller (we suspect a "J" pitch...they aren’t totally sure what it was). They ran this machine on pump gas at 7300 rpm for some 6 hours (hard). This machine radared 55 mph in stock form, and 65 mph with the pipes and porting. Since the FPP technicians were unaware of the problems related to the stock GP1200 trim tabs, this entire test (and all their radar runs) were made with stock trim tabs of very questionable fit. All the same, we were impressed by these tests strictly from the standpoint that they could run 7300 "at all" on 92 octane pump gas. With these tests done, FPP sent us a set of "production" pipes for our own on water testing.

Our First Tests - We already knew from our previous tests of the prototype FPP pipes that the key to getting the best performance would be to aim for an rpm peak very close to 7300. It was our hope to make just enough power to pull the steepest possible pitch impeller to this rpm (hopefully resulting in 70 - 72 mph speeds). It was our goal to accomplish this by using the minimum amount of compression, ignition timing, port timing, etc. We believed that the pipes themselves were capable of doing all the heavy work of horsepower production. The rest of the engine components needed merely to "stay the hell out of the way".

When we prepared to port the cylinder on our ’98 GP, we noticed that the bores were a bit loose. Closer inspection revealed that the piston to cylinder wall clearance on our new machine was more than we had seen on any previous 97 GP's. We also noted some exceptional "out of roundness" of the bores. However this out of roundness was not a function of poor workmanship, but rather a function of the absence of the large stock "log" type manifold that is notorious for pulling the bores out of round. (see our website update re. Yamaha Triples Bore Distortion).

We realized that the FPP manifolds would not mirror the natural bore distortion characteristics of the stock "log" manifold. Since we were planning to use a nearly stock dome volume head on this test machine, we considered it fundamental to have "no compromise" bore diameters for this engine. Perfectly round, and close fitting, bores can easily net improved power without increasing compression ratio (the closer bores will actually indicate another 10 - 15 psi on a compression gauge). After seeing the results of this re-fit, we would strongly urge any serious FPP/1200 owner to seriously consider immediate .25 oversize boring of their cylinders. We have subsequently seen similar bore diameter "issues" on other 98 GP1200 cylinders that have come into our shop.

Besides the trued and welded crank, and the Sleeper ported cylinder, our ’98 GP1200 short block was completely stock. We used the stock carbs (re-jetted) with an R&D flame arrestor and the choke plates removed. For all FPP/1200's we strongly recommend that the crankshaft be trued and welded to avoid the crank twisting between cylinders (we have often seen this on our own single pipe Type 2 kits). All our original tests were run on 100% race gas, but we later found that a 50/50 mix of 92/110 octane worked fine. The Riva cdi (used with the pipes) offered four different ignition curves. We elected the "mod 1" curve because it had the least advance at high rpm.

For the pump we used the Solas X1 prop, Riva trim tabs, and the R&D "Pro Series" ride plate and scoop grate. This ride plate and scoop grate were developed to reduce the "nose drop" that takes place on modified GP 1200s when the throttle is shut off quickly at high speed. In addition, this combination added about mph. We consider them mandatory for any GP hulled 1200...especially triple piped ones.

After some preliminary jetting, our test boat easily ran 7300 rpm @ 71 mph...cold. However as the engine was run hard at peak speed, the rpms would begin to decline to stabilize in the low 7200's. After allowing the machine to cool off for just a few minutes (with easy riding), we could again make a few passes into the high 7200 rpm range. During these tests, we suspected that this "heat soak" condition is likely a result of peak rpm ignition timing that is still a little too advanced. We would have liked to had the option to get another 1 or 2 degrees of retard at peak rpm, but the current cdi boxes do not permit that. We would note that some technicians feel that they have made significant progress on the "heat soak" problem by increasing water flow to the cooling system, however that mod can only have a limited impact on actual combustion chamber temperatures.

During our earlier tests of the prototype pipes, we fabricated an offset key for the ignition flywheel that allowed for this additional 2 degrees of retard. Unfortunately that overall 2 degrees resulted in "unacceptable softening" of the low speed acceleration.

Our 98 GP test boat accelerated "nicely" at low speeds, but we didn’t think that "trimming" the low end power (in the interest of better top end) was a good choice. It bears noting that any increase of compression ratio would feed into the same temperature problem that we are trying to resolve with ignition timing. An offset flywheel key with higher compression would likely net the same overall "heat soak" problem that we already have. Part of the reason for the aforementioned problems is that all the currently available cdi boxes were developed for use on single pipe platforms.

Our Second Round of Development Testing - Since that first round of triple pipe GP 1200 testing, we have learned much about the triple pipe platforms. We have also learned much about the modifications that improve performance of this platform (and those that don’t).

Without exception, the most common question asked of us has been that of pump gas compatibility. Or, more accurately, "how fast can a reliable triple pipe GP run on pump gas?". During earlier FPP pipe testing, we could make our test machine produce a few good runs on pump gas, however the performance eroded very badly as the temperatures of operation "soaked" into the engine. These collective temperatures could often result in detonation that led to fatal piston scoring and/or piston crown damage.

We decided to re-visit the development of the "70 mph pump gas GP" with a whole different approach. This new approach had a two-fold goal. The first goal was to reduce and/or minimize the loads that the engine needs to drive against to generate peak speed. The second goal was to minimize the "heavy heat generating" engine specifications that might contribute to performance loss as the engine becomes "heat soaked". This testing resulted in the creation of our 92 octane Hammer kit.

About 92 Octane Performance - The Hammer 92 is a reliable GP 1200 that is capable of running at 70 mph. Please note that these peak speeds are only available on glass smooth water. In water with a short wind ripple, the speeds can drop 2 – 4 mph, however this kind of water has the same effect on the peak speeds of anyone you might be racing against. Like any fine tuned machine, weather conditions will also effect speeds. Depending on prevailing weather (air density) conditions, the peak rpms will run between 7250 and 7400 rpm. The peak horsepower of this engine package is at 7400 rpm, however this peak will only be seen in the best air density conditions.

All this said, ALL our test riders told us that our Hammer 92 was clearly the fastest and quickest pump gas boat they had ever ridden. Our closed course riders told us that this boat was easily capable of dominating local level closed course events...anywhere. This is a machine that commands your undivided attention "at all times".

Hot and Cold Tachometer numbers - When aftermarket manufacturers call a machine "pump gas compatible", that does not mean it can generate it’s peak horsepower number for a twenty mile full throttle pass. It means that the machine can produce it’s best performance for the length of a normal race, and not experience a heat related engine failure when operated under normal riding conditions. Running at 70 mph (non-stop) for several minutes is not "normal use" for anybody. The Hammer 92 can be operated in a "much heavier than normal use" way, but 92 octane gasoline alone cannot support the temperatures generated by this kind of use. The mere addition of 25% avgas or race gas can offer the temperature safety margin to allow for this kind of operation.

In truth, every high performance engine will produce it’s best rpms and speeds when it is "cooled down". On that same tack, "every" high performance engine loses a margin of it’s peak rpm as the engine becomes heated up (called a "heat soak"). These different tachometer numbers are refereed to as "cold numbers" and "hot numbers". During the testing of our Hammer 92, minimizing the rpm loss of heat soak was a top priority. Total heat soak loss is normally 80 rpm or less (this is a very small loss for any high output engine).

Overview of the 92 Hammer Modifications - Among GP owners wanting to construct a 70mph GP1200, there seems to be a general perception that the installation of expensive and elaborate bolt-on parts is the fundamental key to going "really" fast. Unfortunately, our many weeks of on-water testing never supported that belief. As it all ended up, most of the (relatively conservative) modifications we used in our original race gas FPP GP 1200 were also used for our pump gas version. The biggest lessons learned from these tests is that the best performance improvements resulted from "ACCURATELY PREPARED" components...not expensive or exotic components. This is not to say that all you need to do is "blueprint" everything. However all the modifications made, and modification parts chosen, need to prepared to very exacting specifications. Getting a triple pipe GP to run 70 mph on pump gas can be done without too much difficulty…however, based on our tests, it CAN NOT be done with average off-the-shelf bolt-on components.

Cylinder and Head Preparation - The cylinder porting modification used for the Hammer 92 GP is the same specification used for the race gas triple pipe kit. This porting modification uses slightly more port area and timing than our Sleeper cylinder, so a Sleeper cylinder can easily be upgraded to this specification.

For our Hammer 92 kits, we prefer to modify the stock cylinder head. The stock head casting has excellent cooling characteristics, and we find that the stock head gasket (used with this head) offers a more lasting long-term head gasket seal than any of the "O" rings used in many aftermarket heads. We will not prepare any Hammer 92 top ends to use an "O" ring (non-head gasket) type cylinder head. While the compression ratios we use are somewhat conservative, the design changes we make to the cylinder head domes are very significant.

With respect to compression, our Hammer 92 has a narrow tolerance for "ideal" compression ratio. Too little compression results in insufficient performance, and too much compression results in an unacceptable loss of rpms after the heat soak. The issues connected to bore clearances and bore roundness (discussed above) are also important to the Hammer 92. Boring the cylinder to .25mm oversize (in the interest of better bore sealing) is certainly the more preferred way to improve cylinder pressure (as measured with a gauge). With this boring, a slightly lower compression ratio head volume is used. However many owners are unwilling to do this boring (especially on a near new machine). For these GP owners using standard diameter bores, we must cut the head volume to a slightly higher compression ratio than the 1st oversize setup. For owners who choose the standard bore diameter spec, we would need to re-cut these dome volumes when that engine is later bored to .25mm oversize. This seems like extreme detail work, however we believe that this level of detail is required to maintain safe 92 octane operating temperatures.

Lower End Preparation - As previously mentioned, truing and welding of the crankshaft is considered to be absolutely mandatory for any triple pipe GP 1200 format. We recommend that you have this work done by a crank rebuilder that is familiar with the GP 1200 crank, and capable of accurately checking and setting the "index" rotation between the flywheels.

Case porting is an optional modification that can net a slight performance improvement through the entire power range, however we did not utilize case porting on our test machines that ran 70 mph on 92 octane fuel.

One new item we are recommending for our modified GP 1200's is a "Fluid Balancer" drive coupler that is fitted to the engine. Despite it’s somewhat small diameter, this balancer (that replaces the stock engine drive coupler) makes for a very significant reduction in overall engine vibration, as well as a noticeable increase in acceleration and peak rpm ability (we don’t know why it increases rpms…we just know it does). We consider the installation of this balancer to be "highly recommended", for no more than it’s ability to reduce wear and tear on all the hull and driveline components. The acceleration and rpm increases are just an added bonus. You can obtain this balancer directly from the manufacturer (Fluid Balancer (716) 937-7903 ext. 254).

Intake System "Fuel" - After much testing, we found no carburetors (modified or otherwise) that offered significantly better acceleration or rpm than the stock 44 Mikuni carbs (re-jetted with the choke plates removed). This is not to say that there are no functional carburetor alternatives for high output GP 1200's...just none that our Hammer 92 kit responses to. The stock carbs (properly jetted) offer easy starting, clean idling, and excellent overall metering.

The installation of the FPP pipes does have one unforeseen side effect on carburetion that is important. The resonating vibration of the engine itself is very much changed in the 2000 - 5000 rpm range. The weight of the stock pipe (attached firmly to the engine) apparently minimized the vibration in this rpm range. With the FPP pipes this vibration is so vigorous that it can literally shake the float needles away from the seats. The result is a serious rich condition between 2000 - 5000 rpm that cannot be adjusted away with the adjuster screws. We were not able to completely "fix" this problem, however we were able to minimize it by replacing the stock 95gm float arm springs with 115gm springs. We were initially concerned that these heavy springs (and the very high resulting pop off pressure) would cause a fuel flow problem at full rpm...but we never experienced any problems. The heavier springs are part of our jetting modification for these kits.

Our Hammer 92 still uses the stock reed cages and petals. No aftermarket replacements (to date) have offered the combination of longevity and performance that the stock parts offer. We do use R&D reed stuffers, as they slightly improve the authority of acceleration.

Of all the arrestors tested, we consider the R&D "Pro Lock" to offer the best in performance and convenience. This arrestor element can easily remain in place with no clamps at all, thus making it easy to remove for carb tuning access. We also consider the "single plenum" design of this arrestor to be a definite performance advantage. A single plenum design allows the carbs to induce pressure waves to one another in a way that benefits overall carburetion. This sharing of pressure waves doesn’t take place with individual arrestor pods.

The "much higher than stock" operating rpms of the Hammer 92 are "unfriendly" to the stock oil injection pump on the GP 1200. While oil injection is certainly a convenience, the risk of engine damage from a failed oil pump is simply not worth the convenience. In addition to this, the extra rpm of the Hammer 92 creates a higher oil requirement than the injector pump can accommodate. As a result, we recommend that the Hammer 92 be operated on a 32:1 premix (1 pint/ 4 gall).

Intake System - There is much made of increasing the air intake ability of the GP hull for high performance formats. Our stock-piped ’98 GP 1200 Sleeper ran 66 mph with the stock air inlet system. Removing the seat (to allow for unlimited air availability) netted a 20 rpm increase (not much). On our triple pipe Hammer 92, this same "seat-off" test netted 40 rpm. While that’s still not a lot of rpm, it’s too much to ignore. To avail the extra air access need, we simply opened up the air inlet holes at the front of the grab bar, and then drilled four 1inch holes through each side of the rear seat base. This offers all the extra access our Hammer kit needed. 

Ignition system - We use the Riva cdi box on the "mod 1" setting with the limiter set at infinity. We use the infinity rev limit setting because we question the accuracy of the lower limit settings (there were times we felt we were bumping a limiter at rpms well away from the "set" limit). We made no other modifications to the ignition system.

Hull Preparation - Normally, we do not get involved with issues of the hull, however the hull on the GP is a source of great resistance to higher speeds. Based on our testing, the GP hull has two primary difficulties that require attending to. The first is the "trim tab area" at the rear of the hull, and the other is the nose heaviness of the hull.

Trim Tab Area - All the ’97 (and many of the ’98) GP 1200's come with plastic trim tabs attached to bottom rear of the hull (on either side of the ride plate). On models that have these plastic trim tabs, THEY MUST BE REPLACED with billet aluminum trim tabs (Riva makes very nice ones). There is no way to seal or repair the stock plastic tabs. If you have plastic trim tabs...you have bad trim tabs.

Many of the newer 1998 GP hulls do not have the replaceable trim tabs. Their hulls simply extend back to include the area where the old trim tabs used to be. Unfortunately, the rear area of these "tab-less" hulls is not nearly as flat and "true" as the earlier hulls are (with billet tabs attached). The only option for these later style hulls is to have them "trued" to eliminate any high spots or surface irregularities. The fundamental part of this "truing" is to block sand the rear area of the hull to assure flatness and symmetry.

The ’98 GP 1200s employ an exit nozzle that has a 5 degree upward angle to help lift the nose of the hull off the water. The net gain of this change is about 1 mph. Installing this nozzle on the 97 hulls has the same good effect, and we recommend it.

The stock trim adjustment on all the GP 1200's allows you to set nose ride height, however this is done by re-aiming the direction of the water exiting the pump nozzle. This re-aiming process compromises the efficiency of the thrust, and therefore peak speed ability. The more effective way to lift the nose of the hull off the water is by altering the bottom face angles on the ride plate. By changing these angles, the front of the hull can literally be lifted away from the water surface, thus decreasing water contact area (and increasing peak speed). It bears noting that, like everything else, it’s easy to cut too much angle on to the plate, resulting in uncontrollable porpoising.

We chose to start out with the R&D Pro Series ride plate (which already carries some multiple negative angles). After testing with many angle combinations, we found a specification for the ride plate that allows for maximum nose lift along with "porpoise free" operation on smooth water. While the cutting of accurate dimensions on ride plates is not common fare for most high performance machines, it is a mandatory modification for this Hammer 92 kit. While this mod still allows for reasonable rough water handling, it is intended to allow the best in smooth water speeds. Rough water racers may not benefit as much from this mod. We strongly recommend the R&D Pro Series scoop grate to go along with this modified ride plate (there is no mod for the grate).

Hull Finishing - When you take delivery of any new GP 1200, the bottom surface of the hull is very smooth and shiny. While this finish looks real nice, it is totally non-functional. The ideal bottom surface finish is a non-shine finish created by numerous full-length front to rear "scratches". The best way to accomplish this finish is with a piece of very coarse emery (40 - 60 grit is best). All the sanding strokes should be front to back (continuous) for the full length of the hull. The deep, full length, scratches should eventually eliminate any part of shiny surface. While this preparation may not look attractive, these scratches will act as thousands of small rudders that will make the hull track "a lot" straighter in all water conditions. These scratches will also allow for much better surface holding in high-speed turns.

We consider this preparation to be mandatory for our Hammer 92 kit. The added nose lift, offered by our ride plate modification, means that there is slightly less "steering" hull contacting the water surface. A shiny hull, at this attitude, can tend to "seek" at high speeds. This sanding preparation allows the same GP 1200 hull to run arrow straight at peak speed, along with much more responsive steering control.

Impellers - It used to be that we merely tested the available "over the counter" impeller pitches to see which ones best suited our engine kits. Unfortunately, as time has gone on, we have observed very significant variations in the specification and symmetry of these over the counter impellers. These variations may not be a big deal for general purpose applications. However on setups that are intended to deliver the maximum in performance, the accuracy of impeller specification is every bit as crucial as accuracy in cylinder port heights.

On our race gas version of the triple pipe kit, we utilized the Solas X1 impeller (steeper than the Solas J used on our Sleeper kits). The X1 could work well, however we have since learned that it induced a heavier than needed load against the motor that resulted in excessively high operating temperatures. The only effective way to deal with those excessive temperatures was to mandate race gas.

For our Hammer 92 kit, we chose to start out with the milder "J" pitched impeller in an effort to reduce the excessive loads against the engine, and the temperatures that go along with them.

About this same time, we had observed some significant variations in the specification (and on water performance) of "off the shelf" X1 and J pitch impellers. We realized that we first needed to eliminate these variations, and then custom tailor the blade design of our test impellers to suit the Hammer 92. Of all the testing we did with our Hammer 92 kit, this customizing process of the impeller made for some of our biggest overall performance improvements, and engine temperature reductions. Note that this specification adjustment is custom suited to the needs of our Hammer 92. We have no data on how this adjustment might effect other engine combinations. We consider the Solas J "specification adjustment" to be a mandatory modification for the correct performance and engine loading on the Hammer 92 kit.

Pumps - The stock Yamaha pump case is easily up to the task of delivering the power that the FPP/1200 can produce. Our blueprinting of the stock pump case makes for a noticeable improvement in rough water hook-up along with a slight improvement in peak speed ability.

For owners who want the ultimate in pump technology, the Skat Trak all stainless steel "D" pump is the last word. Be aware that this pump uses special Skat Trak "swirl" impellers that do not fit the stock pump case or housing. As of this writing, we were unable to complete comprehensive testing of the Skat Trak pump on the GP hulled boat, so we will post that data as it becomes available.

Details - We strongly urge every FPP/1200 owner to get a PET 2100 digital pulse tachometer. This will be an invaluable tool for the tuning and monitoring of your machine. There are other tachometers that can work well on these machines, but we’ve found that the PET tach's have the best in accuracy, durability, and update time. The PET tachometers are available from Watercraft Connection of Oregon at (503) 232-2026. We also recommend the air leak test kit from W/C Connection to check your engine for air leaks.

Complete Engines - For customers who want a turn-key package, Group K will construct complete FPP/1200 short blocks or complete boats to your specifications.

PRICES

Includes cylinder porting, decking; cylinder head modification; and carb jetting. 

Yamaha 1200 "Hammer" ENGINE KIT (specify 92 octane or 105 octane)

(SEND head, cylinder, and carburetor set) --------------------------------------------------------- 889.00

INDIVIDUAL ENGINE LABOR & PARTS

FPP TRIPLE PIPE SET --------------------------------------------------------------------------------2500.00

CYLINDER PORTING & DECKING --------------------------------------------------------------------600.00

CYLINDER HEAD MODIFICATION ------------------------------------------------------------------- 195.00

1200 44 mm CARB JETTING ---------------------------------------------------------------------------- 90.00

PRIMER KIT -------------------------------------------------------------------------------------------------39.00*

R&D "PRO LOCK" FLAME ARRESTOR KIT ----------------------------------------------------------299.00*

R&D REED STUFFERS ---------------------------------------------------------------------------------- 225.00*

RIVA CDI BOX ------------------------------------------------------------------------------------------- 329.00

OPTIONAL CRANKCASE PORTING & MATCHING ------------------------------------------------ 300.00

CRANKSHAFT TRUING AND WELDING ------------------------------------------------------------ 250.00*

FLUID BALANCER DRIVE COUPLER---------------------------------------------------------------- 399.00*

Cylinder boring, hone, & chamfering (one oversize) -----------------------------------------------195.00

SHORT BLOCK TEARDOWN, REASSEMBLY & PRESSURE TEST --------------------------- 490.00**

**NOTE: Group K will bill an additional $35.00 handling charge for engine assemblies via UPS 

DRIVELINE LABOR & PARTS

RIVA TRIM TABS & MOUNTING KIT -----------------------------------------------------------------109.00*

OPTIONAL PUMP BLUEPRINTING (send vain case and impeller housing) ------------------210.00

R&D "PRO SERIES" SCOOP GRATE ---------------------------------------------------------------105.00*

R&D "PRO SERIES" RIDE PLATE-------------------------------------------------------------------- 140.00*

R&D RIDE PLATE MODIFICATION -------------------------------------------------------------------- 48.00

SOLAS "J" IMPELLER ------------------------------------------------------------------------------------279.00*

SOLAS IMPELLER SPECIFICATION ADJUSTMENT (Hammer 92) ---------------------------- 78.00

*prices subject to change based on manufacturer's current pricing

ORDER INFORMATION: Send all parts required for modification to:

GROUP K
4597 CALLE DEL MEDIA
FORT MOHAVE, AZ. 86426
928-763-7600
email: groupklemm@aol.com

GETTING THE WORK DONE - Most customers send GROUP K the parts needed for modification via UPS, and then do the engine assembly work themselves. We also do complete engine and pump assemblies for customers who want a finished unit ready for installation. The new 150 lbs. UPS weight limit makes engine shipping practical and affordable.

All orders prepaid with a cashiers check or money order will be returned freight free via ups ground service anywhere in the continental United States. All other orders will be billed to a visa/master card (UPS no long carries cod cash shipments). If you would like to pay additional for 3 day, 2 day, or 1 day return shipment, please specify your preference in a cover letter with your parts. Be sure to include your return address and day phone information in case we have any questions regarding your order.

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