X2 semi stock class for 07

[Crab]

Anyone have the rules for this class, is it new?

 

[shawn_NJ]

Just saw this posted by Harry Klemm in the GroupK tech section on PwcT, very interesting note about the semi-stock class:

"An 850 X-2 sounds like a great project, but we feel that there will be alot of interest in the new X-2 semi-stock class. This new semi-stock class will be a class where the new X2s will race under current stock rules, and older X2s (with a pipe, single carb, and several other mods) will be allowed to race in the same gate. While this will be a start-up class, the formula allowed to the old X2s should result in a fast and fun rec/race boat. The old X2s will be requied to run 650 cases and crank, but will be allowed 725cc. We are currently testing with an older X2 prepared in this way to have a good evaluation example for testing .... we think it stands to be a popular class .... but sadly, no post 1994 850s permitted.
Respectfully, Harry Klemm "

http://www.pwctoday.com/showthread.php?t=96288&page=4

 

[Crab]

Just saw this posted by Harry Klemm in the GroupK tech section on PwcT, very interesting note about the semi-stock class:

"An 850 X-2 sounds like a great project, but we feel that there will be alot of interest in the new X-2 semi-stock class. This new semi-stock class will be a class where the new X2s will race under current stock rules, and older X2s (with a pipe, single carb, and several other mods) will be allowed to race in the same gate. While this will be a start-up class, the formula allowed to the old X2s should result in a fast and fun rec/race boat. The old X2s will be requied to run 650 cases and crank, but will be allowed 725cc. We are currently testing with an older X2 prepared in this way to have a good evaluation example for testing .... we think it stands to be a popular class .... but sadly, no post 1994 850s permitted.
Respectfully, Harry Klemm "

http://www.pwctoday.com/showthread.php?t=96288&page=4

Looks like I won't be playing, a boat that you can't buy in this country off the shelf, and an old one you can't fully update. Sound like a fair matchup? Seems like you should be able to use the 800 drivetrain as an option.

 

[shawn_NJ]

I wonder how many new X-2's made it into the US, and out of that number, how many of them are going to stay stock? I dont think there will be many new X-2's. But I totally agree with you about using the 800.

 

[Project Ski]

with the mods you are allowed and the weight differnece i think you might be able to keep up.

Besides, if kawi allowed the 800 engine in the old boat it wouldnt provide much insentive for people to buy new machines. Also same powerplant in 100 pound lighter hull would make the old boat the one to go for. No?

 

[Crab]

with the mods you are allowed and the weight differnece i think you might be able to keep up.

Besides, if kawi allowed the 800 engine in the old boat it wouldnt provide much insentive for people to buy new machines. Also same powerplant in 100 pound lighter hull would make the old boat the one to go for. No?

Agreed, but first you need to sell the new one at any dealership, and not make it an import that may not be liscense ready.

 

[Legdragger]

The weight difference is only because of the plactic parts the old X2 came with. Half the pump is plastic and the exhaust is a tiny thin wall stainless unit. It is way lighter than a wet pipe. The small block not only make less power but it weighs less as well. After you replace plastic and tin with some more stout parts, toss the 650 and add some extra fiberglass stuff like sponsons and reinforcement the weight difference get smaller. Besides, last I checked weight was your friend on a race track. It keeps you planted and hooked up. Doesn't anyone remember the lead weight they use to sell for under bed plates?

My X2 is a tank. It is like 350 with gas. The lightest hull I have is 120 lbs stripped with no hood. The difference is in the cheap parts they came with. Anyone riding an old X2 with a 650 based single carbed engine against a new 800 X2 is bringing a knife to a gun fight.

It is a crime to run any X2 with a 650 in it let alone race one against a better designed hull with more motor. If you took an old X2 with a 750, wet pipe, updated pump, tubbies and proper set it would be a decent race against a new X2. You are still at a disadvantage to the SXR hull. The old hull hates chop. It pounds the filling out of your teeth. The new hull has a way more planted nose shape. It is a like mini Scarab. It just slices chop to pieces like an SXR except better I bet.

Besides who would want to blow money working over a 650 when they could be getting way more bang for the buck do the same thing to a 750.

I would race the hek out of a an old 650 X2 with some tubbies against other old X2's though. That would be fun and cheap. Especially a surf race :Banane01: .

 

[D Slicker]

I second that....

 

[X2Pilot]

....... It just slices chop to pieces like an SXR except better I bet.

Yep its true. I think my top speed is even better in the chop as well. Yes its the same SXR bottom hull and weighs the same, but the overall weight is distributed a little different. It also comes stock with a pump wedge. It took me a bit to get used to it, the nose would plant so hard in corners if I was right on someone, I'd end up sinking the nose deep from the hole that the ski ahead of me left. Its more pronounced following an SXR also haha. A change from the stock steering head to A/M helped me, putting my body position lower and back some. It not only LOVES the chop it zips around corners like a madman. My upgrades so far are wet pipe + jetting, flame arrestors, intake grate, rideplate, impeller. Its running 50 - 52 MPH and it hits OK, but it needs more.

Still to come: porting, carb upgrade, girdled head and ignition with water injection. I am also gonna try an R&D pumpcone, I hear they do make a noticible difference in hookup and low end. Theres a few other minor things to dial it in but I'll have a little rocket when I am done. I expect about 55 - 56 MPH and a large increase in the bottom end. Maybe I am dreaming but a guy can be hopeful. JSU is gonna do the engine work so It could happen...:biggthumpup:

If the X2 semi stock class happens, I am going to buy another 05 or 06 X2 and leave it stock to race. I am confident that, if I build it to the current stock rules, the new X2 will dominate even piped single carb 751 X2s.

If the new X2s were to be held to TRUE stock, with no engine, driveline or electrical modifications, it would be a more evenly matched race, tho the new X2 still has the hull advantage...

I am excited to see what kind of participation this new class generates. I do not want to race the HXs again. Its futile. Even if I could get a dry pipe in the thing the HXs will still be hard to beat. The B1s on the other hand are a good match for the new X2 and I would race them anytime!!

 

[Water Worx]

Nobody that I know of on the east coast has a "new" X2 much less even seen one.

Here in Region 7 I am trying to get a "old" X2 only class as I already race in sport class with a HX,it would be cool to have another class to race the X2 in so that it would be a run what you brung kinna format because of all the X2 that are still around & dont want to get waxed by Mod Blasters & HXs.

We need to get some more people interested in this class as it would be awesome to see X2s going at it again.

 

[X2Pilot]

I have a pretty fast old X2 that I would race in a vintage only class like that. I think 10 guys on old X2s would be the most fun race ever! However, in reality even when given the opportunity, very few participate. Even at Pahrump only 2 old X2s showed. Its sad really because its such a fun boat.

 

[Legdragger]

I have a pretty fast old X2 that I would race in a vintage only class like that. I think 10 guys on old X2s would be the most fun race ever! However, in reality even when given the opportunity, very few participate. Even at Pahrump only 2 old X2s showed. Its sad really because its such a fun boat.

Ditto.

Old X2's with 650's and tubbies. It would be like racing 125 motocross bikes again. There is more strategy racing with less motor.

 

[X2Pilot]

From Harry @ Group K:

650 Semi Stock Class
Overview : With the release of the SXR800 based X2 (aka new X2) it is logical to establish a ”Stock” racing classification for that machine (as currently exists for the 800cc stand-up machines).
Given the large number of competition minded “old X2” owners that exist nationwide, the new X2 stock class could easily be bolstered by allowing the inclusion of old (635cc based) X2s that are permitted a selection of specific modifications that nets a performance level very close to that of a new X2 prepared to IJSBA stock rules…. For the purpose of this document, these specific modification set allowed for this proposed set of specific modifications will be referred to as 650 SEMI-STOCK.

Objectives : The original “stock” class is intended to be a form of racing that allows the use of a machine that is reliable, affordable, easy to tune, and easy to maintain. A primary intention of “stock” class is to allow owners to race with the same reliable machine that they use for routine weekend recreational riding. Given this, the 650 SEMI-STOCK modification allowances should maintain exactly that same set of intentions. Beyond those expectations, a “good” set of rules will be ones that entail a technical inspection that does not require great expertise, nor significant teardown.

650 SEMI-STOCK Equipment Overview : All the technical specifics are explained and detailed below, however for general understanding, the 650 SEMI-STOCK allowances and requirements will be:
OEM Kawasaki 650 crankcases with no externally visible modifications (per SS)
70mm stroke (which is stock oem Kawasaki 650). (per SS)
725cc limit (calculates to maximum 81.22mm or 3.197” cylinder bore diameter)
OEM 650 cylinder required; porting, decking, and re-sleeving allowed (per SS)
One Single throat carb only, any size allowed, aftermarket flame arrestor allowed
Aftermarket reed petals and cages allowed (per SS)
Aftermarket exhausts with water-jacketed head-pipes, and “non-water-jacketed” bodies
OEM waterbox (per LTD)
Any exhaust exit location allowed (ie rear exhaust, mid exhaust, etc)
Aftermarket cdi/coil allowed (per LTD)
OEM ignition flywheel with all magnets required, lightening allowed
OEM charging coil must be present (per STK)

OEM aluminum pump case required, grinding & polishing allowed
Aftermarket ride-plate, scoop-grate, impeller & nozzles allowed
Hand operated trim nozzle allowed, Aftermarket steering allowed
Lanyard switch required

Overview of 650 SEMI-STOCK Tech Inspection - The previously listed rules have been configured with quick and easy technical inspection as a top priority. Since most internal engine mods are permitted, little engine teardown is required. In 30 seconds, the machine can be visually confirmed to have oem 650 cases, oem 650 cylinder casting, single carb, oem waterbox, legal (non-dry) pipe, and oem aluminum pump case.
Where need be, teardown would only include:
Stroke measurement through the front spark plug hole
Head removal to confirm bore diameter
Front ignition cover removal to confirm presence of charging coil and flywheel magnets.

Why not allow total loss ignitions? – As stated above “A primary intention of “stock” class is to allow owners to race with the same reliable machine that they use for routine weekend recreational riding”. Given the maintenance and reliability issues that have always been connected with total loss ignitions, they are not compatible with the objectives of the “spirit” of this racing class. Furthermore, technical support for such ignitions is becoming more and more difficult to secure.

Why not allow 750 engines or 750 cranks?? – A valid question, with two very important answers.
Firstly, short of piston diameter, the 95-2001 Kaw 743cc engines are virtually identical to the later Kaw 781cc engines…. Except the earlier 743cc engines have much higher port timing. A bone stock 743cc Kaw engine bored to 800cc (as the rules permit) would be an easy match for any “stock” 781cc engine. Given this, if an owner wished to employ a 743cc based engine, that engine platform would (or rather “should”) be subject to all the standard “stock” class rules (exactly as the rules apply to the 781cc platforms).
The second important reason is related to maintaining the “reliability” mindset of the class. In short, allowing stroke increases on a Kaw 650 engine would greatly harm reliability.

The most important measuring basis for predicting 2cycle PWC engine reliability is “average piston speed”. This speed (normally represented in “feet per minute”) is calculated from stroke-length and peak-rpm. For pure racing engines, it is generally accepted that it is impossible to expect predictable crankshaft life at piston speeds in excess of 4000 fpm. That is, over 4000 fpm, a crank could last 20 hours …. or 20 minutes. The other end of the spectrum is the piston speeds that OEM makers choose for stock recreational machines (generally between 2800-3000 fpm).
Piston Speed relationships shake out as follows
4000+ fpm – Completely unpredictable life span of crankshaft components
3700 fpm – Crank life will predictably be 30-40 hours
3500 fpm – Crank life is predictably a full season of use
3300 fpm – Crank life is predictably 2-3 seasons of use
3100 fpm – Production unit range, predictably 4-5 seasons of use
Yamaha Super Jets (with a 68mm stroke) are well known for their excellent long term crankshaft life … even in racing applications. The Kawasaki 650 engines (70mm stroke) enjoyed a similar reputation. However Kawasaki 750/800 stand-ups have experienced a higher rate of crankshaft and connecting rod failure than any other stand-up racing platform. The table below shows the piston speeds resulting from the different stroke and rpm combinations …… The numbers speak for themselves.
SXR800s & X2 800s turn 6550 rpm in bone stock form (3238 fpm). “Stock” class prepared 800s turn well over 6800 rpm (3361 fpm). By contrast, a stock 650 X2 turns 6100rpm (2720 fpm). When the 650 engine is modified to spin 1200 rpms more than stock (as most 650 SEMI-STOCK configurations would turn), it’s piston speed is still less than an average “stock” Kawasaki 800 platform. Permitting 74mm stroker cranks in 650 SEMI-STOCK platforms will result in the same (negative) crank life “issues” that the modified 750/800 engines currently have.


Stroke Length 68mm SuperJet 70mm
Kaw 650 74mm Kaw 750/800
Stock OEM peak rpm 6150 rpm 6100 rpm 6550 rpm
Piston speed @ stock RPMs 2742 2801 3238
Piston peed @ 6800 rpm 3032 3122 3361
Piston peed @ 7000 rpm 3122 3214 3460
Piston peed @ 7200 rpm 3211 3306 3559
Piston peed @ 7300 rpm 3255 3352 3609
Piston peed @ 7400 rpm 3300 3401 3658
Piston peed @ 7500 rpm 3345 3444 3708

 

[Wetracer]

What about the rule stating update or back dating of the same model. Mike

 

[waterfreak]

What if you replaced the top deck on an sxr hull with an new x2 top deck and convert it . Would it be legal? It would not be too hard to do and I may be interesteed in making these new top deck conversion.
What do you guys think? This would bring the new x2 to us at a reasonable price.

 

[D Slicker]

What if you replaced the top deck on an sxr hull with an new x2 top deck and convert it . Would it be legal? It would not be too hard to do and I may be interesteed in making these new top deck conversion.
What do you guys think? This would bring the new x2 to us at a reasonable price.

I would by that. I just picked up another X-2 hull to do for semi stock this year.

 

[Crab]

The class is dead.

 

[D Slicker]

The class is dead.

Looks like I will have a rippin 650 then :arms: as a spare.