Gp800 motor in a sj

[Vortex]

So I've been looking into this concept as a possible future build as a high power buoy race motor with stock-ish reliability. I would look to run a Lamey cylinder but I'm undecided about running a billet cylinder wide open due to heat issues...

I'm aware that wdk does offer a lot of parts for this which is really cool.

I saw an article from the early 2000s about one of rius's old mod skis that used this motor with an r&d dry pipe and msd t/l.

My questions are how much work is it to adapt exhaust manifolds from 61x/62t cyl to the gp800 cylinder. And also is the msd t/l the only option for a/m ignition? I imagine the electronics are totally different from the 701 based engines.

Any insight is appreciated. Thanks in advance

 

[Wizards Powersports]

You are basically stuck using WDK's exhaust setup which isn't easy on the wallet (if you can get it). I believe Advent made a replacement programmable CDI but can't recall. Also hard to get/expensive. Yes, electronics are totally different, except the ignition coil and starter solenoid.

There is a reason why the fad of people running these died out about 10 years ago. Basically you need a bunch of expensive WDK parts, and end up spending as much as a quality 62T based AM setup would be, and have a much heavier crank. Also need Gas PV setup, upright motor mount kit, upright intake manifold kit, etc.

IMO, if you want reliable, race oriented power, go with either a Yamaha 1200 Non-PV or a Kawi 1100. All the power you want and can easily retain stock reliability.


Sent from my iPhone using Tapatalk

 

[Big Kahuna]

Hit up Toby......... He did this once........... with a B-Pipe..........

@TOBY

 

[Vumad]

So I've been looking into this concept as a possible future build as a high power buoy race motor with stock-ish reliability. I would look to run a Lamey cylinder but I'm undecided about running a billet cylinder wide open due to heat issues...

I'm aware that wdk does offer a lot of parts for this which is really cool.

I saw an article from the early 2000s about one of rius's old mod skis that used this motor with an r&d dry pipe and msd t/l.

My questions are how much work is it to adapt exhaust manifolds from 61x/62t cyl to the gp800 cylinder. And also is the msd t/l the only option for a/m ignition? I imagine the electronics are totally different from the 701 based engines.

Any insight is appreciated. Thanks in advance

Xmetal built a 900ss for brian Dennis which was in a 2008 superjet tuned for racing. Bryan placed first racing every race on the 900 except the last race which was an 1100 bullet. I think the ski did ballpark 55+ with tons of balls from zero to wot. It was a great ski. If budget wasn't an issue, I'd suggest looking into such a thing. What you save in money on a 800 you will pay for in headaches. The1200s I've seen people build say it's too much work don't do it.

 

[Vortex]

I would definitely rather have more acceleration than top speed. I had started an 1100 kawi build but backed out because it would not really fit in a superjet hull. And I definitely prefer the feel of a lighter ski with 2 cyls for a number of reasons. So it seems the best option would be either an 85mm dasa stroker cylinder, the xcream 850ss/900, or a super stock type build that's a little more cc than my current ported 701. My thing is, if I'm looking at 2k+ to further upgrade my existing motor into a stroker and or big bore for only a bit more of a gain than I might as well spend 3-5k to get a lot more of an upgrade with the addition of power valves and the porting they can allow.

 

[tomski]

Rius also used the cast Lamey cylinder.

 

[Vortex]

Rius also used the cast Lamey cylinder.
View attachment 324690

You might be right the article reads like something was lost in translation. It definitely looks different than the gp800 cylinder head would look with the replacement individual cylinders.

My first choice would be a cast lamey. I know first hand how well they run. 60+mph. Talk about finding a unicorn though lol...

 

[Big Kahuna]

Xmetal built a 900ss for brian Dennis which was in a 2008 superjet tuned for racing. Bryan placed first racing every race on the 900 except the last race which was an 1100 bullet. I think the ski did ballpark 55+ with tons of balls from zero to wot. It was a great ski. If budget wasn't an issue, I'd suggest looking into such a thing. What you save in money on a 800 you will pay for in headaches. The1200s I've seen people build say it's too much work don't do it.

That ski is here in Tuscaloosa. Rode it in early September. It was a handful.

 

[Vortex]

So is there any real cause for concern running a billet cylinder and a larger piston 89mm-91mm in race conditions? Would think you would get hot spots on such a large piston...

I wouldn't even think about running pump fuel either. Too inconsistent.

 

[Big Kahuna]

That's a chucky question. But with the race classes being allowed to transplant in the 1100 tripples. You got more power for a fraction of the cost of a billet cylinder. And this is the entire motor vs just the cylinder. Rob Flores was one of the only ones that still ran a AM Twin up until a year or so ago if I am not mistaken.

 

[user_error]

Honeatly you are asking for a nightmare trying to piece together a rare setup like this.

If you are dead set on a sj, the 1200 sj is not that bad, just have to do some custom fab like any project. Definitely wouldn't recommend it in an old hull but they work in a new one because they handle so much better. Doest ada even make a kit now to install them? Way simple

 

[user_error]

Big kahuna Flores was on a triple since like the late 90's, I bet you're thinking of Jeff Trogner. They both have yellow skis. 2 years ago trogner qualified for pro ski on a twin, pretty impressive. He wasn't around this last year I don't think

 

[Big Kahuna]

Your right!!!!!!!! it was Trog!

 

[user_error]

Ya that guy is a machine

 

[Big Kahuna]

I remember when Flo showed up at Nationals on an old SxiPro with these crazy spikes on the bottom of the hull and I believe he was running a 1100 then also. This would have been 2008!!!!!!!! Late 2000's, not 90's. GP class came around 2006-2007.

 

[Vortex]

If I was just purely racing yes I would go for the triple build. Several reasons why I want to stay on 2 cyls, one I already have a lot of the high dollar parts like novi 48s, billet intake vf2 reeds, b pipe and c4 chamber. Ada head enhancer etc. Also want to be able to go free riding and not worry about killing motor mounts and my back lugging around 400lbs of ski. And I think there is more resale potential on the 2cylinder platform. If youre selling a built triple, that's a smaller market than all the FS/fr 2 cylinder crowd. And also there is the element of nostalgia on the mod class twin motors that I'm sentimental to. Finally there is the ignitions available for triples, you are stuck with advent which has been known to be finnicky.

Cost wise it is not far off either between each build when you really break it down. Triple novis, intake, rebuilt crank, advent ignition, etc etc

And on top of all that I've already beaten a triple ski with a built 701 in my first race lol. Holeshots each Moto.

 

[Big Kahuna]

But was yours still a 701 or just the platform?

 

[Vortex]

Rambling for sure but I've also had the opportunity to actually ride both types of skis. Three different kawi triple sxrs, a stock hull, a Trinity, and a bullet. And a full mod cast dasa stroker superjet. The SJ was definitely the most fun all around machine.

 

[Vortex]

But was yours still a 701 or just the platform?

Ported 61x cyl. stock sleeve and stroke. 62t case also ported.

 

[Big Kahuna]

Trinity would be Jimmy Wilsons, the Bullet would be Bill Haig's. and the Dasa was Ralph McGreggor's!!!!!!!!!!!!! Am I close?