Ski runs fine on trailer but not in water.

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Jan 18, 2006
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wisconsin
#21
You are running lean. (Piston wash) you have detonation for sure on the rear cly, scoring, and aluminum transfer to the cyl from piston. Time to go through your engine completely.

Make sure you look over your crank very carefully.

We offer complete machine shop services if you need. I have rebuild kits, crank seals, case sealer, and can bore your cyls is you want.
 
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May 17, 2011
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australia
#23
You are running lean. (Piston wash) you have detonation for sure on the rear cly, scoring, and aluminum transfer to the cyl from piston. Time to go through your engine completely.

Make sure you look over your crank very carefully.

We offer complete machine shop services if you need. I have rebuild kits, crank seals, case sealer, and can bore your cyls is you want.
Why you say i am running lean. Thought the piston wash was from running rich as in undetonated fuel washing the piston head.
 
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#24
Anyway here is the problem. rings gone mostly and scoring on rear piston. see pics. also top of piston worn on edges looks like from combustion.

I am not sure if its from piston seizing or from detonation. I was thinking because my flywheel and stator where so dirty maybe the timing got thronn off and it detonated early. not sure what else would cause detonation. If seizure not sure how at moment. Motor did get flooded with water due to a major hull leak causing it to fill up. i got motor running again a couple hours later. seemed fine at the time. the water leak is fixed now.

I am already at max bore 1.0 over pistons. I am thinking maybe just hone cyl and new rings and piston. ant do much about the scoring on the cylinders as i cant bore for bigger pistons.
 

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Jan 18, 2006
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#25
Why you say i am running lean. Thought the piston wash was from running rich as in undetonated fuel washing the piston head.
More fuel (Rich) will "wash" more carbon off the piston tops.

Running lean will create heat, which can and will lead to detonation.

Sorry, but there is no way you are still in spec and be able to just hone that cyl.
 
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#26
More fuel (Rich) will "wash" more carbon off the piston tops.

Running lean will create heat, which can and will lead to detonation.

Sorry, but there is no way you are still in spec and be able to just hone that cyl.

Are u saying because of more carbon on rear cylinder it was imdicates running lean and caused detonation via heat.

Wierd as both carbs rebuilt not that long ago. After water got in motor i cleaned both carbs out. Both carbs had same screw settings for hi and lo.

I will have to check cyl specs as i cant bore. Dont think they make sxr cyl any more to get new one.
 
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Jan 18, 2006
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wisconsin
#28
Are u saying because of more carbon on rear cylinder it was imdicates running lean and caused detonation via heat.

Wierd as both carbs rebuilt not that long ago. After water got in motor i cleaned both carbs out. Both carbs had same screw settings for hi and lo.

I will have to check cyl specs as i cant bore. Dont think they make sxr cyl any more to get new one.
Lean condition can be from many things, bad/dirty/out of spec carbs, air leak, etc. may very well be you have bad crank seals.
 
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Jan 18, 2006
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wisconsin
#29
You can bore those out to 84mm.
This is a Kaw SXR 800. Even though Wiseco does list big pin Kaw "750" pistons up to 84mm, I would definitely not recommend running them with out big bore sleeves. Kawi's run hot as is, and the stock sleeves will be very thin. Not to mention standard Wiseco Piston issues....

Shank, look for agood used, standard bore cyl. They are out there.....
 
Joined
Feb 27, 2012
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LOTO
#38
I have a fresh big bore 850cc Group K cylinder, ported with new sleeves, pistons, rings, pins and bgrs. I have the matching head, ported and dried out exhaust to go with the kit. If interested send me a PM.
 
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