Overheating?

[02Bansheeee]

My brother and I fully rebuilt his 99 Shee. But while switching cylinders I noticed that after it had been broke in, the rubber plug on the bottom of the cylinder wasn't installed into the new cylinder on the bike. We are gonna take that cylinder back off to put it back in but that might have something to do with my problem... It was originally a stock 64 and he found some 66.5 cylinders and pistons. We Installed those and it ran until the day after a big family ride for about 4 hours. It started normal and ran normal until it got warmed up.. Too warm. I noticed that the clutch cover was too hot to touch and then bogged out and wouldn't start until the whole bike was cool. The pipes are a greenish-blueish color at the header and the plugs are black and dry. I think it's overheating. Could it be because we upped the pistons so big without rejetting or porting? Or water pump? Any helpful replies are appreciated. & it know that we should have double checked before making a stupid mistake such as the rubber boot, don't need to know that.

[02Bansheeee]

It ran fine until the day of our family big ride***** typo above

[bigweav81]

id guess being that the rubber boot is there to block the cylinders coolant passage it couldn't cool properly. you don't need to know that, sounds like you may need to know something. could've fried that new top end if it was over heated enough.

[WINDYCITYJOHN400]

Motor got bigger…..didn't re-jet the new combo…...

 

Might have had an air leak after the rebuild….

 

No mention of piston to cylinder wall clearances or ring gaps on rebuilt combo…..

 

Burndown. Sadly a common story. 

[trickedcarbine]

Even worse, you bought 66.5 cyls and torched them. Now you need to buy new ones. Or did you keep the stock 64mm bore ones around? If that's the case get them freshened up. Order new coolant plugs, gaskets and seals. Refresh the waterpump as well.

[02Bansheeee]

Thanks for your replys, just got back from vacation. I checked the compression, it was 100 in both cylinders. Pulled the head and there was oil all around the underside and some on the top side of the head gasket. Pistons rings looked like new and piston wall was smooth as well. Installing the plug after I type this. But With that being said, what's with the oil under the head gasket? Could that be part of the overheating and low compression problem?

[02Bansheeee]

& when it was assembled, we followed every step in the clymers manual. Except for the plug part.

[bigweav81]

maybe blown head gasket from overheating, just because your cylinder walls seem smooth doesn't mean they aren't worn. you should leakdown test to make sure you don't have an air leak, check your jetting, or throw it back together and burn it down and rebuild it right.

[02Bansheeee]

Yeah, I checked the jetting. But the guy who had it before my brother must've bought off brand jets, cause I don't see shit on them. No numbers that I could see. I'll check again with a magnifying glass. & I always do a leak- down.

[bigweav81]

you need to list all your mods. make sure you check your water pump.

[02Bansheeee]

98 Shee

66.5 pistons and rings

Oem crank

Vito's big bore gasket kit

FMF sst

I think boyseen reeds

Stock carbs

Ngk br8es

Airbox w/O lid with k&n filter

32:1 yamalube

Stock intakes with white brothers boost bottle

Stock waterpump

& bolt number 13 was broken off in case

Oem stator and radiator

660 elevation

Average temps: 70-95°f

That's all I can think of.

[02Bansheeee]

On the water pump, what do I need to check for? The plastic gear? What about the impeller, do I take it out to check it?

[bigweav81]

if I was checking mine I would, broken case bolt? boost bottle? sure you don't have an air leak, you said you always leak down test right? pilot jet maybe around 27.5 to 30 main jet should be around 280 to 300. take your boost bottle, and throw it at your neighbors dog.

[02Bansheeee]

Yeah... Lucky number I guess. & yeah I'm sure, his held 6lbs for 6 minutes last time I checked, which was around April or so. We hadn't really rode them so wasn't much of a need to test it since then. & thanks. Did you tell me those as being the fat ones to start with. Or that should be the sweet spot, either way I'm starting with 300.

[bigweav81]

as in it should be close to them, up to you to find the sweet spot. one good ride is all it takes for a boost bottle to crack a intake boot, look at them closely for cracks.