[bjd98]

Was out on the trails over the weekend when my 96xlt triple would not get up to speed. Pulled the plugs to check, & one of them was pinched closed (no gap for spark). Replaced it and it started to back-fire so I did a compression check. Read 80 on 2 good cylinders and 0 on the one with the bad plug. I'm hoping it's just the rings or gaskets :dunno:

If that's all it is, and the cylinder is not scuffed, how difficult would it be to repair myself? (Keep in mind not too familiar with engines, I'm learning as I go and just tinkered with carbs for the first time at the begining of this season)

If I decide it's above my ability, how much would it set me back to bring it into a dealer (assuming it's not worse than what I mentioned above)?

 

[jwaldmann89]

80 psi=rebuild time. You will have to pull the top end and inspect for wear, I'm not sure if there is a sticky on the forum for a DIY but it's pretty simple.
-Drain coolant
-Remove head bolts
-Pull head, and inspect/have someone inspect for you/maybe just post pictures.

Most likely with 0 psi you will need a new piston in at least on cylinder, if not all. Personally I say do them all and have a fresh complete motor and not have to worry about it later. You may need to have the head bored and re-plate depending on damage.

 

[smokingcrater]

so replacing the piston is easy... an hour or two and you are done. But the bigger problem is to figure out why it happened. Chances are if you drop in a new piston, its going to suffer the exact same fate shortly after starting it up.

 

[ken3296]

sounds like something came loose in the cylinder with the pinched plug. something probably hit it on the upstroke. replacing pistons is no big deal. might get some help with the rings if you have never done them. I have the 680 I just replaced all three. just take your time and pay attention to detail. you'll also need a torque wrench. But the main question is why did it happen. find the cause and fix it

 

[bjd98]

Thanks for the help. Found a youtube clip on top end rebuild and it doesn't seem too difficult. I just hope there is no major damage and I can find what pinched that plug. Hope to pull it apart this afternoon.

 

[RJ Gleason]

Which cylinder was it, middle or clutch side, or recoils side?

My bet is on middle cylinder.

 

[bjd98]

Which cylinder was it, middle or clutch side, or recoils side?

My bet is on middle cylinder.

It was clutch side... Middle and recoil side both gave 80psi. When I bought the sled this summer, all three read just under 120psi. I put about 200 miles on it when it blew.

 

[RJ Gleason]

Suggest crank seals and all new pistons and rings then.

 

[bjd98]

Pulled it apart today, clutch side was in bad shape. Lots of carbon build-up and the piston was chipped away, down to the rings in some spots. The cylinder walls were scored and the head cover was pretty beat up (explains why the plug was pinched). So my next question is... would it be cheaper to have that cylinder bored out til smooth again and get larger rings for that piston or just replace the whole head? And if I do take it to get bored out does anyone know a good place in or near Chicago to have that done?

 

[Yamaha440]

When you get it bored, yo will have to do each cylinder, and get the whole kit and kabotle.

 

[RJ Gleason]

US Chrome.
Send in the cylinders along with the pistons that are going in it and they will fit it properly.
Not sure of the cost, but I think that it's around $150 each.