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Discussion Starter · #1 ·
Hey Guys
I rebuilt my 1989 Yamaha exciter bored it out to .50mm over, had puttered around the house abit, got some snow today and decided i test it out. I had previously burped the sled.Sled was starting and running well. Anyway Had it out for 20 mins or so in a couple fields was comming down the side of the road doing 60 km, approx 5500rpm crusing and she lost all power and locked up. ETG was reading 1150. I knew as soon as the motor stop and i coasted to a stop what my problem was. I inadvertantly forgot to torque the bleeder screw for the coolant( thats a Big damn) anyway so it ran dry....kicking my self hard core here on this one, pretty dumb not the first motor i've rebuilt....but theres a first time for everything and this is one.

I popped the exaust manifold and carbs off, its scuffed up good on the intake side of the piston on the pto cylinder and mags not quite as bad, motor still turns over, but the brandnew Yamaha pistons, well they wont be the same..the look like they'd "go up and down" haha anyway what everyones thoughts and experiences, i will likely pop the head off and get a closer look.

Any thoughts...i've dumped to much into this sled has a rebuilt crank too.. its not my trail sled but something to mash around on and have fun but the same time i dont want to toast the bottom end..if i havent hurt it yet due to this abuse its taken.

Won't forget seeing the steam shooting 5 ft high out of the bolt hole when i opened the hood.
 

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If your cranks still good ill by it from you if your going that way lol Ahh And yea I did the same thing last winter brand new pistons and rings and then one of my connection rods barring went and was done for so I haven't fixed it yet because i need a crank bought a whole motor that just need to a piston because of some dumb ass leaving outside and froze and when broke it loose skirt broke on piston so I got the piston and gaskets all ready but still deciding if I wanna use a crank that has a few minor rusty barrings you can pm I know quite a bit on them since i done pretty ripped everything apart on them top to bottom to see how they work. let me know I would be interested if you wanna part it out.
 

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if it still has good compression and turns over fine i wouldnt think much about still running it, just give everything a good looking over though, hard for anyone to say with out seeing ya know?
 

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Discussion Starter · #4 ·
Gunna tear into it this weekend, No chance i'm selling that motor....i'd be stupid too to much sunk in it now! Thanks for your two cents!
 

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A little off topic but those exciters were notorious for blowing up seizing.Very lean in the 1/4 throttle range especially coming off a wot across a lake then seizure.That combined with Yam injecting the oil into the fuel line before the pump so it takes a bit to richen up oil wise.Its about 100:1 at low speed and about 20:1 wot.PSI came out with a radical taper to try to cure it with so so results.There is a fix for it though.
 
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