hello im new here, I got a 86 yamaha moto 4 yfm225s and im planing to do a top end rebuild. Now i have looked all over for a book for it but can't find one any ideas? And what should i wach out for with the moto 4.

 

well if no one knows where to get the book. Any one know the torque spec for the cylinder and head?

 

i don't know the torque values. and they are not "torque to yeild" bolts, but as a rule of thumb i always use new cylinder bolts due to stretching and fatigue. can you call local yamaha dealer, or all the top mags. dirt wheels, 4-wheel action etc. have alot of sites and places to call for parts, books, technical support. sorry not much help.

 

so i don't have to torque the down?
This is my first atv so i don't know to much i mostly work on cars and trucks.

 

one of my riding friends had an old tri-moto 225 84'. he said it's the same engine in the moto-4, 10ft.lbs, criss cross pattern, then 17ft.lbs. and i treat all critical engine bolts like auto trans valve body bolts. walk away for ten minuets for the bolts and mating surfaces to relax then re-torque 17ft.lbs. evan in my raptor and yfzr manuals they show a simple torque procedures, you dont have torque then yeild any degrees. how ever i like to use knew bolts and coat them in light engine oil when working on critical sealing surfaces. good luck and i like the seanery in your photos, looks peaceful...

 

thats awsome dude thax alot man for the help, and yes it was peeaceful the pic in the first post is a fild next to my house and i got some in my album of a place i was riding this summer with my dog till they had it clear-cut now it sucks . 16 acors of fun

 

so im hoping to get my parts this weekend. I was woundering is there any thing i can do to get more power out of this old 225?

 

so i took the moto 4 apart and this is what i find.




now i think im going to need new valves, i know i need a new piston cuz i was told i can't get rings cuz it is a overside 1.0mm piston and there is some scaring on it and the cylinder as you can see. now could i hone the cylinder to remove the burnd spots? And dose any know whaere i can get a piston? (good brands and place to buy) all help is appreciated.
.thanx

 

I'd try ebay. Thats the best place I have found for parts for an older moto. Keep us up to date on the moto4 rebuild.

 

ya i got the oil filter and tusday the gasket kit will be in and im going to take the cylinder to a shop down the road and have it looked at. Im hoping that i can get it bored out to 71.00mm from 70.5 cuz i foind a piston on ebay. So we will see.