I need to know the standard bore size of a 1987 Yamaha YFM100T Champ 100. Thanks.

 

Here is a $15 download service manual if that helps. DOWNLOAD Yamaha Champ YFM100 YFM 100 87-91 ATV Service Repair Workshop Manual - Download Manuals & Technical

 

I was a state certified master motorcycle mechanic and a owner of a state register and certified aftermarket repair facility for 10 years. I have been repairing restoring and customizing motorcycles of all makes and models for 40 years with all machining repair work done in my self sufficient shop by myself. I was always there to help fellow riders with questions or answers pertaining to repairs or diagnosis on their rides.
I posted a question asking for the standard bore size of a YFM100, and of course the only reply was one wanting to sell me a manual.
It's sad that you have to pay someone to ask a question such as this. If I had a manual available on this model I would be glad to have looked it up and answered their question at no cost. I thought that was what these forums were for, to help out fellow riders, but evidently times have changed.
For the people who have a manual and would have helped out with my question I thank you. To those of you who would only have wanted to sell me a manual it goes to show me that making a buck is more important than helping a fellow enthusiast.
Maybe, just maybe, some of these forums and it's subscibers will get back to the main intention of helping people with questions and answers.

 

Sorry,Did not not know all of that.

Did I say you had to buy it?

Pretty uncommon Kids ATV and not being made since 1991 and I do not sell manuals.I just found you a link to one (Big Mistake I now find out).
But for $15 not only would you know the bore and stroke but also how to make it a pile of bolts on the floor and put it back together again, not bad for $15 which is what a afternoon 12 pack of beer cost nowadays. I amazed there is still a manual in print for that uncommon ATV.
$15! Get the Plastic out. Beats staring at it and scratching your head.

It sure was not a $70 shop manual like I bought once.

Anybody who can steer me to a shop manual for a pityful $15 I would take it gladly..

 

The bore size is in the manual.
https://www.yamaha-dealers.ca/ymca/w.../?locale=en_CA