Air cooled 82 R

[rabid]

Im probably going to buy a first gen 250r and my question is What size thread is the spark plug. I want to do a compression test on the bike before i buy it just to make sure im not looking at doing a piston and ring job on it any time soon. I lost all the attachments for the tester except for the one that fits my 200es. Is the thread size the same as the 200es or do i need to find a bigger or smaller attachments.

Also are there any weak points on the first gen 250r Frames i need to look for?

[rabid]

also what should the compression be on it?

[yamaha driver]

i believe the spark plug is bigger on the 250r. not sure how much, but the plugs that go in a 250r are BR8ES if u want to look it up. anything lower than a cold motor 120 psi is bad. 1 weak point is next to the footpegs also underneath them on the frame. also check rear swinger bearings they can be a trailprotrailprotrailprotrailprotrailpro to replace GOOD LUCK:TrikesOwn