i just bought this R and noticed that the bolt that goes through the head to the bracket on the frame wasnt there....the hole in the head and the bracket doesnt quite line up...i took a screw driver and stuck it in the hole and the bracket and couldnt get the motor to budge at all...im wondering if they wont line up because i have a '86 '87 motor in the '88 frame...one guy said i should try getting a '87 head stay tube for the motor i have....the tubes might be a little different...im sure i have a '86 or '87 R motor because on the back of the motor there is a hole all the way through it where the swingarms pivoted on the '86-'87 models. would loosening up all the motor mounts and try moving the motor up some werk or not, or should i try a '87 head stay tube????

 

just loosen the other motor mounts up..then slide the bolt through and tighten them all up

 

All of the moters have the holes in the back. There might be a way to look at the engines when they ar together and tell the years. You can tell cyclinders by the colors. The reason that the bolt in the headstay doesn't line up maybe is that the pervious owner had the head or cyclinder milled or decked. This will cause one of the holes to be higher than the other. If losing up all of the bolts don't line them up. Move the hole on the head stay so that they do. I dont think that there is any difference in head stays for the years.

 

the cases and mounts about are the same but the 86 and 87 had bracket that went between the swing-arm ears with upper and lower engine stays. if i remember right the 88-89 only uses the hole thats above the swing-arm with it's own bracket welded to the frame. they all inter-change. even a 85 atc motor. the differences are in the motor it's self not the case bolt holes

 

Does the engine have a spacer plate below the clyinder?

The 86 engines were all silver. If you look at the cylinder, the porting was also different if you look in the intake. The 86 cylinder(and 85 I think) didn't have bridged ports. 85 and 87-89 had black engines. Also go to www.macdizzy.com/ and compare part numbers on the micro fiche and TRX specs.
ERIC