250r flywheels: questions and discussion

[Dammit!]

My 250R's flywheel is extremely rusted. To the point that it wasn't even getting enough spark to rev out at the dunes until I sanded the rust off the raised part of it. It's pretty pitted underneath the rust so I'll just replace it soon.

I have a spare that's in great shape but I'm unsure of the year it came from. Is there any way to tell what year the flywheel is besides the weight? I know 1985 is a little lighter than the 86 and newer. Does anybody know the exact weights?

I've also thought about having one of them lightened. I've never done that before and would like to hear impressions from people that have. Especially duners and desert riders. Quicker to rev, I know. But any downsides? I've heard they stall easier.

Edit: 1985 and 1986 flywheels are 100% interchangeable right?

[JohnR.]

I had the one on my R done back when I first built it back around 1995. I really didn't notice much of a difference at all. Theoretically it will stall easier but I didn't notice a difference. Now my PVL is a different matter, its a lot easier to stall and anyone who ever gets on it for the first time stalls it. I put a billet clutch basket in it this year and that seems to have helped some but honestly once you got used to it you didn't stall it anyway.

John

[3Razors]

The 85 and 86 are 100% interchangable. The 85 flywheel is 60 grams lighter over the 86. My belief is that in 86 when the 250R quad came out Honda used the heavier flywheel to give it a bit more launch off the line with the motor being in a quad chassis. I stay away from modded lightened flywheels unless they are expertly done, even then I would limit it to the track. Most shops will just grab with a 3 jaw chuck and turn it down which is bad because it becomes unbalanced, vibrates more, and eventually comes apart. I would just go with the 85 over a modded one myself.

[Racerguy381]

I have done a few on different bikes in the past on my friends lathe. He has several old crankshaft journals that he cut off so he can bolt the flywheel to then then clamp the lathe jaws on the journal rather than the flywheel. Alot of weight has to be taken off of the stock flywheels to make them so light that they stall really easy. The most you will notice is better throttle response and alittle more over rev.