Deristriction

[UKbandit]

Hi People

First of all I have read some of the FAQ's and I can tell you that I am an electronics engineer. However, I didn't feel that I could answer any of the electronics questions because I haven't seen the electronics fitted to the bike (in particular the questions about the CDi unit).
I did notice that one comment was that maybe the capacitors needed time to charge. This would happen very quickly (milliseconds) and would definitely not take several minutes as was implied by the post.

Now for my question. I have only just acquired a 1991 250 Bandit (GJ74A) which I believe was imported from Belgium. I also believe that it is restricted for the Japanese market where it would have been originally intended for sale. First of all, what sort of performance should I expect from this machine? In other words, how can I tell if it is restricted? If it is restricted, how can I derestrict it? It does seem to be quite quick when warmed up but it struggles to reach a ton. I would expect that the bike would exceed a hundred miles an hour with some ease.

Thanks in advance

UKbandit

[Red01]

Other than a few SE Asian countries, the B250 is/was pretty much a Japan only bike. I know Indonesia got new B250's, don't know if anywhere else did. (And in Indonesia, a 250 is a BIG bike... unless you're real rich and can afford a GSXR750 that costs about 3-4X it's USA price.)

I didn't think the Japanese required 250 4-strokes to be restricted to any specific level, but if they did, I would doubt there's any simple way to change its output, other than standard hot-rodding methods. It's state of tune is just the way it would have been built since this bike didn't have a new market to speak of outside of Japan.

[echomadman]

mine has done ~110mph* and it was terrifying, that was at 18~19000 rpm in top gear, lying flat on the tank. I think you're asking a lot of an unfaired 250 to do a ton with ease, it'll do 85/90 mph all day without missing a beat.
If you mess around with the sprocket ratios (bigger front/smaller back) you'll get higher top speeds, but less acceleration, but in all honesty, the bike doesnt feel comfortable or stable to me beyond 95mph

*My speedo doesnt work, i was chasing a mate on another bike who was doing 115mph indicated so i guesstimated 110

[UKbandit]

Thanks guys. I must admit that at around 90mph it is starting to feel like the front wheel was going to lift up and take off. I put this down to the fact that there is no fairing and the wind resistance was trying to throw me off the back of the bike.

Perhaps I'll just leave it as it is for the time being at least.

 

[Jamesobrady]

I read recently that a lot of japanese 250 bikes are restricted for that market....as in moreso designed to be under engineered for the engine capabilities if that makes sense. Not restricted as in washers in the intake or a remapped cdi.....just an engine that could put out "X" bhp putting out a lower 40 bhp instead. Not sure if that applies to our likkle bandits...but is there much difference in a b250 and a gsxr 250 and why..they share the same lump dont they?

And after having the sv650s for the last few months i cant imagine doing 90mph without a fairing again !