Disappointing RB20.

[10 inch Terror]

had similar probs with mine
are you running with full panel work ,could be an airflow prob ,try no panel

this is a very good point, ive cut a hole in my panel as im running a 34mm delly, makes a big diffrence, what carb have you got on it, and is it filtered or open, how much room between carb and panel ?

holty

30mm Dellorto, now correctly jetted ( according to AF's recommendation ), with a hole in the panel, no air filter. It runs fine in 1st and 2nd.

[Adam_Winstone]

Road tested? Any better?

Adam

[10 inch Terror]

Road tested? Any better?

Adam

Yes. I've been out, and it's 100% better. It's still a bit boggy and will need a fine tune jetting wise. Gearing wise though, I think it's all good.

[garry inglis]

so is it 46 x15 ie 5.2 and running better ive got lost with all the changes

[10 inch Terror]

It's 15 / 46 on an Italian Pacemaker 150 box, giving a final drive of 5.64 with NK Mid / Road pipe. It's a completely different ride now. The carb will need a bit of fine tuning, and I'm thinking of going 5 speed. I've just done 40 miles on it, and all seems ok so far.

[garry inglis]

hi 10inch this is one of those cases when tall gearing wont work when you think about it 18x47 back to 15x46 but onto a pacemaker of 5.65 it just shows how sometimes going back over wins

[Adam_Winstone]

Road tested? Any better?

Adam

Yes. I've been out, and it's 100% better. It's still a bit boggy and will need a fine tune jetting wise. Gearing wise though, I think it's all good.

Result!

You may find that you can fit a slightly higher ratio and still pull that, as the change from 4.8 to 5.7 is a pretty big (ok, very big) jump, however, this seems to be suggesting that the 4.8 was too long for it. TBH I'm not surprised in the least that this was made a big improvement as the kit is designed to make power at revs, which means over gearing simply results in a motor that doesn't make power in 4th.

Well done for testing. Make sure that other setting are good and it sounds like you'll end up with a bike that you're much happier with.

Adam

[garry inglis]

yes i agree with adam 46x16 gives 5.29 and 46x17 gives 4.91 so you have plenty to play with to fine tune the pacemaker box

[10 inch Terror]

I've whipped the plug out after everything cooled down, and it's a weird mustard colour. The photo isn't very clear, but something isn't right....

Any suggestions.

[Adam_Winstone]

Hard to see tip in that photo but yes, it does look a very odd colour!

On the gearing issue, I'd consider going as high as 5.2 (or close) so the 16 tooth sounds like a good option, however, 17 and I imagine you'll be undoing all the good that changing to a lower ratio has resulted in. Out of interest, if you consider that the Imola is much like a baby TS1, you'll find that the recommended gearing with a revvier expansion is exactly what you're currently running (down at the bottom of the page):

http://www.imolamonza.plus.com/settings.html

I'm sending you this as a little reassurance that going short on the gearing isn't something that you should worry about if it is what is needed to work in harmony with the kit's porting.

Adam