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Re: Disappointing RB20.
Posted: Thu Jul 28, 2016 10:03 pm
by 10 inch Terror
holty wrote:Twinny wrote: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.
Re: Disappointing RB20.
Posted: Sun Jul 31, 2016 12:58 pm
by Adam_Winstone
Road tested? Any better?
Adam
Re: Disappointing RB20.
Posted: Sun Jul 31, 2016 2:23 pm
by 10 inch Terror
Adam_Winstone wrote: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.
Re: Disappointing RB20.
Posted: Sun Jul 31, 2016 3:02 pm
by garry inglis
so is it 46 x15 ie 5.2 and running better ive got lost with all the changes
Re: Disappointing RB20.
Posted: Sun Jul 31, 2016 3:43 pm
by 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.
Re: Disappointing RB20.
Posted: Sun Jul 31, 2016 5:18 pm
by 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

Re: Disappointing RB20.
Posted: Sun Jul 31, 2016 5:49 pm
by Adam_Winstone
10 inch Terror wrote:Adam_Winstone wrote: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
Re: Disappointing RB20.
Posted: Sun Jul 31, 2016 5:56 pm
by 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
Re: Disappointing RB20.
Posted: Sun Jul 31, 2016 6:04 pm
by 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.
Re: Disappointing RB20.
Posted: Sun Jul 31, 2016 6:11 pm
by 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