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Need a bit of gearing & exhaust advice

Posted: Tue Jan 01, 2013 3:06 pm
by djh66
Time to concentrate on my Lammy now!
I have a 150 special with a GT 186 kit, 28 mm delly, standard li150 gearing with a 16 tooth front sproket, blowing through a scootrs expansion.
It runs lovely, really impressed with the gt kit, but what I did notice last year as soon as I hit a bit of head on wind or an incline, it slows down drastically!
Is this down to gearing, exhaust or a combination of both? Would there be any benifit of upping the front sprocket?
Happy new year to you all
Dave

Re: Need a bit of gearing & exhaust advice

Posted: Tue Jan 01, 2013 3:15 pm
by Doom Patrol
Wouldn't that make it more difficult to pull? I know the ScootRS pipe is supposed to be quite revvy, so you'd be going the wrong way I should think. Maybe you should be thinking of a pipe that pulls better?

Re: Need a bit of gearing & exhaust advice

Posted: Tue Jan 01, 2013 3:46 pm
by djh66
Would a 42mm clubman be a better option?

Re: Need a bit of gearing & exhaust advice

Posted: Tue Jan 01, 2013 3:57 pm
by bristolmod
djh66 wrote:Would a 42mm clubman be a better option?
a better "all rounder" IMO

Re: Need a bit of gearing & exhaust advice

Posted: Tue Jan 01, 2013 4:42 pm
by djh66
I assume my jetting would need to be altered if going from scootrs expansion to 42mm clubman?

Re: Need a bit of gearing & exhaust advice

Posted: Tue Jan 01, 2013 5:47 pm
by Doom Patrol
It's all a bit of guesswork on my part, but it does sound a little bit over geared. You could cadge a Clubman off a mate and try it. Or you could use a 15 tooth front sprocket.

Re: Need a bit of gearing & exhaust advice

Posted: Wed Jan 02, 2013 9:31 am
by Donnie
Dave, I would have thought that a clubman would strangle it a bit, after all it's a reed valve motor? (and yes, changing exhaust ALWAYS means redoing / checking jetting).

I definitely don't think that upping the front sprocket will be of benefit, I'd think it's got to be worth coming back down to a 15tooth and seeing how that goes? Failing that, a genuine Taffspeed pipe like Boxer has on his but you'll be lucky to get one of them for less than £300

Re: Need a bit of gearing & exhaust advice

Posted: Wed Jan 02, 2013 11:38 am
by Doom Patrol
Donnie, isn't the GT kit more of a touring set up and not that revvy? If that's the case a Clubman would be well suited.

Re: Need a bit of gearing & exhaust advice

Posted: Wed Jan 02, 2013 2:41 pm
by Donnie
All down to set up but the nature of the reed valve motor is responsiveness, I'd be surprised if a clubman would be a good match.

I could well be wrong to be fair but have never heard from anyone that chose a clubby on a GT kit.

Re: Need a bit of gearing & exhaust advice

Posted: Wed Jan 02, 2013 4:13 pm
by goldeneye
2 mates who have GT186 kits both run 42mm clubmans with 16x46 LI 150 box. both go well.