14-47 gearing

[dave wheeler]

Hi
after too long Ive decided to lower the gearing on my muggy 186, it currently has straight TV175 gearing but its just too tall so as im a tight wad im planning to put 14-47 gearing in which should reduce the final drive to around the 5 mark, my only concern is what effect will such a small sprocket have on the clutch? I know the recieved wisdom is its harder on the clutch but has anyone actually ran this set up? The motor puts out around 17bhp
thoughts?
Dave

[Muttley McLadd]

Is there something wrong with it?
Did it pull well with the standard TV barrel on?

[Special X]

Bad for the clutch . . . . VERY bad for the chain.

[FREAK]

dont you have to have 14 tooth sprockets machined to stop the chain comming off???

[Adam_Winstone]

14 tooth front sprockets..... really not a good idea

Consider that Innocenti only developed the 18/47 sprocket arrangement for the GP200 because of the increased power of the machine and the fact that GT and SX200 experience had indicated that a re-think needed to be had. The SX had to drop back to TV175 strength springs as the GT had a number of 'stiff clutch' comments in period reviews, however, softer springs meant that the standard 4-plate clutch couldn't take an increase in power. With the GP200 intended to make more power and needing to cope with an increase in RPM too, the clutch situation needed to be resolved so that it could take an increase in BHP, not cause stiff clutch operation but also not slip.

The change to 18/47 sprockets and a lower ratio gearbox (GP125) resolved all of the above issues in one fell swoop! Indeed, this change worked so well that Innocenti found they didn't need the GT's springs to cope, nor the SX's, rather, they found that the standard 4-plate could now cope perfectly well with the weakest of their springs (as fitted to 125/150 machines)! As such, any motor that increases BHP and RPM but doesn't want to suffer stiff operation or slipping really should be considering the development work that Innocenti already carried out. Rather than continuing to put in stiffer and stiffer springs, or stuff in more and more plates into a limited space, a change to bigger front sprocket (with change to lower ratio box) should always be considered.

Adam

[dave wheeler]

thanks for the replies, its a gp125 originally but when i got the kit off jb tuning they said tv175 gearing would be ideal, mind they also said this was a `touring tune`and with a jl3 curly its very peaky. Alas i sold the original gearbox and put a tv box i had lying around in, am planning to sell it so didnt really want to spend unnesesserally on the rebuild, but a 15-47 set up wont fit the chain and am looking for options to reduce the gearing at relatively little expense, looks like there isnt one, anyone want to swap a tv box for a gp125?
regards
dave

[cev]

Dave, if you have other chain/sprocket combos available you may be able to get around the problem with a pull-down tensioner? Theyre around 40 quid.

[shadyady]

I run 14-47 on my Rapido race 205ish,on sx 200 gears and a jl3 exhaust. I did run a 5 plate clutch for several years, but changed to 6 plate when it eventually gave up the ghost, for some reason it decided it didnt like 5 plates anymore, other than that Ive had no problems with the chain or other components (apart from an incorrectly machined 14tooth sprocket when it was first built). It goes like stink, Ive been to France twice on it and various other UK rallies, Its been in there for about 4yrs now.

[lambro]

I run 14/47 with an LI150 box on my Muggy 186.
JL3 and 30 Delly.

Been like it for last 2 years, and goes really well.
Never had a moments bother since fitting it.
Got a 5 plate clutch as well.

Shaun.