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Final drive ratio

Posted: Fri Oct 04, 2013 1:57 pm
by woody
I am looking for info on final drive ratio on my latest project please , i,ve got a 200 block with an ally barrel slightly cleaned up 225 top end on it , li 150 gearbox , 30mm dellorto carb and a stainless scoots rs exhaust so my question what crown wheel and front sprocket should i use please ?

Re: Final drive ratio

Posted: Fri Oct 04, 2013 2:28 pm
by bigmuff
ScootRS is a copy of a PM i think so quite revvy. I would try std LI150 gearing if you have not already. 46 x 15 with 80 chain gives 5.2 : 1. If you overgear it you will be dropping down into 3rd all the time.

Re: Final drive ratio

Posted: Mon Oct 07, 2013 1:49 pm
by woody
Thanks bigmuff what do all these ratio numbers mean ie 5.1, 4.6 etc

Re: Final drive ratio

Posted: Mon Oct 07, 2013 2:11 pm
by RICSPEED
bigmuff wrote:ScootRS is a copy of a PM i think so quite revvy. I would try std LI150 gearing if you have not already. 46 x 15 with 80 chain gives 5.2 : 1. If you overgear it you will be dropping down into 3rd all the time.
go with the above then review front sprocket size if need be after road testing but I don't think you will need to

Re: Final drive ratio

Posted: Mon Oct 07, 2013 2:51 pm
by goldeneye
woody wrote:Thanks bigmuff what do all these ratio numbers mean ie 5.1, 4.6 etc
they are next weeks lottery numbers....you not been putting them on like? ;)

Re: Final drive ratio

Posted: Mon Oct 07, 2013 7:02 pm
by Muttley McLadd
Even with a revvy pipe, a 225 should pull taller gearing than a standard 150, surely?

My revvy 185 pulls a 16t sprocket on an Li box. I'm not heavy enough to pull people into my orbit, but even so, I'm not 50kg.

Re: Final drive ratio

Posted: Mon Oct 07, 2013 8:31 pm
by corrado
woody wrote:Thanks bigmuff what do all these ratio numbers mean ie 5.1, 4.6 etc
5 to 1 is an outsider, 4 to 6 on is the favourite. Always back the favourite and double your stake every time it loses. :P

Re: Final drive ratio

Posted: Tue Oct 08, 2013 1:44 pm
by woody
goldeneye wrote:
woody wrote:Thanks bigmuff what do all these ratio numbers mean ie 5.1, 4.6 etc
they are next weeks lottery numbers....you not been putting them on like? ;)
ask a silly question !

Re: Final drive ratio

Posted: Tue Oct 08, 2013 1:44 pm
by woody
corrado wrote:
woody wrote:Thanks bigmuff what do all these ratio numbers mean ie 5.1, 4.6 etc
5 to 1 is an outsider, 4 to 6 on is the favourite. Always back the favourite and double your stake every time it loses. :P
ask a silly question !

Re: Final drive ratio

Posted: Tue Oct 08, 2013 2:27 pm
by DaveTomo
This may help you http://avantone.wordpress.com/ download it and have a bit of fun , I'm running a fettled race rapido 225 at the moment with a delly 30 & LI150 gearbox 16X46 , 48 mm clubman- goes like fook acceleration wise, but top end ain't brilliant. So over the winter going to give 17X46 a go (speak to you soon Mr Corrado about a few bits ;) ) depends what you want from it, fast acceleration but possibly lose out at top end, myself I want a steady tourer which can sit on the motorway at 60ish comfortably .At present it pulls the 4.89 very easily so I'm hoping when I change it to 4.6, it'll still pull that .Like I say download the Lambretta Gearbox Visualiser and it may give you a better idea.