140 drive sprocket options

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140 drive sprocket options

Post  bigbilly on Tue Mar 10, 2015 4:42 pm

Hi
Finally getting to do my first decent journey - 80 mile return to the Sandford rally at the weekend and getting a 69.33 mph (gps) top speed I was wondering if there are options for changing front sprocket, if this was anyone of my full frame Lammys I would have stuck in a 1 tooth bigger sprocket as the pulling power was there but I ran out of gearing.
I haven't pulled the chaincase cover to have a look , as need to have at least one scooter on the road but guessing it's got a 14 and not compatible with series parts?
Any thoughts would be appreciated

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Re: 140 drive sprocket options

Post  Scooter Paul on Wed Mar 11, 2015 1:58 am

I have limited knowledge but here goes; there is a 15 tooth sprocket available for the Lui 50 but it is different to yours. I bought one to achieve the same end as you. I've still got it if anyone is interested. The series sprockets are for double row chains but I'm not sure of the pitch. My best suggestion would be to buy a spare standard sprocket, so you can keep yours on the road, and find a sprocket manufacturer that can make you a larger blank. Then have the old teeth machined off and the new sprocket, suitably machined to fit your modified boss, welded on.

Paul
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Re: 140 drive sprocket options

Post  gc on Wed Mar 11, 2015 5:13 am

I have a 15 tooth sprocket for mine when I eventually get round to using it. I've only ever seen one (mine) and will be using it with a 46t crown wheel able to take a 4 plate clutch.
I looked at Starstream gearing and thought 15-45 would be way too tall. 15-46 might be a struggle but I'll give it a go.
Gary.
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140 sprocket options

Post  bigbilly on Wed Mar 11, 2015 1:06 pm

Didn't think it was going to be straight forward Rolling Eyes

I guess I really need to have the side casing off, and have a look at what I have and what I could do, having one made or another part altered to work is an option but could be expensive if it doesn't work.

Wondering wether it maybe possible to alter/adapt the crank drive sleeve for series compatibility?

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Re: 140 drive sprocket options

Post  Thackers on Wed Mar 11, 2015 1:34 pm

Blimey a genuine 70mph, I would of thought the sprocket etc would be ok at that. I would be more than happy, well done. How is it for vibration at that speed? Cool Cool Cool
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Re: 140 drive sprocket options

Post  bigbilly on Wed Mar 11, 2015 3:18 pm

Funnily enough the vibration seemed to ease off, it was worse at 55-60, not quite 70 but was certainly enough to put a dumbass smile on my face and surprise the 5 TS1s 1 RB and a very quick Lammy auto I went with. Did vibrate out all the head cowling bolts though Rolling Eyes
70 was wringing its neck though and I definitely think the gearing is holding it back some. Would say I'm a lightweight (bigbilly was a pisstake that stuck  Razz )too probably 11stone in riding gear which helps Very Happy and weather was probley ideal for a/f ratio.
One problem is lack of rapid acceleration which meant having to wind it up a lot earlier for overtaking and praying things wouldn't slow down in front taking the speed off, that aside I couldn't be happier, faster than I was expecting.

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Re: 140 drive sprocket options

Post  Scooter Paul on Wed Mar 11, 2015 3:21 pm

A quick test would be to slip a 3.50x10 rear tyre on to see if that up gearing is going to help. There isn't a lot of room so not all tyres will fit.

Paul
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Re: 140 drive sprocket options

Post  bigbilly on Wed Mar 11, 2015 4:15 pm

Did think of that but had ruled it out as lui I've got had a 350x10 with a nice groove in the tyre from rubbing against the stator wires outlet.
Can give that a try when I convert the hubs for tubeless (just waiting for the right day)
Any idea of a tyre that will work? I've got some Schwalbe sportsmans that are smaller than the race/pacemans but those last 2 are quite big 350s anyway

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Re: 140 drive sprocket options

Post  trotsky on Wed Mar 11, 2015 4:45 pm

Hiya Fella, Chiselspeed do a 15T front sprocket conversion for Starstream cranks by machining a S3 sprocket Wink . Supply or buy outright....Steve
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Re: 140 drive sprocket options

Post  bigbilly on Wed Mar 11, 2015 5:00 pm

trotsky wrote:Hiya Fella, Chiselspeed do a 15T front sprocket conversion for Starstream cranks by machining a S3 sprocket  Wink . Supply or buy outright....Steve

Spot on!! Will phone em tomorrow, pretty certain if I rummage round in back of garage I can find at least 1 15t that I thought would never use cheers

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Re: 140 drive sprocket options

Post  trotsky on Wed Mar 11, 2015 5:04 pm

Wink ... Also if your chain won't fit with the bigger sprocket on, Jockeys Boxenstop do bigger chains & a lovely pull-down chain tensioner.....Steve
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Re: 140 drive sprocket options

Post  bigbilly on Mon Mar 23, 2015 5:02 pm

Got the 15t front sprocket from Chiselspeed, cheers Trotsky Very Happy although I never gave the chain a thought until I opened package Embarassed
you can supply your own li150 sprocket or buy directly from them for £38 quid, or in my case about 600!! As got into a coversation with Martin about what I could with a 50cl and well you know the rest...... Rolling Eyes

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Re: 140 drive sprocket options

Post  Snails on Tue Mar 24, 2015 1:11 am

And what can u do?
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