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Old 09-02-2010, 01:29 AM
mr ripley's Avatar
mr ripley mr ripley is offline
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I had to pop out to the local bike shop to get a side light bulb & a new breaklight switch so I popped in the 140 main jet before I set off

it absolutley killed it

it was fine up to half throttle & then it just started spluttering & tried to die, so I had to ride the 5 miles to the bike shop at half throttle, but I could still hit 50mph

while I was there I bought one of those k&n/s&b (can't remember the make) cone shaped power fillters for it, you know the ones,

I put that on before setting off on the home journey, instead of the old BSA pancake fillter I had on it, & it took off like a scalded cat again,

slightly calmer through the mid range than with the 123 jet & it still wouldn't rev much over 5,500 in 4th with a top speed of 52, but I got the impression from the way it felt that if I had found a decent down hill stretch it might have picked it's feet up

one thing I did notice is that I used to be able to hit 55mph in 3rd gear when it was in the old frame where as it strugles to hit 45 now, so I checked what sprockets I have on there at the moment & it's 16 front 53 rear (3.3125:1) it used to be 16/49 (3.0625:1) in the old frame, which can make a very big difference on a low powered machine like this

so I think, if I can track down a 49 tooth sprocket for this REH hub then we should start seeing the proper performance for this engine, & by my calculations would put the top speed at about 62 @5,500rpm in 4th (minimum requirement for a motorcycle A1 test), then if I can just make it rev out in top we should be onto a winner

on another note, the bike shop I went to is the same shop that sold this bike to its 1st owner back in 1974 & the bloke there was saying it's sacralige for me to be riding round on this bike as it was probably the best scrambler made at the time

I think in it's current state of tune it probabley could be competetive if entered in a classic scramble, as they rely more on acceleration & low down power rather than the top end that I'm hoping to achieve

Last edited by mr ripley; 09-02-2010 at 01:35 AM.
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