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By windmill john
#95442
Phew! :mrgreen:

It might be a week or two before I can fit it. My 650 is in the shed and I have a few little jobs on him first.
I’ll fit the new main jet, check the needle jet, get some test rides and feed back.

Thanks again Paul.
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By windmill john
#95445
I had to pay attention there, sounds like you have a five speed box; which I guess boosts your top speed slightly.
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By Wheaters
#95451
Having an extra gear in the 5 speed doesn’t necessarily result in a higher top speed because the “top” gear on both gearboxes is 1:1. There is a very slight “overdrive” effect on my setup because the rear chain drive is 18/42 teeth compared to the standard 16/38 of the 350, but it’s hardly significant. However, the 5 speed box has nicely evenly spaced ratios so it’s easier to maintain speed on long hills than having to leap between 3rd and 4th of the 4 speeder.
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By windmill john
#95474
Well, 220 main jet now fitted. It is a 106 needle jet.

Test ride... definitely slightly less hold back at full throttle, but top speed.... speedo said just over 60. So to test, I started a GPS app on my phone and it showed achieved top speed of 57mph!

I love Gupta, but I’d like a tad more. Okay, I’ve still got the super meteor piston to fit and retard the inlet cam by a tooth, but surely standard should give me more than a max of 57mph?
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By Wheaters
#95478
Have you confirmed that the ignition timing is set correctly? Retarded ignition = slow top end.

Another thing that kills top end is an over restrictive exhaust.
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By windmill john
#95481
Thanks Wheaters.

I have this silencer:

https://accessories.hitchcocksmotorcycl ... andard/536

I’ve not checked timing. It has a red box Boyer fitted by a PO. I guess there’s no way to test this without pulling the primary case. Shame I didn’t check when I changed the primary oil.

I guess that’ll be a future job, or just the price of a gasket.
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By windmill john
#95485
Which way to rotate the back plate on the Boyer plate, gives advanced?
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By windmill john
#95490
Many thanks for that. I’ll mark where it is a try a little clockwise. I guess I’ll know if I go far by the knocking!

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