Nipping up

[double h]

Looks like a big chunks been cut out, could this possibly be the reason for nipping up when all else is set up on the safe side?

[double h]

[Daggs]

Assuming you mean a 'big chunk' of the head cowl (as you don't explain clearly) No.

This expression 'nipping up' It's meaningless. The scooter either runs o/k or it siezes. If it's siezing you need to open up and see what damage has occurred and find out why.

[Adam_Winstone]

Nope, if all else is well then this will not make the slightest bit of difference.

[double h]

Damn, i thought id found the problem when looking through the flywheel cover towards the barrel I seen lots of light and floor. B9 plug,28mm carb, bored out sil cylinder,70mm Avanti piston and an af rayspeed 225 head. Running in so running rich.118m trouble free running in before the sieze. Cheers for the replies.

[coaster]

Have you checked the plug colour Immediately after it seizes?

[Adam_Winstone]

What ignition timing are you running?

[double h]

Have you checked the plug colour Immediately after it seizes?

No mate,I was on my way to work so had to restart it to get home and jump on my bike. Was choc Brown when I got the chance to check it.

[double h]

What ignition timing are you running?

19 btdc cheers.

[Adam_Winstone]

That's what I thought you might say. 19 is pretty much suitable for standard motors these days, especially with a clubman, but anything running an expansion, kit, or high comp head may well need 17 or less on today's fuels. I know a number of people having to run mild road tune motors at 17 to stop their bike from seizing and plenty of people (me included) running 16 or 15 static on tuned motors, with many advance retard ignitions suggesting a range of 19 starting and retarding to 14.

These days 19 is simply too advanced for many motors and will lead to nothing but trouble. I helped a mate setup his iron 175 (22 + clubman) and it would always run hot at anything more than 17. Like this he did a number of Euro Lambrettas and thousands of reliable rally miles. He then took it to a dealer to have the main seals done and they told him that they had 'corrected' the ignition timing to 19 dbtdc, which he didn't inform me of until we were stuck on the hard shoulder with no compression, following the motor seizing. We then had to get recovery to the ferry port, strip the motor down, replace the piston and rotate the stator to my marks that I'd put there for 17 degrees. The bike then did the Avignon Euro without issue, including over 400 miles in one day. Yeah, thanks for 'correcting' the ignition timing!

Adam