Losing power when in high gears

[TGR90B]

That would also indicate that someone doesn't know the difference between tight and slack advance.

[Billington]

Thank you everyone for taking time to respond, I will use your ideas when investigating. The tyre size is one I can rule out, I know they are the same size.

[iansoady]

I agree with Rex and TR90GB (ps I preferred my 2.5PI with manual /overdrive - when it was running!). It's probable you've actually got it timed on full retard. I would guess (but check the manual) that it should be of the order of 1/2" BTDC when fully advanced.

[Billington]

THANK YOU!

Thank you so much for the kind help offered by the members of this (and two other) forum. Today I rode my bike for 10 miles in the glorious sun.

With your advice I’ve been able to identify and correct the problem of losing power when in high gears. It was a small head gasket leak which resulted in insufficient compression when dropping down the rev range in higher gears. A new head gasket and some advice on torque setting and I have a bike that runs sweet.

This type of support is invaluable for inexperienced vintage bike mechanics like me.