English French German Italian Spanish

Can you work this one out, there's a story.

Submitted by john_neely on Wed, 18/04/2018
Forums
Commando

Hi

Me again and would appreciate your views please.

I removed the barrels today and the following pictures tell a tale but not sure what sort of tale.

The barrels are within tolerance but don't look good with a few dark grey half hoops at various levels the wear in these areas is on the limit.

Now looking at the pistons it looks like some serious heating has been going on or is this normal, plus if you look closely the lower parts of the pistons seem to be scuffed.

The cam shaft and followers are perfect no wear at all, big ends also seem fine with no movement up and down.

I am thinking the scuff damage was done by the owner kicking the bike over year after year and maybe they got jammed and he moved them by kicking it over.

I am thinking along the lines of a rebore what would you do.

Submitted by john_holmes on Wed, 18/04/2018

Permalink

The brown staining is burnt oil varnish not overheated aluminium, look at the colour of your steel gudgeon pins to find out it has been overheating.

Submitted by robert_tuck on Wed, 18/04/2018

Permalink

Timing side piston running weak(carb problem?) Drive side rich ,both with blowby from bad rings ,pistons dont look too bad . If mine I would check clearance and if not outside wear limits remove step at tdc and glaze bust ,clean out ring grooves fit new rings and chance it.Possibly use next size up rings and set gaps.Check timing on both sides.

 


Norton Owners Club Website by 2Toucans