Hi folks. I wonder if anybody can solve this for me. After extensive work I ran the engine for a couple of minutes yesterday and all seemed well apart from the interface between the exhaust down pipe and the head. Gases were leaking out where the pipe enters the head. I do remember that when I first stripped the bike some bits of rusty metal fell out when I removed the exhaust - could this have been some sort of shim? Do I make a new shim, fit the down pipe using exhaust putty, or do I have a downpipe that is simply too small in external diameter and I need to get a new one? Any ideas much appreciated. Mike
I also use a thin film of Holts exhaust assembly paste. But most exhaust fitting places and definitely tube bending firms will have the means to swage the end of the pipe up a bit if it's too slack. Ron
Well, that explains the rusty bits that fell out when I took off the exhaust! Was worried that I might have an exhaust pipe that was too small. I'll make up a shim and with some exhaust cement all should be well. Odd that the pipe end was not swaged as a matter of course though. Thanks for all your replies. Mike
Originally the pipe would have fitted the cylinder correctly..
The effects of corrosion, the removal and refitting of pipes over the years and vibration between the two components lead to the increased clearances...
It's not an uncommon problem, particularly with side valves, and there are a number of solutions with varying degrees of complexity depending on whether you just want to stop a leak or to restore the original tolerances...Ian
I try to get the pipe expanded to a slightly bigger diameter as the exhaust port then run the engine for a few minutes to heat the head coat the outside of the pipe with exhaust sealant then shove to cold pipe into the hot head & bolt it up quickly.
makes it a bugger to get out but it stays in there solid.
