Barn Hawk cont...

[Vtwin650]

I started the research on the Barn Hawk Last night and this is what I found
Remember that this thing has over 85,000 miles on the clock

I started by checking the valve clearances and setting them to the manual specs

The front Cylinder Exhaust was at .010, so only a bit off\
one of the Intakes was a spec, the other was only a bit out.

The rear Cylinder was a different story, the exhaust was right on,
but both Intakes were WAY off spec, like .03

so I set everything back to spec, and went to tearing into the carbs
There had been gas sitting in the floats for years, and it had pretty much clogged everything, but no big deal.
The only problem I found was the slider rubber diaphrams are toast.
little rips everywhere. they want $80+ online, so I am looking for a better deal.

Cannot wait to get back to work on it this weekend and see how it runs once back together.

[Vtwin650]

got the bike back together, borrowed the carb diaphrams/sliders from my good hawk, and got it started.

problem is the rear cylinder does not seem to be firing as it should.
there are occasional backfires as I rev the engine, and the rear exhaust is definitely not as hot as the front???

any suggestions?

[ponley]

If by backfire you mean out the carb and not the exhaust then it is probably a lean misfire. check for vacuum leaks or torn boots between the carb and head.

[Vtwin650]

nope it is backfiring out the exhaust

[ponley]

After-Firing (out the exhaust) would tend to indicate a rich mixture or no ignition. Try pulling one of the ignition leads and connecting a sparkplug and letting it sit on a ground (or connect a ground lead to the plug body) and start the engine and see if you have a spark. Since both plugs fire off the same coil if one of the wires is bad you may lose both plugs.