Mastiff running rough.

[ericetz301]

The problem showed up on a recent trip,
Although the bike started and ticks over and ran fine, but, after about an hour it started to play up, I could not get above
45-50 mph it would back fire and cut out if I tried, I changed the plug but this didn't improve things.( so, a very tedious, 100 + mile trip home )
any advice would be appreciated.
cheers Eric.
p/s getting the carbs off looks like a big job.

[manxie]

Hi Eric. I had a similar problem with a car many moons ago. I changed everything I could think of, it turned out the HT leads were breaking up? May be worth a look since you`ve already done the plug....just a thought? Good luck, Steve.

[DAVID THOMPSON]

mine did this once turned out to be a wire falling off the coil the 12volt feed from the switch
Dave

[ericetz301]

Thanks for the advice guy`s,
The electrics being the problem had`nt occurred to me, I`ll check them out, and getting to the HT coil etc. looks easier than getting to the carbs.
cheers Eric.

[lowgloss]

Try adjusting the valves.
Intake valve tends to close up when the engine heats up.