Hitchcocks Forum

Thought I'd do some mods today and wishing I hadn't. Took out the PAV system and put on a new exhaust. Removed the air filters whilst I was at it. I've had problems when trying to kick start the bike, difficult to get it to start and then engine dies when you try and open the throttle, so stripped and cleaned the carb.Found the points weren't opening so adjusted them, but haven't touched the advance retard timing.

Put everything back together and it won't kick start at all. Nearly caught a couple of times but after 45 minutes It got dark and I gave up. I tried to use the electric start and there was the most horrific grinding noise, like someone had put a load of scrap metal in a tumble dryer! Carb is coughing petrol out of the air intake! hacked off, this should have been simple and now it just won't run!

Mmmm.
"put on a new exhaust. Removed the air filters whilst I was at it"
The bike will now be lean. The carb will need re-jetting and setting up for the new exhaust/lack of air filter.
I hope you sealed off the pipe from the carb to the PAV, otherwise it will be even leaner,
"Coughing petrol out of the carb" sounds like the ignition timing might be out as well.
The nasty noise from starter is (probably) the sprag clutch disintegrating, probably because the engine is kicking back due to the incorrect timing.
I'm not making your day am I?

Pony, what annoys me is when somebody doesn't know really what they are doing and then claim it is a simple job. You fell for the oldest trick in the world by altering 2 things that are vital to the engine running, carby and points so now it is hard to pinpoint what is actually wrong. Are you really sure how the points work, how did you know the points weren't opening. When you reset them did you had the points open on the correct part of the cam lobe. You are going to have to come back with more info before we can help

Yeah, Thanks Norm, not like this is my first bike, just rebuilt a T120 without this grief. I checked everything with hitchcocks who said the mods I'd made wouldn't result in a need for rejetting. There is a universal sports air filter, I just took it off to observe if there was fuel delivery. This is how I noticed it coughing back fuel. I observed the fact that the points didn't open by watching them as I cycled the stroke and they were stuck closed throughout. So they've been adjusted to 0.4 mm. I haven't yet advanced or retarded the ignition as it was running before the mods without any kickback when starting and was idling fine. Was more worried by the unearthly racket when trying to use the starter.

Pony, forget about the grinding noise, the sprag is shot so either fix or forget the sprag removing it is probably your best option. Don't touch the timing at this stage because it was running before. Have you checked to see if you have spark. As Peter said , have you blocked off the vac line that enters the inlet manifold after the carby. If that isn't plugged you won't get it started. Another silly question, do you know how to kickstart a single, there is a knack to it and once you know it is easy, but if you don't you are uphill all the way

Thanks Norm, Did block of the inlet hole for the Pav, swapped out the inlet manifold rubber for a new one as the old one was looking perished. So no air leaks. Well practised at kicking the single (as you know the starter hardly ever works on these things. Looks like I'll be spending the morning removing the sprag as the thought of loose metal bits whirring around the inside of the primary will give me nightmares.

I start with the caveat "I know nothing!" But....I find that my Classic was very sensitive to a battery that was anything less than fully charged. Simple (sorry Norm!) and probably absolutely nothing to do with your troubles. All the very best.

Decided to fit Hitchcocks electric start to kick start only conversion. Got the clutch, alternator etc out. The sprag clutch has 6 teeth missing. Found them all in the bottom of the primary case and no other damage seems to have been done. Drilled the new holes in the engine today to receive the new inner primary case. Test fitted it and with a little persuasion it went on OK. Decided that whilst I'm at it I might as well fit an 18 tooth sprocket so ordered it. Hopefully it'll arrive in the morning along with the new jets etc for the carb. If so, it should be back together tomorrow and ready for the local Bracknell Bike Night. If the new carb is still disappointing I have an Amal 930 I might throw on for giggles to see if I can squeeze a little more out of her!

Pony - a couple of observations re "found the points were not opening". If this really were the case, the engine could never have run in the first place. Also, opening up the points gap WILL advance the ign. timing, even without altering the position of the baseplate.

Your right John, It would be more accurate to say that the points weren't opening every time they should. One of the contacts had a hole burnt through the middle and they were just sticking.

Job is now done! Mods completed:

PAV ripped out
New straight through Header and turn out muffler fitted.
Air box and filter ripped out and new wire mesh sports type cone filter fitted.
Complete new set of richer jets and carb slide fitted.
Starter motor ripped out along with it's associated gears and inner primary.
Kick start only primary fitted.
18 tooth sprocket fitted.


Also adjusted a noisy tappet and replaced the points.
Timing is still a little out and I'll adjust it in the morning.

Bike started up and she roars like a lioness! will finalise the timing tomorrow and tune the carb.

Then it's off for a long and well deserved Rideout!