Nc35 issues

[makz2008]

I bought the bike some months back, and have never had it running or heard it running.
Bought it from someone off here, who said he had it running some 6months before i bought it but it refused to start thereafter and the reason was unkown. It was a steal of a price so I just had to buy it

Anyways since i have had it iv just been going over it and making sure everything is torqued according to the NC30 torque settings because i dont have a service manual for the 35, and im assuming most things would have the same torque settings. Coolant is fresh, oil is fresh, oil filter is fresh, NGK ER9EH plugs are fresh, Carbs have been cleaned etc but the bike won't start. In fact it scare the living daylights out of me when i was trying to start it!! With the airbox off the carbs, and spraying carb cleaner down the velocity stacks it sounds more likely to start and the BANG!! BIG BIG BIG backfire sounds like a massive explosion. The exhaust smells very petrol-ly as well. I did check to make sure that all the plugs are sparking so i don't think that is an issue

Ive asked a few friends who used to own NC30s to come and have a look and they mentioned that it could be something to do with the timing being off. Now i have absolutely no idea but would like some opinions on what could be causing this to happen?

and if it is the timing being off then how can this be rectified?

[Delboy]

Silly q, have you tried fresh fuel?

[makz2008]

sorry fogot to mention that im using fresh fuel aswell

[magg]

You can check the timing with a powered timing light. Remove the spark plugs from the cylinders to reduce the load on the starting system. There timing marks on the starter clutch, visible are under the inspection cover located on the right hand side of the engine.

[Cammo]

If you can smell fuel out the exhaust and are spraying stuff down the velocity stacks, the plugs will be well and truly fouled. It's always the plugs...

Forget even trying to start it without the airbox on. Replace the airbox and filter. Take all of the spark plugs out, they'll need drying (you can do this by putting them in a hot oven for 15 minutes), they can't always be revived but often can. Leave the plugs out overnight to dry out the cylinders.

Make sure the idle adjustor is open enough to let air into the carbs. When starting, use FULL choke and NO throttle. It will start up eventually if petrol's getting to the carbs.

[CMSMJ1]

as Cammo said

Put the airbox back on..

you can spray easy start/carb cleaner near the headstock and the bike will breathe it in and try and start.


timing beng off? no, not that...very very rarely if ever.

new plugs needed IMO

[Neosophist]

you will only get the timing off if you take the camshafts out and move them around.

most unlikely.

With the airbox off the carbs, and spraying carb cleaner down the velocity stacks it sounds more likely to start and the BANG!! BIG BIG BIG backfire sounds like a massive explosion. The exhaust smells very petrol-ly as well. I did check to make sure that all the plugs are sparking so i don't think that is an issue

This is the quickest way to loose 50 quid.

Seriosuly, its quicker than setting fire to the money.

It's also the worst way to try and start and NC.


Airbox on is the way.

Full choke and NO throttle at ALL until it catches.

Try 5 seconds of cranking with 2 minutes of rest.

If it doesnt catch after 3 or 4 goes then check fuel fuel in all carbs by cracking the drain screw.

If its not a fuel flow issue then start to check more indepth.

Plugs are probably dead by now. Blowtorching them off might fix it. but make sure airbox is on next time

[makz2008]

You can check the timing with a powered timing light. Remove the spark plugs from the cylinders to reduce the load on the starting system. There timing marks on the starter clutch, visible are under the inspection cover located on the right hand side of the engine.

Just want to make sure Im not misunderstanding, so plugs out and open the inspection cover and shine timing light down the cylinder? or through the inspection cover?

Also I will try using a set of known good plugs from my nc30 to see if that helps with the air box back on etc
As far as the engine being opened and things being altered, I have absolutely no idea, no knowledge on the history of this engine or bike even other than the member who I bought it off mentioned it was put together from spares.

[magg]

The inspection cover, a large circular plate, is located on the right side engine side cover centred over the end of the crankshaft. The timing marks are visible after the cover is unscrewed.

If you prefer not to crank the engine, do not use the timing light just use a long screw driver down the spark plug hole and hand crank the engine to find Top Dead Centre (TDC) and then check against the timing marks under the cover.

While you have the timing cover off you can check the cam timing too if you want, but you will have to remove the rocker covers to observe the valves are all closed when the pistons are at TDC.

[Neosophist]

While you have the timing cover off you can check the cam timing too if you want, but you will have to remove the rocker covers to observe the valves are all closed when the pistons are at TDC.

Surely you can just check that the timing marks of both sets of cams line up with the corresponsing timing marks? (as per the valve cleanrace guide)

p.s as above.

unless somebody has had the cams out the timing will not be off, they are gear driven cams.