Have you run the engine with a dummy fuel tank , such as a bottle or funnel.
Do the float bowls all contain the same amount of fuel when drained.
Does the tap flow fuel freely, rather than a trickle.

Sit the tank across the frame with the vacuum hose connected and the fuel hose over a container.
Switch the kill switch off and spin the engine for 5 seconds or so and watch the fuel flow speed.

Dave.

arsey30 wrote:Best clean the carbs before refitting, did you blow them clear with an air line and remove pilot screws, jets, tops.
Dave.

arsey30 wrote:Have you run the engine with a dummy fuel tank , such as a bottle or funnel.
Do the float bowls all contain the same amount of fuel when drained.
Does the tap flow fuel freely, rather than a trickle.

Sit the tank across the frame with the vacuum hose connected and the fuel hose over a container.
Switch the kill switch off and spin the engine for 5 seconds or so and watch the fuel flow speed.

Dave.

Answers:

I did clean carbs, used a few cans of carb cleaner! But did not blow them clear with an air line as I don't have one. The main jets and pilots are new, I didn't remove the pilot screws. I haven't taken the carbs apart, I have removed the needle valves, and valve seats and cleaned them and made sure the gauze filter is clean and swapped needle valves and seats from front to rears just to see if it made any difference.

I ran the engine with a dummy tank (funnel) no difference.

When I took the carbs off the other day and drained them they seemed to contacin the same amount of fuel.

I have lifted the tank and taken the hose off, fitted a longer hose and ran it with the kill switch off, fuel does run freely, a nice steady stream

The carbs are back on the bike but tray, air filter and airbox are not on, so I can either take them off yet again and remove the pilot screws, or put it all back and run it at 5k to see what happens then?

Thoughts?

Pilot jets really should be removed and the circuit blown through with compressed air in reverse, ie through the 3 small holes near the butterfly. Then spray carb cleaner down the pilot jet holder and you should get fulid out of all three holes, it was quite easy to see all 3 holes flowing on mine although dave did suggest to block 2 up at a time if you struggling.

Drunkn Munky wrote:Pilot jets really should be removed and the circuit blown through with compressed air in reverse, ie through the 3 small holes near the butterfly. Then spray carb cleaner down the pilot jet holder and you should get fulid out of all three holes, it was quite easy to see all 3 holes flowing on mine although dave did suggest to block 2 up at a time if you struggling.

The Pilot jets were brand new though, still I suppose yet another lift off of the carbs won't hurt! I can't remember how many holes there were though, or am I getting mixed up with the emulsion tubes.

Without access to compressed air it'll have to be the track pump from my bicycle!

oldgreyandslow wrote:

Drunkn Munky wrote:Pilot jets really should be removed and the circuit blown through with compressed air in reverse, ie through the 3 small holes near the butterfly. Then spray carb cleaner down the pilot jet holder and you should get fulid out of all three holes, it was quite easy to see all 3 holes flowing on mine although dave did suggest to block 2 up at a time if you struggling.

The Pilot jets were brand new though, still I suppose yet another lift off of the carbs won't hurt! I can't remember how many holes there were though, or am I getting mixed up with the emulsion tubes.

Without access to compressed air it'll have to be the track pump from my bicycle!

That's why I offered to blow them through. I have a portable compressor.
The jets may be clear but the airways not.
Are the pilot screws set near enough, i.e not fully in.
Are the rear brass choke valves working freely.

The "NC30 FROM HELL" had one stuck fully on, killing 1 cylinder and plug.

If the carbs are on, then run it without airbox to check the rear pots, the weakness won't matter for this excersise
By saying tray, do you mean the plastic airbox base, not the aluminium tray.
Dave

arsey30 wrote: That's why I offered to blow them through. I have a portable compressor.
The jets may be clear but the airways not.
Are the pilot screws set near enough, i.e not fully in.
Are the rear brass choke valves working freely.

The "NC30 FROM HELL" had one stuck fully on, killing 1 cylinder and plug.

If the carbs are on, then run it without airbox to check the rear pots, the weakness won't matter for this excersise
By saying tray, do you mean the plastic airbox base, not the aluminium tray.
Dave

Dave

Perhaps if I brought the carbs over to you it may be less hassle for you?

Pilot screws are all two turns out as per standard

I haven't checked the choke valves, didn't even think about those, better check them I guess. so it is carbs out time!

I'll run it at 5k se if the rears get hot

Yes I meant the plastic airbox base

Cheers

Update

Its a pilot issue, at 5k revs the rears get hot very quickly, so it isn't sparks it must be something in the pilot circuit.

At least its heading in the right direction - ish

No more than I expected, as that is the usual problem, but mostly just 1 at a time.

I wanted to come over and look/listen as often it is soon obvious where the problem lies, if not exactly but in what area.
Now that you have proved the area, if you want to bring the carbs, I will clean them , I am 3-5 miles away.

e mail or pm me.

Dave.

arsey30 wrote:No more than I expected, as that is the usual problem, but mostly just 1 at a time.

I wanted to come over and look/listen as often it is soon obvious where the problem lies, if not exactly but in what area.
Now that you have proved the area, if you want to bring the carbs, I will clean them , I am 3-5 miles away.

e mail or pm me.

Dave.

PM sent

Cheers

Steve

oldgreyandslow wrote:

arsey30 wrote:Do the rear ex get hot at all, i.e at high revs.
I am not far from you, e mail or pm me if you want me to have a look and listen, I can take your carbs home to clean them.

Dave.

Haven't really tried at high revs, I will do that later this morning.

I'll try that and let you know, thanks for the offer of a look and listen etc.

Cheers

I did say run it at 5000rpm to isolate pilot circuit!

Hopefully you'll have a sorted bike soon :D