74 Commando left side pipe is cool to the touch (2009)

Bike takes 10 kicks when cold to start. Choke makes no difference.
Once warmed up starts instantly on one kick.
Rides fine @3200 rpm at 55 mph and seems to have decent power.
I can put my bare hand on the muffler on the left side and its not that hot. Installed 2 new exhaust pipes, right side turned a bit bluish right away, left side is still chrome out of the box. after 1000 miles.
Installed 2 new plugs and left side plug is whitish looking, whilst right side is correct colour.
I can cover left exahaust tip competely, bike does not stop running, even when revving on the stand up to 3000 rpm.
On the right, it tries to stall right away.
Pulled plug off from right side with lead attached, bike will fire on left side only, but barely idles. Looks like a decent spark on the left side.
Checked all elect. issues and valves. Boyer seems to be working ok, as do coils and all grounds. Cleaned both petcock screens.
Bike sat for 5 years with gas in it.
Am I thinking correctly it could be plugged idle jet on the left side?
Boyer hiding some other issue? Bad, or going bad cam on left side?

Do a compression test, throttles wide open ten kicks or so. Both sides. And by all means use a .016 drill in the pilot jets.

74 Commando left side pipe cool

Thanks. I forgot to mention I did a comp. test on both sides: seemed to indicate all is well with that issue. Appreciate the drill bit size for the idle jets.

If you can touch the left pipe and not the right then it's not firing on the left side. Period!

left Pipe cool to the touch

Thanks to Chopped 850. That was my first impression, that the left side isn't firing. But after removing right plug, I can get the bike to run on the left side only. How do you explain that?

There is no idle circuit it's blocked and or that slide is so out of sync that there is no vacuum to pull the fuel through the circuit. A drill bit that small needs to be epoxied into the end of a brake clean tube to reach back into the carb. A great spring tune up tool you will have forever.

It would be a good idea to clean both carb idle circuits. It can be done on the bike. Use your #78 drill, epoxied into one of those little red WD40 hoses, and carefully clean out both idle circuits. Slow, gentle twisting motion will clean out whatever is in there.

Reset your idle mixture screws, and put a carb stick on the bike (vacuum balancer). Adjust idle mixture and idle speed so that vacuum is equal at both manifolds.

Once carbs are balanced at idle, you can synchronize the slides with the carb stick, too.

Slowly open the throttle, vacuum should drop equally at both manifolds, then climb back up equally. If one drops before the other, that slide is moving first. Slacken that slide or tighten the other slide until both carbs have identical vacuum readings. You'd be amazed at how much difference 1/2 turn on the cable adjuster makes.

Can be done without even taking the tank or air cleaner off. Just connect the carb stick hoses to the nipples on the manifolds. Don't forget to put the balance pipe back when you're done!

Also check the left side plug wire for continuity. It will show spark but not all the time like the right side.

I recognize this problem. Been there ...
One easy check to do first. Hook up a strobe light on the left side, run the engine and see if the light is flashing at idle and up. If OK you have spark at that side and I bet my 2 cents on a clogged idle circuit, try to clean it with the carb still on the bike (as already proposed by others).

/Per

Cool to the touch

Hi after reading your post I think maybe your number 1 concern after a bike has been sitting so long is a complete break down and cleaning of both tank and carbs and thats just the beginning. Check that the ign timing is correct, incorrect timing can cause exh headder pipes to turn blue. You have mentioned 1 pipe is blue that shouldn't be happening. A white plug can also be timing related however too lean a mixture can have the same effect on a spark plug. So both fuel and ignition should be checked. Did the bike run before it was parked? Is this your bike or have you just recently purchased this machine. If this is your bike and it was running ok when parked then I would have to agree it is all fuel related. However if it is unknown to you the actual condition of the bike then I would suggest to you a very very close look before riding. Engine, transmission, primary, gearbox, clutch, brakes etc etc plain and simple something may blow up...and most likely will if you are uncertain of the condition before the bike was layed up Doxford

74 commando pipe cool to the touch

Thanks everyone for the great suggestions.
I bought the bike from a Norton club member who had it "sort of running", with 15000 miles on the clock.
It had sat since 2005 in his garage, after his failed attempts at getting it right. He abandoned the idea and bought a new Bonneville.
Regarding Doxford's suggestions. Compression test looked ok.
Tank and fuel lines were cleaned, new taps installed. float bowls off and cleaned. Valves adjusted to spec. Oil change, all nuts and bolts tightened. Gearbox oil changed. All leaks fixed, (a victory in itself)
Boyer cracked wire re soldered in place.
Have not yet timed the machine, since it did start up reasonably well on the third kick.
So I thought: ok I will ride the beauty for a bit and see what developed.
After riding it about 1000 miles this is where I am:

Now it takes 9 or 10 kicks from cold to get it running:
But it will start first kick when warmed up. and stay running at about 1000 rpm no trouble.
Left side pipe is getting warm to the touch as I burned myself on it yesterday, I think its because I have used some really strong carb. cleaner called "Quick Tune" in the last tank of fuel. I know, lazy way of trying to fix the problems. Seems to opening up some orifices though.
I can do about 55 mph in 4th at about 3200 rpm level ground. 46 mpg.
It has used about half a pint of oil in 1000 miles.
I plan on pulling off both carbs now and give them a thorough cleaning.
But I will follow Doxfords idea and check the timing before that.
If bad timing can cause a whitish looking plug, then I do have a plug that looks like thats it alright.

Check the timing and also get the idle circuit cleaned out on the left carb. You stand the chance of running that left side lean and burning a hole in the piston.

74 Commando left side cool to the touch

Hi 850: I did the static timing but not with a light.
Boy, that would be a stupid mistake to burn a hole in the piston, for sure Thanks again.

74 left side etc

chopped850 said:

Check the timing and also get the idle circuit cleaned out on the left carb. You stand the chance of running that left side lean and burning a hole in the piston.

Click to expand...

Hi 850. I installed a brand new left side plug and ran the bike for about 20 miles. I just checked the left plug and its now turning that good light brown colour.
All I've done is use that "quick tune" carb cleaner.
Do you think I'm on the right track, and its definately a carb idle circuit issue rather than an electrical problem? It seesm to run fine at speed.
Do you agree with the other posts that its possible to carefully clean out the idle circuit with a 016" drill bit whilst the carb is still on the bike?

Do you think I'm on the right track, and its definately a carb idle circuit issue rather than an electrical problem? It seesm to run fine at speed.

Yes

Do you agree with the other posts that its possible to carefully clean out the idle circuit with a 016" drill bit whilst the carb is still on the bike?

Yes, both sides are accessable

I've had that work once and not work once. Seems worth a shot as it take about a minute.

74 commando left side cool

Thanks to Kommando from Scotland for the confirmation.
Any ideas why it takes 8 to 10 kicks to start the bike when cold, tickling correctly, and only one kick when the bike is warmed up?.
Is this further proof this is indeed a carb idle circuit issue?

I'd wonder is the choke is working correctly first. Easy to check.

74 commando left side pipe

Cookie said:

I'd wonder is the choke is working correctly first. Easy to check.

Click to expand...

Hi Cookie choke doesnt seem to have any effect at all even if its full on, and it is connected.

What throttle opening are you using when starting from cold? I crack open the throttle about 1/8th, without choke, and it makes a big difference to easy cold starting. Having said that, I once had a partially blocked pilot jet on one carb, and it was hard to start from cold until I cleared it. BTW, have you checked your float levels?