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Last Saturday I got the Chief to fire up. It roared and then ticked over 2 or 3 revolutions and quit. I removed, disassembled the carb. I had put a gasket under the float seat (not supposed to have a gasket there). Checked all the jets and passages. None were blocked. Got the carb back in place today and kicked it over. Now when it fires, it roars up and then runs about 5 or 6 revolutions and quits. I try to open the throttle but it quits too soon. I get the feeling opening the throttle is helping it to quit rather than stay running.
Is it just too cold to be starting a bike - its 37 degrees F (about 3 dgrees Celsius). I'm pretty sure if I go over to the Interceptor it would start right up.
I can only kick the things so many times before it makes me sore.


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The carb is rebuilt from the original and with spare parts from Tom Thomson? Was everything soaked in carb cleaner? I once had a (non-motorcycle) carb in which the fuel had been left to evaporate repeatedly. The inside was coated in varnish from the residues. Main jet looked clear but, when I tried to push a wire thru, a perfect little cone of amber colored varnish slid out. Problem solved, and I could drive with the choke fully open.

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From experience, when a carb is 'clean' and has difficulties in running from cold,
then it needs another 5 or 6 cleans before the idle passages are truly clear ... !!

Do you have a choke system on this ?
Pulling on some choke often makes a huge difference with cold running.

Failing that, continuing to tickle the float to keep the fuel level up helps also.
Which may have been the difficulty all along ...
Tried tickling it at the point of starting ?
Having a tame octopus to assist may be required here.

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And since 99% of carby problems are electrical - and vice versa -
have you cleaned and gapped the points ....

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Will search the internet for a tame octopus. By the time I can move to adjust or turn anything - it quits!
Yes the points gap is good and I think timed correctly. But I will be rechecking that.
Fuel flow is good and no debris is coming from the tank (it cleaned up remarkably well).
Yeah the used carb body from Tom was cleaned and rebuilt with some new parts, some original parts. I never did soak it in carb cleaner. I blew thru the passages with aerosol brake wash and they appeared clear. On the second disassembly I inspected closer and everything still looked allright. If the ignition recheck doesn't fix it, then I'll soak the carb in carb cleaner.
One thing I did not look at was the valve lash. I was loath to remove the valve covers because I know that some of the 1/4 W studs are stripped in the head. I have a thread repair kit, just didn't want to get into it yet. I checked the compression and while it was quite low, it was even side to side, so I took that as a good sign and just went ahead from there.
So, ignition recheck next.


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Unscrew the pilot jet and look it over closely. Make sure the tiny hole in the pointy end is clear. Poke it out with a strand of wire brush bristle to verify it is clear. If you have an index of those tiny number drills, (#60 through #80) you can use one of those to clear it out. Start with the blunt end of a smaller one and work your way larger but don't remove any metal. Clear pilot jets will make all the difference in cold starting and running.

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I feel like Doctor Frankenstein! It's alive! It's alive! Yes it fired up and stayed running (for a half a minute til I shut it down). I would like to thank my faithful lab assistant Igor, uh, I mean, Rohan, for telling me to hold the tickler button down while starting. It wasn't hard to do, so the octopus could have the day off.

Not being the greatest mechanic, what the heck does this mean? Is the fuel level too low? How would I fix that as the float has a non-adjustable tab. Maybe I should compare the length of the new float needle to see if it's longer than the original. I'm fairly certain that the carb is built correctly and there are no blockages.

Tomorrow the weather will be in the 60's. I hope I can get it running and take it out on my neighbor's horse track for some video.

Also today I got my New York State transferable registration (title)! Odin the cat approves...
[Linked Image from i.postimg.cc]


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Hey I resemble that remark !
Congratulations, always a good feeling.

A lot of words have been written about those float needles, so I don't know what to suggest.
But that tickling has worked for me too. I just don't recall what the ultimate fix was .. !
Ask Odin, cats always know - behind that inscrutable umm nonchalance ...

P.S. Is there a washer under something involved in the fix ?
It raises the fuel level up to where it needs to be ??

It could be that the pilot jet drillings are not yet entirely clear.
I don't quite recall if we discussed these, but after you think they are clean they need
another 5 or 6 cleanings. Any trace of that white corrosion is tough to completely remove

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I think the drillings are clear. I think what was happening was valve related. I was firing it up while holding the tickler, and it ran for a half second and spit raw fuel back out the carb mouth. I loosened the valve lash to where I could just feel movement.
The manual says to tighten the intake valve lash til you can't move the rocker sideways across the valve stem. And the exhaust til you can just still move the rocker. I thought that was crazy but I tried it. Apparently I didn't do it correctly, or maybe time has shown a better way to adjust them. I set them to where I could just feel up/down movement but not hear or even feel a "click".
After that it would fire and stay running and I was able to make carb adjustments. It is by no means running well. The rpms go high and slowly settle down to idle, then it gets too slow and I have to turn the idle speed screw a little. The other bugaboo is that the left side will die out (or weaken). When this happens if hold my hand behind the exhaust muffler - on the right side the exhaust pulse is so strong it hits my hand with a slapping sound. And when the left side weakens I feel a pulse but it doesn't make any noise as it hits my hand. If I grab the throttle and give it some small twists it will pick up again, strong on both sides.
It's a nice day here, temps in the 40's, but sunny. I hope to get it out and have Tammy get some videos of me starting and riding it.


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I had it out for a ride around the yard. Tammy took video but I don't know how to upload it here. Anyway not that interesting. I took it around the yard but never out of first gear.
More about the way it runs. There is not good idle control which I suspect is air leaking past the slide. On start up it revs up and takes a while to come down to a steady idle.
A worse problem is that if I lean the bike to the left (even just to rest on the sidestand) the revs drop, lean further and it will quit. If I lean right the revs pick up considerably. This has to be related to the carb - maybe fuel level. I'm 99% sure it is not cable related. I had raised the fuel level slightly by placing a fiber washer under the needle seat. That helped it stay running but it didn't help this problem.
The other issue may be ignition or valves? The right side runs great, but the left cuts in and out. When I hear it start to fail I can "catch" it by revving the throttle. When it picks up again there is a big power surge. Makes it hard to ride - which is why I didn't shift to second.
(Edit) I forgot - when you rev it, it also spits and backfires on the left side.
The engine seems to have awesome power when it is running on both cylinders.

Link to video - https://vimeo.com/658016428

Last edited by Al Eckstadt; 12/18/21 3:08 am.

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Originally Posted by Al Eckstadt
...A worse problem is that if I lean the bike to the left (even just to rest on the sidestand) the revs drop, lean further and it will quit. If I lean right the revs pick up considerably......
This is a Monobloc "feature", I mean annoyance.. Because the float is off to the side any leaning one way or other changes the float level relative to the pilot jet. The speeding up when leaned to the right means the engine wants a richer mixture than the carb is providing.

Originally Posted by Al Eckstadt
.. ....... The right side runs great, but the left cuts in and out.....
Have a close look at where the intake manifold bolts to the heads. A leaky gasket on the left could be a big part of your running problem. To troubleshoot, have the engine idling and squirt some carb cleaner spray around that gasket and note whether the engine idle steadies or picks up speed. If it does, you've found a leak that needs fixing. This will help the starting and the unreliable idle .

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Huge air leak at the manifold! The cylinder heads are misaligned by about 1/16 more or less. The photo doesn't accurately show the misalignment but it can get the idea across.
[Linked Image from i.postimg.cc]
Alignment is done by tightening the manifold prior to final tightening of cyl head bolts. Will I be able to looosen the head or heads and perform the adjustment? Or to what extent of disassembly will be necessary?
Thanks, Stuart!

The float level problem will probably be minimized with the air leak fixed. I raised the float level slightly, which helped. I used special made tool to check the float level, a tool I found years ago but never used til yesterday. It's a plexiglass cover with crosshatch marks to indicate optimum level. I found that you can't raise the level very much before the float will hit the carb body and prevent sealing at the needle seat. I used one fiber washer to raise the seat. Two washers would be possibly too much.
[Linked Image from i.postimg.cc]


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Congratulations, Al. And, what a terrrrrrific exhaust note!
.. gREgg


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Great video and nice bike, good to see you got it running well enough to ride around the paddock.

I know nothing about these bikes but some random thoughts are:-
- I understand the cylinder heads are independent, so I would be reluctant to loosen them to get the manifolds aligned. Maybe another way is to use more paper gaskets on one side and try to take up any gaps. Whatever you choose, getting the air leak fixed is a good idea.
- I have no chokes on my twin carb A65 firebird, so using the ticklers is essential. In cold weather when the bike fires it needs coaxing for a few minutes and riding slowly until its warm enough to open the throttle, the engine wont idle properly until its warmed up.
- make sure you are using fresh fuel, I've had petrol go stale after only 2 months and cause all kinds of starting issues.


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Ha ha! Wait til I get running properly on both cylinders! When I was cleaning/checking the bike I found the mufflers were a food storage bin for mice. Corn kernels were falling out but also stuck inside. The muffler is straight through surrounded by perf metal (who knows what is or was behind the perf metal, sometimes fiberglass), and front and rear of the perf were two restrictors, like a washer, with holes maybe about 5/8 more or less. I took a hole saw on an extension and drilled them out to 1-1/8". I tapped out all the mouse material and wire brushed the inside. When I fired it up a lot of stuff still blew out but they're clear now, and I'm sure a bit louder than when they were new.


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If you do decide to just loosen the head nuts, be sure to loosen any head steady it has. Enfields twins used some serious head steadies to prevent the cases from fretting so badly. And just another opinion since it sounds like you are in the triage stage of finding out just what you are dealing with, I would give it a try. Loosen your head nuts and head steady and bolt your manifold on without gaskets and then snug down the head nuts. Once it is running well, you will quickly find out what else needs doing.

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It's fixed. But I could not budge the cylinder heads. I loosened the head steay, the exhaust pipes and the head bolts. Even thumped things a littlle with a rubber face hammer. No movement at all. So I tightened everything back down, installed the manifold with a gasket and measured the gap (0.,040"). It was the thickness of two gasket I happened to have. Installed the two gaskets on the left and the original gasket. Now the engine starts easier and runs smoother. Strictly a temporary repair - will fix properly later.
I rode it around my yard and my neighbor's horse track. Had to go slow on the track because the track was wet and a bit muddy on oneside. Could only use two gears, by the time I try third I'm out of yard.
At this point I will probably play with it a little more then put it down for the winter. Now I will shift my attention back to Project 39-1/2 the Triumph engined special. Its getting very close to being finished.
A big thanks to all of you for the help!
[Linked Image from i.postimg.cc]


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Good news, Al. The heads are dowelled to the cylinder barrels, so that is likely why they will not shift,

My guess is that the gap at the manifold is because the left and right heads are not originally a pair: I expect that the factory machined them as pairs so that the faces for the inlet manifold would align when installed. The proper repair would be to remove the heads, fixture them correctly and re-machine the faces so that they align. Your Chief is really too nice to resort to other methods involving machining one flange of the inlet manifold to compensate for the gap.

Congratulations!
...gREgg


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