Running flat

[KiwiGS]

Hey guys,
I have just finished working on my bike for the day.
And I have more questions than answers.
I have just rebuilt the carbs with new orings.
Replaced the the plugs, plug caps, leads and done the coil relay mod.
Oil and filter change.
Once all this was done I hit the starter and the old girl fired into life and settled into a steady 1200 rpm idle. So far so good. ( i didnt need any choke)
After a warm up. I went for a ride.
The bike pulled real well from down low (even had wheelspin).
On the return trip the bike seemed to go flat.
Got back to the garage and revved the motor it still was flat and didnt sound crisp anymore.
I opened the throttle right up there was a flame out of the pipe and the engine seemed to clear it self. Quite a bit of back fire as the revs come back down.
Plugs looked good.
Any ideas?
I dont know how the bike ran before so I dont know if jetting etc is ok.
My feeling is electrical miss fire. The dyna leads are thinner than the standard and i have just poked them into the coils with out any sealant etc. (could be tracking).
Help!
Cheers

[Guest]

Crimped fuel line?
Battery low?
Carb vent(s) blocked?
Fuel cap not venting?
Petcock ok?
If you are low on gas the petcock and fuel line issue would show.

[Guest]

couple of things come to mind:
normally, you do need a choke to start the engine (so may be that the pilot mixture screws are too "out")
also, make sure that the floats' height is in spec

can you elaborate on what you mean that the bike run "flat"?

in my experience the "misfire" problem usually gets better as the bike warms up, and you seem to have the opposite effect

[KiwiGS]

Crimped fuel line?
Battery low?
Carb vent(s) blocked?
Fuel cap not venting?
Petcock ok?
If you are low on gas the petcock and fuel line issue would show.

Good points.
I am a bit suss about the petcock.
Before I put the tank on I pre filled the bowls.
How long do you think the bike would run just on fuel in the bowls?

couple of things come to mind:
normally, you do need a choke to start the engine (so may be that the pilot mixture screws are too "out")
also, make sure that the floats' height is in spec

can you elaborate on what you mean that the bike run "flat"?

in my experience the "misfire" problem usually gets better as the bike warms up, and you seem to have the opposite effect

The carbs are cvs not sure they have a pilot screw(could be wrong) the air screws are 2 turns out as a base point.
I still need to check the valve clearances before i vacuum sync the carbs.
When I first started the bike it sounded crisp and revved up and down quickly and evenly.
When I got back it no longer sounded crisp and would not rev up freely.

Cheers

[bonanzadave]

How long do you think the bike would run just on fuel in the bowls?

Not very long at all.

Fresh gas ?

Could be a small POS in a carb has something pluged up. Can you get some seafoam ?

Let her cool down. Start it up. Check the pipes to see if one or more are running cool. That may isolate the problem.

Good Luck !

[earlfor]

Every now and then, when I had the 1150 with a Pingle on it, I would
forget to turn the fuel on and take off, only to go a short distance before running out of gas. The answer to your question is about 800 feet. :-) :-)

Earl


[quote=KiwiGS;
How long do you think the bike would run just on fuel in the bowls?

[Guest]

The carbs are cvs not sure they have a pilot screw(could be wrong) the air screws are 2 turns out as a base point.

there is only one adjustable screw on the cv carbs (called "pilot mixture screw" as per the service manual) so i think we re on the same page here

while 2 turns out sounds about right, for the correct troubleshooting you do need to adjust them properly (using the highest rpm method or colortune preferably) and have the carbs synced

before the above carb adjustment you want to have the valves in spec

it might be a good idea to go for another one or two rides in the same fashion (from the cold start) to see if you get any different results in the throttle response

[Guest]

When I first started the bike it sounded crisp and revved up and down quickly and evenly.

this is why i think your problem is the fuel not the electrics