T350 wont start

[Ian T]

Hi
Bought a US T350 import to UK and going through it. I've rebuilt the carbs with new jets etc, set timing correctly using timing marks, set new points, charged new battery. I have a good spark and compression seems strong. I've fed fuel via a dummy bottle to both carbs but she wont fire on her own. The only way I get her to temp run is to spray quick start directly through the carbs then she stalls as the fuel runs dry. It seems to me the carbs aren't sucking in mixture so before I replace crank seals, I'm wondering if I'm missing something more obvious from a more knowledgeable other. Many thanks in anticipation.

[daxman]

Hmm, there's other here with a lot more experience that me, but my feeling is it should still start even with quite poor crank seals . Under load it would be a different matter.. Can you be sure you really cleared all the small passageways in the carbs?

[karl pa]

I've rebuilt the carbs with new jets etc,

Did you use mikuni jets? aftermarket jets aren't the best and can cause issues.
I would definitely go through carbs again before thinking of seals. You may want to check choke plungers and float level.
A quick check on crank seals is to put your hand over carb or intake and kick over, you should feel suction on your hand, it won't suck your hand tight but you should feel some. Like said, crank seals would have to be very bad to not run.

[Ian T]

Thanks Daxman. On both carbs I've checked the main jet and tiny brass jet that can be unscrewed and both are clear. I've checked float heights. Do you know if I am missing any others jets which might be blocked?

[Ian T]

Thanks Karl. I havent changed the jets, just made sure the main and little brass screw out jets are clear. I'd be interested to know which passageways I need to check?

[karl pa]

I'd be interested to know which passageways I need to check?

All of them
A lot of time the idle circuit is plugged or restricted. I strip the carb and remove the air mixture screw, then spray carb cleaner and compressed air in hole where mixture screw was in, it should come out a hole on air filter end of carb and also come out in the tube where the small idle jet was removed.there should also be a passageway from where the idle jet was up into intake under the slide, there should also be a passage that angles up into the intake on engine side of slide. you want to make sure the tubes in the float bowls are open also, these are where the choke pulls gas through.

[daxman]

Yep as Karl says - (probably some Youtube stuff on this too). Good luck and report back!

[malky]

may be worth checking that the carb bowls are on the correct carbs as I think the 350 was the same as the 250 and only has a choke jet in one bowl - another thing to check is the leads - are they on the correct plug I've had a few instances where the left coil feeds the right pot and vice versa

[Ian T]

Thanks Malky - It runs with 'quick start' so I guess the leads are on the correct cylinders - I've swapped them round just to see but no difference. When you say choke jet- I have two choke plungers, one in each choke body - there don't appear to be any service replacement jets in either bowls but I have cleared out the airways. Have I missed something here?

[Ian T]

In each carb I've now replaced main jet, air mixture screw and spring, the small jet that you remove to replace the pilot jet, pilot jet itself, needle (set on correct notch) and blown out all airways and passages. Still it wont fire on its own but will run temporarily on 'quick start.

With the carbs off I placed a flat tissue on the cylinder where the carb attaches and greased the tissue to get a reasonable seal then kicked bike over - the tissue seemed to such in and blow out. Is that to be expected?

[karl pa]

It sounds like you have a fuel issue. Do you have good fuel flow from tank to carbs?
When you remove carbs, or drain screws on bowl, do you have fuel in the bowl?
Float level correct?

[Ian T]

Thanks Karl. I am using a small dummy tank hung up in garage about 1 m above the bike - fuel flows to carbs and carb bowls are full - carb floats set as per manual. All very odd that it wont even splutter unless I spray quick start through the carb??

[daxman]

It is in deed 'very odd'. You mentioned earlier that you have a good spark - a nice fat blue one?

My bike was running fine last year (occasional issue) but wouldn't start/run well at all this year. I was testing the spark with an old plug that was lying around and it was 'OK' but the actual B8ES in the cylinder wouldn't spark at all. A clean up of the points and a new condenser have helped - now starts much more easily.

[Ian T]

Thanks daxman. Yes, new plugs and points - timing spot on - nice fat spark on both plugs. Runs on 'quick start' first/second kick.
I'm still suspicious of carbs because the plugs don't seem very wet after several attempts to start?

[daxman]

Have you stuck your nose up the exhausts - petrol smell?

What about a teaspoon or two of petrol down each plug hole instead of easy-start?