Forum

[Paul007]

Hi Guys,

Just purchase a 2007 Bullet 350cc Trials Conversion, Kick start model.

Just order my instruction book but having trouble getting it to run properly, can anyone shed light on this matter please.

He's what I do:
Turn fuel on
Decompress and kick over 3-4 times
Pull-up choke knob on to of carb (original one I believe)
Turn key on
Kick over again and eventually she fires (10 kicks today)
Standing it on drive and not riding at all.
Engine runs but erratically, revs high then low then high again then low again about 20secs between each speed.
Engine warming but if choke pushed down engine stops
Pull choke knob up and kick again and engine fires 2-3rd kick.

Can anyone shed light on this please???
Am I doing wrong....... or is their something wrong???

Without my instruction manual I'm blind to it's procedure.

Help me please please !!!

Regards,
Paul

[Adrian]

Could be that your carb needs a good clean, there are various tiny drilled passages for air and fuel needed for starting and idling, any teeny piece of dirt could be causing a blockage. You also need to check that there are no air-leaks around the carburetor flange.

A.

[stinkwheel]

The "searching" sounds like an air leak round the inlet manifold. It's very easy to overtighten the carb flange and bend it where it attaches to the engine. Another possible cause is a restriction to fuel flow (you can check it's running out of the tap sufficiently if you pop the hose off and open the tap over a jam jar).

Starting drill on mine is to kick it as many or few times as you feel like with the decompressor held in. This will get it all moving but I only do it if it's been sat for a while.

Fuel on. Choke on. Ignition on. Hold in decompressor and slowly kick over until you see the ammeter dip. Ease over a little more until it flicks back up again. You are now at the "sweet spot".

Release decompressor. Allow kickstart to return to the top. Mine likes a tiny whiff of throttle, just enough to feel the tension n the cable. Swing it over but keep the kickstart at the bottom of itsd arc until the engine has either started or stopped moving (avoids a nasty kick-back, not so important on the 350 but a good habit to get into). Resist the temptation to open the throttle further as you do so.

If it doesn't start, find the sweet spot and try again. Rinse and repeat.

I can usually take the choke off almost straight away but it needs a hand on the throttle for the first 30 seconds to warm up a bit or it'll stall. Don't blip the throttle.

I made a video essentially saying all of the above a few years back in response to the multitude of people videoing them leaping up and down on their bikes to start them. It's a small, low compression engine.
https://youtu.be/xYAqgsYRyZw

Same bike 8 years later following a crank-up rebuild (literally first starting attempt).
https://youtu.be/mvoGCZ4kfKY

[Daiwiskers]

As Stinkwheel said it does sound like a air leak on the inlet side
Also a carb strip and clean won't go amis

[Paul007]

Wow thank you guys for your quick response, very much appreciated.
I take heed of what you all say and thank Stinkwell for your in-depth motions on how to start.
Interesting about using the ammeter I must admit and makes logical sense.
I've certainly learnt alot today and thank you all immensely.
Will view the youtube bits too.

To do if time now permits during the week or save until weekend........
Will get fresh petrol and drain tank and refill , check flow rate etc.
Will remove carb, strip and clean.
Check flanges for flatness and sealing.

I'd rang the dealer and told of the starting problem and cutting out.
He said.........
Start on full choke and set off on journey, the choke is automatic and will shut itself off when engine hot.....ummm?

Thank you all so much again.

It's good to talk.....

Regards,
Paul

[Daiwiskers]

When tightening carb if you have spring washers only tighten just enough to flatten the washers
If they do work loose a bit of hylomar or similar on the thread will hold them

Hope this helps Dai

Keep safe all

[stinkwheel]

If the flange has taken a warp, you can sort it out by sticking a bit of wet and dry paper to a flat surface (marble block, sheet of plate glass) with water then rubbing the flange in circles until it has the same texture all the way across the gasket facing.

The choke on a VM24 mikcarb is not automatic. it is 100% manual. Some of them may have a loose fitting plunger that turns itself off eventually with the vibration but there is no mechanism to do so. I know this becauase I rode mine to the shops the other day and it was running really badly, down on power and conked-out when I arrived at the shop. I'd left the choke on.

[windmill john]

Re the air leak, you can do the good ol’ spray. Get the bike running, then spray something like brake cleaner, quick start if you have it, round the gasket/join area. If the revs change, you have a leak.

[PeteF]

Don't think "kick" start, think "swing" start. A good firm swing from the very top of the travel to the very bottom - keep your weight on to the very bottom.
These bikes have a pretty low geared kick start mechanism so you need to use it all.

[Wheaters]

My technique for my 350 is to set the mixture enrichment "on" before "sucking in" twice on a closed throttle with the decompression lever pulled and the ignition off. That's usually enough to start the bike from cold. When warm it might not need the mixture enrichment but "sucking in" in the same way seems to help prevent a kickback.

This has been the same since I replaced the Mikcarb 24 with a 26mm Concentric; it works the same. I tickle the carb on the Concentric, as opposed to pulling up the enrichment knob on the Mikcarb.

Edit: It's reliable enough for me to start the bike with 36 steel clips in my lower portions - got told off by the missus though.

BUT...every bike is slightly different; often because the idle mixture depends on how the owner/garage has set it. A weaker idle might need a slightly different technique.

But the OP's carb sounds like it's in need of a clean and as others have said, the carb to head joint might be sucking in air.