cold starting problem on 3tj

[Tomahawk]

I'm still having real trouble starting my 3tj from cold. My dad has just completely rebuilt my carbs balanced them and set the floats right and it still wont start from cold. But it bumpd first time. I've changed the plugs about 2 months ago hasn't changed a thing. I'm hoping its an electrical problem like weak spark or the starts not spining it fast enough. When i tried to start it earlier it tried to go but as soon as i gave it some choke it cut out. didnt seem to like that at all. I really dont want to have to spend a lot of money trying to fix it as im only a student. As soon as the bikes warm it will start straight away! If anyone can help or has a fix please let me know. Its a lovely bike with this being the only thing letting it down.
Cheers Tom

[dobbslc]

Have you tried a good car battery with jump leads? If it starts straight away with a bump it could be a bad battery, you will be surprised what a difference a new battery will make over an old one.
If your's is bad just turning over the engine will drain it and leave the coils low on voltage.
When it does fire up check all 4 down pipes are warming up at the same time on idle be careful though!
I had a bad coil on a GSXR 400 that caused all sorts of starting problems, if you have a cool pair of down pipes (1&4 & 2&3 are pairs) swap the coils over, (plug leads & supply wires also) to see if the fault moves to the other pair of cylinders. Check the pilot air screws are set to standard settings these control the start / idle on the bike, They are under the carbs next to the float bowls. I think 1 1/2 to 1 3/4 turns out from fully in, Evilchicken will probably know this of the top of his head.
Make sure you have no air leaks on inlet rubbers or loose pipes etc.


Dobbs

[Evilchicken0]

When you start it from cold do you allow the fuel pump time to prime ? Turn the ignition on and wait until the pump stops ticking, it should slow down then stop. Open the choke and start the bike.
I hold the starter a little after the engine catches.

[Tomahawk]

I will give that stuff ago and check all of what you have said cheers dobbs.
Evil Yeh i let it time out. Ive tried it before putting choke on and it just doesnt like alot of revs when its trying to start at all don't know why. Only likes about 1/4 revs.

[Evilchicken0]

You shouldn't use any throttle when you start the bike

Try full choke no throttle.

[Taggyd]

what revs does the bike idle at when it has started? maybe upping it a little might help i start if it doesnt like full choke. also try whacking a rag over the end of the can while its trying to start if it helps the exup might need adjusting.
you do have the exup fitted?

[Tomahawk]

Ok will try no revs evil. It idles at just over 1000. Once its warm. Wont idle unless its warm. May have found the problem going to try and solve it tomorrow

[Evilchicken0]

I'd tickle the idle up a little, come up to 1200.

[Tomahawk]

Ive adjusted the pilot air screw to 1 and 1/2 turns from all the way in. Hasnt helped at all. balanced the carbs but the idles still not so great and abit lumpy. May need balancing again. I still need to go down the route of coils and battery as they are the only things we havent tried. Im really just lost with what to do now. I really dont want to have to sell it with the problem i will end up loosing so much money.

[MarkT]

I won't bore you about the story of my bike but my idle has to be worse!! Because the bike goes so well I will leave alone for now but air leaks can be a problem worth looking at. Spray carb cleaner all around the carbs and see if the revs rise? You say it bumps ok is that with or without choke? A good quick check of the coils and leads etc is to run the bike in the dark and look for any blue flashes around the area.

Lastly a valve check would not hurt but a lot of hasstle. Did you say it was ok when warm?