23 replies to this topic

[shercoman2k8]

Hey all, started having a rather annoying problem with my 2010 Gas Gas Txt Racing. The bike is a 125, should this make any difference.

Anyway - The bike will not start from cold on the kick start, I end up running down the road and bump starting it. I dont know whats causing this, but often, if I manage to finally kick her into life, she'll run as if choked for five minutes or so with lots of smoke. If I bump start her, it'll run fine.
The bike is quite hard to bump start also, takes two or three attempts.

The kickstart mechanism is not damaged atall, so it is delivering the normal stroke to the starter gears.
The bike kickstarts when warm easily.

So far, I have put it down to the fuel mix... Too much oil solidifying slightly on the plug as it cools due to too much oil in the mix and fouling the plug, the plug is often black when taken out, but the plug works perfect, and I have tried multiple plugs.
I use Ipone Samurai Racing, strawberry - 80 ml's to a Gallon of super unleaded. Just ordered a Castrol oil, see if this makes any difference.
Carb has been cleaned thoroughly, multiple times. Airbox and air filter are clean. Airbox has all modifications done and flaps fitted.
When started, occasionally the bike will run choked, and not rev out atall, occasionally at revs feel like someones holding the kill button, but once the bikes warmed up and the problem cleared (five minutes or so) it will run perfect. This is why I think its a problem with something ON the plug, as its almost like an intermittent spark when cold, but when hot (crud burnt off?) it doesn't have a single problem.

I'm completely stumped, normally I'm alright at solving problems like this, but not on this occasion.

All help greatly appreciated, its more embarrasing than annoying, turning up at a trial and having to bump start the bike.

Thanks,
Jamie

[JSE]

shercoman2k8, on Jun 8 2010, 07:57 PM, said:

Hey all, started having a rather annoying problem with my 2010 Gas Gas Txt Racing. The bike is a 125, should this make any difference.

Anyway - The bike will not start from cold on the kick start, I end up running down the road and bump starting it. I dont know whats causing this, but often, if I manage to finally kick her into life, she'll run as if choked for five minutes or so with lots of smoke. If I bump start her, it'll run fine.
The bike is quite hard to bump start also, takes two or three attempts.

The kickstart mechanism is not damaged atall, so it is delivering the normal stroke to the starter gears.
The bike kickstarts when warm easily.

So far, I have put it down to the fuel mix... Too much oil solidifying slightly on the plug as it cools due to too much oil in the mix and fouling the plug, the plug is often black when taken out, but the plug works perfect, and I have tried multiple plugs.
I use Ipone Samurai Racing, strawberry - 80 ml's to a Gallon of super unleaded. Just ordered a Castrol oil, see if this makes any difference.
Carb has been cleaned thoroughly, multiple times. Airbox and air filter are clean. Airbox has all modifications done and flaps fitted.
When started, occasionally the bike will run choked, and not rev out atall, occasionally at revs feel like someones holding the kill button, but once the bikes warmed up and the problem cleared (five minutes or so) it will run perfect. This is why I think its a problem with something ON the plug, as its almost like an intermittent spark when cold, but when hot (crud burnt off?) it doesn't have a single problem.

I'm completely stumped, normally I'm alright at solving problems like this, but not on this occasion.

All help greatly appreciated, its more embarrasing than annoying, turning up at a trial and having to bump start the bike.

Thanks,
Jamie

What type of plug is in the bike and is it the original one?

Jon

[shercoman2k8]

Bp5es, no, current plug is new, but it is the same type of plug as standard.

[JSE]

shercoman2k8, on Jun 8 2010, 08:08 PM, said:

Bp5es, no, current plug is new, but it is the same type of plug as standard.

That plug should work fine set at .024".
I'd probably start by checking grounds near the CDI and connectors to be sure a wire
is not loose. The Kokusan system is pretty stout and should fire it right off.

Black plugs can be a symptom of several problems and oily (wet) or sooty (dry) make
a difference in diagnosis.

Jon

[copemech]

Glad to hear you are getting along with the new bike there Jamie!

I thought all proper Scots kept a spare coil/ cdi unit in their pack by now!

I hope you can help this kid, Jon! He is a good lad, bit dense at times, but still ok.

Did you ck the gap on your trigger?

[Jools]

Sounds like water in the flywheel. If you do not have a puller, start the bike with the flywheel cover off and let the water evaporate.

Goodluck!

[Pete_Scorpa3]

Do you always turn the fuel tap off? Just wondering if the crankcase is filling up with fuel possibly?

[bilc0]

2010,Warranty???
I would chuck it back to where you got it from and let them sort it for free.
Sounds like a dodgy carb to me.

[max1956bikes]

Pete_Scorpa3, on Jun 9 2010, 12:36 PM, said:

Do you always turn the fuel tap off? Just wondering if the crankcase is filling up with fuel possibly?

i agree with this bloke.do you use a trailer to take bike about.i do and if forget to turn of fuel carb floods.
i doubt if problem with mixture or plug,as it runs ok after starting.

[shercoman2k8]

Most of the time, yes... Could be the problem, use a trailer.

I would take it to the dealer, but its an 800 mile round trip. Compatant mechanic though, carbs been off, all jets checked cleaned, choke assembly cleaned, mixture set according to manafacturers spec.

Will try making sure to turn the fuel off, and see then... but it does it even when sat still in the garage over night.
If this doesnt solve the problem, I'll whip the flywheel off and check for moisture


Copey - dont have the money for a spare coil, spent every last penny of mine on the bike Finding it very nice to ride, and a slightly more capable bike than the Sherco, hate to say it, but I dont think I'll be riding one again for a while, despite being great bikes. Gonna stick with the gassers for a while

Thanks guys!

[max1956bikes]

it should have a overflow pipe on carb.make sure it goes to open air

[gasser_david]

How old is bike
Was it OK when new
Did problem suddenly appear

[sherpa325]

I agree with Max and Pete always turn the fuel off, particularly when travelling, also you need to check the float valve in the carbie and clean the valve itself and the insert it seals against, a small amount of grit can cause this valve to dribble slightly causing your problem. You need to take off the brass tang that operates the floats to get to the valve. Also make sure all the vent hoses on the carbie are clear and not kinked or blocked. I also find when starting my 300 not to use any throttle when hot or cold. Hope this helps
Cheers Greg

[shercoman2k8]

max1956bikes, on Jun 9 2010, 05:30 PM, said:

it should have a overflow pipe on carb.make sure it goes to open air

Never seen a Dellorto with overflow pipes, but it might be telling me to get myself a Keihin

gasser_david, on Jun 9 2010, 11:32 PM, said:

How old is bike
Was it OK when new
Did problem suddenly appear

Bike is three weeks old.
Absoloutely perfect when new.
Problem suddenly appeared, first noticed when trying to start after changing gearbox oil so after about 8 or 9 hours riding.

sherpa325, on Jun 10 2010, 01:25 AM, said:

I agree with Max and Pete always turn the fuel off, particularly when travelling, also you need to check the float valve in the carbie and clean the valve itself and the insert it seals against, a small amount of grit can cause this valve to dribble slightly causing your problem. You need to take off the brass tang that operates the floats to get to the valve. Also make sure all the vent hoses on the carbie are clear and not kinked or blocked. I also find when starting my 300 not to use any throttle when hot or cold. Hope this helps
Cheers Greg

Had a trial last night, turned the fuel off a few minutes before putting it in the van to drain the bowl. Will see if it starts today okay.

[Stork955]

Gday, if the plug is black it means there is either too much oil or too much fuel. If it looks wet it is oil, if it looks dry it is fuel. Check that first. For oil - check your premix. For fuel -check your air filter is clean and not over-oiled, check the carb float level and make sure it is clean inside there, and make sure the needle is in the correct position. You say you have the correct recommended spark plug so that wont be an issue.

Let us know what you find.

Cheers,


Stork