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2007 Gg 250 Txt Pro - Hot Start Issues


miner
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Folks, new to the forum, GG and trials generally.... can be found on other forums under same ID.

Just bought the above as my first trials bike.... the guys who make this look easy must be magicians! Hard, especially in soft sandy stuff!

Bike is ok for its age, used but used ok and looked after well..... seems to have starting issues, or you need to be a 2T Jedi to get the thing to kick!

Sometimes I can start it ok, other times I can't get it to fire at all. Couldn't get it to start whe it was hot (outside also, low 30's, moderate humidity), was running ok but when I killed it to take a break, it wouldn't come back.... had to push it home! Tank says 3.1L, wasn't on reserve but took 1.9L. Kicked over after a few kicks but the bike was a lot colder. Tonight it was difficult but went after a few kicks, run it for a bit then tried starting it again..... would fire!

Founds lots from.... just tricky to all sorts of issues! Bike idles and runs ok, responds ok to choke, revs maybe hand a little on deceleration. Only had it a few days so no chance yet to strip and check, was running ok for its previous owner (guy in our off-road group).

Bike generally ok so assume something fickle about it....

Appreciate your feedback and also any guidance on other issues with these bikes in general.... cheers.

Edited by miner
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Welcome to the club! As for the starting issues, I would pop off the float bowl and clean the pilot jet and entire carb if you have time.  My 2010 250 with del orto carb sometimes likes to have the choke on to file up even if its warm. Don't really have to unless its been like 20 minutes sitting or so.

 

Water pump seal is common issue so check your gear box oil and if milky rebuild it.  Exhaust pipes like to get bent from rubbing/hitting rear tire. 

 

Trial to be gentle on the kick starter which is another well known problem with these bikes. You can easily chip a tooth off the kick start gear.

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Hi guys, I left the gg hard start club about a year ago. After a year of kicking far too much, and doing all the tips and tricks mentioned on here. I even changed to a flat slide carby, and iridium plugs. Each made a little bit of difference, but not enough for me to enjoy the ride, well, I enjoyed the riding it was the stopping for a rest or to walk a section I feared. Until............I fitted a flywheel weight, problem solved?. I'm over seventy and started my 250 Pro 3rd kick after six week lay up. But you still have to get the kick action spot on. That was one kick more than normal. Cheers Taff

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Cheers guys.... getting spoiled maybe with the e-start on the 300 EXC, it starts first kick from cold then a prod of the button when on the move! Definately a knack to the GG!

Asked the guys who had been using it most (owner was using one of the other guys garage) and neither had any bother, one kicked it over in his flip flops and demonstrated its wheelying capabilities when I went to see it! Not my forte.... either! ? Heard about the chocolate kick starters though..... grim.

Checking all the usual suspects would be a good start I guess.... only thing that worried me were posts about electrical issues..... parts not so easy to come by in the UAE.

My 525XC ATV is a nightmare to start when hot..... and it's hot outside, was wondering if that might come into play (jetting/settings)?

Either that or sharpen up my kicking technique!

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Bike did the same again today......!! Brutal!

Was out yesterday, started after a few kicks, no issues. Stalled it climbing an obstacle, couldn't get it to go..... several attempts, switched to reserve, few kicks and away again. Ok till I got home. Filled it today, only took 1.5L..... wasn't out of fuel.

Out today, a good bit earlier so a good bit warmer, took forever to get the thing kicked over..... several minutes of attempting/ranting at it. Ran ok after that..... stalled it after climbing a small obstacle. Couldn't get it to go again. Tried every trick I could muster..... nothing, no chance of getting going.

Had to walk back in mid 30's heat for about 40 mins with the bike, had to stop in the shade and rest as was close to keeling over..... bike was close to being torched!

Going to strip it down next weekend as I'm on track at Yas anyway..... suggestions for things to investigate most welcome.?

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Got the bike stripped today.... findings:

Carb boot had come loose on the airbox side, bike had sucked in some dust and was on the plug.

Carb stripped and cleaned, a little crud in the bowl and float bowl plug/jet.... how do you measure the float height? Float needle was a little sticky..... square needle in round jet?!

Reeds ok.

Intake/crank ok. No water only either gummed old premix/carbon or maybe a little gear oil..... hard to tell.

Plug wet/fouled..... had a few goes at starting to get the fuel through. Plug dark but cleaned up ok, some crud from bypassing of the filter. Gap was slightly out of tolerance (0.7-0.8 instead of 0.6-0.7), cleaned the plug up and set to 0.65.

Spark.... wasn't convinced at first, didn't look clever and wasn't convinced. Checked it later however when in the garage, then noticed it was crackling in the magnetic bolt dish but a good strong blue arc from the dish to the cylinder head.... should be ok.

Compression.... ~134psi after several stiff kicks. Looks ok. Anyone got a reference value?

Never stripped the exhaust off.... need to take the shock off. Clever idea.... also rotten idea!

Anything else to consider? If not will get it back together and see how she blows....

post-22985-0-56363500-1477160997_thumb.jpg

post-22985-0-02643500-1477161026_thumb.jpg

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I have the same bike and had electrical problems the last few years with it cutting out with no spark and the fan going out. After cooling down a few hours it would start up then cut out again after 20 minutes. I swapped out the Ducati ignition with Kokusan and it has been running good since.

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Where does the Kokusan unit come from? Different model/make?

It's kokusan units on my KTMs.... my 2015 300 EXC hasn't been fired in about two months, went first kick. My old 2002 200 EXC also goes over with a couple of kicks and it's mostly idle now!

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Been out in the garage again tonight, sure my neighbours must love me....! Here are my findings.....

Gas Gas - Dellorto 26 PHBL Carb Details:

Pilot Jet- 35

Choke Jet - 60

Main Jet - 270K

Float Needle - INC (Red tip - no numbers)

Float Jet - 200

Slide - 60

Needle - D36

Clip - 3/4

Idle Screw = ??

Air/Fuel Screw = ??

Starting from cold in garage (at ~25-30'C ambient, 50-70% RH, close to sea level), then latterly after running for a few mins and repeated starts, bike seems to favour choke + 1/2 to cracked wide open throttle to start, otherwise just splutters.

Bike still not easy to start but now more likely to get it fired up with right twist/prod, etc.

Plug cleaned and re-gapped but probably would benefit from a fresh plug.

Didn't note idle & A/F screw positions but A/F responsive to 1/4 turn. Idle screw, responding over wider range.

Questions:

What are the base jetting and screw settings?

Where can you find jetting tables?

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It looks like you have stock jetting. My only change is a 38 pilot jet at 900 ft elevation. Watch this for screw settings:

https://youtu.be/Nd-7N4b_TZE?t=1h28m48s

 

I bought a complete used Kokusan system from trialsbikebreakersuk ebay store for $300 USD. They usually have most separate components but you will need the flywheel also. Any Pro model with a Kokusan system can be used for parts.

 

If your bike dies, doesn't start and has no spark, I would assume it has to do with the Ducati system not the carb.

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