zxr 250, starts only on choke, dies without

[silent]

ok the other day i put a new clutch lever, a new brake lever and a regulator rectifier unit on my bike. i also adjusted the throttle cable at the top near the actual twist grip...

i rode the bike and it bogged down like it was running out of petrol due to me havng the tank off i thought nothing of it, put the pump on primary, waited a moment and it was fine, put it back to on and then set of...3 or so minute later top gear 10000 rev after over taking a car it starts to die and then it just cuts out completely...so i drift to a stop and the recovery come out by which time its dark...

the bike will start with the choke but will shoot very high into the revs or it wont start at all without the choke, you try to take the choke of slowly withit running and it will just die...i have looked t the choke and although the mechanic said this might be the problem it appears to be fully on when engaged and also fully off when not engaged.

i have stripped it down to pretty much bare essentials now and i cant see anything wrong with it!

please somebody suggest something to help me!! i need this bike for college and what not!

thankyou in advance

Andy

[mchaggis]

It sounds a bit like putting the throttle slide in back to front, so the main needle jet is wide open, hence it's a pain to start, then it goes to the limiter. If the carburettor's clean and there aren't any blocked jets, then I'd personally try making sure that it was all put back together properly and starting it again. It's possible that taking the tank off has swilled about muck in the bottom, which has got stuck in a jet.

Just my
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Discovering the delights of Hammerite and a 3/4" brush.

[silent]

how do i check if the jets arent blocked? where are they?

also im confused about what you said about the throttle...are you saying maybe i did it too loose or too tight...when i saw the throttle cable , the bit thats screws onto the bit that the cable comes out of was just off that thread...so i undid the switchgear took out the cable and screwed the cable on a bit and ut it back together...now the throttle has alot more play before it starts to engage but i dont see how this could affect it...but i know very little so please tell me if it could be at fault...

thankyou for your response as well

Andy

[simon1221]

i rekon youve blocked up part of your carb, so that it runs very lean (less fuel:air), that would explain why it only runs with the choke as it may be close to the correct mixture settings,

try running it for a while, or bump starting it with the choke to try to push the muck through, or just take the carb apart and clean it, try checking the fuel filters as well if you can be bothered for large flakes of muck restricting petrol flow

the throttle slide is the bit inside the carb that controls how much fuel and air is going through, it is controlled by the throttle cable, i am guessing that that is what he means
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[Frost]

Did you adjust the slack in your throttle cable? If you backed too much slack off it then it might be trying to tick oer at 400rpm or something silly. once you back the choke off and no longer have that increasing the revs it dies.

Start it with the choke on, blip the throttle till its warm, back the choke off whilst revving the bike. if you find it runs with you revving it but dies when you stop, take some slack out of the throttle cable.

[simon1221]

Isnt that just the same as adjusting the idle speed screw, and i thought there was supposed to be a few mm of play in the throttle grip anyway
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DNA50 (sorry) ->> TZR125l >> GPZ500S

[stinkwheel]

It will have CV carbs, the cable attaches to a little lever which allows the throttle valves to be sucked open by the engine, he won't have been inside the carbs themselves to fiddle with the cable.

Maybe trapped the throttle cable under the tank or some bodywork when you put them back on?

Obstructed fuel tank breather?(does it do it with the fuel cap open?)

Check the vaccuum hose is still attached to both the carb manifold and the fuel tap.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[sickpup]

Also check the fuel pumps working.

[silent]

thanks for the advice but can i ask, how do i check the fuel pump works and how do i check this vaccuum thing?

thanks

Andy

[stinkwheel]

Vaccuum thing is simple. I asume your bike has a vaccuum fuel tap (most modern jap bikes do).

Just in front of the carbs on the inlet stub (between the carb and the engine) you will see a small hole in the top of the casting, one for each carb. Most of these will be blanked off with a screw and usually have a little rubber boot over the hole, they are used to balance the carburettors by attaching vaccuum guages to each hole and measuring how much air is being sucked through the carb.

One of these holes should have a bit of rubber fuel line attached to it, the other end of which should attach to the fuel tap, this is the vaccuum hoise I was referring to. When the engine is running, suction is applied to this hose which opens a diaphragm in the fuel tap allowing petrol to run out of it.

If this had become damaged/ detached then not enough fuel would run into the carbs to keep the engine running (in theory none would run out, in practice these taps are often a bit leaky anyway).
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[silent]

thankyou for all your help everyone...i gt this fixed a few weeks ago now but havent sauid thanks yet...it wasnt a fault as say, more i never took the vaccum pipe off the tank so didnt know to put it back on, then i saw a pipe free i didnt recognise, looked on the underside of the tank and there was a nipple for it, pu it on and hey presto...im an idiot! but saying about the vaccum made me realise what it was so thankyou everyone for your help and ideas

Andy

now the shock has leaked everywhere...whilst it was stripped, so now i need to get one and do that, cos its like riding a bouncy castle...not fun...