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carb problem


Paulwhite
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hi im in the middle of jetting my carb

iv chainged the main jet , sorted out the float , built a straight through exhaust, and put a free flow filter on it

but i cant start the engine when its cold.

iv put in a bigger pilot jet (from 12.5 to 17.5 ) and that hasnt helped

any ideas what i can do or where to start?

cheers.

.Paul.

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yeah but it dont help

the engine just keeps going over

but it will start and run fine if i push it down hill in second

could it b the plugs? iv got standard ones in but dont know what the hotter plug is. is it the next number up or down?

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have you tried richening your idle mixture screw?

yeah and still no luck :angry:

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  • Moderator

maybe the battery is on its way out and the starter sups all the available juice so the ignition gets starved. its just you said that it starts ok on bump

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yeah it starts and runs perfect when bumped

i have noticed that after 5 min of holding the startor switch the battery is about dead so might have something to do with that ...

but what i have found is that when i try to start it with the choke, then have a look at the sparkplugs there isnt any fuel on them .....surely it should flood the engine and plaster the sparkplugs in fuel? the choke works perfect.

note iv put a 95 main jet (from 75) and a 17.5 pilot jet ( from 12.5) so im confused as to what the problem is.

as to the ignition timing iv not touched the cdi just the carb and air filter so that should be ok shouldnt it?

i cant take it to a dealer cause i dont fancy being mugged .

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  • Moderator

you'll need a good amp charge to turn over the bike and run the CDI.

get your battery amps checked or buy a new one as I think yours is on its way out!!

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ok iv checked the battery and its fine

but still not starting :angry:

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  • Moderator

ok iv checked the battery and its fine

but still not starting :angry:

did you just check for volts or amps (hard without the right equipment)

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did you just check for volts or amps (hard without the right equipment)

iv got a volt meter and checked each cell 1 by 1 and they all read 2 volts then checked the overall voltage which was 12, i then put me battery charger/conditioner on it over night .

its helped but it still wont fire up when standing

but as iv said b4 after a 5 min drive it will start up without pushing it, but if it is off for longer than 10 min i have to push it again.

iv set the mixture screw so the bike runs lovely with good acceleration and top speed and iv set the tick over screw so it just ticks over nicely

i got this bike about 6 months ago and it started and ran fine, i could start it up 1st time every time, then when i couldn't get an air filter for it i had to put a performance one on it , then re jet the carb then put a new exhaust on

and since iv done that it wont start without pushing

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so i guess its foooked

Messing with the jets can be a real pain . What I would do is put your old ones in and see if it starts from cold and if it will i would say its the air fuel mix with the larger jets as they letting a lot more fuel and oil in good luck m8

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just to let u know its a 4 stroke and because the air filter is a performance one the original carb setup wont work (thats why i had to re jet the carb) plus if it did start up, the mixture would be sooooo lean it would kill the engine

i was wondering is there a way to tell if the mix is right when trying to start the bike?

e.g when the choke is on and u try to start withought the ht lead connected, then when u check the plug it should b caped in fuel???

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The only way i know how was when my brother used to try starting his Golf Mk2 with the choke on, if you could smell the unburnt fuel then it was too rich :lol:

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ta thats helps a bit, might try to ajust the fuel settings when starting up .

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  • 2 weeks later...

right iv put in a smaller pilot jet and still no luck, :angry: any1 know how to set or change the ignition timing?

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