Author Topic: Few problem i got into this afternoon...need some advice  (Read 7806 times)

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Offline 1983_Enduro_YAMI

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Few problem i got into this afternoon...need some advice
« on: June 15, 2016, 05:45:19 pm »
Suppose to have a good ride with the Big IT250K this arvo.....started the bike..here is the first problem, The bike was tuned by the professional mechanic couple of months ago..when i start the bike with choke...It's revving the hell out of it but as soon as i pull the choke off and warm it up, I have no trouble. Here is the second problem i just find out this afternoon....The bike turned itself off!!! I just put a new spark plug yesterday. It bogged down and die when i rev it (that's when the bike's warmed up) I have to push it all the way back from the paddock.

I have been doing all this work..replaced the crank seal, New boyesen reeds etc. I know it's a 30+ years old bike and it's hard to get it to behave but at least the bike shouldn't die on the paddock and playing up like this..It should run like what it's made for (not the top but like a motorbike)

Offline skypig

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Re: Few problem i got into this afternoon...need some advice
« Reply #1 on: June 15, 2016, 06:13:01 pm »
Disappointing.
Did you get it running again?

Sounds like carburetion.
I wonder if there is debris/water in there somewhere? Maybe something rubber from the choke (cold starter) falling apart?

Keep us informed re your progress.

Offline 1983_Enduro_YAMI

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Re: Few problem i got into this afternoon...need some advice
« Reply #2 on: June 15, 2016, 06:50:47 pm »
Nah i left it.

I don't really have any idea..Have to look in to it... :( :(

Offline Lozza

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Re: Few problem i got into this afternoon...need some advice
« Reply #3 on: June 15, 2016, 07:01:08 pm »
Take it back to where the work was done?
Jesus only loves two strokes

Offline pokey

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Re: Few problem i got into this afternoon...need some advice
« Reply #4 on: June 15, 2016, 07:07:14 pm »
Choke issue sounds  like an air leak around the enricher. check its tight and any boots or orings are in place.

Offline 1983_Enduro_YAMI

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Re: Few problem i got into this afternoon...need some advice
« Reply #5 on: June 15, 2016, 07:39:00 pm »
Choke issue sounds  like an air leak around the enricher. check its tight and any boots or orings are in place.

Where about is the enricher in the carby??

Offline pokey

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Re: Few problem i got into this afternoon...need some advice
« Reply #6 on: June 15, 2016, 08:01:49 pm »
enricher=Choke.. could be an idea to follow lozza's suggestion i feel.

 These carbies dont actually choke they open an enriching circuit hence the correct name should be enricher.

Offline Oldfart

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Re: Few problem i got into this afternoon...need some advice
« Reply #7 on: June 15, 2016, 08:50:09 pm »
You have an air leak ...possible manifold rubber or carb is totally rooted.
spark and petrol is what makes these old girls go and with out one the other wont work ..... do the process of elimination.
step by step checks .... not multiple

Offline Tomas

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Re: Few problem i got into this afternoon...need some advice
« Reply #8 on: June 15, 2016, 08:56:56 pm »
Check your electric. Stator is tight& advance set correctly, check that rotor's woodruf key is not sheared of, make sure your kill switch is not stuck and works correctly, check all ignition connections&connectors,try another spark plug&make sure you have spark. See if the bike starts with choke off. It may take a few kicks. Old CZ had no choke and started.

Offline TT5 Matt

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Re: Few problem i got into this afternoon...need some advice
« Reply #9 on: June 15, 2016, 09:10:14 pm »
when you got it from the pro mechanic did you run the bike with the fuel tap off till it cut out coz no fuel left in the bowl?if not after 2 months the fuel turns to shite then white powder but blocks up jets but they normally fire up on the choke but die when the choke is switched off.try taking the over off on the bottom of the carb for a look/see

Offline 1983_Enduro_YAMI

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Re: Few problem i got into this afternoon...need some advice
« Reply #10 on: June 16, 2016, 06:35:20 am »
when you got it from the pro mechanic did you run the bike with the fuel tap off till it cut out coz no fuel left in the bowl?if not after 2 months the fuel turns to shite then white powder but blocks up jets but they normally fire up on the choke but die when the choke is switched off.try taking the over off on the bottom of the carb for a look/see

The bike runs fine and crisp without choke. The problem is when i turn the choke on, It's revs the hell out of it. Like what the other people said up there..I properly have an air leak..Have to look into it with a can of WD40 and a spanner

Offline 1983_Enduro_YAMI

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Re: Few problem i got into this afternoon...need some advice
« Reply #11 on: June 16, 2016, 06:45:19 am »
Check your electric. Stator is tight& advance set correctly, check that rotor's woodruf key is not sheared of, make sure your kill switch is not stuck and works correctly, check all ignition connections&connectors,try another spark plug&make sure you have spark. See if the bike starts with choke off. It may take a few kicks. Old CZ had no choke and started.

The timing was advanced by the mechanic last time..but not long after i replaced the old CDI with a new one. I didn't care about the timing after i replaced it. Maybe that's an issue too?? Yep, That's what i did the day before. New spark plug and runs like crisp and yesterday..same thing..It died.....

Offline OverTheHill

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Re: Few problem i got into this afternoon...need some advice
« Reply #12 on: June 16, 2016, 08:01:02 am »
You say 'i have been doing all this work' 'crank seals', was that done by the shop or by the owner. maybe the left crank seal has been misplaced or incorrectly fitted [which is unlikely & not easy to muck up--Soooo---, i'd guarantee the choke jet in the bowl is blocked therefor it just opens the air bleed--like opening the throttle a bit in effect.Jet's not easy to clean or even find for the unwary as is down a cavity that a long brass tube fits down. In the bottom of that hole is a minute jet. Get something about the size of wire brush wire or something straight & high tensile so it won't bend easy & give it a poke. then go the other way from the feed into below that jet using something bigger like a drill bit. With the wire, be sure it's gone through the jet to dislodge whatever's in there & maybe follow it up with a squirt of crc with nozzle right into the jet from the top--like down the cavity side. Sorry about the long winded essay but hope you get the idea. [hope i'm right too lol]. ps, doesn't take much to block that jet so unlikely to be related to the mechanics work but i now see you say the bike turned itself off & had to push it home--so maybe another problem or [has left crank seal come out--still very unlikely].

Offline 1983_Enduro_YAMI

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Re: Few problem i got into this afternoon...need some advice
« Reply #13 on: June 16, 2016, 01:15:44 pm »
You say 'i have been doing all this work' 'crank seals', was that done by the shop or by the owner. maybe the left crank seal has been misplaced or incorrectly fitted [which is unlikely & not easy to muck up--Soooo---, i'd guarantee the choke jet in the bowl is blocked therefor it just opens the air bleed--like opening the throttle a bit in effect.Jet's not easy to clean or even find for the unwary as is down a cavity that a long brass tube fits down. In the bottom of that hole is a minute jet. Get something about the size of wire brush wire or something straight & high tensile so it won't bend easy & give it a poke. then go the other way from the feed into below that jet using something bigger like a drill bit. With the wire, be sure it's gone through the jet to dislodge whatever's in there & maybe follow it up with a squirt of crc with nozzle right into the jet from the top--like down the cavity side. Sorry about the long winded essay but hope you get the idea. [hope i'm right too lol]. ps, doesn't take much to block that jet so unlikely to be related to the mechanics work but i now see you say the bike turned itself off & had to push it home--so maybe another problem or [has left crank seal come out--still very unlikely].


Thanks Mate, It was good. I'll give this a try. is it the little jet beside to the main jet??
« Last Edit: June 16, 2016, 01:25:30 pm by 1983_Enduro_YAMI »

Offline Rossvickicampbell

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Re: Few problem i got into this afternoon...need some advice
« Reply #14 on: June 16, 2016, 03:57:11 pm »
grab yourself a parts list diagram.
1974 Yamaha YZ360B
1980 Honda CR250R - Moto X Fox Replica