Author Topic: No Idle IT250K 1983. Anyone help??  (Read 4242 times)

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Offline 1983_Enduro_YAMI

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No Idle IT250K 1983. Anyone help??
« on: February 29, 2016, 02:28:53 pm »
My IT250K won't idle. it die as soon as I stop. They're the Enduro bike so they should have idle?? Probably carburetion problem??
I have a set of Boyesen reeds and DG full exhaust system so it's not in the stock condition.

Someone help me please  :-\

Offline Krikey

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Re: No Idle IT250K 1983. Anyone help??
« Reply #1 on: March 01, 2016, 12:06:46 am »
Without trying to diagnose the whole bike via this forum (impossible) and making the assumption that you've stripped and cleaned the carby correctly, I will ask one question.  How old is the carby?

If it's the original then call TD Hattricks in Townsville, spend $240 and get a brand new one ready to bolt on. You'll be amazed at the difference that makes.

Good luck :)

Offline OverTheHill

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Re: No Idle IT250K 1983. Anyone help??
« Reply #2 on: March 01, 2016, 08:10:58 am »
guessing game so here's a guess. Blocked pilot jet although i'm sure that would have been thought of. Air screw [idle mixture fallen out]. Manifold rubber broken around boost bottle hose--or boost bottle damaged, unlikely i know. choke stuck open but choke [very small] jet down the hole in the bowl blocked so just sucking air [if stuck open]. Mmmmm--worst case, like my IT250K motor, the cylinder was broken around the base on the right side. That was an easy fix--i just put a genuine YZ465H motor in lol. Hell it goes!!. Forgot the obvious--crank seals which they were never hard on. Barrel base gasket sucked in, etc etc. Cheers. ps, float set so low it's only just keeping up with the main jet/emulsion tube and pilot sucks from higher up [by memory]. Next please?.

Offline 1983_Enduro_YAMI

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Re: No Idle IT250K 1983. Anyone help??
« Reply #3 on: March 01, 2016, 09:08:56 am »
I Re-tune the bike yesterday....runs fine. No hesitation at all. Idles fine.

Probably buy a new carby soon.

Offline sleepy

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Re: No Idle IT250K 1983. Anyone help??
« Reply #4 on: March 01, 2016, 11:01:15 am »
I Re-tune the bike yesterday....runs fine. No hesitation at all. Idles fine.

Probably buy a new carby soon.

If it is running fine and the original carb isn't worn to much stick with it as the new carb will be a generic version without the correct jets. You can swap the old jets into it but the new slide may not have the same cutaway or the main air bleed could be different.

Offline Krikey

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Re: No Idle IT250K 1983. Anyone help??
« Reply #5 on: March 01, 2016, 11:17:58 am »
If it is running fine and the original carb isn't worn to much stick with it as the new carb will be a generic version without the correct jets. You can swap the old jets into it but the new slide may not have the same cutaway or the main air bleed could be different.

I think you are wrong here.  Mikuni carbs from TD Hattricks are all set up for your specific bike. Slide, needle, jets etc all as per OE specs.

Offline Rossvickicampbell

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Re: No Idle IT250K 1983. Anyone help??
« Reply #6 on: March 01, 2016, 12:18:33 pm »
yep - tell them what you want in your carby and that is what you will get - for around $160
1974 Yamaha YZ360B
1980 Honda CR250R - Moto X Fox Replica

Offline sleepy

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Re: No Idle IT250K 1983. Anyone help??
« Reply #7 on: March 01, 2016, 12:44:40 pm »
If it is running fine and the original carb isn't worn to much stick with it as the new carb will be a generic version without the correct jets. You can swap the old jets into it but the new slide may not have the same cutaway or the main air bleed could be different.

I think you are wrong here.  Mikuni carbs from TD Hattricks are all set up for your specific bike. Slide, needle, jets etc all as per OE specs.

They only have a limitted range of needles and needle jets in stock so the best you can get is what they think is close. I've seen quite a few carbs turn up that are meant to be setup for a particular engine that are miles from correct.
Alteast they are new and look pretty.

Offline Krikey

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Re: No Idle IT250K 1983. Anyone help??
« Reply #8 on: March 01, 2016, 02:01:57 pm »
They only have a limitted range of needles and needle jets in stock so the best you can get is what they think is close. I've seen quite a few carbs turn up that are meant to be setup for a particular engine that are miles from correct.
Alteast they are new and look pretty.

Really? Do you have evidence to support this statement? Genuinely asking as I don't want to be one of those that goes on what "someone on the internet said".

Offline sleepy

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Re: No Idle IT250K 1983. Anyone help??
« Reply #9 on: March 01, 2016, 05:40:20 pm »
They only have a limitted range of needles and needle jets in stock so the best you can get is what they think is close. I've seen quite a few carbs turn up that are meant to be setup for a particular engine that are miles from correct.
Alteast they are new and look pretty.

Really? Do you have evidence to support this statement? Genuinely asking as I don't want to be one of those that goes on what "someone on the internet said".

I work on bikes for a living and have had a lot to do with tuning and carbs for many years and all I can do is tell you what I have seen over the last 40 years of working on bikes. The only way you will get a carb that is the same as the original is to buy it as a spare part. There are differences in some of the drillings in the carb body that will change the way they work and as I said before the main air corrector sometimes has a jet and others not and it will have a big effect on top end mixtures.
As for needles, there are huge numbers of specials made for OEM that have never been available aftermarket.
What about bikes that came with Keihin carbs, there is no magic coversion chart.

I will say the sevice from Hattricks is great and they carry a big range of bits but I do believe that you only get a carb that is close.   

Offline OverTheHill

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Re: No Idle IT250K 1983. Anyone help??
« Reply #10 on: March 02, 2016, 07:22:34 am »
well that was a waste of a long story i wrote lol. "Gave it a tune & it's ok now". I always make the mistake of going for the worst case scenario. Curious to know what "gave it a tune" means that sorted it so easy. All good though. & love the 250K IT model.