Author Topic: Finally started! Few queries  (Read 220 times)

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Offline Joffa1

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Finally started! Few queries
« on: January 10, 2020, 10:17:49 PM »
So after a lot of work and great advice from all of you here and on the Facebook page my xs500c finally roared to life today. Very happy to hear her running!

A few queries:

1. The idle is high (as in 2500 rpm high!). Adjusting the mixture screw with the white nylon limiter on them seems to make little difference... just after advice on what else to check here? Possibly a throttle adjustment?

2. When on the centre stand and idling in neutral, albeit too high, the rear wheel is spinning quite a bit. I gather a little bit of movement is normal but mine is really spinning pretty quickly. Could this be associated with the high idle (it is in neutral though).

Thanks for any help.

Offline guylr

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Re: Finally started! Few queries
« Reply #1 on: January 11, 2020, 01:53:37 AM »
Have you tried lowering the idle speed with the idle stop screw?  The idle mixture screws won't change the speed much if at all. For now turn them out to as far as the limiters will let them then try backing out the idle stop screw at the cable lever. If a stable 1200-1400 rpm idle can't be reached then suspect that the carb throttle plates are out of sync and or the idle mixture circuits are dirty.

Rear wheel spin at high idle is pretty normal from the drag of oil in the transmission. If you can apply the rear brake and the engine keeps running then it's not a problem.

Guy
Now Retired Yamaha guy. Cut me and I bleed "Cinquasia Red"

Offline Joffa1

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Re: Finally started! Few queries
« Reply #2 on: January 11, 2020, 03:38:20 AM »

Hi Guy thanks again for your help...

Could you identify which one is the idle stop screw for me? I think Iíve got it but like to be certain...

Is it the one with the spring under the head of the screw?

Offline Joffa1

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Re: Finally started! Few queries
« Reply #3 on: January 11, 2020, 03:40:03 AM »
Ah sorry I think Iím with you now ... you mean up at the lever control.

Offline guylr

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Re: Finally started! Few queries
« Reply #4 on: January 11, 2020, 09:46:26 PM »
Look for the lever on the left carb where the throttle cable attaches. The screw that lever contacts when the throttle is closed is the idle stop screw. Screwing it in increases idle speed and screwing it out lowers idle speed.

Guy
Now Retired Yamaha guy. Cut me and I bleed "Cinquasia Red"

Offline Joffa1

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Re: Finally started! Few queries
« Reply #5 on: January 12, 2020, 03:06:47 AM »
Excellent. Managed to play around with it and get the idle to settle nicely. Now having an issue where I can only get it started when I spray starting fluid directly down the air filter. It will idle after that just from the petrol supply then.

Iím assuming this is a fuel supply/carburetor issue... what should I look to first?

Offline guylr

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Re: Finally started! Few queries
« Reply #6 on: January 12, 2020, 03:09:13 AM »
Will it start again after its fully warmed up? Does it start better if no enrichener (choke) is used?

Guy
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Offline Joffa1

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Re: Finally started! Few queries
« Reply #7 on: January 12, 2020, 03:12:53 AM »
It wonít start again after fully warmed...

Offline Joffa1

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Re: Finally started! Few queries
« Reply #8 on: January 12, 2020, 03:13:54 AM »
I think I tried with choke on and off and didnít make a difference...

Offline guylr

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Re: Finally started! Few queries
« Reply #9 on: January 12, 2020, 12:51:41 PM »
The pilot circuits of your carbs are plugged with stale fuel residue and the enrichener jets in the float bowls are also plugged. The carbs need a thorough cleaning and that includes removing the mixture screws which means the limiters have to be pried off before you can unscrew them.

Guy
Now Retired Yamaha guy. Cut me and I bleed "Cinquasia Red"

Offline Joffa1

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Re: Finally started! Few queries
« Reply #10 on: January 12, 2020, 09:17:30 PM »
Ok... carbs out again 🙄 I was pretty thorough with the cleaning up but guess Iíll have to go through them again. Will pay particular attention to the enrichener jets this time too.

Thanks again.

Offline Joffa1

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Re: Finally started! Few queries
« Reply #11 on: January 12, 2020, 09:21:41 PM »
Although I could possibly clean those areas out leaving carb bodies on the bike and just draining and removing float bowls...

Offline Joffa1

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Re: Finally started! Few queries
« Reply #12 on: January 12, 2020, 09:22:18 PM »
And removing limiters and mixture screws...

Offline Joffa1

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Re: Finally started! Few queries
« Reply #13 on: January 13, 2020, 01:21:08 AM »
So basically Iím just asking if I drain the bowls and remove them and remove the limiters and mixture screws can I clean these components out in situ? Only
Because Iíve already cleaned the carbs out very thoroughly and donít want to have to remove them from the bike again.

Offline guylr

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Re: Finally started! Few queries
« Reply #14 on: January 13, 2020, 03:37:48 AM »
No. You must remove them, strip them and soak them in carb cleaner. If the limiters have never been off the idle mixture screws then they have never been out and that means the pilot system has never been cleaned. After 45 years the only way to really clean the carbs is to soak them.

Guy
Now Retired Yamaha guy. Cut me and I bleed "Cinquasia Red"