Commander will not idle when hot

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Dean-Harris
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Commander will not idle when hot

Post by Dean-Harris » Mon Mar 25, 2019 9:14 pm

Hi,
I am a returning commander owner. Had a new one in 1989 and have just bought one again.

The bike starts and runs well, pulls great and has amazed a few friends who have modern bikes with how ell it can get a move on.

I have cured a few problems one might associate with a bike shipped to Australia from UK and unused for a couple of years prior to my purchase.
I have one problem I would like some advice on before I tinker with it and really muck it up - haha.
The bike will not idle, it just slows down and stops. If I hold open the throttle a little it will idle comfortably at 500 rpm and is smooth. When cold the full choke will let the bike fast idle but on anything less than full choke the bike dies. Ir runs well hot or cold, but just will not idle.
I have SU carbs on a couple of old cars -Jaguars - but they are older model carbs and have manual adjustment for mixture and idle.
Please tell me how to I increase the idle speed on my Commander.
Thank you.

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Interpol2471
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Re: Commander will not idle when hot

Post by Interpol2471 » Mon Mar 25, 2019 9:38 pm

I did offer to overhaul it never mind...
It's more likely to be air leaks on the idle control pipe o rings or the choke circuit o rings in carb etc.
There are a number of reasons for not idling and you really need to check carefully and follow Startrights fault diagnosis download from their website.
If the bike hasn't been used for a while you may be lucky and it's just carb strip and rebuild with the kits from Andover Norton.
Have you got the manual with the bike as that shows the idle control adjustment screw on the casting between the carb and engine.
Various rubbish in various states of decay.....

Dean-Harris
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Re: Commander will not idle when hot

Post by Dean-Harris » Tue Mar 26, 2019 11:01 pm

Thanks for the advice I will look carefully at the Startrite web site. One point “ I did off to overhaul it” are you from Startrite? If so I have checked my emails and found nothing that said bike was not idling. I would have happily paid for that if it had needed it. We had time constraints so you might not have had time, I’m not worried the bike is great and you have done everything I asked of you. But I certainly would not have paid to get the bike to you then ignored your advice.
If I have misunderstood your comment I am sorry.
Thanks again for the advice and I love the bike - just need to find an F1 or F1 Sport now I’m hooked.

Anthony Duffield
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Re: Commander will not idle when hot

Post by Anthony Duffield » Wed Mar 27, 2019 7:30 am

Dean,

If you do not have a manual let me know, if you do; follow the instructions for setting the idle.

Air leaks between carbs and engine result in uncontrollable high idle, leaking cold start enrichment O Rings cause a very rich mixture.

The SU carbs are a simple device but can cause issues if you are not familiar with the settings, we will help you as much as we can, keep us informed with what you find.

Tony

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Interpol2471
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Re: Commander will not idle when hot

Post by Interpol2471 » Wed Mar 27, 2019 10:48 am

Sorry Dean I guessed you were the person Richard recommended you to me before shipping?
Nothing to do with Startrights But no may have mentioned Classic Superbikes as I work from there sometimes.
Was the bike being stored with a family member here prior to shipping ?
I replied twice to the mails if you ref overhaul and shipping .
Never mind sorry if they didn't come thru.
First thing now is as Tony said download the manual and review help files on Startrights website and feed back here your findings. Loads of experienced owners and of course Mr. R.Negus
Various rubbish in various states of decay.....

Mick Taylor
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Re: Commander will not idle when hot

Post by Mick Taylor » Tue Apr 02, 2019 9:03 pm

Where exactly can the fault diagnosis guide be found on the Startrite website?....I'm looking but can't find anything thus far red face

Mick.

johnbirchjar
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Re: Commander will not idle when hot

Post by johnbirchjar » Tue Apr 02, 2019 10:54 pm

Hi Mike,you say that you can get the bike to idle if you just open the throttle a smidge,I dont know if Commander are the same but my Classic has throttle cable adjustment on the twist grip end of the cables,have you tried using this to get the bike to idle?J.B.

Anthony Duffield
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Re: Commander will not idle when hot

Post by Anthony Duffield » Wed Apr 03, 2019 8:23 am

Mick,

For Startright paste this into your browser; http://startright.co.uk/index.php?main_ ... &chapter=1

JB's comment re adjusting the throttle discs with the throttle cable adjuster will mask the issue, this adjuster should only be used as follows:

Ensure the throttle cable is adjusted correctly :
(section G3) with 2.5mm (0.10 in.) free plav
at the twistgrip end. Run the engine until
1OO'C is indicated on the temperature gauge.

Do you have a workshop manual? if not I can send you a link, if you have a manual read section D

Tony

Dean-Harris
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Re: Commander will not idle when hot

Post by Dean-Harris » Thu Apr 04, 2019 12:20 pm

Thank you, I do have a manual. It appears to say adjust the idle using the air screws on the inlet manifolds in front of the cards. But my bike just doesn’t seem to respond as it says it should in the manual.
I have a rebuild kit from Andover. I will install that and check for air leaks as suggested.

johnbirchjar
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Re: Commander will not idle when hot

Post by johnbirchjar » Thu Apr 04, 2019 11:09 pm

I had the same problem with the Idle Screws on the Classic for years(like,they didn't seem to make a lot of difference evil)but when I put the Commander engine in the bike and renewed all the "O" rings "vwallah" they now work Very Happy.(the same carbs by the way wink)J.B.

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Interpol2471
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Re: Commander will not idle when hot

Post by Interpol2471 » Fri Apr 05, 2019 9:32 am

Concur JB idle control pipe o rings always worth a look as per my first post.
I have found a few incorrectly fitted pipes as well as they are easy to bend with a bit of ham fistedness....
Once bent they don't sit in the the o rings and hey Presto no idle.
Keep us updated
Various rubbish in various states of decay.....

Dean-Harris
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Re: Commander will not idle when hot

Post by Dean-Harris » Thu May 02, 2019 1:45 pm

I had a few spare minutes today so I removed my carbs and replaced the o rings on the inlet pipes and all but one of the small rings on the idle bypass pipes. First question, how the heck do you replace the engine side small print on the idle bypass tube, I can just about see it let alone get to it get it out and fiddle a new one in.
All re assembled and still no idle. I have read elsewhere that the o rings on the enrichment device can also leak, so I think I’m about to take the carbs off again and go through them again. I didn’t have time to disassemble them this time.
The carbs were quite dirty probably sticky from not being used much I cleaned them with carb cleaner and they looked lovely haha but looks can deceive.
Any advice on getting to that right hand o ring on idle bypass tube much appreciated.

David Rodgers
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Re: Commander will not idle when hot

Post by David Rodgers » Tue May 07, 2019 12:45 pm

Hi Dean

I had the same symptoms, low tickover and eventual slowing down and stalling. I kept screwing the air screws out a whole turn at a time and eventually got the required tickover and good pickup. It was a lot of turns out though!

Regards
Dave R

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