GL1500se Fast idle speed ? Can't adjust.


Information and questions on GL1500 Goldwings (1988-2000)
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Zradene
Posts: 17
Joined: Sat May 08, 2021 6:26 am
Location: Essex, England.
Motorcycle: GL1500SE

GL1500se Fast idle speed ? Can't adjust.

Post by Zradene »



Hi guys, I am trying to work out why my Honda Goldwing GL1500se has a very fast idle speed. The cables are all adjusted correctly and the throttle adjustment thumb screw can be unscrewed to the max without any change to the idle speed.
This Gl1500se is a Trike that I purchased a few months back with a blown engine. I have now purchased a US import replacement SC22 engine with only 29,000 which is in fantastic condition and sounds great.
As I did not hear the original blown engine run, I can only assume that before the catastrophic engine failure, the carbs were working as expected with a normal idle speed at tick over.
Until I rebuilt the carbs and re-fitted them, I did not realise that the pilot jet was actually removable/adjustable, using the ‘D’ shaped adjustment screw ?... (why on earth do Honda use this ‘D’ shaped design knowing that nobody in the world will have the proper key available in their toolbox to remove the pilot jet is simply beyond me). Also, even with the correct tool available, it looks impossible to make any adjustments with the carbs fitted. In case I need to remove the carbs again, I have now ordered a ‘D’ shaped key just in case for some strange reason that the previous owner had over adjusted these pilot screws causing the fast idle speed. Not convinced this is the problem, so I am hoping someone has some suggestions as to what may be causing this fast idle speed which I cannot adjust.
The original engine was a UK/European model which did not have the secondary emissions pipework fitted as some of the US models do. The US replacement engine had 4 holes on the cylinder heads where the original secondary emission’s pipework was removed from, which I have now blanked off, together with the 2 holes on the underside of the engine, as in the UK these emission control regulations are not applicable. Other than this, the UK and US engines are identical so I am assuming my fast idle is nothing to do with me blocking off these holes.
All rubber ‘O’ ring seals were replaced on the engine water pipes, new thermostat fitted, replacement IASA valve, carbs stripped and vapor blasted then ultrasonically cleaned, main jets & jet needles replaced, new rubber gaskets fitted, new rubber intake manifolds, new fuel joint set & seals fitted, new fuel filter, new accelerator pump seal fitted, diaphragm’s are in good condition and all fuel lines and vacuum pipes checked for damage, all look in great condition and are connected to the correct locations etc (took loads of photos before dissembling), all pipework securely fitted with no fuel or vacuum leeks as far as I can make out.
Any ideas or suggestions would be gratefully received.
Many thanks guys.


Zradene
Posts: 17
Joined: Sat May 08, 2021 6:26 am
Location: Essex, England.
Motorcycle: GL1500SE

Re: GL1500se Fast idle speed ? Can't adjust.

Post by Zradene »

Hi guys, I found out what the problem was.... one of the choke starter slides is worn and would not close properly when releasing the choke lever.

I now need to source some replacement new parts, but over here in UK they are not available. Part Honda part number 16031MN5014 (CHOKE LEVER SET, STARTER).

If anyone has a couple of these kits to sell me, that would be fantastic.
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