I just bought a 25 year old wing with 12,000 miles. The old man started it once a month in his heated 50x120 shop since he last regularly used it in 2019. I gassed it up and rode 90 miles home noticing a hesitation on tip in (slight acceleration no matter the previous throttle). If I “give her the beans” she will wind up fast with gusto.
I should mention I did have carbs off last week when I found loose boot clamps and a deteriorated sub air filter. I replaced said filter and tightened the boot clamps. Since then I’ve put 800 miles on it and just about 3 tanks of fresh 91 octane non-ethanol
I am quite versed in carburetors from automotive world (35+ years as professional tech). I watched some videos explaining the GL1500 fuel control system. Now I have a basic understanding of the theory and operation. Based on that I propose my theory on what’s happening.
Under steady cruise the solenoids are off-closed and CV plungers-needles are in “lean mode”. Except I might have particles of old sub filter holding AJ2 and/or AJ3 partially open causing an even leaner condition. Then when I accelerate a little it takes a long time (hesitation) to gain speed. After a bit the vacuum drops causing the diaphragms to pull plungers-needles letting more fuel in and it acts close to normal.
Am I far off on my thought train?
Should I yank my plastics off, pull solenoids, clean them with carb spray-air gun and clean out air jet lines?
Or am I way off and need to dig deep into carb rebuild? I’d like to wait on that until riding season is over. I’ve got a Special Olympics poker run next weekend
Sub air filter, jet solenoids and hesitation
-
- Posts: 8
- Joined: Sun Aug 04, 2024 8:26 pm
- Location: Pipestone MN
- Motorcycle: 2000 GL1500SE
- Rambozo
- Posts: 4036
- Joined: Sun Apr 01, 2018 8:36 pm
- Location: Disneyland
- Motorcycle: 1992 GL1500 Aspencade
Ducati Monster
Re: Sub air filter, jet solenoids and hesitation
You might first try just running it on 87 octane fuel. This engine doesn't really have the compression to run right on 91.
- ct1500
- Posts: 1618
- Joined: Wed Nov 10, 2010 8:09 pm
- Location: Glastonbury,CT
- Motorcycle: 1988 GL1500
Re: Sub air filter, jet solenoids and hesitation
Is it a possible thought train yes, is it probable no IMO.
Lots of folks are riding around with crumbled sub filter and do not even know it. I think the actual vacuum pull is so slight, just check out the size of the brass tube sleeves in the carb throat, minute in size.
Your ride has been setting for a long time. Just starting up to idle for years I would almost guarantee spark plugs are black and fouled. Might even have some sludge/blockage of pilot jets starting. Another thing to check are your slides which can get sticky. Test drive with air filter out noting slide movement in tandem and when shut off check for binding when pushing back and forth with finger. Could also have a vacuum leak in one of the hoses to intake. If machine checks out good a slight tweak to mixture screws would prolly help out also.
Nothing leaves my shop till its' perfect
This is what I do
This is what I do