88 GL 1500 newbie problem

1883 Views 22 Replies 13 Participants Last post by machinehead, Jun 24, 2010

bambam

Discussion Starter · Aug 29, 2009

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First, I would like to say hi to everyone on this site. I am a proud new owner of a beautiful 88 GL 1500. I bought it from a seller in CA and had it shipped to Dallas. I picked it up and rode it to my home in San Antonio (in 101 degree heat). It was a blast and the bike performed almost flawlessly. All of the systems worked as advertised but I discovered that if I advanced the throttle past approximately 1/2 way, the acceleration bogged down and it would not accelerate. Any throttle movement short of that and it would go like a dream. It does not have anything to do with the speed of the bike but it is all about the throttle position as it happens in all gears at the same throttle position.

The previous owner was very good to the bike as it looks great for a 21 year old machine and obviously has had good care through the years. It has 92000 miles on it now and I wantto take care of it for another 100kif possible. I like this body style and I am 6'3" so need the bigger frame.

I have been lurkingon this site for a whileduring my search for a good used wing and have searched the posts for a similar situation. I am currently runningsea foam (1/2 bottle in a full tank of gas) and ran the tank partially down andam on a business trip for 4 days so will see if that does thetrick.

I have also called several repair shops and talked to some of the techs andthey say it may also be a vacuumadvance problem with the vacuum hose being disconnected from the ecu.

If you all have any ideas why this may be happening,I would like to hear your slant on what it may be. I have also heard that the CA bikes (it was purchased originally in Fairfield CA) have a restricter washer in the exhaust to build up back pressure. I dont know if this is even a possibility on this year but would love some advice.

Thanksin advance and hope to see you out on the road.

Bambam

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1 - 20 of 23 Posts

SETHAN12

· #2 · Aug 29, 2009

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Hopefully someone will be along soon to help, but while you are waiting;

Welcome from the state of Pennsylvania!

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treker8098

· #3 · Aug 29, 2009

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When my bike would not accelerate hard under full throttle, or bog down, I found that the fuel pump just was not operating as it should. They are not that hard to correct. I would first look at the fuel filter under the fill lid.

exavid

· #4 · Aug 29, 2009

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It does sound like a fuel starvation issue. No restrictors in the 1500s, California or not. As already mentioned I'd check the fuel pump output and replace the fuel filter as a starting point.

bambam

Discussion Starter · #5 · Aug 29, 2009

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Thanks for the info so far.I am planning on replacing the fuel filter when I get back. The thing that surprises me is that the bike idles so well and runs absolutely perfect up to 1/2 throttle.

This feels like the secondaries are not opening (i know there are no secondaries) on a 4 bbl carb. When I release the throttle from the bogging position, the bike literally jumps forward in an acceleration mode that rivals anything ever driven. It only lasts for a second but WOW is it a hard pull.

Thanks again for the info

Bambam

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Bike...and Dennis

· #6 · Aug 29, 2009

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Welcome to the forum, Bambam.

I wouldn't rule out the vacuum thing. 21 year old rubber can be an issue. May even have a colapsing fuel line.

I always like tolookforthe cheap& easy fix first. :action:

bambam

Discussion Starter · #7 · Aug 29, 2009

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Im all about cheap and easy...

I guess that doesn't sound good when I say that?:dude:

DBohrer

· #8 · Aug 29, 2009

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The only difference I am aware of on the California model is the air filter. There is a "charcoal type" insert in the air filter.

Agree with the others on changing the fuel filter first, that has been known to cause the symptoms you are having. Another possibility might be the auto fuel shut-off valve. The rubber diaphragm could be torn, rotten or such. Either could restrict fuel flow at higher demand times.

Bike...and Dennis

· #9 · Aug 29, 2009

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bambam wrote:

Im all about cheap and easy...

I guess that doesn't sound good when I say that?:dude:

Just seems like most problems on these bikes are little things like leaky hoses and such. Materials that have passed their intended lifespan.

And it sucks to do a $300 fix,then find out the problem was a $3 hose.

Foosman(5)

· #10 · Aug 29, 2009

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The hose off the vacuum advance on the ECM will not cause a hesitation/stall from a timing perspective. Sucking more air, maybe.

If it is a slight irritation, search trigger wheels.Others resort to the accelerator pump,rejetting, and overhauling the carbs. Your carb (88) had a service bulletin on the carb (re-jet, ECM, and (I forgot).

I hate these carbs. Pain in the a$$ to get them setup right especially if they need to taken off several times.

Hopefully theSeafoam works for you.

Foosman(5)

· #11 · Aug 29, 2009

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Maybe I miss understood.

Boggs at half throttle? No response at full throttle?

Check to see if the plastics sliders in the carb throat are opening.

bambam

Discussion Starter · #12 · Sep 8, 2009

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Well, I tried the sea foam and changed the fuel filer. I also checked the plastic sliders and the squiters on the top of the carbs. They are all working fine but I discovered that the PO removed the part of the air box that connects the air hose that comes up from the bottom of the bike to the front of the airbox. There is a 3x6 inch opening where that part would go. The clear plastic hose that connects to the bottom of the airbox (below the filter) is also pulled loose and I cant seem to get it reattached. Anyway, the bike is still running like a top in idle and accelerates great up to just short of half throttle and then any additional throttle slows the bike as it boggs down.

Any ideas?

Thanks,
Bambam

bambam

Discussion Starter · #13 · Sep 8, 2009

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I forgot, the bike is running quite rich and is getting terrible mileage (36 highway and 27 city). Yes, I have been riding quite a bit to get those numbers. My wife is pleasantly surprised that I am more than willing to go out for errands for her.

Bambam

DBohrer

· #14 · Sep 8, 2009

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bambam wrote:

Well, I tried the sea foam and changed the fuel filer. I also checked the plastic sliders and the squiters on the top of the carbs. They are all working fine but I discovered that the PO removed the part of the air box that connects the air hose that comes up from the bottom of the bike to the front of the airbox. There is a 3x6 inch opening where that part would go. The clear plastic hose that connects to the bottom of the airbox (below the filter) is also pulled loose and I cant seem to get it reattached. Anyway, the bike is still running like a top in idle and accelerates great up to just short of half throttle and then any additional throttle slows the bike as it boggs down.

Any ideas?

Thanks,
Bambam

Seems you found the problem......!

bambam

Discussion Starter · #15 · Sep 8, 2009

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If it is the problem, can I just fabricate a chamber that connects the tube to the opening in the air box and do you think that would fix the problem. I was thinking that the bike would breathe even better with the big hole in the front of the box.

Bambam

circuitdoc

· #16 · Sep 8, 2009

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I had a 700 Nighthawk that had very simular symptoms with the airbox disconnected. I was in a hurry to see if my carb overhaul job was sucessful and didn't take the time to completely reassemble the plenum. Wouldn't run under load at much more then an idle. Turns out the carbs needed that intake restriction to open the sliders.

jdjenkins

· #17 · Sep 8, 2009

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said bike doesnt respond right at half throttle,first change fuel filter< 2 nd sync the carbs . if too much air is getting to them, at half throttle thebike will boog down. did my carbs before vacation and i had them adjusted too far out , had to performsync adjustment again even with gauges. you can get too much vacum readings from carbs. this forum does show you how its done. if it idles fine there isnt a problem inside carbs, i dont think so

bambam

Discussion Starter · #18 · Oct 2, 2009

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Well, I think I have figured out the problem. I initially took everyones advise and changed the fuel filter. I next ran some sea foam through the system and it didn't change anything. I checked the air filter and it was a K&N that was OK. I finally took it to the local bike shop for some advise. They checked the compression, timing, firing order, spark plugs, vacuum lines, sliders...

Well, they finally rebuilt the carbs and it still had the same problem. I did notice that the intake box was missing a horn on the front side so went do a local junk yard and got one for $20. Guess what happened...it fixed everything!!!

Who would have thought that the little square tube leading into the air box would make such a dramatic change!:doh:

Now I just have to pay for all of that shop time and I will be off on the road again.

Thanks for all the ideas and advise.

Bambam

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GreggC

· #19 · Oct 2, 2009

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Yep! Unreal isn't it. There is a purpose for everything I would guess. Isn't there a 'dash pot" vacuum line to that piece? It directs hot and cold airflow to carb intake.

I have to ask, how much did they charge you for the carb rebuild and the other stuff. I did my 93 last week and it was a bi*&$ to do but now runs great. The kits to rebuild cost me 265.00 with new aftermarket sliders. I would like to get into rebuilding them for Forum members at a cost but want to be fair.

wingman73

· #20 · Jun 24, 2010

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Hi Bambam,

I'm new to this site too and also have an '88 with what sounds like a similar problem to yours. Don't suppose you could point me in the direction of that horn' you fitted, or what was involved in fitting it. I'm asking because my airbox seems intact, but the owner's manual seems to show that there should be some sort of reed valve fitted towards the frontright of the air box.

Any pointers you might be able to give me would be greatly appreciated.

Apart from that, nice to make your acquaintance and enjoy the winging...

Regards,

John

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