Hesitation in the 3000-4500 rpm range. What to do?

[Anonymous]

I just drove my '82 GS850G home last night from Muscatine, IA to Chicago. Everything is pretty sound except for two things.

1. There is a horrible hesitation in the 3k - 4.5k range.

There are a number of factors that could cause this, but I believe it is that the bike has been given aftermarket exhaust without being rejetted. It could be 20 year-old fuel gummed up in the carbs, I suppose, but I'm no expert on this. I just remember reading that if a full exhaust system is put on a bike other than factory, it should be rejetted accordingly.

If the bike does need new jets, how do I know which ones to get?

2. The windshield on the Vetter Windjammer fairing is cloudy with scratches. How do I buff this out? Can someone tell me a good product that is easy to find and not too pricey? (I've heard toothpaste can work, but maybe there's something better?)

I will try the toothpaste while I await responses.

Any thoughts from people who've been here before?

Thanks!

P.S. - FWIW, I'm pretty quick at figuring things out mechanically, but I don't really have any experience working on motorcycles. Am I better off getting a quote and having a factory mechanic work on it?[/list]

 

[jlmoulto]

I just fixed the same problem on my machine and it turned out that it needed a carb sync and the idle screw'air mixture screw adjusted. Based on the info I was given, the idle screw should be around 1 1/2 turns and the air mixture screws around 2 turns. THe guys that know carbs might give other advice.

Someone also posted info on creating your own carb sync tool and I made it and synced the carbs with it as I could not get a proper tool in a reasonable amount of time.

 

[AOD]

i had a rough running problem from 4500-6000...i cleaned the carbs and it smoothed things out. i suggest you do the same before you try to fix or read into it more.

~Adam

 

[Anonymous]

Thanks for the replies fellas. I think I might just buy a carb rebuild kit and tackle the cleaning part myself. If that doesn't fix it, I may search for the plan for the home-brew carb sync tool and give that a go.

Otherwise, I found a local mechanic who will do the whole works for around $200.

I've been told that when you disassemble carbs on old bikes, the gaskets can go to dust quite easily. Any experience with this?

Jeremy

 

[KEITH KRAUSE]

The bowl gaskets usually are stuck and removing them usually damages them. They must be removed to correctly adjust the float height.
A good carb clean and sinc is what you need to do first.
If your pipe is the only mod' and it is a free flow design, then a main jet increase of one full size (5) will probably work. I don't believe the needle circuit or pilot circuit would need changes. Maybe an additional 1/4 turn or so out on the mixture screws. Your 3-4.5K hesitation is most likely a lean problem caused by dirty jets and/or the carbs needing a good sinc.

 

[Anonymous]

Re: Hesitation in the 3000-4500 rpm range. What to do?

I just drove my '82 GS850G home last night from Muscatine, IA to Chicago. Everything is pretty sound except for two things.

1. There is a horrible hesitation in the 3k - 4.5k range.

There are a number of factors that could cause this, but I believe it is that the bike has been given aftermarket exhaust without being rejetted. It could be 20 year-old fuel gummed up in the carbs, I suppose, but I'm no expert on this. I just remember reading that if a full exhaust system is put on a bike other than factory, it should be rejetted accordingly.

If the bike does need new jets, how do I know which ones to get?

2. The windshield on the Vetter Windjammer fairing is cloudy with scratches. How do I buff this out? Can someone tell me a good product that is easy to find and not too pricey? (I've heard toothpaste can work, but maybe there's something better?)

I will try the toothpaste while I await responses.

Any thoughts from people who've been here before?

Thanks!

P.S. - FWIW, I'm pretty quick at figuring things out mechanically, but I don't really have any experience working on motorcycles. Am I better off getting a quote and having a factory mechanic work on it?[/list]

Sounds like my situation 1 year ago. 1980GS850G. Ebay bike. I found leaking boots on carb & airbox, new air filter was badly needed. Plugs and plug caps. Adjusted valve clearance, syn carbs. Still had a little hesitation in the 4-5K range. I was, and still am afraid to tear apart the carbs. So I just put up with it. I also had a problem with the bike idling fast when it was real warm. After winter storage the bike started to run better. Fast idle pretty much is gone as well as the hesitation. Maybe it was the seafoam that I put into the gas for storage, or just running it cleared the crap out of the carbs, if that was the problem? Do you had a maintenance history on the bike? Both of my GS's were in need of valve adjustment. The one had rusty bolts on the valve covers and I actually broke one. That was not fun! I own 2 GS's, one to work on and one to ride. I don't like being hurried when I work on something and I do not want to be with out a bike. Presently I trust my GS's to take me anywhere. I would ride it first off. Also order some tools and a valve gasket. Hopefully a local dealer will have shims for you when you do your valve adjustments.

 

[Anonymous]

Re: Hesitation in the 3000-4500 rpm range. What to do?

I just drove my '82 GS850G home last night from Muscatine, IA to Chicago. Everything is pretty sound except for two things.

1. There is a horrible hesitation in the 3k - 4.5k range.

There are a number of factors that could cause this, but I believe it is that the bike has been given aftermarket exhaust without being rejetted. It could be 20 year-old fuel gummed up in the carbs, I suppose, but I'm no expert on this. I just remember reading that if a full exhaust system is put on a bike other than factory, it should be rejetted accordingly.

If the bike does need new jets, how do I know which ones to get?

2. The windshield on the Vetter Windjammer fairing is cloudy with scratches. How do I buff this out? Can someone tell me a good product that is easy to find and not too pricey? (I've heard toothpaste can work, but maybe there's something better?)

I will try the toothpaste while I await responses.

Any thoughts from people who've been here before?

Thanks!

P.S. - FWIW, I'm pretty quick at figuring things out mechanically, but I don't really have any experience working on motorcycles. Am I better off getting a quote and having a factory mechanic work on it?[/list]

More stuff I forgot to add from this morning. You will find quite a few posts regarding bad experiences at the dealerships. I think your best bet is to do it your self. I would consider a shop if you really don't want to gave it a try and someone you can trust recommends the shop. Maybe someone in the Windy city could gave you info on a good shop. JC Whitney sells the windjammer windshields. I seen them in their catalog listed under Gold Wing windshields and accessories. www.jcw.com/goldwing. You also need a manual. I think quite often just running a bike will improve it's performance. There are lots of little things that could cause problems with these old bikes. This web site helped me out a lot. Problems I've seen: rust inside of gas tanks, bad spark plug caps, cracked carb & airbox boots, bad & broken electrial connections, batteries that won't hold a charge. You can use the search feature to find good info. I never "messed with my carbs. I understand that there is charts for jetting various bikes. Sounds like trial & error unless you have expensive equipment. As long as my bike runs fine I will not touch the carbs. I use non oxgenized gas and put sea foam it it at the end of the season. I also try to ride my bike at least once a week (normally not a problem). Seems like the more you ride them the better they run.