1981 gl1100 Shutter and shake low rpm high gear

[ChopSocky]

Hi guys. My bike has a bad shutter or shake while at the low end of 3-5 gears. It rarely does it on take off or gears 1-2. It's the worse if the engine gets "bogged down" at all in higher gears. Like just after switching gears. Along with the shake and shutter it has almost a box of rocks sound. If you ease threw it, it will pass, but just comes back after the RPM's gets lower again. My bike runs absolutely great other then this. I am engine stupid, so I'm sure I will have to take it to a mechanic, but is there anything I can try before I shell out lots of money?
Thanks for the info guys.

 

[slabghost]

Get your own tools and the guys here will walk you through whatever repairs you attempt. It might take a bit longer but it's a lot more satisfying and cheaper. Sounds to me like carbs are either dirty or out of adjustment or both. Try the easy stuff first. Add 8 oz of atf to a full tank of fuel and ride it. Add 6 oz at every fill up from near empty thereafter. I think you'll find it steadily improves.

 

[ChopSocky]

Add automatic transmission fluid to the gas? Lol that sounds dangerous, but I will defiantly give it a try starting tomorrow.

 

[slabghost]

No danger to it at all. Tranny fluid is just a very light oil with a lot of cleaners in it. The bike may smoke a little at start up but it clears when warmed. I haven't run a single tank of fuel in my 1200 without atf. It also doesn't require a single wrench.

 

[ChopSocky]

Sounds good to me.

 

[Ansimp]

Also make sure that you aren't letting it get too low in the rev range, the Rats Nest does something similar if I lug the engine instead of reving it.

 

[ChopSocky]

I am considering selling it, but the last guy that came for a test ride didn't like the feeling. It scared him, he didn't want clutch or transmition issues. Now that I may have decided to keep it, I want it fixed.

 

[zman]

May have 2 different issues, If you not shaking in 1-2 it may be because your speed is lower then in gear 3-5..Put it on the center stand and check the swingarm bearing and U joint for play, check the wheel play too.

 

[slabghost]

You'll be happy you kept it once we get a few issues fixed.

 

[ChopSocky]

Here's a pic of the beauty

 

[slabghost]

Oh that is a sweet looking bike!

 

[Ansimp]

slabghost » Fri Aug 01, 2014 10:03 am[/url]":k1ik5ywb]
Oh that is a sweet looking bike!

+1 :good:

 

[Steve83]

That is a nice bike - definitely worth putting a little wrenching effort into. These engines, with stock ignition, don't like low RPM's under a load. Under the #3 carburetor (right rear as you sit on the bike) is a small rubber hose that goes to the rear center of the engine. It's the vacuum advance hose. Pull it off the carb and suck on it, listening for movement at the other end. If air flows and nothing happens, the advance diaphragm is leaking, or the hose is leaking or disconnected. If no air flows and nothing happens, the ignition advance plate is stuck. If no air flows and there's a mechanical sound, it should be OK. Leave the hose off, start the engine, and increase the RPM's slightly. You should be able to feel vacuum at the carb fitting with a finger.

Carbs and ignition are the major issues when dealing with performance problems. They are 30+ years old and still kicking, but far from modern technology.

+1 on all previous advice as well!

 

[OldWrench]

I was just thinking, now I know that is dangerous but here goes. It runs fine in 1 & 2 but gets vibration in the higher gears. I'm thinking transmission bearings or the dampener. I know that is not a pleasant thought, and I hope I'm wrong. I would think if it were an engine or drive train issue it would happen in the lower gears as well.
I would get it on the center stand and start it up, put it in third gear, and let it run at a fast idle. I would get a cheap automotive stethoscope and listen for abnormal noises.

 

[joedrum]

id say its just poor running motor yet ....carbs are screwed i bet at low rpm...... mixed with poor ignition spark

 

[shierh]

Primary Chain Rattle caused by uneven combustion among the 4 cylinders. Shock wave caused by unevenness causes the rattle.
Carburators need to be synched and possibly cleaned or overhauled. Run MMO in the Gas or ATF as others have said. Also switch to NON Ethanol Gas, you will be amazed. Change oil to Rotella 15/40 if not already done so. Check plugs, replace them. Rule out vacuum advance issues as recommended. DO ALL of these not just one. ie if you find bad plugs do not stop there, go through the whole thing. Likely find multiple issues, its always that way with mechanical stuff.

 

[Ansimp]

+1 :builder: :good:

 

[ChopSocky]

Been so busy with work I haven't had a chance to try any of these yet. But will try them all soon.