GS 550 running away

[Nessism]

The problem is not the valves, it's either a vacuum leak or the throttle linkage is hanging up somewhere.

If you take the carbs back off and look at the throttle butterflys, they should almost completely close if you back off the throttle stop screw. If they don't close like this, something is wrong with the throttle linkage. When you hook up the throttle cable make sure the cable ends are fully seated and there is slack in the cable - free play as they say in the manual. If the butterflys are closed, the bike won't idle. If it does, you have a vacuum leak somewhere for sure.

How about pulling the carbs back off and taking some photos showing us those butterflys. Post the photos on photobucket and then link the img code here. We need to see how you have things set up. Regarding vacuum leaks, using starter fluid is an unreliable method. It's been proven countless times before. It's much better to literally trace the intake path and make sure everything is properly sealed. No gaps between the boots and the carbs. Airbox installed, filter installed, airbox lid installed. Airbox fully sealed with foam for the filter and lid.

 

[Steve]

I know that you said you "Carefully Bench synced the butterfly valves", but did you ever do a VACUUM SYNC? :-k

Even a "careful bench sync" is not perfect, it just gets you close enough to get the bike running to do the vacuum sync.

.

 

[gs550rebuildguy]

Valve update

Valve update

I have not had it vacuum synced yet
I had some spare time and checked the valves
Four are flush NO gap and the remaining are borderline .03
So...
Thursday I plan to take em all back to .08 when my tool arrives
If it still runs bad I may pull the head to see if the prev owner burned some valves.
I should not be having consistent backfiring on number two where its easy to tell as I have a clear vacuum line that lights up from the flames
I put my hands on the other carbs and felt pulsations on number three and number one but two is the worst and that one had very tight valve clearances so once there back in spec I will see how it runs
For the bench sync I used a small wire starting with number three like the book says
They all WILL close if I back off the idle screw enough so for the prelim I left them at the wire setting gap and set rpms from there but as we know there is no setting the rpms on this demon yet and the throttle cable is NOT binding nor is the choke.
The CV's play well together also.
My money is on valves right now...
Thoughts??

 

[tkent02]

Once the valves are all in spec vacuum synch the carburetors.
Even if you had already done it, valve adjustments change synchronization.

 

[gs550rebuildguy]

question

question

Do you agree valves get tighter since its manly seat wear not cam wear?
Funny how the book covers "adding" thicker shims in the examples...
Do you have an easy way/trick to find if they are burned??
My guess is that if the valves cant close that would explain how it is possible to idle with the plates closed as it would be getting air on the downstroke like a "systemized" crower cam does on a Camaro with deliberate over lap for better mixing.

 

[tkent02]

Do you agree valves get tighter since its manly seat wear not cam wear?

Usually, but not always.

Do you have an easy way/trick to find if they are burned??

Check the compression.

 

[gs550rebuildguy]

I did a compression check and posted that before

I did a compression check and posted that before

I now have to tool to release the shims
Not sure where topdead center is on my dyna ignition but will learn that and recheck valve clearance as I was doing it with the lobes straight up (Clymer method)
compression was left to right 120, 120, 130, 150
4 intake was zero mm
3 exhaust was zero mm
2 exhaust was zero mm
1 intake was zero mm
the rest were .03 mm
Goal= .08 when Im done
If the compression dose not get better the "beatings shall continue until moral improves" lol
seriously I may pull the heads then and see if the valves are burned

 

[gs550rebuildguy]

Idle screw removal

Idle screw removal

Part of the battle was I got a 1/16th inch cobalt drill for a pilot hole and a 5/64 final I bought a 5/32 with no glasses on at the hardware store so my ten torx bit was not gonna work but my 25 cranked er right out of there however it broke the head off so I had to drill a 1/16 hole in a 5/64 hole
So with 1/64 room left to drill see the attached file
Perhaps this contributed to my higher idle but the new screw went in ok and it did not suck any WD40 down the hole when running so back to valves more tonight
I'm pretty proud of the attached pic though lol

 

[tkent02]

Part of the battle was I got a 1/16th inch cobalt drill for a pilot hole and a 5/64 final I bought a 5/32 with no glasses on at the hardware store so my ten torx bit was not gonna work but my 25 cranked er right out of there however it broke the head off so I had to drill a 1/16 hole in a 5/64 hole
So with 1/64 room left to drill see the attached file
Perhaps this contributed to my higher idle but the new screw went in ok and it did not suck any WD40 down the hole when running so back to valves more tonight
I'm pretty proud of the attached pic though lol

Wow, an easy out actually got something out. First time for everything I guess.

Don't be in a hurry to pull the head. Set the valves, if the comp doesn't come up ride it 1,000 miles or so. Ride it hard. Then check again.

 

[gs550rebuildguy]

Chain support question

Chain support question

Ok so I took the valve cover off my spare replacement engine and under the cam chain is a bridge looking piece to support the chain and MY current engine does not have it...possible the 1981 gs550 "T" does not use one there or maybe that's what my issue has been all along??
I will consult the manual this evening but was pretty surprised.
It is part of the cam chain tensioner??
Ps getting my last shim tonight and then going ridin

 

[tkent02]

I just looked on a parts diagram, the 1980 550 engine had it, the 1981 did not.

Maybe they figured out it wasn't needed.

Enjoy the ride.

 

[gs550rebuildguy]

Multiple valve clearance methods

Multiple valve clearance methods

At long last musical shims is a done deal
Clymers is wrong saying do it on the heal pointing straight up in every instance
Top dead center methods are great if you dont have dyna ignition
So I opted for Basscliff
http://members.dslextreme.com/users/bikecliff/images/gs850valve_adjust.pdf

All are .08 and one is .06 gasket arrives tomorrow and next time I will order that reusable one from here 6000 miles from now.
I plan to ride to the dealer to vac sync the carbs as the tool there is $100 and cant reach my old neighbor who has it.
IF i cannot back the throttle all the way off and have the engine die now I will suspect the carbs are still not right even (soaked blown kitted poked out) with o rings all around incl intakes or not...stay tuned or get tuned right...

 

[Guest]

Do the intake pipes all look good ? Or is the rubber coating cracked where it covers the flange which bolts them to the head? could be leaking through them also. I have seen that alot .

 

[barnbiketom]

Do the intake pipes all look good ? Or is the rubber coating cracked where it covers the flange which bolts them to the head? could be leaking through them also. I have seen that alot .

+1 on intake pipes.. they will leak after running a bit.

 

[gs550rebuildguy]

Intake boots

Intake boots

Fisk at this point I want it to be leaking boots HA..

I agree with the idea the intake boots may be bad But I have had them off the bike twice and they a nice good looking rubber pliable and the PO had gooped them in the o ring area so I cleaned them and put in new o rings.
I have another engine and I know what you mean when they turn hard.
These are nothing like that.
If after the valve work this still does not check out I "may" goop them before I throw them away.
So far junked the pods bought the airbox and filter, kitted the carbs following to procedures on this site, new plugs, new dyna coils, o rings for carbs and intake, bench synced, verified cables for throttle and choke are perfect, new fuel and vac lines, tank is spotless and good fuel flow manually applying vacuum, all valves shimmed to .08 mm.... number two intake ha a .15 gap at first. Several others were at zero so the valve cover gasket comes tonight and gonna take a ride. I will say this.. if it is the boots.. visual inspection is not revealing anything.. nor did any leak testing with WD40 or starting fluid show a flaw. I think at this point I will consider getting new boots period ...due to unobservable anecdotal evidence and common sense.... not ready for the twelve gauge yet but the Ole Lady might be lol

 

[tkent02]

All are .08 and one is .06 gasket arrives tomorrow and next time I will order that reusable one from here 6000 miles from now.

The OEM gaskets can be reused many times. Grease it before installing, don't overtorque the bolts, they last a long time.

 

[gs550rebuildguy]

gasket

gasket

Do you mean the carb boots or the valve cover ones??
I could remove the carbs and grease the o rings
Have not heard that tip before...

 

[tkent02]

No, the paper valve cover gaskets. Probably get to use them 4-5 times before they leak.

Grease them every time so they don't stick and crumble when you take them off.

 

[gs550rebuildguy]

Well boyz

Well boyz

Took it out for a ride twice yesterday and still runs 4500 at idle
While it was cold it was great 1250 rpms and yes I can back it off until it dies on the idle set screw.
Let it warm up and back to the racing idle.
I will get the vacuum sync done and order boots if we cannot get this girl to settle down.
Its what the symptoms indicate but not the observable signs.
I agree I have a leak somewhere but not sure now of where to find it.
The Bike cruises good and really comes on at 4000 rpms.
Should I just buy the boots or is there a better way besides starting fluid WD40 or water to find a leak??
Id consider a smoke test
The valves really made a difference for running smooth though and a compression check will be done after I ride a little more but I have good hops for that...

 

[tkent02]

Once it's warmed up can you lower the idle with the idle speed screw or does it just stay up? Assuming you have vacuum synched the carbs, after it's hot and running faster is the synch the same or has it changed? Might tell you which cylinder has the leak. As a test you could slather the boots near the carburetors and in the O ring area with grease.

Should stop up any leaks at least for a little while.