Starter clutch woes, what'd I do wrong?

[midnightspeeder]

Hows's it going? I have a problem i've researched extensively, on this website's forums and offline as well. I have a 1985 GS1150 and for 30k miles everything was peachy. Until my first starter clutch bit the dust. I figured, no problem, things happen and i'm sure it's not a maintenance-free item. I put the new one on and 200 miles later it starts rattling and shortly after lets go. On inspection the 3 clutch bolts sheared off. Previously I just installed a repair kit which was new pins/springs/rollers. So this time I replaced everything attached to the crankshaft. (generator rotor, new springs/rollers/pins, new starter clutch, new bearing and sealing washer, and the sprocket the clutch rides on.) It did the same thing all over again. 200 miles and it starts rattling, and then breaks.

So after plenty of research and hair-pulling, I realized that those 3 bolts need to be loctited and are very sensitive to proper torque specs. So I gave the entire job another re-do. But this time, I used upgraded 12.9 bolts and loctited everything that needs loctite and torqued every single bolt to spec. I put roughly 100 or so miles on it and it's doing the same familiar rattling again and i'm sure it'll let go.


Is there something i'm overlooking or doing wrong? What the heck. I've asked a few local shops and suzuki dealerships and they all told me that I followed the service manual with military precision and they're as stumped as I am. They did say to check for a leaking petcock but mine's fine. They were also concerned that my crankshaft is possibly warped and out of round/balance but that would cause the engine to run poorly. Besides the rattle of death, it runs like a dream. An ideas to keep me from rage-selling it and buying something new?

 

[posplayr]

The clutches are robust but are typically subjected to high forces when the engines kickback during starting. The kick back primarily occurs when the engine is cranking slowly and the cylinder charge ignites BTC and the engine rotation is literally reversed.
This makes the clutches are very sensitive the the condition of your electrical system. You have not mentioned doing any engine modifications so i assume your bike is stock, but big blocks, high compression and engine advance all exacerbate the problems.

If the engine is cranking slowly (weak starter, low battery) or if the bike is just slow to start and requires a lot of cranking.

There are various fixes to help the problems: (Thank Rapid Ray for the original implementation)

1) Wirte your kill switch so you can crank the engine up to speed before you allow the coils to be energized.


https://www.thegsresources.com/_forum/showthread.php?123877-How-to-avoid-Starter-Clutch-Disaster-Modification&highlight=clutch

2.) Modify the ignition plat to allow manual retard of timing.

https://www.theflyingbanana.com/starterclutch.htm

3.) Get a Dyna 2000/4000 (the 4000 for sure possibly the 2000) that provides ignition retard at startup.

http://www.dynaonline.com/products/drag-racing/dyna-4000.aspx

https://www.z1enterprises.com/dyna-2000-w-coils-ddk3-2c-gs550-750-850-1000-1100.html


Generally ypur bike will start faster with good voltage to the coils. Many have done the Coil relay mods to improve starting.

My GS1100ED with 1166 wisco went to an instant start with good voltage. 10.5V at the coil is enough to make startying difficult.

 

[midnightspeeder]

I'll do a little poking around on that, but I keep my battery nice n healthy and it's always started up instantly.

 

[Steve]

Sounds like you have some vibration going on there. A couple of things to check would include valve adjustment and carb sync.

If those are good, consider a worst-possible case scenario. I worked on a 1000 that had a vibration we just could NOT tune out. I pulled the spark plugs, put a soda straw into #4 and found Top Dead Center (TDC). I moved the straw to #1 and found that it had a different TDC. Evidence of a twisted crank.

.

 

[midnightspeeder]

Last winter I went a little maintenance-happy out of boredom, so it can't be the valves or carb sync because I got those down perfectly. I'll see what I can do to check out the crankshaft more closely.

 

[posplayr]

The 1150 has a welded crank do it is highly unlikely your crank is twisted.

 

[GregT]

Put a timing light on the ignition and check the baseline advance figure. Given your history I'd be tempted to actually check out the backplate marks with a degree wheel. What you've posted smacks of an over-advanced ignition - or if it's got an aftermarket ignition fitted, too steep an advance curve.

 

[midnightspeeder]

That's actually a really good idea, dunno why I didn't check it. I thought the stock electronic advance units were non adjustable though. I'll shine the light on it and see what I got. Off the top of my head its 33 degrees BTDC at idle right?

 

[tom203]

Let's hope not....look for 10 btdc at idle, heading to about 40 by 4000rpms

 

[midnightspeeder]

If it isn't, how do I set it? Or since it's electronic is it a simple pull and replace?

 

[midnightspeeder]

Arg nevermind that last post. No need to set it because the timing light says it's perfectly in spec.

 

[midnightspeeder]

So long story short, I might possibly have it solved.

I just got done with an hour long ride through the backroads at 3am. Very aggressive, daring something to break. The rattle never got any better or worse but the bike runs like an absolute dream with all the work I've done to it these past few days. I think what happened is I misinterpreted the rattle I'm hearing now as the starter clutch, when now the noise seems to have moved to the clutch side of the engine.

If it's just old clutches rattling away, then I'm happy as can be . If I'm mistaken and the starter clutch goes out again I'm going to throw a full-bored two-year-old-style temper tantrum. Complete with kicking feet and screaming.

I'll keep this post updated with the results, and thanks for the help/knowledge so far.

 

[Carter Turk]

Did your starter clutch have the dowel in back of rotor?
It takes some stress off the 3 bolts, but I've had loose bolts even with the dowel in place.

Maybe an APE clutch nut for the other side might be worthwhile, then pulling hub to examine the backing springs on the clutch hub for slop.
It could be a loose stock clutch nut, where the threads have stretched.

 

[midnightspeeder]

Yeah I installed the dowel. I'll have to check out the clutch stuff next weekend.