Twisted my crank?

[jjnorc]

1981 GS1100EX

Maybe someone can help.

Tried to start the bike yesterday. I noticed gas dripping from the airbox
and the fuel petcock set to prime (damm kids). I figured I had a leakey
float in one of the carbs.

I turned the key and hit the starter, WHAM THUMP.

Turned out the #4 cyl was full of gas. I pulled the plugs and cleared out
the gas. Started the bike and it was running very rough with alot of vibration. Pulled off the valve cover and noticed the cam timing had jumped ahead 1 tooth on the cam sprockets. I fixed the cam timing and
tried running it again. Ran better this time but there was alot of vibration.
Somethings out of whack.

I figure #3 cyl fired and tried to compress the gas in #4.
Could this be enough to twist the crank? I have a pressed Crank.

Coils and Carbs are perfect so I know it's not spark or fuel delivery.
Put new plugs it before trying to run.

:? NEED SOME HELP.

I'm going to pull the head to look at the cylinders to see if the pistons
are in sync today. (matching TDC mark on crank end).

If it's off, Does anyone know where I can get a welded crank?

Was going to Americade in Lake George in June so I have to fix it quick.

jjnorc@adaptivedata.com
(856) 982-1192

[Detman101]

First, I'd get to tearing up some kid-ass.
I can't offer much on the crank problem.
I pray that you didn't ruin the engine.


Dm of mD

[Don Lobacz]

You can easily check to see if #1 and #4 are coming to TDC at the same time by using the spark plug holes. #4 will still be matched to the timing mark, so it will be #1 that is off. It is also possible that you bent a valve either from hydraulic lockup or when the timing jumped. I would do a compression check.

[jjnorc]

I'll try to measure TDC on #1 & #4. I think I have a small Tape measure
that will fit.

Compression is Ok and the cams were only 1 tooth off so the valves
should be good. I didn't hear anything break in the motor. When #2
fired the motor stopped before it went 360.

I called Falicon Crankshaft just in case.

[HiSPL]

Buy a crank on ebay and send it to Falicon. Then you'll have time to tear down, clean, and inspect everything from the bottom up. Good luck, and I hope its something simple.....

[SqDancerLynn1]

If you did have a welded crank you would probably have bent rods or worst a broken piston

[jjnorc]

Twisted Crank Update

Well I measured the piston height at TDC and #4 is about
2 degrees off. So the engine is appart and out of the bike.

Does anyone know the best way to split the case? I got everything
off the bike and unbolted the case. By that time it was time to go
to bed. I'm going to split the case after work today.

Any suggestions would be appreciated.

I'm taking pictures of this project if anyone is intrested.

[Hap Call]

Re: Twisted Crank Update

Does anyone know the best way to split the case? I got everything
off the bike and unbolted the case. By that time it was time to go
to bed. I'm going to split the case after work today.

There are a couple of bolts that you need to insure are out...they are often overlooked when splitting the cases. They are under the oil pan and a couple of small ones on top, behind the cylinders.

Use a rubber mallet and start wacking it to seperate the cases. NEVER use a steel wedge or screwdriver to seperate the case halves...if you feel that is necessary then you probably still have a bolt in somewhere.

Drink half a beer before starting then drink 3 more once you have the case split.

Hap

[jjnorc]

Rubber Hammer, OK. Was going to do that.

I got all the bolts, Have a Clymers with them all mapped out.
Even got the cluch roller bearing and plates screws out.

When I put it all back together, is Permatex what should be used
to re-seal the case?

I like the Beer Idea, I have a six pack of Bass and Guiness
just for this project. I may need to get more.

[Hap Call]

YamaBond 4 is a favorite here, I used it on the last rebuild. I've also used Gasgacinch with good results.

Hap

[jjnorc]

YamaBond 4 is a favorite here, I used it on the last rebuild. I've also used Gasgacinch with good results.

Hap

Thanks, I'll give it a try.

[jjnorc]

Got the Crank out and everything else looks ok.
Gonna send it out to get straightened at Falicon
today.

Does anyone know who stocks Gaskets, seals, rings etc.
I was going to go to the local dealer but they take too
long to get parts in.

[dgeorge]

try here https://www.partsnmoreonline.com/PNM...e%20Parts.html I bought one to redo the top end of my gs1100gk seem to be good quality and a good price.

[jjnorc]

Great,thanks.

[cbxchris]

Pay close attention to your bearings on your tranny when reassembling. There are many locating pins there. Good time for a new timing chain if you got the extra cash.