TWO Broken Rocker Arms. GS700E.

[chef1366]

See if the rotor turns on the other side of the crank.
Sounds like a broken crank.

[posplayr]

See if the rotor turns on the other side of the crank.
Sounds like a broken crank.

put straw into the plug holes to see if they move

[kirkn]

All four pistons are moving up and down. No worries there.

Got the intake cam out. Cam chain is broken. That end of the chain lifted right out. Still have to remove the exhaust cam. Chain is still engaged with the exhaust cam sprocket.

Oddly, the cam chain tensioner still looks good, at least what I can see of it. It pivots forward and back but I didn't try to pull it out.


I've been reading that crankshaft has to be lifted out to replace the cam chain. Is that strictly true, or can a 'split' chain be fed in and a master link used?

[jwhelan65]

That's all I could come up with - piston stuck, cam tries to open valves into stationary piston and valves bend / rocker breaks. Repeat for other rocker.

Otherwise, a piston smacking a valve usually just bends the valve and/or breaks the piston, not breaking the rocker.

We'll see...

Related to this - upon disassembly, how loose should the cam chain be? That is, during this effort, I was able to rotate the intake cam a bit and you can see the slack that developed across the top of the two cam sprockets. This doesn't seem normal to me, but I didn't do any further investigating yet. Actually, it wasn't until I was reviewing the photos that I noticed it and got to thinking....

Not sure if this helps but here is a shot of my 700es with the valve cover off your looks extremely loose.

[chef1366]

Well you have to split the cases now to replace the cam chain so now you'll get to see everything right and wrong with it.

[Billy Ricks]

A few people here have done split chains and I've never seen any reports of catastrophic failure from them.

[Nessism]

Broken rockers means the valves hit the pistons and a broken cam chain means there could be all kinds of various damage lurking. Sounds like you are wasting time when you should be pulling the head off at minimum and splitting the cases if you want to do the job right.

[kirkn]

Well, I haven't WASTED any time at all yet because every step I've done so far would've been required anyway.

This bike was completely new to me with an unknown problem described by the PO.

I've pulled the head cover to have a look and found the broken rockers.

I pulled the carbs to remove the auto cam tensioner.

I pulled the intake cam and found the broken cam chain.

In your opinion, how SHOULD I have proceeded?

My next steps will indeed be to pull the head and cylinder block. If I do pull the engine and split the cases, this would be necessary and I'd rather do all this with the motor in the frame so the semi-stripped engine will be easier to lift out...

[Nessism]

Okay, maybe "wasting time" was not the best choice of words on my part. Sorry to have offended. What I should have said is to just get busy pulling the head and cylinder at this point. You can replace the cam chain without splitting the cases; you will have to peen over the pins when you join the chain together. Just make sure to do a very careful inspection of the engine and surrounding parts because broken cam chains tend to cause all kinds of destruction.

[kirkn]

No harm, no foul!

Yep, that's today's plan - pull the head and cylinder and have a look down in there. Right after I cut the grass, and help my daughter's dance team car wash...


How do you remove the chain tensioner blade? The front one (exhaust side) seems to just lift out. Is it the same for the rear one?

Thanks,

Kirk

[Nessism]

I've never worked on that particular type of GS engine but typically the front one pulls straight up and out, rear is attached at the bottom so you need to pull the cylinder to gain access.

[Big Jay]

A few people here have done split chains and I've never seen any reports of catastrophic failure from them.

That might be what we are looking at here.

[blowerbike]

WOW
some more rock solid advice
i will be an observer on this thread and possible catastrophe.
split the cases and do it right or pick up a used engine for 100-400 bucks.

[Nessism]

WOW
some more rock solid advice
i will be an observer on this thread and possible catastrophe.
split the cases and do it right or pick up a used engine for 100-400 bucks.

Instead of jeering from the cheap seats, please bestow upon us heathen what thy would do and why the course of action suggested so far deserves the .

[blowerbike]

Instead of jeering from the cheap seats, please bestow upon us heathen what thy would do and why the course of action suggested so far deserves the .

i said everything in my post.
i have nothing more to add.