TWO Broken Rocker Arms. GS700E.

[duaneage]

I work on massive large IT projects and your project plan for this was executed beautifully. Even seasoned pros forget things, you won't with a list like that.

 

[kirkn]

Chugging along slowly. Lately, doing the valve lapping.

At the beginning, most of the valves weeped immediately when the ports were filled with acetone. Something like 13 of 16.

I cleaned up the combustion chambers using a brass wire brush and some solvent.

Popped the valve keepers loose with my favorite trick of a smart rap on a socket. Pops 'em right out.

Routine valve lapping. Here, I'm doing the intake valve at the lower left of the chamber. The other 3 valves have been done.

 

[kirkn]

Next, the valves, springs, etc. get reassembled using my high-tech C-clamp and PVC-pipe compressor and keeper installation tool. I have a small wooden dowel glued to the C-clamp to keep from damaging the valve or combustion chamber. Takes about 1 minute per valve.

I fill the ports with acetone and check for leaks. Acetone is very thin and finds leaks right away.

Which, unfortunately, it looks like I still have...

The valve on the right is much better, but the valve on the left is moist after a few minutes. You can see a few drips trickling down to the intake port...

So, I popped the valves backed out and lapped 'em a little more. They looked good the first time, with a nice uniform line of gray, but there you go. The second time, there was no weeping after 5 ~ 7 minutes.

So, at this point, I've only done the one cylinder yesterday evening. I'll keep chugging along, and the head will then be ready to go back on.

Kirk

 

[Guest]

Even if you leak a little they will seat in a matter of seconds running.

 

[rapidray]

What Bill said! Ray.

 

[kirkn]

Well, I really appreciate the feedback.

I've read that before, but I've only lapped valves in 3 or 4 motors, and they held fluid the first time, so I don't have any personal experience enough to say - oh, that bit of fluid will seal up. But I DO have experience with intake valves leaking back thru...

I just couldn't bring myself to make that call.

But, based on your input, I suspect I will next time. Not that I'm gonna TRY to get 'em to leak y'know, but next time I might not go to the disassembly / reassembly effort.

Thanks again.

Kirk

 

[Guest]

This is a great thread to read... I was getting the itch to get at my scooter but we got 2 feet of snow last week. The shed might as well be in Alaska.. I wish I was as organized as you have been... I look forward to the startup of your engine...
Curt

 

[rvnkvn]

Kirkin, I'm about to do the same on my GS750/700 bike. I have #2 rod stuck a Top dead center and #3 just about as stubborn.I feel a little more confident to try and take on this job because of you work here! Thanks , and nicely done!

 

[kirkn]

...and after only 4 months of neglect, and a YEAR after first pulling the head, I'm back on the job!

I finished up the valve lapping - all 16 are leak-free now. Woo Hoo.

Got the head put on and torqued with nice new copper sealing washers and new head gasket.

Then, following the book, got the cams back in and set correctly to the marks on the cam sprockets and the ignition timing mark.

Lesson learned: at this point, without the automatic tensioner, if you rotate the crank, all will move well until a point when there's slop on the backside of the cam chain. The intake cam will move forward under the load of valve springs, and the chain will jump a tooth!! AARGHH!!

I got lucky in that there was enough slop to allow the intake cam to be rotated back one tooth and reset the "20 link pins" relationship without having to pull the intake cam back out! Whew - dodged a bullet.


So, I refurb'd the tensioner, which basically amounted to a clean and lube and it was ready to go back in.

Now, all works sweetly, and notice that nice taut cam chain across the top of the two sprockets.

New-used rocker arms replaced the two that broke, and it looks like we'll be back in business. Everything turned nice and freely.

Next is set the valve clearances and I'll be ready to button 'er back up.

Then carbs overhaul, which I hope will be a "routine" disassemble, clean, reassemble-with-new-rubber-bits.

Gettin' closer, and I'm smelling the finish line!

Kirk

 

[kirkn]

And... DONE!

Well, I got the valve cover and new cover O-ring back on successfully.

Then, the carbs had been sitting for a year in MY garage and a year in the PO's before that, so they got the full disassembly, clean and reassemble with new O-rings, etc. Not really that bad. I think he must've drained out the gas before letting 'em sit.

The only unusual bit was a "broken" main jet. Weird. See the thread about that here: http://www.thegsresources.com/_forum/showthread.php?t=178229

So, I got a new jet from Jetsrus.com, and finished up the carbs, which went back on the bike.

And that was it!

Hooked up my IV-type temp fuel source and it fired right up! Woo Hoo!! Tweaked the idle and all seemed good.

So, this past weekend, I put about 150 miles on it, and it seems to be running just great. Filled the tank and got 42.5 mpg for that first tank.

So, overall, I've got about $900 in the complete deal. Not too bad, sez I.

Next up will be tweaking the idle mixture screws, although it seems pretty crisp at the bench setting of 2.5 turns out. Then, I'll do a carb sync with the Carbtune. I did a bench sync as best I could, but that'll be the topper.

Then, I need to source some mirrors and blinkers, and it'll be fully back in business.


And what a nice ride! And strong! It's been a while since I've been on a bike this strong, and it's only a 700. My past half-dozen rides, going back 5 or 6 years have all been ~500cc or less.

So, that's all, folks!

Kirk

 

[blackvolcom]

I know it's been about 8 years since you finished this project but I couldn't find any information as to how to position the cams in time. I know you mentioned a book that told you how to align the cams with the timing mark but I can't see to find anything. If anyone could help that would be great. Thank you

 

[Guest]

wow, this is a deep necro, maybe start a new thread? i dunno....

 

[Nessism]

I know it's been about 8 years since you finished this project but I couldn't find any information as to how to position the cams in time. I know you mentioned a book that told you how to align the cams with the timing mark but I can't see to find anything. If anyone could help that would be great. Thank you

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