78 gs1000e

[R Six]

Hello, I am new to the GS forum, have had numerous GS bikes, 550E, 850G, 1000E & G
I am looking to redo the top end on a 78 GS1000E
OEM or aftermarket pistons and rings? supplier
Imm over? etc,
Have not pulled it apart yet, rest of the bike is in very good order
Do not want to do a big bore kit ie Wiesco(redid a XS1100 last year)
The compression is at 75psi per hole and after putting oil in the cylinder the compression did not change much so I presume the valves need doing as well, the valve clearance is very tight .0015" on #1 & 4(both IN & EX) less than that on cylinders 2 & 4...way too tight
Mileage? shows 111,200 KM (70,000miles) bike is great shape, paint and seat like new, so I am not sure of the real mileage
Any ideas?
R6

[rustybronco]

Adjust the valve clearances and retest the compression.

edit...

then if the compression numbers are still low, make up or by something like this -> http://thegsresources.com/_forum/sho...62&postcount=1 and check the engine for leak down.

[R Six]

I have an original cycleserve manual from 1978 $5.98 Woodwards in Canada at that time actually sold Suzuki MC
Manual show both IN & Ex at .001-.003" .03-.08mm....seems too tight to me
Any thoughts ?

R6

[rustybronco]

.03~.08 mm is the correct clearance between shim and cam.

[Suzuki mad]

See Rusty Bronco's post above.....

[R Six]

Rusty Bronco, my typing skills are challenged at best, could I contact you by phone....am I breaking any Forum rules here?

[Ghostgs1]

Hi R6, I think they are on the right track. Your clearances do sound tight and very well may be causing low compression. Hang in there. Ray

[Suzuki mad]

R Six, how are you doing you compression test? Engine cold and throttle fully opened?

Once you have the correct valve setting you should get a true reading than with tight valves that you currently have.

[R Six]

Yes the engine was cold and throttle fully open
I know the compression is off as the motor takes a while to get back to idle after reving the engine ie wacking it wide open
I have a good compression tester the same as the model in the leak down example

[rustybronco]

No you're not breaking any rules by calling me. unfortunately I'm at work can't take phone calls and don't own a cel phone. now tomorrow, when I'm the only one here that's a different matter!

edit...

if you can attach a regulated air supply to your testers hose, put the engine at exactly TDC for the cylinder you are checking, then you can listen for air leakage out the exhaust valve, intake valve or into the crankcase. that's a good way to 'rough guesstimate' the leakage.

[R Six]

I live in Aldergove BC, Canada
My email address is r6qc@shaw.ca
if you send me your number I will call

thanks again for your help

R6

[rustybronco]

What's local time to you right now?

[Suzuki mad]

Do you have access to a bucket depressor, thin pliers to pull the shims, a micrometer to measure the shims and a pad a paper to write all the info down?

Start as per the manual for checking the clearances, write down each clearance to which valve and cylinder then remove the shim, flip it over. Micrometer the shim for size and write down its value marked on the bottom of the shim.

Once you done the whole engine you change the shims in each valve to give you between the two tollerances preferably near the 0.8 than the 0.3. The run another compression test.

That done, depending on results you can start to strip here down to identify the loss of compression. I think service limit is 125 and you need to be with 10 on all 4 cylinders from memory (sorry no manual to hand presently.)

With the head off do a fuel leak test with the cylinder head upside down and pour fuel into the depressions. If fuel leaks away then its valves.

You can also check the wear on the pistons and bores, it may just need a new set of rings.

Hope that help, but suspect that your more of a mechanic than I give you credit for if you've done an XS1100.

[rustybronco]

Never mind. I see you're -3 hours off local time where I'm at.

If you need to call me, call after 8am your local time.

[R Six]

Wow, that's all I have to say with all the help and info you have provided and yes I know my way around a wrench.....I think
I have decided to pull the top end off,pull the valves, check the seats hand lap them in for fun, new valve guide seals, hopefully just a quick hone, rering it and put her back together
I don't have a selection of shims, or a valve depressor, have a local mechanic who works from his home shop at less then 1/2 the shop rate
Where is a good web site for rings....oem or after market
I can buy a complete gasket set from Parts n More with valve guide seals for $100
Still woud like to chat

R6