GS 850 Rebuild

[busak5]

Hi

This is my first post to the forum so hello to one and all.

Im currently rebuilding a GS880-GZ (my first rebuild), and have run into a bit of a puzzler. Before replacing the cylinder block, the haynes manual states to be sure to replace the o-rings in the reccesses where the rear outer studs are. There are 2 oval shaped o-rings that fit these reccess's - no problem there. But the parts manual also shows another o-ring this time smaller and circular. The parts manual doesnt really give a good idea of where these 2 smaller circular o-rings should go. The haynes manual doesnt mention them specifically.
I know when i stripped the engine i removed these o-rings but i cannot remember if they go to the rear or front outer stud reccesses in the crank case, and like an idiot i didnt take any photos of where they came from originally.

Strangely the smaller replacement circular o-rings suzuki sent to me dont even seem to fit in the reccesses. Are these redundant on my model? I cant seem to see what purpose they serve. I think they sit around the base of the rear cylinder studs in the reccess, but there is no oil way there or anything.??

Does anyone have an idea of where these 2 smaller o-rings should go and what they are for? Any help would be very much appreciated.

My second question concerns piston ring end gaps. I have purchased new piston ring and wondered if i needed to check the end gap before installing them or should they be ok to fit right out the packet. Sorry if this seems a stupid question, but this is my first rebuild. My haynes manual doesnt seem to say to check them when putting the engine back together.

Any help or tips would be greatly appreciated.

Many thanks.
Clive

[49er]

Hi

This is my first post to the forum so hello to one and all.

Im currently rebuilding a GS880-GZ (my first rebuild), and have run into a bit of a puzzler. Before replacing the cylinder block, the haynes manual states to be sure to replace the o-rings in the reccesses where the rear outer studs are. There are 2 oval shaped o-rings that fit these reccess's - no problem there. But the parts manual also shows another o-ring this time smaller and circular. The parts manual doesnt really give a good idea of where these 2 smaller circular o-rings should go. The haynes manual doesnt mention them specifically.
I know when i stripped the engine i removed these o-rings but i cannot remember if they go to the rear or front outer stud reccesses in the crank case, and like an idiot i didnt take any photos of where they came from originally.

Strangely the smaller replacement circular o-rings suzuki sent to me dont even seem to fit in the reccesses. Are these redundant on my model? I cant seem to see what purpose they serve. I think they sit around the base of the rear cylinder studs in the reccess, but there is no oil way there or anything.??

Does anyone have an idea of where these 2 smaller o-rings should go and what they are for? Any help would be very much appreciated.

My second question concerns piston ring end gaps. I have purchased new piston ring and wondered if i needed to check the end gap before installing them or should they be ok to fit right out the packet. Sorry if this seems a stupid question, but this is my first rebuild. My haynes manual doesnt seem to say to check them when putting the engine back together.

Any help or tips would be greatly appreciated.

Many thanks.
Clive

Hi Clive, welcome to the GSR.

Not sure what those o-rings are. The only o-rings associated with the base gasket are the oval ones that you have already fitted and the large thin sectioned ones that fit around the bottom of each cylinder sleeve.

The stock first and second rings should be gapped between 0.004 - 0.012" (0.10 - 0.30mm).The free state ring gaps should be approx 9mm & 9.5mm respectively.

Fit the rings up to each bore and check their gaps with feeler gauges. You should set each ring at 10mm below the deck and then try again another 30mm lower. Any substantial increase in gap will mean that you should measure up with the view to doing a rebore. If the rings check out within spec, you will get by with a light honing of the bores. Any rings tighter than 0.004" will need to be gapped by carefully filing the ring ends. Be careful not to remove too much metal in one go. Recheck often.

Good luck and keep posting your progress.

[busak5]

Thanks for your reply 49er. Im tempted to omit these o-rings and pray !!

Appreciate the info on the ring end gaps.

I have recently had the barrels checked out and they were fine, just needed honing. The company that looked at them for me advised i buy new piston rings as a matter of course. Which i have done.
So , if i underdtand correctly, its good practice to check the ring end gap even if the rings are brand new? I was hoping this wasnt the case as ive already installed them on the pistons. a rooky mistake no doubt.

The bike is about 1/3 of the way there. Ive had the frame etc powder coated but concentrating all funds on the engine at the moment. I stripped it down completely to the bare cases, which i had soda blasted, then i masked it all up and painted it with VHT paint. No too bad a result.
The bottom end is now rebuilt and ive had the barrels honed and have just sent the head off to be looked at. Cant wait to button the engine up and get it in the frame.

Ill keep you posted on the progress. Its been quite slow to this point !


Thanks Again

[BassCliff]

Greetings and Salutations!!

Hi Mr. busak5,

You'll find lots of GS850 lovin' (and a Suzuki shop manual) on my website. Stop by and help yourself. Now let me say "Hi"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[49er]

Thanks for your reply 49er. Im tempted to omit these o-rings and pray !!

Appreciate the info on the ring end gaps.

I have recently had the barrels checked out and they were fine, just needed honing. The company that looked at them for me advised i buy new piston rings as a matter of course. Which i have done.
So , if i underdtand correctly, its good practice to check the ring end gap even if the rings are brand new? I was hoping this wasnt the case as ive already installed them on the pistons. a rooky mistake no doubt.

The bike is about 1/3 of the way there. Ive had the frame etc powder coated but concentrating all funds on the engine at the moment. I stripped it down completely to the bare cases, which i had soda blasted, then i masked it all up and painted it with VHT paint. No too bad a result.
The bottom end is now rebuilt and ive had the barrels honed and have just sent the head off to be looked at. Cant wait to button the engine up and get it in the frame.

Ill keep you posted on the progress. Its been quite slow to this point !


Thanks Again

Good to hear that you have honed the bores. You need to check the ring gaps before assembly. It's very important to establish the correct ring gap before engine assembly. Without this info, you could too loose (burning oil), or running too tight!! What CR would you like to be running?