'81 550T…ring job

[mike_of_bbg]

I'm not sure I'm following along here. I did rebuild an old Pontiac Firebird engine so I am familiar with what you are doing but I'm not getting what I am seeing.

Big difference. On journal crank bearing motors like almost any car and most any other motorcycle, you can drop the pistons down one at a time into the motor, then bolt the caps. On the roller bearing crank GSes, the rods are pressed with bearings on the crank. Short of using a press they're "permanently" attached. There's no way to lower the pistons into the cylinders. The pistons go onto the rods first and you drop the cylinders over the pistons, which thus go in two at a time.

I understand you are using the hose clamp to tighten the rings to slide the piston in but what is that other sleeve?

I think you're looking at the cylinder bore; they project below the cylinder base into the crankcase when installed.

Do you just loosen and slide the hose clamp down once the top part of the engine slides over the first ring? Are you just completely loosening the hose clamp once it is at the last ring to remove it?

Just install the clamp loosely enough to where it slides off as the cylinder pushes it down. Normal ring compressors usually can't be taken all the way apart (and thus would be stuck around the con rods) so hose clamps are a cheap and effective alternative to the specialized ring compressors needed for RBC motors.

And even with reading the other posts, why do you need to support the inside pistons with the wood? Again, I'm not following along even after doing the car before...sorry.

First, the pistons really have to be square to go into the bores nicely. So the wood blocks help hold them square, together, as the bores are dropped over. Second, it keeps the bores from pushing the pistons down into the crankcase.

Usually once the inner two pistons are in it's a bit easier to get the outboard pistons installed. If someone fairly strong is helping you it's not that hard to compress the outboard rings with your fingers as the cylinders come down. The cylinder bores do have a taper inside at the bottom to help get the rings in.

[Suzuki_Don]

[QUOTE=Steve;1251497]You have a big-bore kit on your 550?
The stamp on the cylinder block sure looks like it says "673 cm^3" /QUOTE]

Yes STEVE, it has a big bore kit and out of interest with the 1mm overbore it gives 700cc or 699cc to be exact.

The hp figures for the bikes of that era were:
GS550 -- 49hp
GS650 -- 73hp
GS750 -- 72hp
GS850 -- 77hp

The 650 swish head with centrally sited spark plugs gives the extra power as well for the 2-valve motor, add less weight that the 850, add a 6-speed transmission.

It's all looking good. Only about 1 hours work to be done before I can do the initial startup after 2 1/2 years work on this project.

[Buffalo Bill]

Wow, give us some sources and prices!

Hey Don,
Way cool! Can you give us some sources and prices for that job? We'll really appreciate it!
Bill
[QUOTE=Suzuki_Don;1251827]

You have a big-bore kit on your 550?
The stamp on the cylinder block sure looks like it says "673 cm^3" /QUOTE]

Yes STEVE, it has a big bore kit and out of interest with the 1mm overbore it gives 700cc or 699cc to be exact.

The hp figures for the bikes of that era were:
GS550 -- 49hp
GS650 -- 73hp
GS750 -- 72hp
GS850 -- 77hp

The 650 swish head with centrally sited spark plugs gives the extra power as well for the 2-valve motor, add less weight that the 850, add a 6-speed transmission.

It's all looking good. Only about 1 hours work to be done before I can do the initial startup after 2 1/2 years work on this project.

[Buffalo Bill]

Got them up the holes…

Yes, I got dem in dere!
Took 2 hours of fiddlin' though. This ain't a job for a squid. What it say in the manual is simple and correct, but you have to have lots of patience, and the mechanical gift to get it done.
This is what I can ad to the data base, these made it easier for me, little steel strips inside the hose clamps.

[Suzuki_Don]

Yes, I got dem in dere!
Took 2 hours of fiddlin' though. This ain't a job for a squid. What it say in the manual is simple and correct, but you have to have lots of patience, and the mechanical gift to get it done.
This is what I can ad to the data base, these made it easier for me, little steel strips inside the hose clamps.

Yes BB, you certainly need to be an ingenius B**t**d to work on these GS bikes at times. On the 550 some tasks are easier than the bigger bikes, but not very often. The larger bikes generally have more space to do things, e.g. removing the air box and carburettors from a 550 compared to a 1000.

Great you got the job done. I will probably do a project write up on my whole conversion in the near future and will not clog up your post with all the infinite detail. BTW there are a couple of other posts in the search feature on this conversion from 550 to 650 or to put it another way from 49hp to 73hp (49% increase in power).

[Buffalo Bill]

Bike is running, have taken test ride, but…

Yes, I got it all back together and have ridden 40 miles!
I rode down some lonely country roads and did a lot of up and down the RPMs to set in the new rings. I'm following advice from Dan's Repair Info web site: http://www.dansmc.com/engine_breakin.htm
The bike has a problem though, it won't hold an idle without some help on the throttle, and raising the fast idle is not the solution. This problem predates the ring job. I hope it's just a mixture or cleaning issue. It seemed to develop slowly last fall.
Bill

[Suzuki_Don]

Yes, I got it all back together and have ridden 40 miles!
I rode down some lonely country roads and did a lot of up and down the RPMs to set in the new rings. I'm following advice from Dan's Repair Info web site: http://www.dansmc.com/engine_breakin.htm
The bike has a problem though, it won't hold an idle without some help on the throttle, and raising the fast idle is not the solution. This problem predates the ring job. I hope it's just a mixture or cleaning issue. It seemed to develop slowly last fall.
Bill

BB it sounds like you are too lean on one or more of the carbs at idle. Try a mixture adjustment. Check which spark plug looks lean. Also do a vacuum synchronisation to get all throttle valves equally adjusted.

At what mileage do you intend to retighten the head bolts.

[Buffalo Bill]

Mixture-pilot screws…

BB it sounds like you are too lean on one or more of the carbs at idle. Try a mixture adjustment. Check which spark plug looks lean. Also do a vacuum synchronisation to get all thrttle valves equally adjusted.

At what mileage do you intend to retighten the head bolts.

I went through a carb tuning in March-2009. Ran good at that time. I will do it again. Just a quick look at the pilot screws I see they're 3 turns out, the service manual spec.s show 3-1/2 out.
I haven't thought about a torque re-tightening, but now I remember that from my race car days 20 years ago. Maybe after 200 miles, as I will change the oil and filter too.
Thanks for the reminder.

[Suzuki_Don]

I went through a carb tuning in March-2009. Ran good at that time. I will do it again. Just a quick look at the pilot screws I see they're 3 turns out, the service manual spec.s show 3-1/2 out.
I haven't thought about a torque re-tightening, but now I remember that from my race car days 20 years ago. Maybe after 200 miles, as I will change the oil and filter too.
Thanks for the reminder.

No probs. Glad to help.