Finally getting around to the 550/699 project....

[pete]

I like the graceful curves of those headers too...

[82 GS550L Basket Case]

Looks good!
subscribed.

[tkent02]

She's Alive!!!

Sort of. Got it running for 30 or so seconds at a time, couldn't get it to take throttle or rev up much, couldn't get it to run without full choke at all. All four pipes got warm, even the one with zero compression. Not sure I understand that, but at times it certainly sounded like it was running on four cylinders.

Time to play with some carburetion and try it again.

[tkent02]

OK, back at it.
Fresh gas instead of what's in the lawnmower can from whenever it was last spring, now it fires right up, revs up, running more or less evenly and all four pipes were definitely hot. How can a cylinder with zero compression run evenly and get it's pipe hot? Maybe the compression fixed itself? WTF?

I'll check into it once the smoke clears from the garage.

[UncleMike]

OK, back at it.
Fresh gas instead of what's in the lawnmower can from whenever it was last spring, now it fires right up, revs up, running more or less evenly and all four pipes were definitely hot. How can a cylinder with zero compression run evenly and get it's pipe hot? Maybe the compression fixed itself? WTF?

I'll check into it once the smoke clears from the garage.

Is it possible the zero compression was a false reading?

[tkent02]

Is it possible the zero compression was a false reading?

Not really, I tested it several times. Cylinder #2, each test it came up zero. Maybe a ring was stuck or a valve was stuck or something, and it unstuck itself from running a few minutes? Don't know yet, but it goes through the gears just fine, clutch works although it drags a lot, no funny noises.

Also added brake fluid to the front (650E) brakes, they work just fine too.


Edit, now the compression tests at 100 - 90 - 40 - 100, better than zero anyway.

Still leaking fuel from the Ts, got to dig into that.

[gustovh]

I'm on board, enjoying your challenges and inovation.
V

[musicman]

Might be the rings, maybe pour a little marvel mystery oil through the spark plug hole and let it soak for a while? Wouldn't hurt anything. Also could do a leak down test and see where the air is coming from. Exhaust would be a burnt valve possibly, intake would be a bent valve (intake valves usually don't burn), crank case would be rings or piston damage. Any who, just an idea.

[tkent02]

Might be the rings, maybe pour a little marvel mystery oil through the spark plug hole and let it soak for a while? Wouldn't hurt anything. Also could do a leak down test and see where the air is coming from. Exhaust would be a burnt valve possibly, intake would be a bent valve (intake valves usually don't burn), crank case would be rings or piston damage. Any who, just an idea.

Been there done that. It's coming back out the intake. Intake valves do burn if they are too tight. But intake valves once burnt, don't unburn. I'll find out once it comes apart.

[chef1366]

Could be a combination of both. Some valves may of been open for some time and had to re-seat.
The rings also may have re-seated too.

[tkent02]

After being sick most of last month, got around to fixing the ignition. Totally burned up points, bad condenser, a broken rotted spark plug wire cap, cracked coil (that still worked by the way) all of it screwed up. Parts from another 550 engine, a little filing and adjusting, it's all good.

Installed the second set of carbs after the dip, the first set was still messed up.

All put together and it fired up quickly, a minute on the choke and now it revs right up. The engine sounds good, all four cylinders firing for sure, even the one with the compression problem. Need to test drive the transmission just a little bit and then tear into it for the 675 mod.

I am curious to see what's up with that one cylinder.

[tkent02]

Stator is good, 75 VAC at 5,000 RPM.

Compression after running ten minutes or so, running up to 5,000 or 6,000 for a Stator test, now 98 - 93 - 102 - 102. Getting better. Those are fairly high numbers for up here at 6,000 ft.

Need to check the valves again. I'm thinking this might be a pretty good engine.

[Toasty]

Wow you work fast! Btw, what base gasket did you end up using? 550 or 650? I bought both just in case...

How hard was it to install the 650 ignition advance onto the 550 crank?

[tkent02]

Wow you work fast! Btw, what base gasket did you end up using? 550 or 650? I bought both just in case...

How hard was it to install the 650 ignition advance onto the 550 crank?

No, I don't work fast at all. Very slowly nice I missed all of January. Just trying to run it as a 550, to see if the lower end is good before doing the 675 swap. It seems like it is, haven't ridden it yet though. Need to get a gas tank cleaned up and on there, and snug up some bolts here and there.

I know nothing of gaskets and advances, although my plan for now is to use the complete 550 ignition.

[Toasty]

Ah okay. Btw from what I've read from a few other guys who have done this swap, you need the 650 ignition advance or it'll ping. And that it takes some modification on the bolt for it to clear the 550 cover.