Intro and Problems Running

[Laptop_geek]

I fixed the kink and the miss went away, looks like it actually needs fuel to run, who'd of thought so!...

Well now I've got some more diagnostics to do. I got it running and the left exhaust was smoking. Smelled like oil, I'm going to loan a compression tester from autozone tomorrow (or whenever I get the chance) and see what I can do to see what the problems is.

[natemoen]

I fixed the kink and the miss went away, looks like it actually needs fuel to run, who'd of thought so!...

Well now I've got some more diagnostics to do. I got it running and the left exhaust was smoking. Smelled like oil, I'm going to loan a compression tester from autozone tomorrow (or whenever I get the chance) and see what I can do to see what the problems is.

Keep in mind that that oil and smoke may just be crap that is in the pipe and not have anything to do with the engines current state.

[Laptop_geek]

Keep in mind that that oil and smoke may just be crap that is in the pipe and not have anything to do with the engines current state.

Hope so, checking compression tonight to get a base point. We'll see what happens.

[Laptop_geek]

Alright, I checked compression and got some interesting results. I started from 4, then did 3, 2, and 1. I got about 60 psi (90 after I added some oil) on both 3 and 4, when I did 1 and 2 I got 35 psi (same with oil added). I think the tester might have been reading a low, but not that low. Question is, what should I do? I took it for a quick run and it had horrible power and was backfiring really bad. I think I could clean some of that up with tuning the carbs, but will that help that much? I guess the next thing to do is take off the valve cover and see whats in there.

[crazy steve]

Did you have the throttle held all the way open while doing the test? If not, that will give low numbers. If you did have it open, you've got badly worn rings.... time to look for a motor...

Do check your valves, if a couple of intakes are too tight that would do it.

[XS1100_OEM4ME]

Compression

I pay little or no attention to compression reading on a motor that is not in service and fixed to run properly and then run and some miles or hours put on it. The poping sounds like carb issues, emulsion tubes would be my 1st guess (had the same problem till I removed and cleaned the crap put of them) Once the motor is running right and you can put some miles and higher RPM on it, all kinda stuff frees up, sticking rings, rusty valves contacts. Then check the compression and I will bet it is alot better

Alright, I checked compression and got some interesting results. I started from 4, then did 3, 2, and 1. I got about 60 psi (90 after I added some oil) on both 3 and 4, when I did 1 and 2 I got 35 psi (same with oil added). I think the tester might have been reading a low, but not that low. Question is, what should I do? I took it for a quick run and it had horrible power and was backfiring really bad. I think I could clean some of that up with tuning the carbs, but will that help that much? I guess the next thing to do is take off the valve cover and see whats in there.

[natemoen]

Did you have the throttle held all the way open while doing the test? If not, that will give low numbers. If you did have it open, you've got badly worn rings.... time to look for a motor...

Do check your valves, if a couple of intakes are too tight that would do it.

I wouldnt go and jump tp that conclusion so fast. The no change when oil is added on 1 and 2 points at valves. You are getting some sealing so that is good, maybe just a simple valve lapping and clean the carbon up and those 2 would be good. With 3 and 4 I would run it before I condemned it. Rings get gummed up and stuck and getting the engine going often gets them working again.

[DGXSER]

Alright, I checked compression and got some interesting results. I started from 4, then did 3, 2, and 1. I got about 60 psi (90 after I added some oil) on both 3 and 4, when I did 1 and 2 I got 35 psi (same with oil added). I think the tester might have been reading a low, but not that low. Question is, what should I do? I took it for a quick run and it had horrible power and was backfiring really bad. I think I could clean some of that up with tuning the carbs, but will that help that much? I guess the next thing to do is take off the valve cover and see whats in there.

As Steve asked, did you have the throttle held full open for all of the testing, for the results to mean anything it has to be. I've made that mistake myself once or twice so don't be afraid to repeat it to make sure.

For a motor that has been sitting a long time, the 60-90 numbers do not bother me alot. The 35 with no change after oil is not good news. That would indicate a valve issue. Which I would then pull the head and clean and lap all of the valves. While you have the valves out of the head, check each one for being bent. If you have a drill press, chucking one in it and turning it on really slow speed will quickly identify a bent valve.

[GLoweVA]

+1 on checking the valve clearances. If they are too tight, then the valves open a little earlier and stay open just a little longer, thus the cylinders don't have as much time to compress. That could be a part of your compression numbers being low.
As far as running and

I took it for a quick run and it had horrible power

The low power is a result of the low compression.
You can mess with the carbs all day long, but until that engine gets decent numbers for compression, you're wasting your time.
( I mean decent numbers like in the 70's or 80's at least)
If you're gonna do valve shim swaps (if needed for vavle clearances issues) then pulling the head off at the same time might not be too bad of an idea.
Then you can actually look at the valves and combustion chambers and see what's up there.

When I picked up my 80SG project, I didn't have any compression in #3.
My clearance on the exhuast was huge! (like .4mm) Turned out that the exhaust valve was slightly bent and thus not seating fully and open a little.

ps. if you don't have a drill press, you can turn the valve by hand in the head after you pull the springs out of course.
That's what I did and I noticed right away the 'wobble' the the disc head had and I could see the crecent light that shined thru the exhaust port.
With the head upside down, you can pour some liquid into the combustion chambers and see if it leaks by the seats.

[XS1100_OEM4ME]

Adjust

I would check / adjust the valve clearance because it it easy and you dont have to take off the head to do it Clean and adjust carbs, as it always need done, then run it easy for a while around town. The valves wear on these against the seats, if you had a bent valve you wouldnt get cmpression on that cyl, so as you run the bike, any rusty edge on the valves will wear smooth and then some high rpm pounding will seat them fine IMHO (at 7000rpm, the valve's are being pounded againest the seats 3500 times per min or 58 times a sec, that has a great effect on seating them)

I wouldnt go and jump tp that conclusion so fast. The no change when oil is added on 1 and 2 points at valves. You are getting some sealing so that is good, maybe just a simple valve lapping and clean the carbon up and those 2 would be good. With 3 and 4 I would run it before I condemned it. Rings get gummed up and stuck and getting the engine going often gets them working again.

[Laptop_geek]

I rode it around and it did much better. I've got some electrical gremlins to work out, but other than that Its doing much better. Next step is getting the brakes up to par. I've got them off now, but am having trouble getting the pistons out of the caliper. What do you guys normally do to get a stuck piston out? I've tried using compressed air, and also using the master cylinder. The air was a total fail, and I couldn't get the master cylinder to bleed. Any good tricks or should I just keep trying the master cylinder?

[XS1100_OEM4ME]

Dead pony

Not beating a dead pony, but get the fuse box from TopCat and replace it before you even start thinking about the wireing stuff I was about to spend 100 bucks + on new coil's and found the fuse box fixed ALL my gremlins, good luck on your bike

I rode it around and it did much better. I've got some electrical gremlins to work out, but other than that Its doing much better. Next step is getting the brakes up to par. I've got them off now, but am having trouble getting the pistons out of the caliper. What do you guys normally do to get a stuck piston out? I've tried using compressed air, and also using the master cylinder. The air was a total fail, and I couldn't get the master cylinder to bleed. Any good tricks or should I just keep trying the master cylinder?

[crazy steve]

Sure-fire way to get the piston out is to install the caliper bleeder, pour a bit of fluid in the brake hose hole, then close that hole with a bolt. Open the bleeder a bit, then use a grease gun on the bleeder. Pump grease in until the piston comes out....

A mess to clean out, but this will remove even the most stubborn pistons.

[JasonRedbeard]

When I tore mine apart and cleaned them up a couple of weeks ago it took about 25-30 strokes of the master cylinder to pump each piston out, but it worked and they feel a lot better (and don't stick) now that the crud is out of the calipers.

Also, +1 on the fuse box. Easy easy upgrade and straightened out my turn signal issues, and the old girl seems to start much better now to boot. VERY worth the $15 investment.

[XS1100_OEM4ME]

Brakes

If the M/C is working and it wont push the piston out It should / will if working, if not, start with a rebuild of the M/C (might just need cleaned, no parts sometimes) then it will push the piston out even if rusted in place on the fronts, when one starts to move, put a C clamp on it till the other moves

I rode it around and it did much better. I've got some electrical gremlins to work out, but other than that Its doing much better. Next step is getting the brakes up to par. I've got them off now, but am having trouble getting the pistons out of the caliper. What do you guys normally do to get a stuck piston out? I've tried using compressed air, and also using the master cylinder. The air was a total fail, and I couldn't get the master cylinder to bleed. Any good tricks or should I just keep trying the master cylinder?