Yeah... find a 16 yr old neighbor kid and pay him to kick for you.
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Winter project #2
- Thread starter bosco659
- Start date
I thought you wanted to start the bike????
Well I’m a bit bummed out right now. I checked static timing and all looked ok. While looking for tdc I saw the exhaust valve that looked a bit odd. This compelled me to try a compression test again. I don’t think my gauge is boogered but dry I’m getting around 55+ psi and wet with oil a bit over 60. Tells me the bore is buggered or I have valve issues.
I don’t want to throw good money after bad and am considering abandoning the project. O the other side I know where I can get a freshly rebuilt motor for maybe $750? Trouble is I need to act fast on the motor for sale because it won’t last long.
If I’m into a valve job, guides, seals, a possible bore with piston and rings and I’m guessing in at $500+ already.
I’ll have to sleep on this. If I decide to go for the motor I’m going to have to ride the bike got a while because the investment will be hard to recover next season.
Any thoughts?
I don’t want to throw good money after bad and am considering abandoning the project. O the other side I know where I can get a freshly rebuilt motor for maybe $750? Trouble is I need to act fast on the motor for sale because it won’t last long.
If I’m into a valve job, guides, seals, a possible bore with piston and rings and I’m guessing in at $500+ already.
I’ll have to sleep on this. If I decide to go for the motor I’m going to have to ride the bike got a while because the investment will be hard to recover next season.
Any thoughts?
Check the decompression parts/system and make sure it's adjusted correctly. If it's not, you could be losing compression there.
Iirc, it holds the exhaust valve open to kill compression.
Iirc, it holds the exhaust valve open to kill compression.
Can you get a pic of that?
Well I squirted a bit of gas in the spark plug hole and kicked it over half a dozen times then I heard a faint fart. Encouraged I kicked it again and it started.
Ran rough as hell, lots of smoke as it warmed up. I eventually got it off of choke and it died again. Fortunately it fired up on the second kick. I was able to adjust the mixture and got it to idle pretty well.
Still smoking I walked around the right side and saw the header was cherry red for about 12”. I guess it doesn’t like sitting there without air flow.
I wanted to cool it down so I went for a spin around the block. Motor pulled hard and tranny worked as it should. No headlight and no rear brake so time to get it back in the garage.
Once parked I noticed quite a bit of oil was leaking from somewhere in the top end. That’s ok though. Something to fix over the winter that shouldn’t break the bank.
I’ll post a video later if I can figure out how.
Picture of the decompression assembly.
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Since the video was made, the carb was adjusted to a nice smooth idle. I’ll swap in fresh fuel this weekend and have a quick look for the oil leaks up top. Several possible sources: valve adjustment covers; tach drive; oil rocker shaft end caps, all of which are easy fixes. It will be a lot more work if it’s leaking between the rocker cover and head. There isn’t a gasket between the cover and head, just sealer. Not sure if it can be resealed with the motor in.
I enjoyed the short ride i took last night. The bike is quite a bit lighter (very noticeable) than the Moto Guzzi, maybe close to 100 lbs less. Lighter than the XS too. I think once I get things straightened out it will be fun to ride!
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Took a bit of hunting but found the oil leak. The end of hose fitting to the in frame oil tank was seeping oil. It travelled down the hardline, dripped on the rubber vent hose then carried on to the top of the rocker cover. About 1/16 of a turn tightened the connection up. In the process I resealed anything that had a copper crush washer.
Attachments
Bought these shocks today to replace the rusty old originals. Hopefully they’ll work ok. If not I’ll swap ‘em back.
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In my experience (and this is of course a generalization), if you do not get much improvement transitioning from dry to wet, it is more likely a valve issue than rings-sealing.
I’m not putting too much faith in the compression test results. The numbers are scary low yet riding it around the block it pulls real hard. I haven’t tested it since I got it started. Maybe sticky rings or valves have loosened up? I’m getting fresh fuel this afternoon. If it starts up and runs well I’ll do another compression test.
In my experience, if it really only had 55 to 60 psi compression, it would run very poorly, if at all. My sense is that if the engine hasn't run in a long time, the valve seats need a "run-in" to clear debris and re-seat themselves and the rings also need some movement to free themselves up. An overnight soak with a penetrating oil may help that.
Agreed. I went to start it today with fresh fuel. First kick and it burped but didn’t start. I kicked and kicked until my leg and back said no more. Pulled tge plug and it was wet. I dried it off with a torch , spun the motor several times with the plug out to clear excess fuel. Back together, kick, cough and nothing more. I figured out a couple of things (most of you probably already know this). When I kick it and it doesn’t start, if I bring it to TDC and kick again it won’t even fart. Roll it another 360 degrees and I’ll almost always get a puff out of the exhaust. The general instructions to start these tells you don’t touch the throttle unless you want to flood it and get a good kick back. Although the plug was getting wet I had a notion the idle was set too low for it to fire with the slide so low. I adjusted up the idle screw a bit and kaboom - it started. @Bob Wegman ] mentioned a fast idle button on the idle screw. I found this and cleaned it so it would move. This helped tough starting too. My kicking technique is improving too.. I’ll test all my theories tomorrow with a cold start. Fingers crossed it will go.
Once I got it running I warmed it up and put a big fan beside the motor to cool things down. I adjusted the mixture and idle and got this… video to follow.
Happy to report, oil leak free
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That doesn't sound unhealthy at all! Steady idle, responsive to to throttle snaps, no smoke at all from the pipe and you've reported that it pulls hard. Sounds like a good runner to me!
All I could ride it was up and down our driveway and across the street - maybe 100ft. Pulls hard, felt like the front wheel was about to lift off the ground if I had more space and rear brakes! I agree, I think the motor will be ok. Just need to get the starting process perfected.
I'm enjoying this thread . . . in fact I might do sommat silly.
I’m going to look at another SR500 in pieces soon. Who knows I may end up with another!
