Help! Trouble with Kickstart/Clutch?

I’ll do that right now. About 1,000 miles. It was put in last summer so has sat about 10 months. He had to stop riding his frame because it cracked. Pulled the motor and said everything was in good running order when he pulled it.
 
80 psi is not good. Normal is about 150 and you may begin to have starting and running problems at much below 120. I think your last glimmer of hope here to avoid a teardown and rebuild will be valve settings. If set too tight, some valves may not be closing completely and allowing compression to bleed off.
 
If you exhaust all the external adjustment options then that only leaves internal stuff, things the motor will need to come apart for. That could be bad rings, worn bore, or valves not sealing or bent. If there's only about a thousand miles on the motor, worn out bores shouldn't be the issue. But maybe a ring has broken? Or maybe some were installed upside down? They won't seal that way, lol. But you have to keep in mind, P.O.'s are notorious liars, lol. Who knows what the mileage could be, or if he just cooked the motor from beating and abusing it, and that's why it went up for sale. He broke the frame after all.

Try GLJ's tip of adding oil to the cylinders and re-testing the compression. That will seal around bad rings and bring the readings up. It won't help with bad valves. It's a way to possibly narrow down the problem area a bit more.
 
I wouldn't be too hasty in tearing anything down just yet.;)
Most owners have no idea how to apply a compression test properly and its notoriously difficult to get a full pressure buildup using a kickstart.

The test should be done with the throttle held wide open and the engine should be turned over continuously for a minimum of 8 revolutions which you can only achieve with a starter motor or by putting the bike in gear and pushing it along the road preferably down hill. Turn the engine over until no more pressure build up is noted on the gauge then do exactly the same test with the other cylinder.

I very much doubt if your engine only has 80psi
 
peanut,

Do you have any inclination what could be causing the lack of pressure building in the kick? It's just a sloppy sponge on kick through.

Before I got it started for those two lovely seconds, it would build back pressure before I kicked through.

Thank you!
 
Something else you should check is the cam timing. Since you really don't know a lot about the engine it should be checked. Recently there was a member on here that bought a bike that was supposed to be in good shape. It had been recently rebuilt. The cam chain was the wrong length and caused the cam to jump a few teeth. 5T has some good pictures of what you will need to do and look at.
 
Actually those no's are worse than 5twins says.............a new 750 Kit should be up around 170 at least and some 750 kits are reported to be 190...........

Do as many tests as possible before stripping down..............just a caution...........if by chance there was a broken ring, (a possibility), then the more you turn the engine over the more damage will be done to the bore..........until this possibility was removed from the equation............

i would definitely not wind the engine over and over using the electric starter, (yes i know you only a have kick start bike i read your posts), and definatly wouldn't recommend trying to push the bike downhill in gear trying to get a compression test done...........For starters they are a bitch to push back up a hill. LOL
 
I was thinking he could use a drill with a 17mm socket on the Dyno nut. Maybe? Throttle locked wide open and run drill in reverse?
 
aDotInTime said:
I’ll do that right now. About 1,000 miles. It was put in last summer so has sat about 10 months. He had to stop riding his frame because it cracked. Pulled the motor and said everything was in good running order when he pulled it.
Click to expand...
:laughing:
Any motor you didn't SEE AND HEAR run is suspect. A couple times looking at "built" small block chevy motors that "run great" ready to load in your truck. We'd show up with tools, agree to a price, show the cash and tear it down in his driveway, then walked away when the junk, broken parts saw daylight.


Way above 5twins asked you to open the LH alternator cover (two screws, no gasket) and watch the motor while someone kicks, did you do this?
 
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GLJ said:
Something else you should check is the cam timing. Since you really don't know a lot about the engine it should be checked. Recently there was a member on here that bought a bike that was supposed to be in good shape. It had been recently rebuilt. The cam chain was the wrong length and caused the cam to jump a few teeth. 5T has some good pictures of what you will need to do and look at.
Click to expand...
Since you said it felt like good compression prior to the 2 sec. run, and now only 80psi, I'd say a cam chain jump is a distinct possibility. Have a look here. Starts around comment #109
 
"Way above 5twins asked you to open the LH alternator cover (two screws, no gasket) and watch the motor while someone kicks, did you do this?"

I did do this. The ignition rotated
 
Hey all. So I'm educating myself on how to do the valve adjustment and decided in the interim that what gggGary said about not really knowing what I got should push me to do some investigation.

This fellow I bought the bike from had informed me that there was a new sump filter from MikesXS with a gasket. I thought "Hmm, why would he be specifically replacing the sump filter?"

So I pulled the filter this evening and found it to be pretty beat up. There was a SIGNIFICANT amount of debris in it. Also a red fluid in and around it. Could this help with any diagnostics? Was this just years of shitty crud built up? Why did he want to replace that filter? Is there something that filter is linked to that would put a piece together regarding my loss of compression?

I took photos to help give a visual. Hope you're all well!
IMG_4404.JPG
IMG_4400.JPG
IMG_4403.JPG
 
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aDotInTime said:
peanut,

Do you have any inclination what could be causing the lack of pressure building in the kick? It's just a sloppy sponge on kick through.

Before I got it started for those two lovely seconds, it would build back pressure before I kicked through.

Thank you!
Click to expand...

well the most likely reason for a sudden loss of compression is usually an exhaust valve not seating either due to being stuck or burnt or having the wrong ignition timing as per Jims suggestion (slipped cam chain) or the valve settings being set too tight as per 5twins suggestion.

if the motor has not been run in a while and all the lubricating oil has drained and the valve settings are tight, as they usually are on xs650 then an exhaust valve sticking and not seating is a distinct possibility .

I should ignore broken rings ....the likelihood of all of the rings suddenly breaking after 2 seconds running is extremely unlikely. .
Likewise cylinder bore scoring . That could never cause a catastrophic compression loss .
Gators suggestion of using a drill with socket adaptor is a good one and something I have used myself but you would need a drill capable of a slow start speed adjustment and if you fuc**d up the rotor nut you'd be in a world of woe. Far safer and effective to use the push bike method

lets start with the basics .

You need 3 things for an engine to run ............compression , a spark at the right time and a fuel and air mix close to 14:1 .
You have compression ( 80lbs would be sufficient to start and run the engine),
Do you have a spark at the plugs ?
Are the plugs getting wet with fuel ?
 
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ok . is the engine showing any signs of trying to fire at all ? a cough or splutter ...anything ?
Try drying off the spark plugs and no choke, part throttle start. if you had some Easy start to put in the bores it would help
 
No. It doesn't want to catch at all. It's just going through a soggy kick with the minimal compression. I (today) dried spark plugs and tried both with choke and without and gave it some throttle as well. Nothing.
 
well if you are certain that you have a consistant spark whilst kick starting and the bores are receiving fuel I would say that you are not getting both a spark and compression at the correct time . This could cause a soggy feeling kickstart .
Either your ignition system is mis-timed or possibly your cam chain has slipped a tooth but I would still expect the occasional cough or backfire.

I still say that you best bet is to push start the bike down a hill or tow start it with another bike or car . your kickstarting is probably not turning the engine over quickly enough to compensate for an ignition timing or fuel air supply issue
 
So would you suggest adjusting the timing and also checking out the valve clearance and adjusting if necessary?

Could that shit I found in the filter be from the cam chain guides? Would that cause part of the issue?
 
aDotInTime said:
So would you suggest adjusting the timing and also checking out the valve clearance and adjusting if necessary?

Could that shit I found in the filter be from the cam chain guides? Would that cause part of the issue?
Click to expand...

The bike has started and run so I doubt that there is much wrong .

I would not recommend that you start randomly adjusting things until you have exhausted the easy tests first because you could make the situation worse.

You have no electric start which is a real bummer when you get this kind of problem. Personally I can never understand removing the kickstart from a bike . Its always good to have that in reserve , even if an owner is determined to damage their knees lol

I would buy a can of Easy Start or similar to squirt into the cylinders or inlets and get some help push starting the bike. if that doesn't start it then yes you'll need to look further into your ignition and valve settings
 

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