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1980G Build
- Thread starter suiteo
- Start date
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- Tags
- tci repair transistors
DAMN. Looks like I've got to tear the motor out. And yes, that is a coffee stirring straw. Fits in that hole like it was made for it.
Just a thought, google degree wheel. Print one out , glue to a breakfast cereal box. I like cornflakes. Cut out. Mount to the nut that holds the alternator rotor on. Put timing marks at TDC. put a piece of wire on someplace so you can bend the end to point at zero degrees.
Now turn the crank to put the coffee straw pointing straight up. Look at the pointer on the degree wheel. How many degrees is it off?
Easier than pulling the engine. If it is less than ten degrees, go with it. If over then pull the engine and reset the cam.
And as you say, the chain tension can change to alignment. You might be able to tip the engine over on it's side to pull the rocker box.
I know that on car engines they sell timing gears with more than one key way and timing marks. You can set the cam timing right on or advanced or retarded 4 degrees. I can't recall just which way does what. One way gives more power down low, the other up high.
I think Grizld1 has talked about this when discussing degreeing in a cam. Perhaps he can help with this.
Now turn the crank to put the coffee straw pointing straight up. Look at the pointer on the degree wheel. How many degrees is it off?
Easier than pulling the engine. If it is less than ten degrees, go with it. If over then pull the engine and reset the cam.
And as you say, the chain tension can change to alignment. You might be able to tip the engine over on it's side to pull the rocker box.
I know that on car engines they sell timing gears with more than one key way and timing marks. You can set the cam timing right on or advanced or retarded 4 degrees. I can't recall just which way does what. One way gives more power down low, the other up high.
I think Grizld1 has talked about this when discussing degreeing in a cam. Perhaps he can help with this.
suiteo
XS650 Enthusiast
Searched and found a post from Grizld1 on the old rider site and here is a quote:
"your cam has a 36-tooth sprocket turning at 1/2 crank speed, so 1 tooth=10 degrees of cam rotation=20 degrees of crank rotation"
So I'm reading that even at one tooth off I'm going to be 10 degrees off. I've been unable to "tune" my problem away and I've literally tried everything else. I will try the degree wheel as well to verify, but to me it looking like I'm off and there's nothing left to do but to get the cam correct. Like you said, hopefully Grizld1 will chime in, but I think the evidence points to me installing the cam incorrectly. Since it starts and runs I'm guessing it's only off one tooth.
J
"your cam has a 36-tooth sprocket turning at 1/2 crank speed, so 1 tooth=10 degrees of cam rotation=20 degrees of crank rotation"
So I'm reading that even at one tooth off I'm going to be 10 degrees off. I've been unable to "tune" my problem away and I've literally tried everything else. I will try the degree wheel as well to verify, but to me it looking like I'm off and there's nothing left to do but to get the cam correct. Like you said, hopefully Grizld1 will chime in, but I think the evidence points to me installing the cam incorrectly. Since it starts and runs I'm guessing it's only off one tooth.
J
Got your PM. A 1-tooth error is an error of 20*, as explained; it's timing at the crank that signifies. The OEM cam timing is specified for the very start of the valve opening at an inspection valve lash of .012". If you want a quick-and-dirty way to tell if you're in the ballpark, without degree wheel or dial indicator, here's what to do.
With the motor at TDC and left cylinder valves closed, remove the left cylinder intake valve cover (easier to turn the crank from that side), then set the valve to the inspection lash of .012", and insert a piece of cellophane between valve stem and tappet. Rotate the engine CCW until the valve closes. Pulling gently on the cellophane, continue rotating CCW just to the point that the cellophane is released. This should occur at 36* BTDC--very close to the full-advance timing mark.
With the motor at TDC and left cylinder valves closed, remove the left cylinder intake valve cover (easier to turn the crank from that side), then set the valve to the inspection lash of .012", and insert a piece of cellophane between valve stem and tappet. Rotate the engine CCW until the valve closes. Pulling gently on the cellophane, continue rotating CCW just to the point that the cellophane is released. This should occur at 36* BTDC--very close to the full-advance timing mark.
suiteo
XS650 Enthusiast
Hey Grizld1, thanks for taking the time to answer my PM and posting back. I will give this a shot and see what the results are, although I'm pretty sure I already have my answer. I printed out a degree wheel as well so I can verify 100% what the deal is. I'm going to try and pad the frame up and see if I can just tilt the motor to the side to pull the top off and have access to the cam bearings and such to get the cam aligned properly. Hopefully this has been the source of my problems and I can finally get this thing on the road.
Thanks again all.
J
Thanks again all.
J
suiteo
XS650 Enthusiast
Quick update: I ended up being off a tooth on the cam. Got the motor loose and tilted in the frame and got it corrected. Got it fired back up again. Definitely an improvement. Got the cam tension set again, and valve clearances set. Still working on dialing in the new carbs. Fouled the plugs so bad I'll have to pick up another set. Plus I seem to have a float problem on the left side. Was running ok, then stopped on that side. Fuel started coming out of the overflow, so I pulled the carb and gave it a shake thinking the float got stuck. Now no fuel on that side. Going to have to pull it again. At least they are easier to pull than the old linked carbs.
J
J
suiteo
XS650 Enthusiast
Well, I'm finally getting somewhere with this build. Slowly getting the carbs dialed in after fixing the cam timing. Took it out for a short 10 miles spin to check the plugs, and still have some work to do there but it's getting really close. I want to send a big thanks to everyone one this site that has helped out over the past 2 years that I've owned this bike to get it from a non-runner POS to where it is now. Still have some small things left to do, and I think this bike will always be a work in progress, but here are a couple of photos of where it sits today. Thanks again to all.
J
J
Attachments
gentlemanjim
More Wrenchin than Ridin
Very Nice - what the paiant dinish? How do those pipes sound?
BigJimmyW13
XS650 Guru
Rhino liner.
suiteo
XS650 Enthusiast
Yep, everything in black minus the frame bits are done with Line-x truck bed liner. It turned out to have more shine than I had hoped, but no worries about gas spills ruining my paint. Or anything else for that matter.
I really dig the sound of the pipes. Nice low throaty rumble without all of the annoying high end usually found in smaller displacement motors. Still pretty mild when just putting along, but has a nice sound when you get on the throttle.
I really dig the sound of the pipes. Nice low throaty rumble without all of the annoying high end usually found in smaller displacement motors. Still pretty mild when just putting along, but has a nice sound when you get on the throttle.
