Way out of synch will do that. Did you bench (eyeball) synch them before you installed?
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Cam chain timing?
- Thread starter Robert Dell Aquila
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- advance unit cam chain pamco timing
Robert Dell Aquila
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Yes I did. The bike wont start unless I use the starter fluid. What would cause the white smoke? Burning oil? Starter fluid?
Look at the plugs? a misfire, unburned charge would be my first guess. Lets see the pamco with LH at TDC. I'm wondering if the indexing is off, the wrong cylinder is being fired ie; one is in time, the other crazy wrong.
Robert Dell Aquila
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The RH spark plug are definitely more black then the left. They are brand new plugs. However, white smoke was coming out of left carb?? This is the pamco with LH at TDC. Followed Hughes install and says magnets are suppose to be horizontal.
Attachments
Compare to this: http://www.yamahaxs650.com/277_rotor_installation.htm
Your pic may not be tdc FIRE but TDC both valves open.
Your pic may not be tdc FIRE but TDC both valves open.
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Robert Dell Aquila
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Compare to this: http://www.yamahaxs650.com/277_rotor_installation.htm
Your pic may not be tdc FIRE but TDC both valves open.
There was a section in Hughes's instructions that said it did no matter whether or not the magnets were above or below the center, just as long as they were horizontal. However, this 180* difference would determine if the LH cylinder is on it's compression stroke or exhaust stroke correct? Also Pamcopete's write up talks about 443 timing?
While uncommon a "reverse offset Crank" ie 443 is possible. One denizen here long ago had a crank offset one way, cam the other, he tore his hair out for quite while getting to the bottom of it. Note how 443 + 277 = 720 or 2 complete crank revolutions. Couple guys installed cams backwards. If you have compression both sides that's not your issue, just saying anything can happen, rule out all the maybes no matter how rare.
I'll add, like pete suggests, open the valve covers confirm both cylinders line up for spark at compression. (TDC Both valves closed) the rockers will wiggle easily when the valves are shut.
Robert Dell Aquila
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Thanks again, appreciate the quick response. I've definitely been trying to rule out the maybes. There's just way more "maybe's" then I would like ahaha. However, learning a lot in the process. You spoke earlier about a unburned charge. What is that exactly?
A cylinder that has gone through compression but not fired will have an unburned charge, it will be a "white smoke" for a few seconds til the fuel condenses out of the air. If that plug fires with the intake or exhaust valve open a big bang results. Many an XS owner has looked down to find his carbs blown off and laying on the motor after an intake backfire.
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Robert Dell Aquila
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Alright I'll check to see if both cylinders line up for spark at compression. Also try and get the carbs synced. Thanks again.
Robert Dell Aquila
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The first picture is the LH cylinder at TDC on the compression stroke (rocker arms loose and matches with Pamcopetes instructions). The 2nd picture is about 277 degrees later when the RH cylinder fires on compression (marked it with a degree wheel on my stator cover). However, when the RH cylinder is at TDC on compression stroke only the intake valve is loose not the exhaust valve. It seems like my bike is firing at the appropriate times so I don't understand why I could be getting white smoke out the carbs or unburned charge as you called it. Maybe @pamcopete could shed some light on this issue as well.
Attachments
No, it isn't. The ignition rotor has turned about 222°, indicating that the crank has rotated about 443°.
Watch the valves motions. After an intake closes, that side's piston is rising. When that piston reaches top, set the lash for that side. And, check the timing mark below, mark it left or right. Do this for both sides.
360° after ignition TDC for a cylinder, both valves will be slightly open, the overlap stage. Ensure this occurs for both cylinders. This can help to get your orientation...
Are you familiar with piston and valve motions in 4-stroke engines?
This animation shows what the XS650 would look like from the right side.
Can you see how the valves move relative to the piston?
At the piston TDC on the ignition event, the valves are closed.
360° later, finishing exhaust and starting intake, both valves are slightly open.
It's only at the ignition TDC where you want to set valve lash.
If these events aren't aligned for both cylinders, you could have a rephased engine where the crank and cam were twisted in opposite directions. If that were the case, only one cylinder could run, and it would run (if at all) quite badly. Your description of it running well in the past would negate this, leaving you with simple valve lash and ignition timings...
This animation shows what the XS650 would look like from the right side.
Can you see how the valves move relative to the piston?
At the piston TDC on the ignition event, the valves are closed.
360° later, finishing exhaust and starting intake, both valves are slightly open.
It's only at the ignition TDC where you want to set valve lash.
If these events aren't aligned for both cylinders, you could have a rephased engine where the crank and cam were twisted in opposite directions. If that were the case, only one cylinder could run, and it would run (if at all) quite badly. Your description of it running well in the past would negate this, leaving you with simple valve lash and ignition timings...
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Earlier threads had the bike running............this was before the new Reg/rect and pamco so i would think the cam is in the right way around...........
Something to be said for one thread instead of many...........
Something to be said for one thread instead of many...........
Are you rotating crank in operating direction (counterclockwise)?
Robert Dell Aquila
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Honestly no. I rotated it CW (clockwise) to get LH cylinder at TDC then continuing clockwise 277* to see where RH cylinder will fire (or so I thought would fire. I marked the stator in both CW and CCW directions 83* from TDC mark. I guess I used the wrong mark. If I was at TDC on LH compression stroke and rotated the crank 83* CW or 277* CCW then should the right cylinder be on its compression stroke or exhaust?
Robert Dell Aquila
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Thanks for the insight I used the wrong mark on my stator to get TDC on RH cylinder. @5twins explained the 4 stroke engine movement before, thanks for that. But when you say valve lash are you referring to the clearance for the tappets?
Bingo! for MOST rephase cranks, as mentioned before there are a few done (backwards). Pretty much positive you have a standard rephase, get your valves set at RH TDC compression and see how it goes.
Yeah was thinking about it after my post, and most (all) degree wheels are marked clockwise. An easy trap for the uninitiated.
PS props for quick response and answering questions, makes it fun to work with you and hopefully get to the bottom of things so you can make "for real" brrm brrm noise!
