shotgunjoe
XS650 Hunter
Sounds like a good reason to eliminate the auto advance altogether.
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Ok, so to conclude the Pamco being too far advanced, I have verified that my cam is in correct (or very close to the correct timing position, in relationship to the crank). The cam locates the mechanical advance unit, the mechanical advance unit locates the pamco rotor...
Hugh got back with me and mentioned the "new" advance unit from mikes could be suspect. The timing marks on it should line up perfectly, mine did not, it was very visible by eye, that the timing marks on the advance unit were NOT perfectly in line. I did happen to have some old OEM advance unit parts, and what do you know....
They line up perfectly, which corrected almost all of the advance issue.
From there I just had to adjust the Pamco plate a small amount to get the timing right on Hugh's "Fire" mark on his PMA supplied sticker. The mark on my PMA rotor has be verified to line up with the TDC mark on the sticker while #1 is at TDC....
Hugh got back with me and mentioned the "new" advance unit from mikes could be suspect. The timing marks on it should line up perfectly, mine did not, it was very visible by eye, that the timing marks on the advance unit were NOT perfectly in line. I did happen to have some old OEM advance unit parts, and what do you know....
They line up perfectly, which corrected almost all of the advance issue.
From there I just had to adjust the Pamco plate a small amount to get the timing right on Hugh's "Fire" mark on his PMA supplied sticker. The mark on my PMA rotor has be verified to line up with the TDC mark on the sticker while #1 is at TDC....
Are you referring to the slash marks on the little advance disc and the advance unit main plate? The ones on my original unit don't align exactly, never have (yellow arrows), but I just attributed it to wear in the unit. It's always timed up fine though .....
Are you referring to the slash marks on the little advance disc and the advance unit main plate? The ones on my original unit don't align exactly, never have (yellow arrows), but I just attributed it to wear in the unit. It's always timed up fine though .....
5Twins,
Yes that is exactly what I'm referring too. Mine were off a little more than your picture, and the OEM one lined up almost dead on. It's fairly simple though (now that I understand what all is going on), this devices locates the pamco rotor, that needs to be timed to the crank. So if the advance unit locates the pamco rotor, say 5 degrees one way or the other from nominal, well you'd see 10 degrees off at the crank when you check your timing...
Changing the advance unit didn't fix all of the advance condition, I did still have to adjust the pamco plate a bit, but well within it's adjustment range...
gregoryp
XS650 Enthusiast
I am having a similar problem with my rephrased motor. It's a 1981.
I put it back together over a year ago, but am finally getting the rest of the bike finished. Now trying to get the motor dialed in and ready to ride. I have a Hugh's cam and crank and a Pamco ignition. When I checked the ignition timing I had to fully retard the Pamco to get the left cylinder to 15 degrees. When I checked the right cylinder (made a separate TDC mark on the stator for that side) I'm getting a reading around 25 degrees. (checked TDC with a piston stop on both cylinders) I only have marks at 15 and 40 degrees, so the 25 is a guess. I assembled the Pamco per Hugh's blog and he said the magnets should be horizontal, sort of at 10:00 and 2:00 when installed properly. Mine were slightly rotated counter clockwise (see picture). Then I read a thread and decided to check the lobe center to see if my cam was maybe off by a tooth. I set the valve lash at 0.012" per the clymer manual and put a dial indicator on the intake spring retainers. My calculations are as follows:
Left Cylinder - Open 32 BTDC, close 64 ABDC
32 + 64 = 96
96 + 180 = 276
276/2 = 138
138 - 32 = 106
Right Cylinder - Open 31 BTDC, Close 61 ABDC
31 + 61 = 92
92 + 180 = 272
272/2 = 136
136 - 31 = 105
Based on that it looks like the cam is in the correct position.
I'm not sure why I would get different timing reading between the two cylinders, doesn't seem like that is possible? Also why would I need to fully retard the timing if the cam is dialed in correctly? I had the Idle low enough, so it doesn't seem like I'm getting any advance and when I rev the motor the left cylinder advances to 40, so that all seems ok.
I know there are a bunch of ways to setup the Pamco, so I'm hoping I missed something and just have that wrong. Don't really want to have to pull the motor out of the frame and take it apart to change cam timing.
Also looked at the marks on the mikes XS advance plate and advance cam and they seem to line up fine.
I also went back and checked the lobe centers using a more standard method of taking the readings at 0.050" of lift with zero lash and I seemed to get more repeatable results. Here they are:
Right intake open 10 BTDC, close 38 ABDC for a lobe center of 104
Left intake open 12 BTDC, close 39 ABDC for a lobe center of 103.5
Questons:
* what would make the timing read different between the two sides of the engine?
* what would make the pamco require full retarding to get to 15 degrees?
* what is the correct lobe center for the 447 cam (saw 106 in another post) and how far would it move if I was off a tooth?
* I've seen a few ways of checking if the cam was off a tooth, but none seemed really conclusive anyone have any hard fast numbers? The Clymer book says the intake opens at 35 BTDC and closes 69 ABDC, but not sure what valve lash should be for this reading, I'm guessing the 0.0024"?
I put it back together over a year ago, but am finally getting the rest of the bike finished. Now trying to get the motor dialed in and ready to ride. I have a Hugh's cam and crank and a Pamco ignition. When I checked the ignition timing I had to fully retard the Pamco to get the left cylinder to 15 degrees. When I checked the right cylinder (made a separate TDC mark on the stator for that side) I'm getting a reading around 25 degrees. (checked TDC with a piston stop on both cylinders) I only have marks at 15 and 40 degrees, so the 25 is a guess. I assembled the Pamco per Hugh's blog and he said the magnets should be horizontal, sort of at 10:00 and 2:00 when installed properly. Mine were slightly rotated counter clockwise (see picture). Then I read a thread and decided to check the lobe center to see if my cam was maybe off by a tooth. I set the valve lash at 0.012" per the clymer manual and put a dial indicator on the intake spring retainers. My calculations are as follows:
Left Cylinder - Open 32 BTDC, close 64 ABDC
32 + 64 = 96
96 + 180 = 276
276/2 = 138
138 - 32 = 106
Right Cylinder - Open 31 BTDC, Close 61 ABDC
31 + 61 = 92
92 + 180 = 272
272/2 = 136
136 - 31 = 105
Based on that it looks like the cam is in the correct position.
I'm not sure why I would get different timing reading between the two cylinders, doesn't seem like that is possible? Also why would I need to fully retard the timing if the cam is dialed in correctly? I had the Idle low enough, so it doesn't seem like I'm getting any advance and when I rev the motor the left cylinder advances to 40, so that all seems ok.
I know there are a bunch of ways to setup the Pamco, so I'm hoping I missed something and just have that wrong. Don't really want to have to pull the motor out of the frame and take it apart to change cam timing.
Also looked at the marks on the mikes XS advance plate and advance cam and they seem to line up fine.
I also went back and checked the lobe centers using a more standard method of taking the readings at 0.050" of lift with zero lash and I seemed to get more repeatable results. Here they are:
Right intake open 10 BTDC, close 38 ABDC for a lobe center of 104
Left intake open 12 BTDC, close 39 ABDC for a lobe center of 103.5
Questons:
* what would make the timing read different between the two sides of the engine?
* what would make the pamco require full retarding to get to 15 degrees?
* what is the correct lobe center for the 447 cam (saw 106 in another post) and how far would it move if I was off a tooth?
* I've seen a few ways of checking if the cam was off a tooth, but none seemed really conclusive anyone have any hard fast numbers? The Clymer book says the intake opens at 35 BTDC and closes 69 ABDC, but not sure what valve lash should be for this reading, I'm guessing the 0.0024"?
gregoryp
XS650 Enthusiast
gregoryp
XS650 Enthusiast
Out of desperation I pulled the rocker box to look at the cam. With the left cylinder at TDC the notch looks perfectly vertical and the dot on the opposite side looks aligned with the head sealing surface. My next thought is that the cam gear is not in the right position. Anyone out there that has degreed a bunch of these 447 cams have the correct method for checking the timing. For example what do you set the lash at and what are the opening and closing values for the valves?
I've done it two ways, per the Clymer book set the lash at 0.012" and the intake should open at 47 degrees. I don't get that, I'm getting 31 and 32 per earlier post.
In the Specifications section for an 81 it lists values, I think opening was either 35 or 36 and lists the running lash setting of 0.002", so I'm guessing these values are at that lash setting.
I just want to make sure I'm using the correct method and values before I start trying to reposition the cam gear. Don' see this fixing my ignition timing difference between the cylinders, but if I can find a happy medium between them I think that would be ok.
Thanks
Greg
I've done it two ways, per the Clymer book set the lash at 0.012" and the intake should open at 47 degrees. I don't get that, I'm getting 31 and 32 per earlier post.
In the Specifications section for an 81 it lists values, I think opening was either 35 or 36 and lists the running lash setting of 0.002", so I'm guessing these values are at that lash setting.
I just want to make sure I'm using the correct method and values before I start trying to reposition the cam gear. Don' see this fixing my ignition timing difference between the cylinders, but if I can find a happy medium between them I think that would be ok.
Thanks
Greg
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gregoryp
XS650 Enthusiast
Pulled the rocker box to look at the cam. Looks like the notch and the dimple line up where they should, so at this point I'm guessing the cam gear needs to be rotated. Can anyone confirm the specs for lash and valve opening and closing? The Clymer manual says intake open at 35 and close at 69, but I'm guessing this is at 0.0024" of lash?? Book also says intake opens at 47 degrees with 0.012" of lash. Do you get the same result with either, or is one a better way to go than another? Doesn't solve my difference in ignition timing between each side, but maybe if I get the cam right I can find a happy medium with the timing.
Attachments
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gregoryp
XS650 Enthusiast
ippytattoo
Just another grumpy old hack.
Okay here goes, if you look at the first picture in the attachments in post #48 you will notice that the notch is actually in the cam itself and not in the gear so the left side is timed correctly assuming that you made you marks correctly on the rotor using a degree wheel and piston stop. Looking at your 3rd pic in the attachments in post #48 I see what looks like a weld around the camshaft so I am assuming that this is Hugh's handy work so I would be willing to bet that the timing for the 2 sets of valves are spot on. In order for there to be that much of a difference in spark timing between the 2 cylinders the placement of the sensors on the Pamco plate would have to be off by 10* and these plates are probably made by a cnc machine. I am not saying that it is impossible for these 2 things to happen but it is very very unlikely.My suggestion would be to double check your timing marks on the rotor using a degree wheel and piston stop. Hugh had a great write up on his blog on exactly how to do this.
I wish I could help you out, but sounds like you've covered most of the bases. You'll just have to go over everything again. In the end I wound up opening up the pamco rotor internal key slot so I could cheat the rotor into position. I only did this after triple checking everything you've brought up. Hugh did chime in at one point and noted he has had several brand new advance units from mikes that were just off too much to get things were they needed to be. I did look into getting an OEM replacement, but couldn't find one, so I just modified the pamco rotor. I really didn't want to do that... But given everything else was verified I figured why not.
pamcopete
Ride.Enjoy.Life is Simple
This thread has gone on for a while so I don't remember if you were asked to make sure that all three locating pins are in place for the advancer, slotted disk and PAMCO rotor. There are two pins located on either end of the advance rod. The third pin is in the cam shaft and it locates the advance plate. It's usually the third pin that is overlooked.
gregoryp
XS650 Enthusiast
Thanks for the feedback. The cam and crank were done by Hugh and am not questioning his work in any way. I have double checked my timing marks, itnitally it was done visually looking thorugh the spak plug hole, but then to be sure I made a piston stop and set it up thanks to Hugh's isntructions. I also assembled the Pamco per Hugh's instruction. All three pins are in place on the advance shaft and on the cam. Just for some background new parts in the motor are rods, pistons, cam chain and guides, valves, valve lash screws, cam and crank rephased by Hugh, pamco ignition and PMA charging system.
I beleive I have two issues, the cam timing seems to be off. What I'm not 100% comfortable with is what the actual specification for the 447 cam timing.
If I use the lobe center method with zero lash and read opening and closing of the intake values at 0.050" lift I get a lobe center of 104. I've seen posted, I think by mriggs that the lobe center specification is 106. I think that comes from using the opening and closing values published in the manual to calculate lobe center? However those values seem to be based on a lash value of 0.002" and from the lobe center theory it sounds like that can lead to inaccuracy due to variation in the cam base circle. But since these are published numbers by Yamaha and not measurements it may be irrelevant.
The manual also says to check cam timing set the lash to 0.012" and the intake valve should start to open at 47 degrees BTDC, with this method mine is opening at 32 degrees.
The second issue is that when I put the timing light on the left and right cylinder with respect to their TDC marks the right cylinder seems to be advanced 10 degrees more the the left.
I think the plan will be to try and rotate the cam gear and get the cam timing right, then tackle the ignition timing.
Can anyone confirm the correct or best method to check the cam timing?
I beleive I have two issues, the cam timing seems to be off. What I'm not 100% comfortable with is what the actual specification for the 447 cam timing.
If I use the lobe center method with zero lash and read opening and closing of the intake values at 0.050" lift I get a lobe center of 104. I've seen posted, I think by mriggs that the lobe center specification is 106. I think that comes from using the opening and closing values published in the manual to calculate lobe center? However those values seem to be based on a lash value of 0.002" and from the lobe center theory it sounds like that can lead to inaccuracy due to variation in the cam base circle. But since these are published numbers by Yamaha and not measurements it may be irrelevant.
The manual also says to check cam timing set the lash to 0.012" and the intake valve should start to open at 47 degrees BTDC, with this method mine is opening at 32 degrees.
The second issue is that when I put the timing light on the left and right cylinder with respect to their TDC marks the right cylinder seems to be advanced 10 degrees more the the left.
I think the plan will be to try and rotate the cam gear and get the cam timing right, then tackle the ignition timing.
Can anyone confirm the correct or best method to check the cam timing?
Lets see... 3 things affect the ignition timing in this case.
1. the right side of the cam (which locates the Pamco rotor thru the pin/advance plate)
2. the rotational spacing of the components on the Pamco plate
3. the rotational spacing of the magnets on the Pamco rotor
If the cam were mis-rotated (considering it's source I highly doubt it) it would not change the ignition timing as far as one cylinder relative to the other because the pamco rotor is rotating 1/2 as many times as your crank, no matter where the other half of the cam was at. Of course this is assuming the sprockets on the crank and cam are correct. So once one cylinder is set, if the spacing on the Pamco components is correct, everything should fall into place.
Don't forget that a 10° reading at your crank means only 5° at the cam, 5° isn't much movement. Especially when you consider all of the stacked up slop in between the advance plate / cam pin, and the fly weights and their key slots. And all of these components are relatively small diameters which again makes 5° a pretty small movement.
If I am WAY wrong here someone please correct me, as I'm trying to work all of this out in my head to better understand it also.
Also I just have to say, I highly doubt any of Pamco's components are off as well as Hugh's work.
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Just for an example, a 5° rotational movement at the circumference of a 2.00" circle is about .087". Actually a little more than I was thinking. I'm not sure what the outer diameter of the Pamco plate is, but if we knew that, technically we could anticipate how much to move it (using the corner at the outer notch as a reference), and know what the timing change would be.
Sorry I know that is a little off topic.
Greg I think you have the right idea though as far as looking at each issue independently, starting with the one that drives the other.
Sorry I know that is a little off topic.
Greg I think you have the right idea though as far as looking at each issue independently, starting with the one that drives the other.
gregoryp
XS650 Enthusiast
RCGRT I agree with your three points above. I doubt that there is a defect in the cam work or pamco. My guess is more likely that the cam gear wasn't installed correctly from the PO, there were a few dents in the top of the original pistons indicating that there may have been some valve contact at some point in its life. I'm not sure if Hugh takes the cam gear off to do his work, but if he put back where it was it may have not been right to start with. I've never ridden the bike, so I don't have any past knowledge of how it ran before. I get a radius of ~0.59125" for the magnets in the rotor, which gives about 0.0103" per degree and at 5 degrees that would be 0.052"
Yep, that's what I was getting at, that is a pretty small movement.
All though moving your cam sprocket to get you cam timing spot can't hurt anything, I don't believe that will correct the timing relationship from one cylinder to the other...
Do like you said and eliminate one at a time...
All though moving your cam sprocket to get you cam timing spot can't hurt anything, I don't believe that will correct the timing relationship from one cylinder to the other...
Do like you said and eliminate one at a time...
Ok all I know this is a older thread, but I need a quick yes or no. I recently did a tank on the bike so it was down. While doing this I decided to fix a leak that was on the left cylinder cam cover( behind the cam cover plate) The PO installed this pamco ign, the bike is rephased) I marked the module plate and plate it bolted to so that when I reinstalled it it would go back in the same way line to line. Now after I got the bike back together, addressed the leak, I reinstalled the rotor( 2 magnets in it) However I noticed that the cam rod may have turned( not the engine or cam) It looked to me the rotor could only go on that rod one way, but the pin in the rod slides. Would this have anything to do with the timing advance or retard if the actual rod turned and did not go back in the same way? Thanks, hope that made sense
pamcopete
Ride.Enjoy.Life is Simple
Raty...,
Well, it's pretty difficult to answer that question. I would suggest that you start over by reading the installation instructions for the 277 PAMCO on www.yamahaxs650.com and also take a look on the HHB site where Hugh has posted some very detailed instructions on how to install the PAMCO on a 277 engine.
Well, it's pretty difficult to answer that question. I would suggest that you start over by reading the installation instructions for the 277 PAMCO on www.yamahaxs650.com and also take a look on the HHB site where Hugh has posted some very detailed instructions on how to install the PAMCO on a 277 engine.
If you mean the pin slid through the so it protrudes out the other side of the advance rod?
I don't recall exactly but I don't think the pin will slide through the advance rod. I think there is a small lip inside the hole in the rod to prevent this.
If it did it would throw the ignition timing out 180 degrees.
Leo
I don't recall exactly but I don't think the pin will slide through the advance rod. I think there is a small lip inside the hole in the rod to prevent this.
If it did it would throw the ignition timing out 180 degrees.
Leo
