277* rephase timing issue?

JNizza92

JNizza92

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Hey guys,

I finally got my bike running (sorta). I am having some issues with timing, I have a 1975 with a rephase, pamco rephase ignition, Hugh's cam, and the crank was done at a local machine shop.

I just re-installed the whole electronic ignition unit as per Hugh's guide.

I will try to explain the problem as best as I can. I have scrolled through the rephase timing threads already and could not seem to understand/apply them to my situation, thus the new thread.

I got the bike running and started to dig into getting the timing correct, so I got out my timing light and started to rotate the pamco unit so that the mark on the alternator line up between the lines that are on either side of the "F".

Also... I measured the temps of the exhaust pipes, the right cylinder was consistently 100*F colder than the left one, assuming I advance the timing 30* to the fire mark, I think that should retard the left cylinder (thus lowering the temp) and advance the right cylinder (thus raising the temp) and the temps will meet at some common point?

I managed to get the mark to the line that is slightly before that (see picture)
0advancecloseup_zps403e24dc.png


I can not advance the engine anymore to get it between the "F" lines because I am maxed out on the slot on the pamco unit... I have been tempted to just dremel out a larger slot...
ignitionrotor_zpsc5ffa70b.jpg


I found out that I am 30* off from where I need to be by making the timing light 30* advanced. when I adjust the light to 30* advanced the marks line up.
advanced30degrees2_zps685f8af0.jpg

advanced30degrees_zps30493597.jpg


any ideas on what to look at next?

Jordan

PS: Photo-cred to iPhone 5s for snapping the high movement pics...
 
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The problem most likely is the use of that preset timing light which is not going to work correctly in this setup. Just set the advance on the timing light to zero and try again.
 
This is where the timing mark lines up with the timing light set at 0* and the pamco rotor maxed out in the counterclockwise direction.

0advancecloseup_zps403e24dc.png


ignitionrotor_zpsc5ffa70b.jpg
 
JN...,

OK. Trying to understand what I am looking at. Are you saying that the timimng mark at idle is at the full advance position? Is that true for both cylinders? Even with the plate in the position shown, I don't think it is possible for the timing mark to be at full advance, so I would start looking for the problem in the installation and the condition of the advancer and also check to see that all three of the locating pins are in place. Also check to see that the advancer is not binding in the full advance position. It should snap back when released.
 
correct, the mark is at full advance when the pamco rotor is spun all the way counter clockwise. When the rotor is spun clockwise, the timing mark moves to the left of the full advance mark.

I followed Hugh's write up on the install very closely, I checked to make sure that the advancer snaps back into place and it does, I will double check the things on the right side of the engine when I get out of class for the day.

How do I check it when it is in the full advance position?

Picture of marks:
http://650rider.com/uploads/forums/thumbs/t_full_advance_125.jpg
 
Did you check your advance rod? Make sure that the pin on the pamco side is inserted properly. The hole is conicle shape and the pin needs to go through wider side and out the other. I had a similar problem and that fixed me. Can you post a pic your advance side.
 
JN...,

Still a little unclear. Do you mean when the plate is counter clockwise? Why would you spin the rotor clockwise when it rotates counter clockwise? Are you experiencing the same timing on both cylinders? Just to be clear, the rotor is the part with magnets. It rotates. The part with the sensors is called the plate. Remember that there are at least 16 ways to install the system. That means that 15 of the 16 ways are incorrect. The only sure way to determine if you have it installed correctly is to "walk" the engine through its complete 4 cycles for each cylinder. Did you do that? Here is a link to the installation instructions with a link to Hughs well written instructions as well. Please review both. With 16 different ways to install the system, its easy to get things wrong.
 
When I said "rotor" I meant "plate". When I hook the timing light up to the other cylinder the mark is no were to be found, I can find the mark if I advance the light 77*, it lines up with the full advance mark.

I did install the system by walking through Hugh's writeup, I will go through it again later today.

Here is the advance assembly side...
advanceassembly_zps742cfab5.jpg
 
Unless you put a mark there for the other cylinder, one of the cylinders will be on the timing mark but the other will not be at the timing mark. Remember that this is a 277 degree system, so the timing marks will be 277 degrees different or 443 degrees different depending on who did the cam shaft rework.

The other thing to check is to be sure you have a two magnet rotor and not the standard four magnet rotor.

When I suggested that you walk through the cycles, I meant to actually rotate the engine and observe when the spark occurs, IE: on the compression stroke for each cylinder. You can do this with the spark plugs removed to make it easier to turn the engine.
 
After class today I got out my other timing light (no advance knob or anything) and when I hooked it up and started the bike up, the mark was very close to being between the two "Fire" lines... It is still slightly towards the full advance line.

I can tell that the left cylinder is running well, and the right cylinder is running well most of the time, occasionally it will miss-fire.

I took the bike out for a short ride (<10mins) and I was getting temp readings on the headers of 450* consistently on both cylinders. I think that is about 100* to hot, am I correct?

I will be walking through the cylinders mid-next week as I have a dual-sport weekend trip with some friends over the holiday.
 
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I am having a similar issue.

What was the solution with this timing issue. Is it possible that when installing the cam, you may have been one link off?

Cheers
Dan
 
I am still working on getting things figured out, the bike actually died after that ride and I just now got it running again, college SUCKS, and it was grounding issues elsewhere on the bike.

I took the bike out for a ride and the left cylinder went dead on me, I am almost 100% sure that the pamco failed on that side, I have been in contact with Pete about getting a new unit and should have one before the end of the week.

I haven't checked the cam yet, and the timing mark is still almost between the firing marks but slightly towards the advanced side.

So, unfortunately I have no new information at this time.
 
Sounds like the Mike's XS advance unit are notorious for advancing the ignition too far. I'll toss in the old advance unit and see if that makes things any better.
 
I know this is a little old, but Ive heard from a good source that the new springs from MikesXS are to soft, and need to be modified to keep the advance from coming in to soon. This may be your problem, if the ATU is opening to soon.

HTH but maybe you already solved the issue.
 
I should have updated when I solved the issue. It was the advance mechanism purchased from xs650direct (Canada's version of Mike's XS.

Cheers
 
So I have a similar problem. I installed the cam and crank from Hughs myself for starts.
I aligned the cam and crank per yamaha, Crank line up with the T and the Cam slot(line) is 100% vertical. Now the two dots(magnets) are not 100% horizontal on the rotor but I decided to start it anyways. Well the timing is off exactly just like JNIZZA92.
I moved the the cam chain one tooth put it together and the timing is spot on. The left side lines up. The rotor magnets are 100% vertical but as soon as I go to drive it one cylinder drops out, the Right side. It idles fine, carbs are clean, plug is even wet with gas and there is spark. I know the carbs are clean because the bike ran fine 4 day ago.

Is there any way to find out how to install the cam and also see/check the right side timing? I am wondering if for some reason Hughs might have not installed the cam sprocket 100% with the cam.
 

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