timing -problem getting right side to align...

Snake

hi, i have a rebuilt 82 motor, made of of different motors. my question is re timing, i am having trouble getting the right side to time to the "F" mark (yes this bike has points), there is not enough movment to get it there, could it be the timing mark is "wrong", if so, what do i do, or is there another problem?

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

Timing these bikes with points is always a question of minimising errors.

Either accept you got it as close as you can, or buy an electronic ignition system, if you can afford one, get with with a programmed advance curve. You time them to the mark and rev out and they line up perfectly timed to either end of the curve.

I recommend boyer, although it has limitations in setup due to its design. It has worked without fault for me on every bike I've fitted it to. A massive improvement in startup and general reliablilty and you can always get the timing BANG on.

jpowell

Well you're supposed to start with the right side, as it thats the whole plate, then the left side. are you too far advanced or retarded??

Retiredgentleman

Snake;
The problem may be related to cam chain stretch. I had the same problem on my bike. The fix is to remove the large back plate and simply file the slot that the screw goes through, so that the slot is longer. I put mine in a vice and used a small round file.

pamcopete

RG

Well, if the cam shaft chain has stretched to the point where you can't set the ignition timing, then that means that the valves are not opening and closing when they should as well, because the points are driven from the cam shaft. So, time to change the cam shaft timing chain.

If you install an electronic ignition system that allows you to time the ignition in spite of a worn out timing chain, then you are just masking the larger problem.

In this particulat case, with an '82 motor, if you are using the stock stator housing, then the timing marks can be adjusted, or, can be moved out of their correct position. So, you should verify the timing marks by checking for TDC to see if the timing plate is set properly.

Snake

pamcopete. thats exactly what i was wondering, but thanks RG, im sure as usual it will be a combination of a few things. i have recently adjusted the cam chain tensioner. then i set the points gap. then i adjusted the right set, but couldnt move it far enough to have the mark hit the "F" zone. that what got me thinking i need to check if these timing marks are correct, how do i check for TDC?

Snake

by the way, im using a strobe light to do the timing.

Snake

jpowel, iit's retarded, and yes, i started with the right side

Retiredgentleman

pamcopete;
Yes, I agree pete. If the chain is stretched, then the valves opening and closing positions are probably not 100% correct. I used the elongated slot in the back plate as a temporary measure, and am now installing a new cam chain. My bike ran really well the last 2 driving seasons, with this modification using points ignition.

I'm now up-grading to Pamco ignition, along with new cam chain, front chain guide, rings, valve seals, valve lapping, etc.

Snake

thanks guys, i found a thread re checking for TDC, i hope the chain is good as it is a new rebuild...

xsleo

snake the way to find top dead center is to pull the plugs so the engine turns easy. turn the engine over with your finger in the plug hole. as the piston come up on compression, air will push out around your finger. as this is happening watch your timing marks. when they get close. stop, get a piece of dowel. put it in the plug hole. tip the end that is in the plug hole down till it touches the top of the piston. now very gently turn the engine over, watching the end of the dowel that sticks out into your hand for when it reaches the lowest point. when the dowel reaches this low point, the piston is at it's highest point. you may have to roll the engione back and fourth a few times to see this well. when you get the piston up/ dowel down then look at your timing marks. the mark on the rotor should line up at the tdc mark. if you have the points type stator you can remark the stator or just remember how much it is off and allow that much when you set your points. if you have the electronic ignition stator the marks are adjustable, just reset the mark. with the timing marks lined up at tdc, on the end of the advance shaft that runs thru the cam the pin that holds the points cam in place should point straight up or down with the advance wieghts are held in. if not then your cam chain may need replacement.

Snake

cheers xsleo, i shall have a go at that, i hope it nots the chain as i don't want to do that yet

Snake

ok, so the TDC mark is correct, that means if i am unable to slide the right set of points to the correct position, then my cam chain is streached, is that correct?

Snake

come on people...iot's only 7:22 saturday night.....are you all asleep already.....:)

xsleo

a good possibilty. if your point gap is a little wide, that can have an effect too.if your setting them to .016 try .014 it may help some. if you have to go further i would change the chain. the hard part of the chain replacement is pulling the engine from the frame. if the compression is good and it's not useing oil i would just do the chain and the front chain guide. if the chain guide is original then it's about ready to crap out. when they get old they break apart, then the chain rides on the aluminum bracket.

Snake

xsleo, thanks for that. i set the points gap to .14.....but i will have another play now, as it is a nice warm still evening ..so it will annoy the neighbours....

pamcopete

snake

Before you condemn the timing chain, check the three locating pins on the cam that locate the position of the points cam. One pin for the cam itself, one pin for the slotted rotor part of the advance mechanism and the third pin that locates the "basket" that holds the weights. Also, check for excessive wear in the weights and the mounting pins for the weights.
ake sure that the springs are fully retracting the weights as well.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Besides rotating the plate, sometimes there is some side to side or up and down movement in it as well. This may need to be played with to get the setting right. The plate may be pushed hard over to one side.

Running out of adjustment slot is a good indicator of cam chain stretch. With my old original chain, I was nearly out of slot and would have needed to start filing it soon. After I installed a new cam chain, the plate timed up correctly with the screw right in the middle of the slot.

Retiredgentleman

Snake;
You said it was a new rebuild. Is it possible that the camchain was installed 1 tooth out of correct timing. That would put everything 10 degrees out of time.

Pamcopete brought up a good point; if the bob-weights or the slotted disk are worn excessively where they mesh together, that could introduce some error.

xsjohn

RG.....from my little bit of experience with cam timing I doubt if it would even run one tooth off.....and if it did it would be horrid at best.....easy enough to check though.......just .020-.030 thou of movement in that chain wheel is quite a change I found....

1 degree per .010 thou movement measured at the press fit of the chain wheel and cam....

...xsjohn

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

I made my point earlier in the thead, as even in the manual it suggests that getting the points right is a question of minimalising the error.

I've had quite a few bikes with points in the past and never been able to time them, leave them, ride them, come back after a short time and find them where I left them...

Electronic Ignition is cheap and effective, and does away with this..

Sorry if its an unpopular point..but I feel that I should make it non the less Smile

Surely a chain that badly worn would be noisey and out of adjustment?

xs1961

BOYER BOYER BOYER BOYER..... Wink

Snake

thanks guys, a new day has dawned...sunday morning...and...it's raining....anyway, i shall check the weights etc. but i suspect either. 1. when i recently adjusted the cam chain i went to far...or 2. the guy who did the rebuild used the old cam chain....:(...but i shall also play with the points plates, as the bike seems to be running very well otherwise

xsjohn

Should be easy enough to tell if the chain is stretched (worn) excessively....about 3/4 of an inch or so of adjustment left on the thredded portion of the adjuster would suggest a very good or new chain......very little threads left being a stretched chain.....in between well you know......

When a friend of mine acquired his 79......the PO had removed the big nut and just put the acorn nut on....... bit wore out there I would think.....

xsjohn

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