I searched, still need PAMCO help- wont advance?

[THEbananaDZL]

So this is what I have, the bike will run and idle perfect, but when trying to rev up it seems the ignition wont advance timing and the bike with sputter, pop, and never really rev up.

Bike is a 1981, mods are PMA from Hughs , PAMCO kit from Mikes, XS pod filters, carbs cleaned and rejetted +2 mains +1 pilot, headers only until I finish my exhaust, kick only....

Now I don't believe this to be a fuel problem as I have had no chance from stock jets to the larger ones, even with a shot of ether there is no change. These are the things I have tried.

-Timed TDC mark at idle- runs great
-While under 50% throttle adjusted PAMCO plate to which there was no change in poor running
-Rubber banded advance weights down, no change
-Removed weight springs, no change
-Reread Petes install and all looks to be good (solid instructions pete)
-Did the snap back test.... Would work fine when bolts on advance rod were back off slightly, when tightened they would stick. (I dont have a Tq wrench to goes down to 90 in lbs)
-With all the above things I had about 75% throttle input and moved the timing plate with NO CHANGE.

Now I installed this a little over a year ago then left for basic military training, now that I have the time to get back to working on it I would like to get her on the road. What should be my next step? Where did I go wrong? Or what else should I search? The reason I believe it to be in the advance is cause it idles like a champ when set at the correct timing.... just starts to shudder, pop, and not rev up much at all under throttle.

Any and all help would be great... I spent my 23rd birthday yesterday staring at it lost, confused, and lonely...


Great site, tons of info, I troll around here often.... hoping someone much wiser than I can give me a quick hand. Thanks!

-Alec

 

[pamcopete]

The Banana,

If the advance is sticking, as you said, then that is the problem. No advance means the timing is wrong at any engine speed above idle.

There is a separate section on the web site for installing the advancer and advance rod. Please review that as there are a few pointers there that help with a stuck advancer or advance rod.

http://www.yamahaxs650.com/installing_the_advance_mechanism.htm

(Welcome home!)

 

[EvenmoreXS]

Welcome back from basic and HAPPY BIRTHDAY!

You will get it for sure,..no worries...

I would double check your voltage at the battery and make sure your good there...and check it again at the coil......It would be nice to make sure the voltage climbs when you rev it, but got to get it past idle first.

The sticking advance not snapping back doesnt sound quite right....

 

[EvenmoreXS]

typing over me again I see, Pete........

Great job on the quick response...

 

[retiredgentleman]

There was another thread recently, that had a sticky advance rod when the nuts were tightened properly.

I suggested that the Mikesxs advance rod was shorter that OEM part. The advance rod needs to be slightly longer than the camshaft, so that you have a small amount of axial free play. A thin shim washer of say 0.010" or 0.015" placed underneath the slotted disc, might be all thats required................just speculation at this time.

I believe Pamcopete had offered to send him a new advance rod.

 

[5twins]

Well, if it's a 1981, then it would have needed bushings installed in the cam. Maybe they're not seated in all the way and sticking out some?

 

[THEbananaDZL]

Wow, thanks or the fast responses! I'm not home, just stationed out here in Oklahoma, but got the bike shipped out from Massachusetts.

Pete, I will take a look again, I may just pull the whole thing out, try to reseat the brass bushings making sure they are flush.

But wouldn't removing the springs and propping the weights "open" or out give the engine advanced timing? And when the nuts were slightly loosened the snap back tested fine, still no change.

 

[pamcopete]

TheBanana...,

Are you using a timing light or just observing the lack of engine response when you did the weights tied fully extended? Because, you are correct, that would give you full advance, but the only way to verify that is with a timing light.

 

[jd750ace]

For the time, money, and frustration I can't understand why you would go with the ATU I stead of the electronic advance and be done.

 

[XSLeo]

I noticed that in post #1 you said you timed to TDC, that's wrong you time to the between the two marks on each side of the F mark.
These two marks beside the F is the range you set points to.
I know this isn't your problem but something you should know.
I agree that your advance rod binding is the problem. I assume the rod you are using came from Mike's as part of the kit. Often these rods are a bit long. Mine was.
Checking to see that the bushings are flush with the cam ends is likely the problem. They may not press in further. Your 81 had the TCI so no bushings were installed at the factory. It can be very hard to get the holes in the cam 100% perfect. Leaving a bit of rust in the bottom inside corner of the hole. You might have to come up with a way of cutting back the projecting end of the bush flush with the cam.
Leo

 

[TwoManyXS1Bs]

There was another thread recently, that had a sticky advance rod when the nuts were tightened properly.

I suggested that the Mikesxs advance rod was shorter that OEM part. The advance rod needs to be slightly longer than the camshaft, so that you have a small amount of axial free play. A thin shim washer of say 0.010" or 0.015" placed underneath the slotted disc, might be all thats required................just speculation at this time.

I believe Pamcopete had offered to send him a new advance rod.

Here's that other thread: http://www.xs650.com/forum/showthread.php?t=35068

 

[THEbananaDZL]

Thank you all for the info, and ideas. Pete, a light was used and if I can remember correctly it was erratic with the weights open although it would act the same as if they were closed, even with adjusting the timing while running.

JD, the E-advance wasn't out I don't believe when I bought my pamco a little over a year ago, and I'm not one to just throw money at problems, I'm sure I can get it to work as advertised...just gonna take some of my time.

Leo, I will have to look at the bike again later but I do remember having a hard time with those bushings fitting. i may have to shave them down so that they are flush with the engine case.

Wont be able to get to this till later, but thank you everyone for the help. I will read that other post about the rod length.

 

[pamcopete]

TheBanana,

OK. The coil produces a positive voltage on one of the plug wires and a negative on the other. The timing light only works properly on the negative wire, but there is no easy way to determine which that is, so try the other wire. If you are using the positive wire, then the timing light will be very erratic and unreliable.

 

[THEbananaDZL]

Okay well I got into the garage the other day and got to work out some kinks on the bike here is what I did and found.
I first removed the PAMCO, trimmed down the brass bushings on both sides and reinstalled. FIXED BINDING problem. Snapback test was good.
I next started the bike and timed it to the FIRE mark while at idle. did it off both wires with not much difference, Idled well. Tried to rev up, Problem still occurred.
Did some "testing" and found of that it would only fire on the number 1 cylinder once throttle was input. Removed the plug wire from #2 and held it close to the spark plug and idle and it fired normal, under throttle it would spark erratically.
I removed the plug wires from the Mikes coil and switched them, the problem then moved to the #1. making me believe that the problem lies in the rear post (closest to the round and terminals)

But listen to this, mid way through all this testing... After regretting the fact that I removed the starter and made it kick only as my leg was about to fall off from the amount of kicking and kick back it had endured I started the bike without making any changes and when it started it seemed to idle a little faster and smoother, then when I twisted the throttle she came to life and reved like crazy! ran perfect it seemed! my heart was pounding, smiling from ear to ear, problem solved....or so I thought.

I looked down and saw that the positive wire from the battery to my fuse box with a kill switch was resting against the battery box and tiny blue sparks were popping right along as the bike ran, I moved the wire and soon after the bike died, tried to restart, the old problem came back!!! I tried to duplicate with no luck. WTF!! I know the bike will run now, but how?

my next round of questions, Does the fuse box have to be grounded? Why would this make a difference? WHY WONT IT JUST RUN!? and what else could be the cause of the problem in the coil? Still advance?


Sorry for the long winded post, just want you guys and gals to know all that was done. Electrical is not my strongest point...

Thank you in advance!

Alec

 

[gmlafever]

I'm new here and joined this forum in hopes of solving this exact same problem. I purchased my kit from MikesXS for my 1980 xs650. My advance bound up when I tightened both nuts on the end of the advance rod also. I have fixed that but I am still not showing any advance when using the timing light, though my advance mechanism flares out when I rev the motor. Idles and starts just fine, just can't ride it. Any help would be greatly appreciated!

 

[pamcopete]

gmlafever,

1. If you are using a timing light with a built in preset for the advance, throw it in the trash or at least set the preset to zero.
2. If the advance springs are weak, then all of the advance will be used up at idle.
3. If the advance springs are too stiff, then the max advance will occur at a higher RPM.
4. Weak or strong springs will result in either no advance or late advance.

 

[gmlafever]

Thanks for the reply! Is it typical that the springs that come with the kit would have an incorrect tension? What RPM should I expect full advance? Right now it will rev up to 3K-4K and start to cut out. My timing light has no adjustments. I will do a search and try to order a variety of spring sets.

 

[pamcopete]

Thanks for the reply! Is it typical that the springs that come with the kit would have an incorrect tension? What RPM should I expect full advance? Right now it will rev up to 3K-4K and start to cut out. My timing light has no adjustments. I will do a search and try to order a variety of spring sets.

You should get full advance at 3200 RPM. If you don't, then all sorts of things can happen, including loss of power, popping and snorting and just general bad behavior.

I don't know of a source of springs that would have the correct tension right out of the box. You will have to stretch or compress them for best results. When ordering, get two or three sets of springs because you will most likely ruin one or two sets in the process of tweaking them to the correct tension. If they are really too tight, you can try removing one of them. The weight without its spring will still function to advance the timing.

 

[gmlafever]

Looks like that was the ticket! I was getting full advance, with one spring at over 5000 RPM. A little stretching of the springs and I now get full advance at a little over 3000 RPM and was able to cruise it around the block. It's not perfect yet but at least I know everything is working properly. I can't thank you enough for taking the time to help me out!