Engine Knocking

So after finishing the engine rebuild and firing up the motor I am noticing a knocking sound around 2500-3000 rpms. Ill first start with what I did to the motor. Pulled the head and installed new gaskets. Pulled the valves and cleaned them up. New valve seals and a minor porting of the head, pretty much just tried to clean up the casting. I am fairly certain that I have the cam in correct postion, but am wondering if I could be a tooth off? I got pretty good compression, high 140's. I've also installed a pamco system. This is where I'm also a little worried. My bike is an 81 so it no longer has two F on the stator. It has two lines torwards the front and then a third line. At idle I am setting the timing between the two marks torwards the front. But when it revs it advances way past the marks. I've uninstalled and reinstalled the atu just to make sure I did everything correctly. My question is from idle to redline will the timing always be between those marks? And if my timing is off that much will it cause knocking? I'm definitly noticing the knockin more when I'm riding. I've reduced the gearing to 17-31. I've heard XSJohn mention that you need to retard your timing when you're running bigger gears. I'm just looking for some info and suggestions before I pull the motor and double check all my work. I think everything is back together correctly so I'm leaning more torwards the timing. I've also tried timing on both plug leads and my gun preforms the same on both. I am really looking forward to hearing back cause I'm dying to ride my bike. Thanks

Knocking while in neutral at 2500-3000rpm?
Was this engine running before you tore into it? If so was it knocking then?

As far as the gearing, not so much knocking but lugging,'specially around corners.

I don't notice it as bad in neutral. I didn't knock at all last year. And it ran fine, leaked a little oil. The motor has 12k on it

I'd suspect a tooth off, though I don't know how the pete system would figure in.
Heck, I pulled my engine twice after a rebuild due to off timing. I fixed it the first pull and did the second for.......idiocy.
So is it lugging or knocking.

I'd check a manual for the stock settings on the alternator, bottom top dead center on the left cylinder, and compare....if they're off then pull the engine and check the cam setup. Easy to allow the front part of the cam chain to slack off if you don't watch out for it and affect the timing. Other opinions may vary.

You can check your cam timing with out pulling the engine.
Take the alternator cover off. Take the points cover off. Roll engine over till the timing marks line up, You have the Pamco, so take off the nut and washers so you can see the alignment pin of the Pamco rotor. With the marks at TDC the pin should point straight up or straight down. If it does the cam is fine. If it is about 10 degrees left or right it is off one tooth.
With the 80 and later stators without the full advance mark Full advance is about even with the left side of the notch in the side cover where the alternator cover goes on. Or to the right side off the notch, I don't recall which. I think either 5twins or pamcopete has a pic somewhere that shows which side.
As far as the knocking it could be camchain tension or valve adjustment. I would check them first.
The 82 engine I am running now had some knocking. I though it was in the lower end. I adjusted the cam chain and valves the noise went away.

I think you're right with the cam being off. I didn't realize, but I'm thinking that when I was putting the locating pin back in the cam was to the right of tdc. So ill take another look. Interesting that the knocking could be valve clearences, I would imagine clearence issues producing a diff sound, like a tapping sound. I'm sure the cam chain tension is fine, the rod that pushes tension is flush to the face of the nut. Thanks for the info and ill check it out tmmrw.

Breahn, I've said it before, I'll say it again. 1 tooth= 10* at the camshaft. The camshaft turns at 1/2 crank speed. 1 tooth=20* at the crank, which is where ignition and valve timing are measured. If you were 1 tooth off you'd know it.

Your ignition is timed to the idle mark, but you have no idea where it is in the advanced mode because your TCI stator has no advanced mark. As rpms's climb the timing should advance to around 40* BTDC, and you should see the rotor mark move to that point under the strobe. The TCI bob weights can wear and spread the advance curve, which is why timing with any mechanical advance mechanism must be checked in advanced mode as well. You need to find TDC, attach a degree wheel, and create an advanced timing mark at 40* BTDC. If you get knocking at that setting, or a clean-burn line wider than .01" or so on sparkplug electrode tips or aluminum flecks (looks like a sprinkling of pepper) on the plug insulators after a hard run, retard ignition timing a couple of degrees and test again. To find TDC, don't assume that the mark on your stator plate is correct.

If im not to use the tdc plate on the stator, then how do you determine tdc? also, how will a bike run if the cam is off one tooth? do you have a visual of the degree wheel you would use for this situation? Will i get a knocking sound if the cam is off a tooth? is there something that typically causes knocking, certain symptoms? its very helpful to me if i see photos being that i dont have alot of expirience with motors. thanks griz

by the by - if you want to scribe a full advance mark, i'm pretty sure you can just add 28 degrees to the idle mark.

I got this image from Pete when i was asking him about timing.

Now is the postion that i want to be at when im timing at idle? And griz are you saying the mark on the stator plate can become inaccurate when locating tdc. Im starting to remember seeing someone printing a compass with 360 degrees and taping it to a cd. How would you locate 40*BTDC? OR how would I add 28* to the idle mark. And to be clear 28* degrees would be goin to the left of the stator bracket?

If you were a tooth off on the cam the motor would barely run, assuming you could start it at all.

The idle marks define a range centered on 15* BTDC. The advance mark should be at 40* BTDC. Scribing the advance mark 28* to the left of the rightmost mark in the idle range would put you in the ballpark--assuming the timing plate is in the right position.

I locate TDC using a piston locater (a sleeve that threads into the plug hole, with a plunger that follows the piston) and degree wheel (I use a Domi-Racer unit), indexing to the center point of the readings at equal drop either side of TDC; but TDC can be ballparked by rotating the engine by hand until the left cylinder is rising on compression (valves closed), sticking a piece of wood dowel in the plug hole, and finding the highest rise; that'll get you within a couple of degrees. Whatever you use to locate the piston, lift it as you turn the crank or side load will jam it. That method is close enough if you follow up by reading the plugs for detonation (see article at www.strappe.com ).

To locate an advance mark, get the smallest plastic wall anchor and screw you can find, jam fit the anchor in the hole in the end of your crankshaft, and get a clear plastic protractor from an office supply store. Run the screw through the center mark of the protractor and into wall anchor in the end of the crank.

what do i line the protractor up with on the stator bracket? so im prob no off a tooth cause the bike idles really well. it just makes the knocking sound and hesitates as the motor revs.

Rotate the motor CCW to TDC with a wrench on the charging rotor nut, locating the piston with a plunger, and look to see if the rightmost (TDC) mark on the stator plate is aligned with the charging rotor mark when the plunger shows the piston at its highest rise. If you want to be more accurate, attach the protractor as described. Use a TDC locater (the type with scribed marks on the plunger and no spring) and take degree readings at equal drop on both sides of TDC, adjusting plate position so that at the same drop, readings BTDC and ATDC are equal. Don't try to stick a dowel or other piston locater in a cylinder that's rising on the exhaust stroke; it will contact the valves, not the piston, and may lock up in them.

It's possible for the advance curve to stretch if the ATU is defective, resulting in extreme advance even when the ignition is correctly set in the retard mode. This is usually caused by thinning of the bob weight tips. The best cure for this is replacement of the ATU, but if you want to try it, I've had success recurving the ATU by peening the tips of the bob weights to a width of .060". Be sure the stepped nut on the ATU is peened down tight with a drift and a BFH. If it's loose the ATU will self-destruct.

I don't think your cam timing is off. In future you can take all the guess work out of positioning the cam if you install the tensioner to pull the slack out of the front run first. Then run a line from the center of the crank (jam fit it there with a piece of bamboo skewer, etc.) across the center of the camshaft. If the cam's in the right position, the line will run straight down the middle of the timing notch on the cam sprocket. Sight carefully to prevent parallax error.

Thanks for the help. Ill check the cam when i get done work. Im starting to think the knocking im hearing is my valve clearences. ill check that as well.

I'd advise you not to mess with the camshaft now. Get tensioner and valve adjustments right then inspect the ATU and straighten out the timing before you hole a piston.

I adjusted the valves clearence. .006 on exhaust and semi snug .004 on the intake. The camshaft chain tensioner is good, the pushrod is just flush with the end. Timing is good, idle is fine and advances correctly. Stick gettin sounds, but now its sounding more like a tapping sound. The sound comes outta nowhere at 2500 rpm. So at this point I'm thinking I did something incorrect on the rebuild. I read that when installing the cam the left hand cylinder should be tdc on its compression stroke and I don't think that I payed attention to that when I put the cam in. My other thought is that the feet that make contact with the top of the valve stem are beat. Maybe I should reduce the clearences? Somethin like .005 on exhaust and .003 on the intake? All I know is this motor was making no sounds when I tore it down and now I'm gettin the tapping sound around 2500 and above. Any thoughts on what could be causing the sound?

I think it was the intake valve clearences. I changed them to .0025 from .004 and retourqed the cylinder head and its all good.