Setting Timing

[dspshemp]

Can anyone help me with hints or tips on setting the timing on a 1980 XS1100 Special? The cams and sprockets are out of the head. Any help would be much appreciated. Thank you!!

[TopCatGr58]

Setting Timing

Ho boy, that's a tall order for this list!!

Hopefully you mean setting the Cam Chain/sprockets/valve timing!? Don't you have a manual, clymers, something!??

You'll need to set the crank on TDC for #1 piston, the timing mark on the timing advance unit should be pointing to "T", you should have removed the timing chain tensioner, reset the plunger and locked it in retracted position and replaced it back onto the engine; the cams have dots on them that should be pointing almost directly up when the crank is at TDC. The cam sprockets should be loose-fully unbolted from cams, you put the cams in place with the dots up running them thru/under the slack chain and with the sprockets on but not bolted in place, replace the bearing caps which is tricky cause you have to compress a valve as you tighten the caps since one lobe will be pointing down towards the lifter, you usually will have to get the low side of the cam and bearing caps attached, all the way to the middle one, then slowly tighten these nuts and as the cam is pushed downward, it will allow access to the other bearing cap studs with enough clearance to put the flat washers and nuts on which you should do as soon as possible, and use them to even out the tightening pressure, continue tightening until the cam is seated, then you torque the cap nuts to only 7ft/lbs, hope you have an Inch/pound torque wrench so you don't strip these studs/nuts!!!
Hopefully you do know how to match up the bearing caps, they are labelled In and Ex, and numbered

Next, you position the sprockets so that the bolt holes line up with the cam bolt holes, you may have to spin the sprockets sliding them past a few teeth/notches of the chain to get the holes to align, then put the first top bolt in finger tight. You may have to wiggle/turn the cams ever so slightly to get the holes to align but the dots should not move but a few degrees away from straight up. Once you get both cam sprockets in place, the crank still at TDC...timing mark "T", and the dots straight up, then you can now turn the crank with a wrench on the timing plate/ shaft in a clockwise direction, follow the arrow on the plate to the "C" mark then Unlock the lock nut on the cam chain tensionor, and then unlock the bolt, and the tensionor will make a click/thump as it springs into position, then tighten the stopper bolt and then the lock nut, so that you can expose the other 2 cam sprocket bolt holes, then place those bolts in as well, and then you can torque to 14.5 ft/lbs, don't forget to rotate the shaft again and torque the other bolts!! The manual states to rotate the crank 2 revolutions and then recheck the alignments, with the pointer on "T", and see if the dots are essentially straight up in line with the line/notch on the cam bearing cap, if not, manual says to disassemble and repeat process. There may be a slight variance in the DOT alignment, just make sure it doesn't look like a whole tooth distance, if so, then you'll need to remove 1 bolt, rotate to "T", then loosen other bolt, remove the cam chain tensioner and reset it to gain slack in chain, then remove remaining bolt of sprocket, turn cam back up to center, slide sprocket one tooth and then replace on cam, and repeat above steps.

Of course you will have used assembly lube on the cam shaft and bearing caps mating surfaces, and cam to lifter contact surfaces prior to assembly!!!!

NOTE: if the engine is NOT at TDC when you aligned the dots, turning the crank and cams with the chain attached can cause piston/valve damage, also turning the cams once they're bolted in place by more than a few degrees(1/8th of turn/rotation) WITHOUT the cam chain connected can also result in Piston/valve damage.....Proceed at your own risk!! All other disclaimers apply....BEST GET A MANUAL!!!!!
HTH !

[dspshemp]

Thanks a lot!! I have the Clymer's manual, but was hoping for someone with experience like yourself as a 'second opinion'. Will be putting the bike back together tomorrow after a head rebuild, and full carb rebuild. Wish me luck!! Thanks again!! RB

[Cabasa]

Oh man that whole procedure makes me sick thinking about it. I tried it and bent all my intake valves. I think I turned the motor counter clockwise and went against the tensioner. I have since bought another head off ebay, since that was cheaper then getting new valves. Also got a buddy that will help me port and polish the old one if I want. I am very leary about doing it again. What do you guys think? Is it possible to bend the valves just by turning it over in the wrong direction? I was positive I did it right, but that is the only thing different that I could think of. I would be riding now if it weren't for that.

[uk1.1s]

bent valves

Cabasa

Sounds like you managed what I did to my Z1000 a few years back

Valves get bent becasue they hit something, and the only thing they can hit are the pistons when the timing is wrong. If you manage to get the cam timing a tooth (or more likely 2-3) wrong it means that the valves open whilst the pistons are too close.

Never heard of this by spinning the engine around the wrong way. Sure I must have rotated my XS1100 the wrong way loads of times when rebuilding.

Bending valves the way I mention above usually only happens on a couple of cylinders as the pistons move in pairs (the other two should be well out of the way. I took the valves out of the head and measured them for straightness and found I'd only done in three - so rebuild was fairly cheap. Maybe the same for the old head you took off the XS11 when you come to have a look.

[Cabasa]

All four intakes are bent. From the best that I can remember maybe I spun it backwards with the tensioner not yet set. Not sure, the nightmare of that still haunts me. I will be extra, extra careful tonight when I install the other head I bought. I plan on doing the procedure dspshemp outlined. The last experience had it sitting for a year and a half and all I wanted to do was replace the headgasket that was leaking oil. Oh well I'm just glad I found a forum to get help from.

[TopCatGr58]

Originally posted by Cabasa
All four intakes are bent. From the best that I can remember maybe I spun it backwards with the tensioner not yet set. Not sure, the nightmare of that still haunts me. I will be extra, extra careful tonight when I install the other head I bought. I plan on doing the procedure dspshemp outlined. The last experience had it sitting for a year and a half and all I wanted to do was replace the headgasket that was leaking oil. Oh well I'm just glad I found a forum to get help from.

Hey there Cabasa,

I would imagine that to bend all four intake but not the exhaust, that you had the intake cam in the wrong position when you attached the cam chain, that it was probably at BDC, instead of TDC, since the crank spins twice for 1 revolution of the cams, so when you aligned the "T" mark, you didn't make sure that the #1 piston was at the top of the compression stroke!?!?

Heck, I bent 3 valves without even having the head mounted on the engine, was setting the valve clearance, put 1 cam in and then didn't realize the lack of clearance between intake and exhaust valves...they can't both be open at the same time! I then put the second cam in without removing the 1st one, then turned the second cam, a valve was sticking out from the 1st, and the opposing one came out on the second as I rotated the cam, DOH!!!!! Took them out, replaced them and the head was just fine, and these valves were severely bent, they wouldn't even reseat, had 1/4" gap between valve and seat with cam lobe not pushing on lifter!!!

So...the main thing is to ensure the crank and piston are truly at TDC, timing mark at "T", then put in the cams with the DOT's straight up, then slide on the sprockets and turn just the sprockets....not the cams to align the mounting holes, sliding the sprockets past chain links until you can get them aligned., then the manual says once you have the bolts on 1 hole for each cam, you rotate the engine clockwise to "C", then release cam tensioner and retighten it, that keeps the chain from slipping teeth at either the crank or the cams!!

HTH, Good luck!

[dspshemp]

IT"S ALIVE!!!!!! My ride breathes again!!! I also now have compression on all 4 cylinders. Still the same carb problems, but working on it tonight!! Thanks a lot guys!!!! RB

[Cabasa]

Cool, glad someone here is successful. TopCat that makes more sense than anything. Your probably right in my 1 not at TDC. I wll have to just take a deep breath and go really slow this time. Thanks