Itsa sad day in paradise. I was riding the rocket when all of a sudden Mr. Hyde came out to play and i just had to see if i could out run my buddies 929. after missing second and saying hello to my rev. limiter, my screamin demon started running a little poorly. kinda like it was on three intead of four. my cam tensioner is bad, the chain rattled, it has 31,000 miles on it. i believe i jumped timing. what is the correct procedure for setting the time. my trigger wheel has two marks on it and i dont know which one to use. also what are the goofy lookin vacuum operated PCV lookin things under the coil packs. can i do away with them? any ideas and help please.

 

You probably didn't slip time. The upper bracket/guide follows the chain too closely to allow that, I believe. I guess it could on the bottom but with near a 180 degree wrap I don't think it could get the slack needed to do that. Let us know what you find.

The timing mark you're after is the "T". With it aligned and the valve cover removed, there will be a hash mark visible on the left side of the sprocket, below the letters "IN" on one and "EX" on the other. They should be aligned with the valve cover sealing face. If they are facing towards the center of the engine, towards each other, turn the engine over one more turn and they will be opposed and in the correct position. Probably not the end of the world but it's safest to do all of the engine turning in the CCW direction so you're not tensioning on the cam chain in the reverse direction. Otherwise, if you're tensioner is bad, it may give you a false reading on the timing marks because it will take the play out of what's supposed to be the slack side. Good luck.

BTW, while you're there, look it over and see how little more work would be involved to do the chain tensioner. It requires removing the intake cam but little else.

If you do it, the two concerns are to stage the thing in the correct timing position before to di-assemble and then be sure that when you install the cams again, that the cast in "Intake" and "Exhaust" identifiers on the cams themselves are facing up. Then turn them only as needed to get the cam sprocket bolts installed with their timing marks aligned with the cover sealing face. The engine is an interference engine so an error here can bend valves.

 

It sounds like that's a California model. If so, they would be the secondary air system parts. To make sure, see if there are four tubes, one for each exhaust port connected towards the front of the head at each exhaust port or the primary header tubes just as they exit the head. The tubes would be about 3/8" diameter. If they're there, you have a California model.

If you remove them you may get a backfire on decel, not absolutely sure. The real power difference (I've heard about 10 HP, don't know) is from the different cams. And they are noticeably different. If you wanted to change that, you could. If you chose to, I believe anything from the first until '91 are the same, maybe even later, but I'm not absolutely sure. There may be some jetting issues also but again, I'm not absolutely sure. If you chose to do that, I could look through the books and see if I can figure it out. You could do the same with a factory manual. The specs in the front are pretty comprehensive and I know that's where I read that difference. That's the only difference internal to the engine though so it might be worth considering with a cheap set of E-Bay cams.

 

I don't think you "jumped timing" either. I seem to miss second whenever I try and flick it to second. I can do that with the other gears, but not first to second. I have to give it a good nudge or it goes to neutral. As for the rev limiter, on the 90-91 this is how it works. The ignition functions as the rev limiter. Official redline is 10,500 rpm. If the rider overspins the mill, cylinders two and three are cut off, while one and four are retarded. If the rider persists, the whole system shuts down at 11,600. You can use a standard timing light to check the ignition timing to see if it is working properly.

 

Might I add a caution if you decide to replace your cam tensioner? When replacing the cam bearing caps be sure, absolutely sure, the locating pins slide into the cam bearing cap before tightening them down. It is remarkably easy to break the bearing cap if they hang up, as sad experience demonstrated to me.

 

OUCH! Did you have to buy another head? Those kinds of parts are usually machined as a unit, mated for life.

 

i went and took another look at my engine. My trigger wheel has two hash marks on it, one of them goes all the way to the edge of the wheel and the other does not. to the right of the hash marks is stamped sw.id . the pointer on the block also has two marks, one labeled "T" and one labeled "F". i asumed "T" meant TDC. if i line the first hash mark with the pointer labeled "T" both cams are of what seems to be one tooth each. i figgered out the marks on the cam gears lining up with the top of the head( wear the valve cover seats against). thank you for the advise on the cam caps. i have the tendancy to break things just looking at them wrong. my work replaced a faucet in the shop to a washerless unit because i was tightening the old one to tight. they said old people still need to use it.

 

It may well have slipped. If so, that's a handy bit of info to have.

It sounds like you're looking at it correctly. The only extra precautions would be that you approached the timing marks rotating in the CCW direction, the direction that has tension on the chain side facing the front of the bike. The only reason I stress that is because the opposite way may take the travel out of a malfunctioning tensioner and if so, may allow just about that type of error you're describing.

One other thing you might do to further prove out the whole thing is to turn the engine CCW, this time looking at the timing marks on the cam sprockets, lining them up to the head perfectly, then look below again and see if the "T" marks are anywhere near close. They are pretty crude marks and can be awkward to read clearly. If the "T" mark is way off doing that, it probably did slip as you suspected.

The only hope is that if it did slip one tooth, that that's not just enough to ding the exhaust valves. I really don't know on that but if they were to suddenly show excessive clearances all of the way across, there's a good chance you did.

If it's a full tooth off, you WILL be doing the tensioner, right?

And, if this goes back together with just a re-time and tensioner, go find a mirror and take a good hard look. You'll be staring at one of the luckiest guys on the planet!

Good luck with stuff. Keep us posted, please. This would truly be a handy bit of info to have.

 

i found a post from trips that helps tremendusly. what i was calling the trigger wheel is actually the ignition pulse generator. this makes much more sense. i am going to modify my current chain tensioner and guide to meke sure everything is ok in the motor before i spend $200.00. call me cheap but i have many projects on the table and i can only spare so much for each. not to mention i live in Ohio and i dont have much else to do but try new things. if i get it fixed i am going to try to make it from exit 218 in Medina to 17th street in Columbus in under an HOUR. it can be done my rattilier(92 cavalier) made it in an nour and ten min, with fog lights bolted to the hood and all. call me nutz but the cops are only supposed to follow you to 100 then back off and report you with c/b's. im not real sure y i need to do this, my girlfriend doesnt realy like motorcycles anymore but maybe if i can do this just once i might sell it and by a ring. she attends OSU(GO BUCKS) and i guess if i have to sell, i must go out with a bang. more on this later. i will keep my friends posted on my sucess i hope. this is all for tonight.