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Tip for refitting heads or changing belts

Posted: Sun Mar 23, 2008 2:59 pm
by mooseheadm5
I just swapped heads on my 77 (8 bent valves from PO) and one thing that made it super easy (and reduced the anxiety level quite a bit) was that I loosened the tappet adjusters all the way before fitting the heads. I have changed countless timing belts on interference engined cars without doing this, but wanted to be safe here and that seemed to be the best way. I always do this when swapping heads on car engines where possible, belt or chain, and have not f'dup yet! This reduced the valve lift to next to nil. I put the heads on the wing with the cams at a neutral position (no valves open, which I think you can only do if the tappets are loose) then after torquing, set the cams at their TDC positions. This is much easier when you do not have to fight the valve springs much, plus the cams do not want to snap back or forward so you do not necessarily need to use Octane's zip-tied wrench trick. Also reduces the chance of damaging open valves with the piston, or by dropping the head or misalligning it or whatever. It may give enough clearance to make the motor non interference while assembling BUT I did not check this (I will do this on my spare motor later, though.) After timing the cams, I timed the crank, threw on the belts, tensioning the left bank belt first, then turning the motor over 1 revolution and tensioning the right belt. Carefully turned motor over by hand several times and rechecked cam timing and belt tension. When I was satisfied, I set the valve clearances back to spec and ran through again by hand several times to make sure there was no valve contact. Had no problems with this method, and the bike fired right up after I installed the plug wires correctly (duh.) Hope this helps.

Posted: Tue Apr 01, 2008 9:20 am
by muaymendez1
Just make sure when taking the belts off that you mark the crank pulley as well as the cam pulleys. I saw marks on my previous wings pulleys and thought that would be fine.

I didnt realize till after everything ws together that the right side was 180 degrrees off. I made sure to turn the motor over by handto make sure no interference was going on. all seemed fine.
When cranked the bike even ran but the staerter did no want to turn the motor to well.
The bike will run with the cam pulley 180 out but will not run well.

Posted: Tue Apr 08, 2008 5:11 pm
by mooseheadm5
Good point. There is a mark on the crank (make sure you go for T1, not T2) and there are marks on the pulleys, but they are small. White out is good for marking things. The right side pulley clearly says UP at the top so you know which arrow to use to line it up, but you can never be too safe. Always pull it through by hand at least 2 full revolutions and recheck timing. If you feel any mechanical resistance, STOP, turn back and check again.

Posted: Thu Apr 17, 2008 12:23 am
by shoe
Thank goodness for Sharpie's. When I did the belts on my GL1000, I notice that the cam belt pulley could go on both ways and there was an arrow on both sides but 180 degrees off! One of the cover bolts snapped off in the head - which is why I needed to remove the cam pulley.

warped cam pully

Posted: Mon Apr 28, 2008 7:59 pm
by scmedic6
Hey, Something strange happened the other day. Finishing up a carb rebuilding project on a bike that has been idol for 5 years. synking the carbs when I noticed a scraping and rubbing noise on the left timing cover side. also noticed the cover getting very hot quickly. took the timing cover off and the pully started rubbing the inside of housing. became very warped.??????? What would make the pully all of a sudden warp? I almost ready to put it back on the road and dont want the other side to do the same. what say the forum? fluke of nature? bad karma? sign from Above? Gregg

Re: warped cam pully

Posted: Wed Apr 30, 2008 11:37 am
by Frenchy
scmedic6 wrote:Hey, Something strange happened the other day. Finishing up a carb rebuilding project on a bike that has been idol for 5 years. synking the carbs when I noticed a scraping and rubbing noise on the left timing cover side. also noticed the cover getting very hot quickly. took the timing cover off and the pully started rubbing the inside of housing. became very warped.??????? What would make the pully all of a sudden warp? I almost ready to put it back on the road and dont want the other side to do the same. what say the forum? fluke of nature? bad karma? sign from Above? Gregg
I haven't run across a warped timing pully before...... :-? Sounds like it may have been damaged by the PO..... Either way you need to swap it out. I'm sute I've got a good used one laying around, for a reasonable price. Of they're on Fleebay as well.. ;)

bent valves

Posted: Wed Apr 30, 2008 10:18 pm
by Hanky Panky
how did you know that the valves were bent...?

Posted: Wed Apr 30, 2008 11:42 pm
by mooseheadm5
I had 0 compression on all cylinders. Generally if you want to test for bent valves that may be only lightly bent, you want to do a leakdown test if the heads are on the motor. If they are off, you may be able to see the spot where they hit, or light through the port or you can turn the head upside down and pour some solvent into the chamber and see if it leaks out of one of the ports. Did that help? if not, lemme know.

valve job gone bad

Posted: Sun May 25, 2008 4:50 pm
by scmedic6
Hey, not sure this is the place to post this, But I need some help. after replacing the head gaskets on my 83 gl1100 i am having a hard time getting the valves adjusted. when I set the timing and adjust the valves according to the first sequence( #1 intake and exaust,#3 Exaust, and #4 intake) . all is well until I rotate the crank 360deg for the second sequence, which puts the #1 piston on it's exaust stroke. The valves that I adjusted the first time are hitting the #1 piston, causing my engine to lock up. when I back them off, the engine turns. What am I overlooking? something simple I imagine. been working on all weekend and am ready to get finished and ride tomorrow. Thanks

Posted: Sun May 25, 2008 4:53 pm
by mooseheadm5
You may have one bank 180 degrees out! Be very careful how you proceed! You need to go back to square 1 for belting the motor. Slacken all the adjusters all the way, set the crank at TDC (T1 mark) and then check to make sure you are lining up the cams correctly. The pulleys each have 2 marks, but usually people would mess up the right bank by not noticing that the pulley is marked "UP" and that when the motor is TDC on 1, the "UP" is up and the marks should then line up properly. Hope you didn't bend anything by forcing it.

Posted: Sun May 25, 2008 5:37 pm
by scmedic6
Hey Moose head, Thanks for your reply. I'm heading back out there to check it out. BTW just confirming, the pulley for the right side and the left side are the same except for how there are turned. right? I will send photos in a few mins Thanks

Posted: Sun May 25, 2008 6:09 pm
by mooseheadm5
Correct. I believe that the pulley on the right side, when installed correctly has an R on it somewhere. The PO of my wing I believe set the timing with new belts on T2 NOT T1 as he was supposed to. This bent every single valve when he cranked it over. I cannot think of any other way to do this.

Posted: Mon May 26, 2008 3:16 pm
by Rat
Right and left as you see it sitting on the bike. :-?
Not as you look at it fraom the front.
Gord :P

Re: Tip for refitting heads or changing belts

Posted: Tue Dec 24, 2019 8:52 am
by GT-Ron
Quick question how on this.

Im installing my new belts.

My left pulley has its timing mark a tooth or two above the cover plate’s alignment mark. In order to get it to lign up, i need to rotate the pulley somewhat clockwise, which has a cam lobe starting to engage a valve. The adjusters are backed out all the way. Does this sound correct? After reading all the how to’s I was under the impression the left side cam will not be engaged when setting the timing belt...?

Re: Tip for refitting heads or changing belts

Posted: Tue Dec 24, 2019 9:32 am
by pidjones
GT-Ron wrote:Quick question how on this.

Im installing my new belts.

My left pulley has its timing mark a tooth or two above the cover plate’s alignment mark. In order to get it to lign up, i need to rotate the pulley somewhat clockwise, which has a cam lobe starting to engage a valve. The adjusters are backed out all the way. Does this sound correct? After reading all the how to’s I was under the impression the left side cam will not be engaged when setting the timing belt...?
Yep. That's why it is suggested to get down on plane with the cam to sight it in. I can usually rotate the pulley with a 12mm to put it on line.