Timing issues

[Scudder]

Trying to solve some timing issues on my 78 gs750. I've got the cams in the appropriate position and the chain placed as the clymer says. Now the engine won't rotate when I use a wrench on the nut on the points place. It will rotate only a half of a turn forward and then back. Is this right? I don't understand how to adjust the gaps with new shims unless all the nodes on the cam can be lined up perpendicular with the valve, and I can check the gap. Any suggestions on what I've done wrong (again). Thanks.

Scudder

[haztoys]

Not really understanding your problem here ...So are you setting up cams are ajusting the valves ... Are you sure the piston is at TDC and not a 180 out ...?

Sorry on the troubles

[Scudder]

I was first setting up the timing by adjusting the cam placement, and getting the chain in the correct place. Then I was wanting to make sure that the clearance for each cam was appropriate over the valve. That is when I realized I couldn't crank the engine all the way around. When I set the cams in place I had the "T" lined up in the small window under the points cover. Sorry about being unclear. I'm pretty new at all of this as you can probably tell. My big question is... should the engine be able to be cranked 360 degrees?

Scudder

[haztoys]

Think about the 360 there my friend ..Yes it should you have something off ..

Pull #1 spark plug ...Put a screw drive in the plug hole and make "sure" you feel the piston at TDC ....Move the crank at the crank bolt back and forth reeeeeal slow and easy feel the screw drive go up and down to find TDC ..Look at the timing mark see if it right ...

Theres a cut on the end of each cam ..(you know this and have found this ..Right ..?) ...Now we have #1 cylinder on TDC ... Looking at the cams fromthe side of the head ... EX cam should have cam lobe facing the EX pipes (front of bike) with the cut in the cam end facing to the back of the bike ...IN cam should have the cam lobe facing the carbs with the cut facing the the front of the bike ...Cam lobes MUST be facing "out" from the motor and cam cuts facing in to each other ...Cam lobes and cuts should be "flat" with the top of the head were the valve cover meets ...

Look over to #4 cylinder at the cams just to make sure ...The cam lobes will be facing into each other with the cuts facing out ...

You seeing here that I'm not bring up "Timing marks"

(piston at TDC #1 cyl ...cams flat with head ... ex cam lobe facing front end ..IN cam lobe facing back end on bike ... Cam cuts facing each other ...look at #4 cyl for a check cam lobes should facing into each other with the cam facing out ... #4 cyl and cams should be a 180 deg out from cyl #1...)


Hope this is not Greek to you .. Have a lot of time with motors and can speak Mechanic but can be hard to understand at times ...

As some one who does this sort of work to pay the rent ... I set my cams this way and look at timing marks last ...


Are you sure the EX cam is in the EX side and the same with the IN cam ..And the right cam sprokets are on the right cams....??

Let me know


David

Hazardous Toys inc

[SqDancerLynn1]

Valve clearances has nothing to do with your problem of it not turning. You have the cams out of time, go back and recheck them..

[koolaid_kid]

I agree. Just to clarify, it sounds like your valves are hitting the tops of the pistons. This is a bad thing.

[hampshirehog]

You might also have the cam chain crunched up at the bottom end.

[Scudder]

Thanks for the replies. I'm headin' back in over the next few days. I hope to get it done myself, and avoid taking it to someone smarter than I when if comes to the gs. I got this bike for nothin', so I wanted to teach myself (with your help of course) how to do the work. I appreciate the insight.

scudder