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Help locating T.D.C on 660. Valve clearance issue

PostPosted: Wed Sep 30, 2009 3:39 pm
by J-Ball
So I got to the point of checking the valve clearances on my '00 Skorp Tour 660. I did lots of reading here, felt informed, did the job, and noticed immediatly as the engine was spinning over a CLiCK CLiCK CLiCK sound!! I'm pretty sure I did not set the clearances at T.D.C. compression stroke.

I read somewhere here to find TDC you watch the intake calves go down as you spin the motor and as they drop find the "T" mark inside the engine. Is this correct info? Do I set them at this point? Otherwise I am just going by a link to the 660 manuals valve clearance check pages.

Also, when I set the motor as mentioned above the valves all showed to be less than .002. This made me think something was up but I don't know if this bikes valves have ever been checked (currently at 10,500miles) so I adjusted away.

Please help.....

Re: Help locating T.D.C on 660. Valve clearance issue

PostPosted: Wed Sep 30, 2009 8:24 pm
by J-Ball
futher information....

So I spoke with a local mechanic, as far as finding T.D.C. he concurred with watching the intake rockers falll then go back up, check inside cylinder (skinny screwdriver etc) to make sure piston is up. Align "T" mark and you should be at TDC compression stroke.

He explained that the clicking is prob how the engine was supposed to sound when it was new and I (at 10,500 miles) was used to how it sounded with the valves set at below .002. Does this sound right?? Also he said that after the oil pumps up etc the clicking will reduce.

I'm going to check everything one more time and fire it up, see if the clicking reduces.

Any thoughts?

Re: Help locating T.D.C on 660. Valve clearance issue

PostPosted: Wed Sep 30, 2009 11:01 pm
by J-Ball
No dice, somethings up. Help!

Re: Help locating T.D.C on 660. Valve clearance issue

PostPosted: Thu Oct 01, 2009 12:36 am
by Bill Jurgenson
It really isn't that hard.
Take out the plug 'cause it's much easier and more exact turning the engine without compression.
On the left side cover unscrew both the small timing hole plug screw at the top and the big center cover screw - be careful, it is plastic. Use a very wide screwdriver or a large coin with a pliers.
Take off the intake valve cover plate.
Turn the crankshaft with a 19mm socket wrench counterclockwise until you see the second of the two timing marks on the edge of the flywheel. The first of the two is for the strobelight, showing the proper 3ยบ BTDC for the pickup.
This being a 4 stroke, it obviously has two TDC, one with open valves and one with closed.
Obviously you want the TDC with closed valves, so watch that the intake valves have closed when the piston is up. You can of course check this with a long thin screwdriver or allen wrench thru the plug hole, but the mark in the flywheel is for the purpose and more accurate.
The rockerarms should now wiggle a bit.
Screen shot 2009-10-01 at 6.30.21 AM.jpg
Yamaha workshop manual

This should equate (if I did my math right) to 0.004" in and 0.006" out.
You need a 10mm box wrench for the lock nuts and 4mm openend (spanner for the Brits) for the screw itself.
Here is a special set for the purpose:
http://www.motionpro.com/motorcycle/partno/08-0073/
Double-check the left and middle tolerances 'cause this is a single forked rockerarm.
When this is done, remove the round covers from the exhaust valves (19mm box wrench). You do not need to remove anything (radiator etc.) to do this.
Check first with your finger that the rocker arm has play. Compare how that feels to how the previously adjusted intake valves feel. It should be a tiny bit more.
If it feels that way, leave well enuf alone and close back up.
If it is way off, you'll need to drop the radiator but leaving attached to its hoses so that you can actually get at the screws. I "dediated" a short straight box wrench specifically for this by bending it up until it was an easy fit.

Put the rear cover back on and the two plugs and the sparkplug.
Done.
Unless someone has been really messing around, it is rarely necessary to actually reset the valves. Not in 10000km, not in 20000, either.
Practice getting the feel of the properly adjusted valve and then periodically give the exhausts a "feel up." If any valve needs setting, it will be an exhaust valve.
Doesn't take more than 10 min. including the hassle of removing the tank.

Re: Help locating T.D.C on 660. Valve clearance issue

PostPosted: Thu Oct 01, 2009 9:30 am
by DAVID THOMPSON
thanks bill
i needed that for later this month as i check out every thing on the traveller i bought this summer
dave

Re: Help locating T.D.C on 660. Valve clearance issue

PostPosted: Thu Oct 01, 2009 10:12 am
by J-Ball
Thanks so much for the help BIll. I can see where the problem lies. I'm going by a link to the manual (see below) and it shows to line up the "T" mark on the flywheel. It sounds like your saying to use the middle mark? What I see on the flywheel looks like..... I--I I . Again manual says use the mark to the furthest right, are you saying use the middle mark? I think I've got everything else under control , just cant get TDC set correctly. Please advise all who have been beyond this point sucessfully.

one thing i know i was doing wrong was i was spinning the motor clockwise not COUNTERCLOCKWISE.... oops....

MZ Timing marks.jpg





LINK TO XTZ 660 Valve Adjustment
http://www.mzriders.com/download/file.php?id=1628

Re: Help locating T.D.C on 660. Valve clearance issue

PostPosted: Thu Oct 01, 2009 12:41 pm
by Bill Jurgenson
There is no middle mark on my flywheels, nor anything that could be construed to be a letter. Just two indents as if made with a cold chisel.
Anyway, like I said you use the second one, the one to right since the motor turns counterclockwise.

Turn the crankshaft with a 19mm socket wrench counterclockwise until you see the second of the two timing marks on the edge of the flywheel.