Yamaha timing / linkage adjustment ?

[Sigma]

2005 115 two stroke oil inj. 50 hrs

AT 25deg BTDC the full advance marks are off and the adjusting bolt for this is out of spec.

AT 5 ATDC the retard timing marks are spot on.

so it looks like I need to adjust the advance bolt and it should be perfect on both settings since this will not effect the retard setting and then go from there with checking the carbs.

Does this sound right? I dont have a dial gage to inspect the piston position VS the pointer position but it looks like TDC is TDC to me.

It has never been touched since new so why would the adjusting bolt be out of adjustment?

Should ther be a lock nut on the retart adjustment bolt because there is not?


Modified by abu-guru at 12:05 PM 1/10/2008

[Ray Neudecker]

Yes, you can adjust just the max advance timing. Yes a nut can be added to the retard timing adjustment bolt and it is a good idea since it is not uncommon for it to vibrate out of adjustment.
You can use a small philips screwdriver as a crude dial indicator to check the pointer.

[Sigma]

Thanks, I didnt want to mess with it but the idle went up for some reason so I figure i might as well check all of it. Have you seen them be out of adjustment from the factory?

[Ray Neudecker]

Normally, the factory adjustments are pretty close.

[Sigma]

My advance was off about a 1/4. I had to screw the advance stop bolt in some to bring it to the mark on the fly wheel, and doing that also gave the the correct spec lenght on the bolt it self. Seem to run just fine, couldn't really tell any difference