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Valve Adjustment specs

Posted: Sat May 26, 2012 12:59 pm
by hairball
After searching for a service manual for a 150 cc (Blackjack), I can only find Service manuals for 125cc
-Not looking for a Backjack specific service manual.

Just wondering if the Valve adjustment gap on a 150cc is the same as the 125 cc?

YouTube is showing completely different specs for a GY6 150
... example- intake-0.19, exhaust-0.23...
Buddy 125 service manual shows 0.08 for both


Any help from a Buddy guru would be greatly appreciated.

... I know how to do the valve adjustment, I'm always adjusting the lash on my KTM supermoto.

Posted: Sat May 26, 2012 1:07 pm
by PeteH
I haven't heard anything about the PGO 150 engine vs. their 125, but I think I recall that the top end is the same, just the bore is bigger. That online copy of the service manual is based on the 125.

That said, yeah, the appropriate tappet gap is .08 mm / .003 in, depending on your set of gauges. Same for both intake and exhaust, but doublecheck me on that. My old Honda 4 used one of those paper-thin gauge values, too, and it was like working with tinfoil :)

Posted: Sun May 27, 2012 3:41 pm
by ericalm
Valve specs will be the same. Only differences in the 150 are the bigger bore and the oil cooler. (Same head.)

valve gap 150cc black jack

Posted: Sun May 27, 2012 5:32 pm
by 7ate9
IS the 150cc a Honda knock off?? any luck on the valve specs Please let me know.. thanks!!

Posted: Mon May 28, 2012 5:18 am
by ericalm
Honda? No… well, not really, kind of, maybe. :)

It is a GY6-based engine, which are all descendants of a Honda engine. Almost all modern Asian 4T scooters under 200cc use GY6 variants. There are "generic" GY6s which are often used in Chinese-built scooters. The Buddy has a proprietary PGO engine but it has some things in common with other GY6s. Parts aren't interchangeable for the most part, though.

Posted: Sat Jun 02, 2012 11:56 am
by hairball
Well I checked the valve clearance on the BlackJack and both were 006... Tighter than the 008 gap for the 125, Which seems to make sense... Allowing the valves to open more to offset the displacement - Yes, I checked the clearance on a cold engine :D
... I don't really think the valves will get tighter over time and the scoot is running great, So I believe the gaps are correct.