PVL on Sachs 125

[VICTOR MONZ]

Dumb question, but thought I would ask...

I am installing a new PVL on my "White Weapon Six Day"....the PVL paperwork says  1.2 mm BTDC (from memory) and the original motoplat and penton Manual says 3.0 mm  to 3.4 mm  BTDC or so.

I assume it should be set at the 1.2 mm BTDC, RIGHT []?

Any assurance would be greatly appreciated.

It has a stock 54 mm  "D" Cylinder and a 30 mm Mikuni.

Thanks

Victor

[Ernie Phillips]

Good question Victor.  Our 3 racing Pentons 1-100, 2-125 have PVLs.  We run 2.3-2.6mm BTDC.  This works great in Cross Country for both 125s as we get great mid-range pop.  But, they flatten out on top and will not over-rev, so you just need to be ready to shift.  If I backed off on the advance, I'm sure the engine would rev out better, but I like the mid-range as we have them set up now.  (I have not tried 1.2mm)  Compression is bumped up too - 150 to 1?? which hurts ability to over-rev.  In MX, if the rider is good enough, our bikes are quick enough to win. We are running pump gas and have not had any problems of late.

Be sure and firmly attach the blade connectors (add tape) and attach all wires (strain relief) so that they will not get damaged or come loose.
 -EP

Ernie P.
Chattanooga, TN

[VICTOR MONZ]

Thanks Ernie....I am confused now where to set it, I guess somewhere in between PVL specs and 2.2 mm[?]

Is the PVL easily "tweeked" like your comment about the MZB[?]

I should read the instruction in more detail.

Thanks again.  I am racing against the CR High Performance CZ's, Elsinores and 74 Husky's in our mx clubs.  The Penton is faster than all of them....just need some rider improvements in the tight spots !

Victor

[gooddirt]

2.65-3.25mm btdc for the 125s- 3.00 is the ticket .

[VICTOR MONZ]

LG:

It is at Marc's...I visited today.  He set it at 2.8 and he said it was sharp and on !  

I'll check it out tomorrow, the Jackpiner is going to his shop tomorrow for "Rehab" !

250 stuff is getting thin !  You're stuff is saved []

VMO

[TGTech]

Victor,
It's all about the compression. The higher compression, the lower the advance needs to be. If you're running a stock compression, then you should set the timing at 2.6. If you have a shaved head, then you should set it lower, maybe 2.2.

The 1.2 setting, is for the modern engines.

Dane

[VICTOR MONZ]

Thanks Dane.

I set it at 2.8 and it is pretty snappy....I will race it this weekend at Glen Helen and check it out, it is a stock set up.

What will I notice, or what are the "symptoms", if 2.6 should be the call?

Have a great time this weekend, wish I was there !

Victor

[TGTech]

If you have too much advance in the timing, you will/should get some detonation. The compression and the timing has to do with the heat in the cylinder. The engine will only stand so much heat and if the compression is high, then you have to drop the timing down. If you have low compression, you can put more advance in it.

When I was on the Sachs engines with shaved heads (100cc), I would run 2.6mm.

Dane

[Ernie Phillips]

Snappy is good!  As a practical matter, I don't think 2.8 vs 2.6 is significant (0.008") on a stock motor. As a precaution, I run our small bore engines on the rich side which produces an engine with a little more safety margin.  Although I have been guilty of wanting my motors to be at the upper limit of performance, I've learned that a properly tuned stock Sachs engine is very powerful and reliable.    

One area to watch out for is today's fuels, 93 octane with ?? ethanol.  We have not had any problems yet, but it's a variable to watch out for.

Track side timing changes are a snap.  With the PVL internal rotor design, the stator screws are exposed so no need to mess with pulling the flywheel (rotor).  Just loosen the screws and rotate the stator plate:  advance against rotation, retard with rotation.  The plate has "tick" marks but I have not "calibrated" to know how much each tick measures in terms of degrees (or mm BTDC).

Good luck at the track and let us know how things work out.  -EP


Ernie P.
Chattanooga, TN

[VICTOR MONZ]

Dane/Ernie.

Gentlemen, thanks for the education...much appreciated.  

Dane, I guess that's why I would always see the back of your jersey at the Meadowlarks Harescrambles as you lapped me, again !

Have a great weekend, wish I was there.  Any chance Jack Horinek, Sr. will be attending, he worked at R & D, didn't he?

Victor

PS.  I run C-12 110 octane in all my bikes....seems ok.