100 jetting

[Mike Lenz]

Can someone help me out with jetting for a 100 as I was unable to find anything searching the site. I got my 73 100 with the Sachs top end and jackpiner bottom end started (started on third kick!), but its jetted way to rich. Its a 26mm Bing I think, but I cant find the size stamped on it? It has a 140 main, 45 pilot, 276 needle jet and a 5 ring needle in it, prob 125 jetting. Where is a good place to start? I got the cylinder from Ron Carbaugh and it has had some grinding done to it. Trying to get it all ready to go smoke those Hodes at the 100cc national in MO Memorial weekend!
The engine also has a stuffed crank(175),PVL and a alum 1976 125 clutch in it, plus 428 gearing. I put a newer style clutch cover, painted black, and a vintage older style black plastic ign cover on the engine to make it look smaller, red mx tank, tall seat, new rear pipe section and 73 exhaust guard, plus vintage Bilstein shocks. This little bike just looks awesome and should make those hodes shiver and run for cover!!

[pketchum]

Mike,

Does the 175 share the same stroke as the 100 engines?


Phil

[john durrill]

MIke,
 the difference between my 72 100 and a 125 was one size on the main an pilot jet.
 Here is what JP listed for a 100 cc sachs with the new 40-404 atomizer on a 27 mm bing
main-130
needle #4 ( 4 Groove's just below the clip slots)
needle jet- 276
pilot jet- 45 or 35
 My 72 100 with a magnito used 135 main, 273 needle jet, stock 125 needle ( dont remember what # it was) and a 35 pilot. That was with Golden Spectro at 40 to 1 and stock exhaust and foam air cleaner.

[firstturn]

Mikey,
  Nice job on the bike.  I am headed to the shop this weekend so I will get more info on the settings.  Start off with a 135 main and I will get back with on the rest this weekend.  Man I knew I should have kept that cylinder...just kidding.

Ron Carbaugh

[john durrill]

Phil , yep chuckle chuckle 54 mm stroke. thats why it was possible to do the 175 on a 125 Sachs bottom end with out a lot of outside machining.
 It was almost a drop on fit

John D.

[firstturn]

John,
  You mean that 56mm stroke is wrong on my bike?

Ron Carbaugh

[john durrill]

Ron ,
 Wow!!!! That crank could go bad on you. Better send it to me straight away. We better get that one out of circulation befor it causes some one some damage.
[] I know I have a stock 54 mm one on hand to send you in its place! chuckle chuckle
John D.

[firstturn]

John,
  You'd do that for ME!  Sounds good should I also send you the cylinder to go with it?  Remember that some of my cylinders are hard to tune for...you know that second hand stuff.  You are always looking out for me John, thanks.[8D]

Ron Carbaugh

[Mike Lenz]

Thanks Guys, that will get me close. Ron, If your struggling with that jetting just send that pesky ported cylinder and Ill sort out the jetting and return it by the end of the decade.

[firstturn]

Mike,
  You are always the Gentleman.  I finally got the crank to work with two gaskets under the cylinder.[]

Ron Carbaugh