SImplex Mechanics/Owners in SW MI, Nothern IN

[CharlieT]

Anyone know of an experienced mechanic or owner of a SImplex in the SW MI or northern IN area?

Have been working on a 1947 and just cannot get the thing to run. Had it running a bit, bit the old carb was messed up and all it would do is idle until it flooded. Got a newer replacement carb from Wayne and now all we can get is an occasional fire. We are at about our wits end with this simple SImplex.

[Ricks]

Anyone know of an experienced mechanic or owner of a SImplex in the SW MI or northern IN area?

Have been working on a 1947 and just cannot get the thing to run. Had it running a bit, bit the old carb was messed up and all it would do is idle until it flooded. Got a newer replacement carb from Wayne and now all we can get is an occasional fire. We are at about our wits end with this simple SImplex.

What is the compression reading?  If you have low compression, it will never run.  Has the motor been rebuilt?  If so, did you check the ring gap?  More info and we may be able to help you better.

[CharlieT]

What is the compression reading?  If you have low compression, it will never run.  Has the motor been rebuilt?  If so, did you check the ring gap?  More info and we may be able to help you better.

Rebuilt the engine last spring. Mic'd the cylinder, talked to Wayne and he sent us a new piston/rings that would give the correct clearance. Unfortunately did not write down the measurements on bore, piston, ring gap. The compression does bother me, as it is only at 60psi. We have had other engines that low that would run, but its not very impressive. Not sure what to expect from this engine, we are used to working on more "modern" bikes from the '60's-'70's.

We had the engine running with the original carb, however someone had forced the main jet in and stripped the threads and it was unable to be properly seated. It would sit there and run but no throttle control as the fuel was likely going around the main and eventually flooded the engine.

Replaced the carb with one for a later model that wayne recommended and now we can't get it to run.

[Ricks]

That seems a little low to me.  I know Wayne says they will run at around 65 psi, but the couple I have rebuilt are between  75-90 psi.  I would take the engine apart, and check the ring gap.  Don't trust that you have the correct rings, measure and be sure. 

While the engine is apart, measure the rotating valve clearance.  If you have too much, you will not have good vacuum.  I seem to remember about .008" clearance being correct.