A rider ...

[carryall]

Just "spit-balling" but, are there any welch plugs on the rotary carb?  Is it possible that there's a leak or an obstruction in a passage associated with one of them?   

[pd]

Good Morning Paul ,

Yes , there is a welch plug in the idle circuit . I've wondered whether or not there's crap built up under it . Most likely there is , but , when I spray brake cleaner through that circuit the cleaner sprays out the two idle hols in the carb throat . So , at least , some fuel must be getting through . Brake cleaner is thinner than gasoline / mix .
I suppose I should just pull the plug and be sure that it's as clean as possible . I have tried everything else , it seems .

Pete .

[carryall]

Only reason I suspect the carb is that you said it runs and idles but won't start without spinning it with the drill.  That might/could point to the low speed/idle circuit and/or fuel mixture problem and I've had a leak in a welch plug in the past.  It ended up forming a "gunk" all over the inside of that passage way.  Just a guess.  Have you tried starting it with a known "good carb" on it before by chance?

[pd]

A known good carb ?

 I paid a hundred bucks for a Carpenter carb that doesn't seem as responsive to tuning as the old Tillotson I had and now have on .
To be fair , I'm not 100% , absolutely , positive that there is anything wrong with the Carpenter carb . But , it lays in a parts box .
I'll have to see if I can locate a replacement welch plug for the Tillotson .

Pete .

[Ricks]

A known good carb ?

 I paid a hundred bucks for a Carpenter carb that doesn't seem as responsive to tuning as the old Tillotson I had and now have on .
To be fair , I'm not 100% , absolutely , positive that there is nothing wrong with the Carpenter carb . But , it lays in a parts box .
I'll have to see if I can locate a replacement welch plug for the Tillotson .

Pete .

I have used 4 of the Carpenter carbs with excellent results. I have used them straight out of the box, and I have also drilled the addition holes in the emulsion tube. I didn't find much difference in the way they ran.

[pd]

Rick ,

The Carpenter carb I have is likely OK . Just that the motor starts and seems to run better with the Tillotson .

I did try different emulsion tubes , but , like you , found little difference .

Pete .

[pd]

I went looking for welch plugs and ran into a fellow that use to work on outboard motors . He had a palm sized bag packed with various sizes , left over from years of carb rebuilds .
Anyway he gave me 3 of each size from about 3/16" to 1/2".

I pulled the idle circuit welch plug out of the Tillotson carb on the bike . The area under the plug was clean , no debris other than a couple of aluminum chips from my drilling a hole in the old plug .
I ran wire through the two idle holes in the carb throat to insure they weren't clogged and then sprayed the area with brake cleaner before installing a new plug . As insurance against any possible leaks , after the plug was in place , I applied some clear sealer over the plug and its hole .

I was able to kick start the motor with the drive belt loose to the transmission . Once the motor warmed for a couple seconds ,  I could engage the transmission and the motor would stay running .
If I leave the transmission engaged , when I kick the motor , there aren't enough revolutions for it to start . And , the engaged revolutions are slower , due to the extra drag .

Pete .  

[carryall]

Is this a improvement from before?  Would you be able to compensate by raising the idle speed by chance and "freeing up" the transmission resistance somehow?  (new/better bearings, clutch belt adjustment, etc.)

[ndian22]

Sound advice on idle and drive train drag, but sounds like you just made huge progress from electric drill start to kick start. It sounds like you've isolated the carb as the problem and can stop chasing buggers elsewhere. Rick C.

[pd]

Paul ,

I'm not sure I'd call it improvement as I was at the same point a year ago .

There is a very noticeable difference in idle speed from disengaged to engaged . Engaged idle speed is currently set just below total transmission engagement . In other words , it's set just below the point where the transmission primary drive engages the the transmission main group . 
I've tried lowering the idle to no avail .
I installed all new bearings in the transmission assembly when I redid the bike about 4+ years ago . The amount of run time on those bearings has to be minimal .

I am working on something that will , in effect , disengage the transmission . I'll post more on that when I have it worked out .

Rick C ,

I'm not ruling anything out until I can reliably start and ride my bike on a whim .

Pete .

[Ricks]

There should be almost no drag from the transmission when under idle condition.  Does your transmission drag without the engine running?  If so, do you have the correct springs in the trans?  Do you have clutch shoe clearance at rest?

[pd]

There should be almost no drag from the transmission when under idle condition.  Does your transmission drag without the engine running?  If so, do you have the correct springs in the trans?  Do you have clutch shoe clearance at rest?

Rick ,

It seems the only real amount of drag when the system is cold is the thickness of the 'lube' in the bearings and on the main group sleeve . After the motor and transmission have 'warmed' a bit , starting is easier .

I have the original springs installed on the primary drive shoes and there is plenty of clearance between the shoes and the 'bell' . I've been thinking I'd like to try a stronger set of springs to move engagement to a higher RPM .
I should pull the transmission out and check everything separately to insure no abnormal wear .

Pete .

[Ricks]

There should be almost no drag from the transmission when under idle condition.  Does your transmission drag without the engine running?  If so, do you have the correct springs in the trans?  Do you have clutch shoe clearance at rest?

Rick ,

It seems the only real amount of drag when the system is cold is the thickness of the 'lube' in the bearings and on the main group sleeve . After the motor and transmission have 'warmed' a bit , starting is easier .

I have the original springs installed on the primary drive shoes and there is plenty of clearance between the shoes and the 'bell' . I've been thinking I'd like to try a stronger set of springs to move engagement to a higher RPM .
I should pull the transmission out and check everything separately to insure no abnormal wear .

Pete .

Check the bushing that the primary rides on.  Bob Kerr told me to lube it with a pencil.  He says any oil holds grit and makes them bind up.  He says a dry lube is the way to go.

[carryall]

The same dry graphite spray used on the inside of the Comet clutch bell should work.  That would be great if that's all it ends up being huh?

[pd]

A decent coat of graphite on that sleeve makes good sense .
There's a pretty fair amount of surface contact .

If I recall correctly , I put some anti seize on that sleeve . Anti seize has graphite , but it's pretty thick stuff . So , I can imagine it being a source of drag , if it hasn't worn off .
I think I have some dry graphite , somewhere around here .

It would be nice if there was an easier way to lube that sleeve .

And , if this ends up being the 'cause' , it wouldn't surprise me much , as causes are very often simple .

Pete .