Dave's 1650 Project

[CHWNY]

Hey Dave, Just went through your thread. the photo of the timing marks look right on as does your other work.. That said there is something amiss! I am sure others will comment but this is how I would proceed check valve lash, I read you reused the condenser,coil & wire get a new ones or known good ones. clean all electrical connections and grounds. make sure there is no oil on the points as well as between the block and point plate (good ground). I think your getting too stuck on the timing issue. setting the points with the mark in the peep hole should allow the engine to start and run just fine, if the points are set a thousand either way you will only notice the difference under load if at all. Be sure you are getting full voltage to the coil. Assuming the float is set and all other parts correct, set the carb. (which I think you have cleaned good the second time around) to the preliminary settings. fire it up let it run get hot, shut down, restart, run for a while, shut down cool re-torque head, start, set timing w/light, adjust carb. ALL should be good! I know you have done these things mabey many times one more time slow and sure is the only way I know to eliminate the underlying problem.

[westofb]

Originally Posted by CC1650Dave

Can anyone confirm or deny the idea that if I have the S showing in the peep hole on the money as the points open, then by default the camshaft and crankshaft gears must be in time?

Confirmed!
The s is going to show up in the hole since the flywheel is attached to the crank. As long as you did matt's method of timing, it has to be right, the points should only break open as the s appears due the the lobe on the cam that moves them is spot on, ie...your cam has to be right. If you were a tooth off in either direction, the points would be opening (breaking continuity) either before the s made it to the timing mark, or after the s had already passed the timing mark, depending on which way you were off, advanced or retarded.

I originally set my timing per the manual, .020 at widest point, when I tried matt's method, I tested the manual setting, the point were opening somewhere near the mid point of the s and tdc marks, it ran okay that way except it would stumble on rapid accerleration. After using matt's method, runs about the same, but now has no hesitation or stumbling that it had as set by the static (manual method). I did hook it up to a pick up truck and tow it around, is seems to perform well under a load as well, so all is good. I never did remeasure the gap of the points at the there widest gap, but they have to be opening much wider than the orginal .020 I set them at per the manual.

I think you problably have the cam and crank right, I would advise following others advice about changing out some electrical components with known good ones and trying it out.

[CC1650Dave]

Thanks for all the help and suggestions guys. My next step, after putting the carb on, was going to be going after all of those other electrical components - plug wire, condenser, coil, etc.

But CHWNY mentioned one thing that struck a chord with me: Valve lash.

I'm going to check this first thing tomorrow. Something is nagging at me in the back of my head telling me that when I first put the valves in place, I couldn't very well do the adjustment until later in the process of reassembly. And I may have forgotten to go back to that step to wrap it up.

At least I can't exactly remember adjusting them...

I'll have to look back through my pics and documentation as well. But this could be the missing link...

[CC1650Dave]

Looking back through my pictures and documentation, I can't tell whether I did it or not and I don't remember.

I don't have any pictures of me doing it, but that could be just because I had already done pictures and documentation of it before I decided to rebuild, and (as I noted in the documentation) "see previous pictures."

So I'll definitely check it.

[CC1650Dave]

Originally Posted by westofb

Confirmed!

And thanks for that Jeff! It was nagging at me, and I was pretty sure that had to be the case. In all of my reading, two major "tripping points" seemed to stand out in rebuilds - proper rod installation and cam/crank matching. It was something I was acutely aware of, and I was sure I couldn't have messed it up.

[CC1650Dave]

Another thing I paid strict attention to, given all of the stuff I've read here - is Ground.

I made very sure that the engine is properly grounded to the frame. I know this for a fact because it was one of the last things I did, and it's still fresh on my mind. All contacts were paint-free and tight.

Unless there are other ground connections I need to check. Let me know if that's the case.

[cub123]

I just read the whole thread for the first time over the last two days,my I Phones battery wasn't too happy about it, but it's an aweso
E thread! Can't wait to see how your cub comes out! They way it sounds like it is running really sounds like your points/ timing or carb. ( as a note, if you can I would run non ethanol or some water displaceing additive, that ethanol really mess with your fuel system if it's not run every day)

[CC1650Dave]

That must've taken a while.

Back to square one. Got the carb all put back together and then checked the valves out. Both were in spec. I think I do remember doing it during reassembly now.

Put the carb back on and fired it up - same deal. Rough starting. Once it's warm, it'll start best at 1/2 throttle and some choke. So this weekend I'll start working my way through the electrical stuff.

[Matt G.]

Originally Posted by westofb

Confirmed!
The s is going to show up in the hole since the flywheel is attached to the crank. As long as you did matt's method of timing, it has to be right, the points should only break open as the s appears due the the lobe on the cam that moves them is spot on, ie...your cam has to be right. If you were a tooth off in either direction, the points would be opening (breaking continuity) either before the s made it to the timing mark, or after the s had already passed the timing mark, depending on which way you were off, advanced or retarded.

I've spent quite a bit of time thinking about this and I don't agree. If you were off a tooth in either direction on the cam timing, I bet you could still get the points to break with the "S" in the window. The point gap would be different than what it would be if the cam was correctly timed to the crank, but you wouldn't be able to tell due to the amount of variance from engine to engine in the point gap with it properly timed. I have never tried to correlate thousandths of a inch point gap to degrees on the crankshaft, but I'd say 0.001" is several degrees, at least, as I several people have posted about accidentally timing the points such that they break with the "T" mark in the window, which is 20 degrees away from the "S" mark.

Dave-

Are you using a new spark plug? A worn out spark plug can cause hard starting issues. If the plug wire is old or of the wrong type, that could be suspect as well.

The fact that it is requiring choke to start warm makes me think you have some sort of fuel issue...this is why I suggested squirting gas into the intake and trying to start it, as that will determine whether you have a carburetor or ignition problem.

[CC1650Dave]

Yeah, the plug is new and properly gapped. I can't remember the brand I'm using, but it's the one that everyone here likes. Maybe it was an Autolite 216, or 261? Something like that.

Regarding this fuel test you do, what kind of ratio are you mixing this fuel? That's the main thing that has made me hold off on it.

The plug wire, condenser and ignition switch are next. After that, I'll swap the coil and see. Beyond that, the only thing I could do is replace the points (they're new aftermarket, came with the kit) with some Kohler points.