JDX4 loss of power

[Mailman]

This last year I have been doing some restoration on my 73 JDX4 . New secondary clutch, rebuilt primary clutch (new rollers, springs, etc.), Mikuni VM30 carb, new bearings front and back on the track, crank seals, and completely took the chassis apart and back together. I got the motor timed and running good then I took it out of the shop to try on the grass. It worked fine no problems at all plenty of power. I was going to put it in the shed so I wadded up a 6"x6" piece of fine steel screen and put it in the air tube to keep the mice out and when I went to go towards the shed it went a few feet and wouldn't go any farther. Is it possible that the steel screen would restrict the air that much that it would keep the clutch from engaging, it rev. up to around 4000-4500 rpm's and you can see the primary clutch move but it's like the belt is way to big. I have measured the belt and it is fine 1 1-16" wide x a little over 43" long. Can't figure out why it ran on the grass before and then the next time it wouldn't. Any ideas?

[400brian]

Are you sure its still firing on both cylinders?

[JDT]

I'm with Brian.
Maybe when you inserted the screen you bumped the wires to the coils and one is not connected any more.

[Mailman]

I went out this morning and checked to see if there was fire to both cly. and there was good and hot. We had about 3" of snow last night so I took it out to see if that made any difference and of course it did but it still ran and sounded like it just couldn't get up to full power about 5000rpm tops, and it wasn't instant . When I timed it I used a dial indicator and test flashlight and set the points at .16. I got no.1 cly. ok but when I went to do no. 2 they didn't seem to want to open as good, could it be that no. 2 points aren't opening quite as far thus the bog in acceleration and not enough rpm to fully engage the clutch?

[JDT]

Could be the points but also the condensor could be the problem.

Did you check coil resistance?

[400brian]

I got no.1 cyl. ok but when I went to do no. 2 they didn't seem to want to open as good

I've been going to start a thread on timing point engines for over a year now, to share what I've learned, and solicit discussion.

I doubt timing is the main source of your described issue right now.

Being as it ran better after everything cooled off, I'm betting a bad electrical component. In my experience, the 440s will run around 30 mph on one cyl, but the 340s won't hardly pull themselves if they will even engage the clutch.
I imagine your Kohler falls into that same situation.

[Livestock 109]

Did you get it fixed? Is the carb set right and not flooding?

[Mailman]

Yes I did, I set the points on no.2 cyl. first then went and did no. 1. Also the pints on no. 2 were bent so as not to let the arm open all the way. I straightened the arm and that seemed to help get everything back in line. I followed Brian's advise in setting the points and it worked.