Need help on JLO/ST300D Power & Steering

[Papa]

Well, I finally got my JLO 300 running (after new points, condenser, and coil). Ran on the bench really nice. Re-installed to the B/W 7000 tranny in the ST300/D. Hooked up everything except the electric sytem (battery, starter, etc.) so I've been pull starting with a rope (ugh!). Adjusted the calipers to what I think is correct.

Problems: 1) engine wants to bogg down when opening up the throttle. (I've got a new spark plug and am running high test gas). I can get it to idle real nice (for a 2-stroke!), and I can get it to high rpm by being real slow with the throttle. What can cause this 'bogging' down under initial full throttle?

2) Once I get under way, I can't get it to steer. Pulling back on one or the other steering lever causes that side to lock like its supposed to, but the other side doesn't have enough power to turn me. So, I just sit there and I feel the other side just jerking a little trying to turn. (btw, I only have 4 of the 6 tires mounted; fronts and backs; can this make turning harder/impossible?). Any ideas what to look for to correct this non-steer condition ?

Should the driving clutch close up considerably at high rpm and force the belt real high in the clutch? I don't see it closing by more than 1/2" to 3/4" on the shaft. And, I don't see the driven clutch on the tranny opening hardly at all (I thought I had cleaned/lubricated both of them so they could operate freely). Maybe I'm not getting the rpm's high enough because of the bogging ?

This has got me baffled. Adjusting the high speed "screw" on the Tilutson HR carb doesn't really seem to affect the 'bogging' problem. I'm pretty sure its getting enough gas (new in-line gas filter is clear).

You guys with JLO/Attex ST300 experience, I hope you have some suggestions for a newbie trying to get his 'project' running great !

[LarryW]

Hey papa,
Sounds like your getting close.
Bogging problem. Does it do that with the choke on or off any different. I would say a carb problem but that question is better for Don or Racerone3 or jerseybigfoot or the others.

Problem #2 is possible the brake/drive pucks. Sounds like you have the outers adjusted fine. But the inners need to be adjusted more to tighten up on the inner rotors to put the "drive" in it. Or maybe your not pushing forward enough on the sticks? Or maybe your problem goes to the rpm issue you may have? That would do the same thing as you describe.

The clutches should cycle in neutral. The belt should go right up near the top of the drive clutch on high rpm. Maybe you need to tighten the slack out of the throttle cable.
Your getting close. Bet your excited!

[Papa]

Hey, LarryW - thanks for feedback. I'll try to run w/ and w/o choke to see if the bogging changes any. I'll also check the dimensions (width) of my drive belt. Looks like this model is supposed to have a Dayco 1060 (1-3/16" width). If my belt is too narrow, that could cause too much slipping and loss of power ? It looks like my throttle cable is operating OK; I get the bogg even by throttling by hand at the carb.

[LarryW]

As far as I know, all un altered first generatiion machines are suppose to have 15/16" belt width. I can say the 2 300's and the 225 and 208 that I have all did. 1" can be used with some shimming of the driven pulley. The driven pulley is the correct way to check it. The belt should be flat or slightly above the pulley. If its sunk it then the belt is worn.

[Papa]

Hi, LarryW - thanks for belt info. I should be ale to get to the shop today to check it out. Also, I'm going to look for carb rebuild kits on the internet. If not too expensive, I might go that route to see if I can get the high end out of the JLO 300.