more questions on the yerf 3203

[terrys]

Ok I got the harbor fraight motor in today. it started on the third pull. Runs great. looking at the belt it doesent look like it is ligned up perfectly. I may need to do some shimming. My question is about the two sprockets. They are not straight up and down with each other. The driver and driven seem to be straight up and down or on the same angle just not in line with each other. I can fix this. the sprokets are what i can not figure out or fix. It would look some thing like this.
\ -top small sprocket
|-large bottom sprocket
I have looked at it for hours and still cant figure out how they are not ligned up correctly. what could cause them to be out that way. all bearrings in the jack shaft are good and the large sprocket is not bent. Could the frame be bent somewhere getting the axle and sprocket out of lign with the jackshaft sprocket?
Thanks for the help.

[x-bird]

the engine uses the jackshaft plate, but tightens separately from it. 4 bolts for the engine, 2 carriage bolts at the rear of the plate for the jackshaft plate.

Set it up with all the bolts in place, but just tightened where they're not snug (you can still move the engine and plate a little)

Align the small and large chain sprockets then look at the belt pulleys. Alignment of those is taken from the engine-side pulley half. Mind you though, even those are not perfectly flat. The attached picture i took during the alignment process and the rear pulley isn't quite aligned. the straight edge should have a slight gap on either side of the pulley when aligned since the engine side pulley half has a very slight angle to it.

If your sprockets are pretty far off with the pulleys aligned, then you're going to need to remove the driven pulley from the jackshaft and add or remove spacer washers as needed.

[terrys]

thanks for the quick reply. It is hard to explain what i mean but the two sprockets are not in line with each other.
|
| they should be like this but are more like

\
| this.
I wish I coild explain it better.
with the chain at this angle it makes it come off.

[x-bird]

Something simple just has to be way off. Ignoring the driver/driven pulleys, can you adjust the engine and jackshaft to get the sprockets aligned?
Also, can you post pictures or need some help doing that? Pics help a ton with figuring things out.

[terrys]

I dont have any pics right now and i know it is really hard to understand. Looks like the motor and jackshaft needs to have the left side shimmed up to put it into alignment with the lower sprocket. or something is bent on the fram causing the axle and sprocket to be out of alignment with the jack shaft.
Try to imangine if the motor and jackshaft was leaning to the right. causing the chain to not be ligned up with on the same plane as the axle sprocket.

[x-bird]

Go to the bottom and start at the bold text ---leaving the first stuff just in case, but i think your answer is at the bottom of the barrel ...


I have the basic idea of what you're talking about. There's not much to go wrong so it should be something that can be spotted.

The axle sprocket or axle itself may be bent (put the rear on stands and spin the tires to check)

The axle mounts may be twisted or bent (check the bearing carriers/hangars to see if their aligned with the frame tubes.

The rear swingarm may be out of square (measure corner to corner on the diagonal to check for squareness)

The engine or jackshaft may be too snugly tightened yet preventing you from rotating the engine far enough to align it (check the bolts-nuts)

The engine's mounting holes may either be offset or different from the Tec, preventing it from sitting in correct alignment. (basic comparison between the two engines)

The jackshaft may be bent (spin it to check)

And after writing all that, i now have a good picture i think of your issue, because i ran into it myself.

is there an oil drain at the base of the engine on the either end? if there is, the head of whatever is in it may be protruding below the bottom of the engine, lifting it off the mounting plate. I changed my setup and cut my plate short so there was nothing under the engine. The drainplug hung up on the edge of the trimmed jackshaft plate and caused the engine to sit on an angle. Not the same cause as yours, but sounds like the same effect. Hard to spot the gap it creates.

It's either that or there is something under the engine or plate that shouldn't be there like a loose washer. also check for casting flash chunks/excess metal on the bottom of the engine. run a straight edge along the bottom if you don't find anything.

Misalignment in "this" direction is either the above or back to bent axle or axle sprocket or the swingarm tubes are bent or cracked. I had to do soem extensive bracing on mine to fix cracks at the welds in the tubes ...

Hang in there, you'll find it!

[xlint89]

Your output shaft is 3/8" shorter now. Do you need to move the engine over to compensate?

Also there is some room for adjustment of the axle sprocket if that helps.