Is it a possibility to enlarge holes on timing sensor to bump timing up that way instead of offset key?? It would save pulling flywheel.

also-can an automotive timing light that clips on plug wire be used to time a prairie---could you make your own reference marks on the pullstart pulley??

I was up half the night concocting this idea and it may have some merit---I am still awaiting flywheel puller so I have not taken mine apart yet

 

Ole Man Moses-- the key changes CAM timing. The sensor relocation will affect ignition timing..........TWO TOTALLY different critters........................................
Konanian----- thank you for the info that you sent RE: CDI unit, building you own.

 

The key rotates the relational position of the flywheel to the crank. The flywheel has projections on it that is detected by the engine pick-up sensor. It is not optical, and looking for holes because dirt could confuse it easily. The projections are positioned to allow the igniter to know how to time the firing of the plugs. The igniter doesn't know the flywheel has been rotated and therefore the key offsets the entire timing curve. You can also offset the pick-up pulses electronically like Konanian is describing. This has already been done and has issues with the error detection coding of the igniter.

 

Yes you can do that. I don't know how many degrees you get. It does not affect the cam timing, just the ignition. The flywheel key does not affect cam timing. Look at the repair manual or the parts diagrams you will see there is no relation.

You need to move the sensor in the direction opposite the rotation of the engine. The engine spins CCW when viewed from the left side (CW from right side).

The sensor:
you just notch out the rest of the hole on the one side that you are moving the sensor away from.

The other side you widen the slot toward the sensor body, and grind down the edge of the baracket so that it doesn't hit the housing as you slide it. You might need to use an allen head bolt on that side also. Mabye even reduce the diameter of the allen head or delicately grind into the sensor body a little.


I was gonna do all this, but I am goona wait for the CDI.

The 650 idles at 5 degrees. I don't know what the 360 does. But, you can check the timing on it now using the timing inpection plug. Some oil will probably leave the hole as you time, so keep rags handy.

Then if you know the diameter of the flywheel, you can estimate with your eye how far the timing mark moved at idle. Then do the math. You have to know the exact diameter of whatever place you are using as a reference. You could do it on the recoil wheel of you tried.

The radius is half the diameter. Divide the distance between the before and after timing marks by the radius. That gives you the angle in radians. (it will be a small number).

Use a calculator (or post it on the forums) to convert radians to degrees. That angle is how much you advanced the timing. I think the conversion from radians to degrees is multiply it by 360/2PI. PI is approximately 3.14

If you can measure how far you moved the pickup sensor, you could try to calculate the resulting advance from that too if you also found the distance from the sensor bolts to the crank center (that would be your radius).

 

Guess I need to look at the manual. I thought that the offset key was for the cam chain drive gear, and would directly effect the timing of the cam. I did not realize the key was for the flywheel(and, therefore the ignition pick up).

 

Every photo of the crank I can see has the teeth machined into it for the timing chain, so they are fixed.

However, you can change the cam timing by messing with keys on some of the other sprockets.

OleManMoses, you also need to retard your cam timing to raise the horsepower. Not too far or you loose low end. Port, polish, higher compression pistons.

Check for timing retard with your timing light at higher RPM's. I would hope kawi wouldn't do that to the 360, but you should check it.

 

Sloting the pickup is good for about 3deg and no more[img]i/expressions/face-icon-small-sad.gif[/img]
1deg = 1.27mm on the od of the flywheel

 

Excellent thread--looks like I will be up again tonight sorting through all this info.
Back in my day, we used to shave heads to increase compression--anyone know if this is a possibility??
How do I check for timing retard at high rpm?? Is it as easy as revving motor with light attached and seeing if marks retard as rpm increases??
Anyone know if my 360 has a timing inspection plug?? would it be somewhere over the flywheel(sounds like a dumb question but I did not consider looking when I last had it apart)

 

You may be able to shave the head, the only thing you hafta worry about is whether your chain will accomodate less length. My guess is that it will. You are a pioneer in this area - going where noone else has gone yet on their 360. People do this every day on other quads.

Yes, check for a retard by revving it up higher and higher.

Our timing plug is black with a slot that looks like you can open it with a quarter. I had to vice grip mine. I wasted money trying to get it open (I also bent a steel washer). It is on the top of the crankcase right by the recoil starter. Yours is probably in the same spot.

 

The V Twin motors are "interference" motors ( the valves have recesses into the piston )... don't know if the 360 is also, but that would probably limit the amount you could take off... also, IMO, most of the heads today, are much more efficiently designed, than the heads of yesterday ??? But, the reason I did my rebuild / build up in the 1st place, was because my heads were warped, & head gaskets leaking... my machinist took .007" off the heads... I assume that that little of an amount, wouldn't raise the compression much, but my quad seem to be atleast as powerful as the 785 kits, so ???