spock

Something doesn't add up here....isn't this a 350? It has a decompressor in the camshaft, right? The spec is 97 psi for those engines - and you're seeing twice that? I'm not sure that an exhaust problem could do that, it seems unlikely. I'd be curious to know what the compression is with the muffler removed.

I'd recommend leaving the valves as is for now. With the exhaust, usually you can tell by the sound of the quad when running if it's blocked - they tend to get quieter. If you remove it and shake it, sometimes the sound of a loose baffle is obvious.

Another thing that comes to mind is the spark plug cap. These are known to fail and give similar issues. Maybe it just loosened up a bit, being on and off a few times.... Look for corrosion at the end of the wire and cut some off if necessary.

If we assume that the valves were adjusted properly, the only other change made was the air filter. Maybe try another filter, ie. this one isn't flowing properly. What kind of oil was used on the filter? Running without an air box isn't a good test, they require one to function right.

Yeah, even if the compression is sufficient to run it could have worn out oil rings. This would explain the carbon and poor performance. Anything that runs in dust a lot and has pretty high mileage is due for a new top end (piston rings for sure)!

Weak spark could be from a lot of things. Besides the coil, there is a stator, ecm and connections. Check and clean all the electrical wiring connectors first.

Shipping a Hondamatic from the US to Canada cost me $100 cdn plus whatever they nail you with taxes, depending on what province you're in. With the exchange rate these days, you'd be better off buying one north of the border I bet.

Oregon is a wonderful place to ride and explore. Visited the dunes last year, can't wait for the border to reopen so we can visit again...(have family there too).

First I tried for a used one off ebay but that turned into a dud so rather than waste anymore time I bought a new oem one from the states.

Howdy! I just finished rebuilding an old Rubicon and yes, it did require a new Hondamatic! We'll try and answer your questions - there are sure to be a few, haha.

There's definitely some winners out there, eh? Check this one out, all I can say is WTF?? https://www.kijiji.ca/v-view-details.html?adId=1518436803

Exactly! without the preload it won't work.

Just making sure that you have been installing the sensor correctly - it wasn't mentioned yet about the preload on the spring necessary when mounting it to the engine.

Holy Moly! Hope it works out ok, we're rooting for you!

I've noticed that most of the Japanese brands do it that way, but the others expect you to screw in to check.