MarkinAR

You're right, I forgot that 1st to reverse really is almost a half shift.  I can't remember for sure, but I think the cam for the reverse lockout is on the clutch side and if so, you should be able to get at it just by removing the clutch cover.  There's probably a service manual in the downloads section of this forum.  Just check the minimum qualifications to be able to download.

If not swamped, most all of the Japanese motors before the early 2000's will almost run indefinitely.  I've seen old Hondas that the rings are so gone they look like a fog machine but still run like a top.  Been playing with a BRP lately and while the power is a blast, it's just not a Japanese machine.  It likes to kill it's own parts regularly.

In the last year I've bought a couple ATV's and a Nissan Altima that were all great machines...but were suffering from severe lack of maintenance.  Why is it so hard to just check routine wear items?  Grr.....

Pretty common to bypass the neutral safety switch because it can be inconvenient to have to click back down to neutral to hit the start button.  In mud bikes (every Honda 300 or 420 i've owned) I always bypass the neutral safety and reverse lockout because it SUCKS to be in a mudhole and struggle with the shifter and reverse lockout.

On the bayou though, I "think" reverse lockout is cam driven on the side of the motor internally and pretty common for that cam to rotate and lock itself out.  If it were mine, I'd prefer reverse lockout always be bypassed, but there is a danger there.  If you're rolling fast enough forward and drop straight to reverse...boom goes the rear ujoint.

If the 2nd replacement was OEM, was it used OEM?  Pretty unusual for an OEM reg/rect to not last forever, but anything is possible.  I'd check the stator phases and make sure they're all within spec.

Check the oring between the intake manifold boot and head.  I had a Bayou 220 that had the same issue and out of curiosity I tried a new oring and that was it.  Looked fine, but must have had a flat spot.

Finger nails and patience.

You sir, win the shitbox of the day award.  That's a monumental amount of heat damage.

Congratulations.  Now are you being helpful to the group and telling what the kit is or are you advertising a product for sale?  In either case, more information would be helpful.

Not a big fan of Namura, but they usually do ok in lower CC utility machines.  I've seen them blow to pieces in the 400EX.  Much better than the Niche from the first try though!

Glad you got it ironed out.  I'd bet for what the customer spent on a couple pistons, sets of rings, gasket kits and labor, they could have just got a quality rebuild kit and been done with it the first time.

Original Warn 424 will bring about double original retail. If it's functional it'll bring $500 on the Honda 300 Facebook page. Wide open bought the patent and ceased production a few years ago. Rumor has it wide open will make another run but as of today, they're scarce and worth a fortune. 

Here it is after cleaning the carb, gas tank, and replacing the fuel pump.  Next up is what to do about tires.  The back two are dry rotted and won't hold air.  They are also 10" wheels so there's no good options for a replacement tire that aren't more than the thing is worth.  Thinking about drilling an extra set of 4x110 wheels I already have that aren't on anything.

So my oldest strolls up to the garage the other day with this fine specimen of day's past, a 96 or so Quadrunner.  Doesn't run, but it's complete...and free.  Had to soak the carb for 3 days in lacquer thinner and replace the fuel pump, but yesterday it ran down the road and back.  Always fun to ride one that's been sitting for years.

I have recovered a lot of seats, but not one with that many compound curves.  If the cover is a formed cover I'd just recover it.  If it's flat material though, it's going to have a lot of wrinkles.  The picture seems to be a formed cover though....

The last 300 seat I recovered had several holes in the foam.  I ended up filling them with spray foam and then shaving it to form with a cheese grater type of file.  Worked really decent.

Any time. I have a soft spot for Honda ATC's and thereby the 300's since they were the Big Red 250 turned into a ATV.  I've been through a few of them from one end to the other.  Super simple, super reliable.

You can put it in gear and bump it forwards a couple times to turn the engine over to time it. Take the spark plug out so it'll bump easier. Not ideal but it works. 

Or bump the kick start. 

Man that sucks. Definitely an oil starvation issue. Usually from someone putting the oil filter in backwards at one point. 

So if it coughed the rag back out that tells me the timing is off. Either the chain is loose enough it skipped a couple teeth or the woodruff key on the crank is sheared. I'd bet the chain is loose. 

Once you get it running listen to the timing chain. If it's worn enough to chatter it needs replacing. One thing the 300 doesn't do for long is run with a toasted chain. It'll smack a valve into a piston like it owes it money. Replacing is extremely easy with the top end and side case off. Sounds like you about have it licked though. 

I would doubt they are the same as the Grizzly wasn't a whole lot like any other machine at that time.  Do you know for sure the CDI is at fault here?  They are pretty rare to go out, so I'm curious if the issue, I'm assuming no spark, is really a CDI issue.

Do you just want to check to see if it's tight?  a 300 will run with a worn smooth out, stretched like a rubber band, timing chain.

Never had a 2 stroke.  I've had a 125, 185, have a 250 quadrunner in the garage now, king quad in the past, about everything Honda made in an ATC, some Kawi's, a Can Am now. Just no 2 strokes.  Thought about buying one recently just because I have no experience with them at all.

Ha, good catch.  I read quad runner, not racer. 

I'd check the timing before going too deep into the motor.  Sounds like the chain flopped and jumped a tooth or woodruff key sheared on the crank.  Backfiring  is usually caused by either firing at the wrong time or intake valve not closing completely.

Welcome to the forum @bobbo.  This is about the only forum that I know of anywhere that has a good mix of resources for about anything ATC/ATV/UTV related.  There are even a few real fans of chinese clone quads so you can usually get help with those too.