300ex Loud bang in tranny under a Heavy load
 

This is on a 300ex

Ok so this past weekend. I was out at Sprink creek. Doing a couple water crossings and just generaly playing around in the deep water.

Heres the Problem.
The guy that Gave me the 300ex. Also put in a 250ex mainshaft bushing and in doing so locked up the clutch and would ride it around Banging through the gears with no clutch.
Now that I have fixed the clutch and put in new fiber plates...
While under a heavy 2nd gear or 1st gear load. While in knee deep water. My tranny would make a Random BANG. and the wheeler would only for a split second loose forward momentum. This happend 3 times. 1st time was the hardest bang. 2nd and 3rd wasnt so bad. but that was probly me just not getting into the throttle has hard as the 1st time..

Now heres what I think is the problem. Im thinking my shift forks and possibly the shift drum are Worn pretty badly. Allowing the gears to temporarilly to pop out and then back into gear.. Thus making the bang noises..

Let me know what you guys think maybe the cause for this noise.
Im open to all suggestions.

Also. How have you guys solved the Extreme heat the lil 300ex produces? the frikin engine case burnt my anckle!
Im looking for a FOOLPROOF solution to the excessive heat. Ive already wrapped tghe header and silncer... and dropped from 93 to 87 octane. But its still WAY to hot... I know all about the oil coolers but and worried that a Stick will puncture it.
anyways.. like above.. Im open to all suggestions..



Thanks in advance.


Doug

300ex Loud bang in tranny under a Heavy load
 

Im pretty sure wrapping the exhaust will make it hotter...


oil cooler is your only way out here, put a fan on it to be sure, than you
could also throw one of those inline coolers there..


burn your ankle? what are you wearing sandals?

Wear BOOTS and PANTS

the 300ex runs hOT

live with it!

300ex Loud bang in tranny under a Heavy load
 

Wrapping exhaust Keeps the heat in. So that the "FELT" heat is reduces drastically. Along with improving the scavenging effect of the exhaust increaseing low end tourque.
Now It DOEs increase the Exhaust TIP temps dramaticly. as a by product of keeping the heat inside the pipes. but thats not my concern..

The Engine Temp's and oil temps are my concern...
The oil cooler, yea. Thought about a stock 400ex oil cooler. But dont know if I want to be forced to use the shitty oring fittings. Would mutch rather use some standard AN fittings...


LOL and no buddie I dontr have to get used to it... the extreme Heat radiating from that tiny engine tells me sometrhings not right... Theres NOWAY it should be so hot that the lower case BURNS skin!

And I wear hiking shoes and shorts... Its almost 100 degrees here.
I dont ride like a idiot. So I dont need anything but gloves, helmet and goggles...

Thanks for the reply.
Hopefully someone has something alil more constructive..


Doug

300ex Loud bang in tranny under a Heavy load
 

My bet it your chain is loose or your sprockets are worn out.

That sure sounds like the chain jumping a tooth on the sprocket.

Have a look at the condition of the teeth and the chain tension.

300ex Loud bang in tranny under a Heavy load
 

OMG! Bro you just dont know how right you are!

Remember I got this 300ex for free.. from a dork.. and shure enough the rear sprocket Was loose. like the nuts was on the last 2 threads!
tightend them and noise is gone..

300ex Loud bang in tranny under a Heavy load
 

Good deal....

I'm glad I was able to help, and I'm glad it turned out to be that simple and not something internal in the trans gears.

I've ridden a few abused, neglected and worn out 300EX's over the years, and have had it happen to me on their bikes, which is unerving to say the least.

But the good news is that you and I have been able to experience this because these quads are tough enough to stand up to this and still be around for us to put back in proper working order.

When you get a chance, I would change that out with a new chain and sprocket set. You may be wanting to re-gear it anyways.