300ex questions

[Dave223]

ok guys,
I picked up a 97 300ex from my brother in law(he swapped it for a GO-CART!)for 300.00 running.
Anyways, we found out that whoever had rebuilt the starter, turned the case around backwards. Hehe, this reversed the polarity of the starter and would make it spin backwards, thus NOT spinning the engine over!
Im tearing it down to go thru it and fix a few things, repaint, refresh....so my 13 yo daughter can race it at a local mx track. What should I know about these things? any defects or tricks I should know about? what weak points should I know about and fix before she jumps this thing? What rear fenders from other quads, trikes would fit ? The ones I have are trashed, someone cut em and then cracked em so they are ugly! Also anyone have a rear grab bar lying around that would fit this thing? She pulls wheelies but I stopped her as it has none on it now and Im afraid of it goin back on her...any help , advice, info or anything you can tell me will be appreciated...Thanks, Dave A.

anyone have links to other web sites that are Ex specific?

[trikerider2oo7]

a good site on 300ex's is http://www.atvriders.com formerly known as exriders.com. 300ex's are very good bikes. i know several people that have them and have never heard any complaints except for problems the brought upon themselves.

[OldSchoolin86]

ok guys,
I picked up a 97 300ex from my brother in law(he swapped it for a GO-CART!)for 300.00 running.
Anyways, we found out that whoever had rebuilt the starter, turned the case around backwards. Hehe, this reversed the polarity of the starter and would make it spin backwards, thus NOT spinning the engine over!
Im tearing it down to go thru it and fix a few things, repaint, refresh....so my 13 yo daughter can race it at a local mx track. What should I know about these things? any defects or tricks I should know about? what weak points should I know about and fix before she jumps this thing? What rear fenders from other quads, trikes would fit ? The ones I have are trashed, someone cut em and then cracked em so they are ugly! Also anyone have a rear grab bar lying around that would fit this thing? She pulls wheelies but I stopped her as it has none on it now and Im afraid of it goin back on her...any help , advice, info or anything you can tell me will be appreciated...Thanks, Dave A.

anyone have links to other web sites that are Ex specific?Anything from a 250x will work on a 300ex because they are one in the same(besides staring and a little longer stroke). TRX250R a-arms will swap into it for a wider front end and with an upper shock mount relocation kit you can use the 250r front shocks too. I would't use them without the relocation kit because they will make the front sit too high. The 300ex is really a 282. You can get 80mm piston sleeve kits(329cc) that don't require case half boring and is very reliable. There are a lot of good cams out there for that motor too. The cylinder head has casted in restrictors on the exhaust side that really need to be ported out for better power.

Here's a site dedicated to ex's:
www.exriders.com

Becareful, there are a lot of people there that believe in bad advice. Just make sure you double check what you find. You will find a lot of info there.

Good Luck!

[bad ex]

i own a 300ex and i would say to watch the timing chain.cause mine has gone bad once every year now.kevin

[SpeedBump]

Anything from a 250x will work on a 300ex because they are one in the same(besides staring and a little longer stroke). TRX250R a-arms will swap into it for a wider front end and with an upper shock mount relocation kit you can use the 250r front shocks too. I would't use them without the relocation kit because they will make the front sit too high. The 300ex is really a 282. You can get 80mm piston sleeve kits(329cc) that don't require case half boring and is very reliable. There are a lot of good cams out there for that motor too. The cylinder head has casted in restrictors on the exhaust side that really need to be ported out for better power.

Here's a site dedicated to ex's:
www.exriders.com

Becareful, there are a lot of people there that believe in bad advice. Just make sure you double check what you find. You will find a lot of info there.

Good Luck!

I am not sure, but I think the 250R arms will NOT fit. I know the 400EX arms will 100% sure. If you are going to relocate the upper shock mounts...don't waste your time on the 250R shocks. They don't offer as much suspension travel as the 400EX shocks. Just check Ebay, there are always multiple sets of Aarms/shocks up for auction. As far as a grab bar goes....email my friend Rick at ramracing311@aol.com he may have the stainless grab bar I made for my old 350EX conversion quad. I know he bought a new aluminum one right before he traded the quad off, so he prob got the other one layin round. I am sure he would sell it relatively cheap. Tell him I gave YOU his EMAIL. Later.

[OldSchoolin86]

I am not sure, but I think the 250R arms will NOT fit. I know the 400EX arms will 100% sure. If you are going to relocate the upper shock mounts...don't waste your time on the 250R shocks. They don't offer as much suspension travel as the 400EX shocks.
I assure you they WILL fit. I've done the swap more then once. As far as suspension travel goes you may be right, I just wouldn't think it would be enough of a difference to worry about. A buddy of mine still has one of these set up with 250r arms and shocks if you would like pics.

[TimSr]

The 400EX arm swap is really common with racers here. The arms and shocks are also common and inexpensive, especially on quad racing sites, because they 400EX racers are always putting on something bigger. You have to change the tie rods as well.

I havent seen one done with 250R arms, probably because there not nearly as many 250R arms lying around in like new condition, and probably the same deal with 250R shocks. I think both shocks are the same length, but 400EX shock offers more travel.

As with any racing modifications, though, especially those that change displacement, check the rules from the tracks or sanctioning body where you will be racing. I big bore kit isnt much help if it moves you into a bigger class. Some also offer stock classes for beginners, and certain modifications make a machine inelligible.

[honda200]

throw an FMF powercore 4 on it, it makes a BIG difference

Curtis

[Wickedfinger]

I found the Pro-circuit T-4 to be a good power gainer on my 250X.

[Dave223]

hey thansk for the replies, I will look into the a-arm swaps...for not its got plenty power and my daughter is going to be riding it so it doesnt have to be REALLY fast yet...she still has a good bit to learn first....it already has a FMF megaphone? exhaust on it, and even with a worn clutch it will pull a wheelie in 1st an 2nd with me on it...so Im willing to bet it already has a few other mods on it....