I’ve got a 2001 trx300ex and I cant get it to start. I was running into a carb problem so i had it rebuilt, that helped a little bit then i got a new one and got it in tune. But if i let it sit more than a day i cant get it to start without pull starting it. So I ran a compression test and it ran at 30, I saw that if you put a little bit of oil in the spark plug hole that it could help it but it only ran at about 32-35. I thought it could be the valves but how can i tell. And whats a normal compression psi on a 300ex?

I recently picked up a 2000 trx 90 that had been sitting for a couple of years. It had no compression when I took it apart. New piston,rings, head job, and brand new carb. It will crank with a shot of ether but will not stay running, and it will not start with out ether. I’ve done every adjustment I know of to the carb to fix this and I am at the end of my rope. Anyone have any idea of what to try next.

I have a full hmf KN air filter and 105 main jet and I want to install AMR stage 3 cdi box , what size jet should I use?

So I bought a 2000 400ex about a month or two ago, fixed the major issues and the bike was running fine for about a week. I went to go trail ride and I pinned it down the road to feel it’s power on the way. After fully feeling the power I began to ride the bike threw the trail and it was not running right. It’s bogging after about 1/2 to 3/4 down on the throttle and when it begins to bog the bike slows down and will SOMETIMES get random spurts of power. After this happened I removed my carburetor and cleaned it all out and made sure all seals were tight to keep no air seeping in or out. I also put in a 162 Main jet and 42 pilot thinking it may help. When I replaced the jets it began to run fine for about 15 minutes and went back to running like crap. Please help, thanks.

So I picked up a 2001 Honda trx400ex and it’s missing the rear grab bar and tail light and when I looked up one online everyone says it’s built into the frame and mine has two bars sticking out on each side with two bolt holes on each side any idea how to fix this I don’t know if this is factory and easily fixable or I’m stuck like this for awhile

Here is what I’m dealing with now: Imgur: The most awesome images on the Internet

Replacing some components on my 1996 300’s rear end. I bought a used but good condition rear axle to replace mine. The axle came off a 1990 300 FW. I cross referenced part numbers before I bought it and it had same part numbers for both years. Get it installed tonight and when I go to put my hubs on there is about 1 1/2" of less that is splined on the new axle. Anyone know if these axles were different for these years or what I missed?

Howdy TRX friends. This past June my buddies and I went to Little Sahara Utah and rode the dunes for a day. We spent a bit racing up the south face (steep face) of Sand Mountain. My 400EX (seen in many of my Youtube videos) was (sold earlier this month) an ’04, all stock/original with King’s Tire paddles on back. Note all three 400EX’s in this video had been geared down one tooth on the front sprocket. My buddy’s 2002 (yellow) 400ex was also stock/original with low hours. My other buddy’s red 400EX (’07) is not stock: open air box, K&N with filter lid and pre filter, parking brake block off, ITP Sand Stars, Pro Circuit exhaust, and professional rejet. Riding that day and switching around on bikes I saw two things that made the biggest difference in the races we ran: rider weight and paddle tires.
The guy who always won was the lightest guy = 130 lbs. In the race on film you’ll see the red 400EX come in last, but it is easily the most powerful of the three. However, the rider is 200+lbs. Then, my paddle tires are a worn down, heavy paddle vs the the new light Skat Traks on the ’02 yellow 400EX. He had the best flotation of the day in the big climbs, and those Skat Traks are easily the lightest set of paddles of the three. I weigh 160 lbs and you can see I fall in the middle of the pack racing up the face.
https://www.youtube.com/watch?v=WtWNLrkL2S0

Hey guys I’m new to this forum. I just bought a 2004 400ex from a co worker. It has a blown motor. I believe it has a bent valve because the cam chain tensioner was messed up but I’m thinking of completely rebuilding with a 440 big bore kit. What additional upgrades will I need to do to acompany the bigger bore. The carburetor is also missing so I will need a whole new one. Thanks.

Im having difficulty with my 2008 TRX420TE ES (electric shift) 2wd.

To start with, the bike would have NO response when the key was turned on. After fiddling with the bike I bypassed the kill switch by soldering the 2 wires together and now the backlight on instrument panel will come on but there is no writing that comes up. Its just an orange screen with nothing on it. The bike will not crank, shift, or anything but the light is on. I’ve checked the connections on everything but cant seem to figure out what may be wrong or how to check any possible problems. Thanks ahead for any help you may be able to offer!!!

what gasket kit do you guys recommend heard good things about cometic any suggestions and what do you recommend for valve seals should I just go oem thanks