What's up everyone? I need some help, I have a 2005 TRX400EX that I'm trying to increase some low to mid range power, I'm trying to get better response when I hit the throttle and I'm trying to gain some more power for climping hills, I recently went to Gorman and went up the big hill and I realized that the quad ran out of power. I recently (last week) put an FMF powercore 4 pipe on it and it sounds alot better but I'm hoping to find a way to get some more power. Any suggestions?

 

Why not just go to a smaller drive sprocket?

 

Change cams, get one that is designed for low range. I think a hotcams stage 1 will give you better low end.

 

I would go with a cam, (I think cam changes would be pretty easy on the 400) Im doing the same right now and just ordered a stage 2 cam, jet kit, an hmf pipe. Make sure you get the right jetting after every mod. It makes the biggest difference!

 

if you want better throttle response get rid of your choke.i havent done it but i hear it helps.also put a 42 pilot in so it starts a lot easier without the choke.

 

Get rid of your choke and install a Curtis Sparks timing advance key and 13t sprocket. Cheapest and easiest mods you can do for more bottom/mid power gains.

 

One thing about Gorman is that there are some monster hardpacked hills there, that can be a challenge for any machine! Plus, the altitude is deceptive. I think the top is something like 5,000+ feet, so you may have been experiencing the effects of the altitude as well. On a big hardpacked hill, little things like tires and tire pressure can also have a huge effect.

Are you sure you are perfectly jetted, since you put on the new muffler??? Did you do a header as well??? Did you do any other mods like the air intake and/or air filter???

I have monster hillclimbs behind my house (steeper than Gorman!), and I would actually rather ride them on the 400EX than on the 450R. The reason is that the EX has some low end grunt, while the R is all rev. I run the PowerCore 4 muffler, PowerBomb header, EHS Racing airbox lid with Outerwears, and a ProDesign (ProFlow) adapter and foam air fiter (made by UNI)....and am perfectly jetted.

If you are properly jetted, a gearing change is the quick and easy solution. My experience has been that 1 tooth in front on the EX is way to much. It turned mine into a wheelie machine, and that isn't something you want when you are near verticle on the side of a hardpacked hill. 1 tooth in front = 3 teeth in back, and I have settled on 1 tooth more in back as a good compromise for trail riding.

 

I have come to the conclusion that reconranger is getting a lot more out of his EX than most of us... I think because he may have did a much better job than most of us with putting his mod choices together.

My EX had 14/38 gearing on it when I got it, and I just left it that way. It's real common here for people to drop a tooth in the front on about anything for our eastern trail riding.

Now I have a K&N, full Yoshi exhaust, and jetting that is ok, but I don't think "spot-on-perfect". To me it just feels pretty good on pull with that gearing... and will stand up but is not a wheelie king.

I know the gearing is low though, because the gears are SHORT and I feel I shift a bit more than I should have to. But I haven't moved back to a stock 15/38 because I'm not sure it has the ***** for that still. I prefer to always be able to stay above neutral except for dead take-offs... 2-5 ...because I despise how you have to hunt neutral when you want it, but catch it by accident at the worst possible moment... LOL...

Try 14/38 or 15/40 or 15/39

 

Gorman.....I was at the big hillclimbs south of Sterling Canyon campground once, and a Suburban tried to make the hill. He lost traction about half way up (probably wasn't aired down!), and go stopped. As he tried to back down, most likely his ABS bakes couldn't hold him and he lost it, got sideways and came so very close to rolling it. I would have thought he was in low case, and could have just idled down the hill on compression braking. Maybe he wasn't experienced and didn't think of all those issues.....

 

15/39 gearing works well for me.