trx jetting

[l1tech]

Just a quick question here. I have a 2007 trx 450r that is stock right now. I have a Motoworks slip on that I plan on installing along with a Dynojet kit that I picked as per Motoworks recomendation.They are telling me that I should be running a 128 jet with with basically a stock motor but on other forums people seem to be saying that i need to be somewhere in the 160 range. AFAIK the stock main jet on the 07 450r is a 120, does just adding a slip on justify such a huge jump in jet size? ANybody here have any recommendations on a good starting point for jet size. Please keep in mind that the 04-05 450r are different than the 06-08, seems like the jetting for the 06-08's doesn't need to be so high due to the larger carb.

[Jeremy]

The jetting differences are due to the FCR, not necessarily the size.

Keep in mind that a dynojet jet and a Keihin (stock) are not equivalent.

[Dxun]

I would throw the dynojet kit right in the garbage for starters and get yourself the hrc jet kit for 21 bux. That comes with a needle and clip, 162 main and 55 pilot. The 162 is going to be to big if the only mod you have is a slipon pipe. Are you running with a airfilter lid or not?

The 128 they are telling you to run is prolly dynojets 128 which is different than keihin jets.

What i did was go over to RATV and purchase every juet from 120-185 in increments of 5 at 2 bucks each, which is cheaper than that dynojet kit. And then you will have all the jets you need for future upgrades.

[l1tech]

I would throw the dynojet kit right in the garbage for starters and get yourself the hrc jet kit for 21 bux. That comes with a needle and clip, 162 main and 55 pilot. The 162 is going to be to big if the only mod you have is a slipon pipe. Are you running with a airfilter lid or not?

The 128 they are telling you to run is prolly dynojets 128 which is different than keihin jets.

What i did was go over to RATV and purchase every juet from 120-185 in increments of 5 at 2 bucks each, which is cheaper than that dynojet kit. And then you will have all the jets you need for future upgrades.

I am leaving the lid on, and on a conversion chart that I saw the Dynojet 128 is equivelant to to a Keihin 137. What's wrong with the Dynojet kit, I'm new to all of this and don't know the difference

[l1tech]

Would the 162 that comes with the HRC be a good starting point for a slip on and no lid? Where is RATV? or do you mean Rocky Mountain?

[Dxun]

With lid the 162 is going to be big. Richards ATV is on 43rd ave and Peoria i believe. They have just about every jet you will need in stock.

This is a link to the HRC kit i ordered but you can check with some of the site sponsors.

http://www.woodwardspecialties.com/s...chProducts=hrc

Make sure to get the kit for the 06. I would say 140 would be a good starting point, but again with just a slip-on it may be a tad to big.

Most will tell you the dynojet kit is junk. I would think you're better off using keihin jets, and avoid using that stupid little adapter for the main jet.

[Zach648]

why would you want to keep the lid on in the desert? Is like asking you to run a mile only breathing in through a straw. Dosnt make much sence.

The dynojunk stuff needs to be sold on a forum were someone dosnt know better. You'll be much happier with the HRC needle, jets and no lid. IMO

[l1tech]

So today I took back the dynojet kit and then had to go to Coyote Honda(I live in Chandler) and got the HRC jet kit. I put it in, which was incredibly easy, and removed the airlid. the first thing that surprised me was even after having the carb off and drained the bike started the instant I hit the starter...it's never done that. I let it warm up and then noticed that the stumble off idle when you nail the gas is 95% gone. I took it down the street about 75 yards and was very impressed with the throttle response and overall the bike sounded ALOT happier. Will the jetting be fairly close with the slip on, air lid removed and the HRC jet kit(needle, 55 leak jet&162 main)because it sure seems ok now, I realize I won't know for sure until I get it out this weekend but I am hoping to be fairly close.

[Dxun]

I'm glad you got rid of that 60 bux worth of garbage. Did you end up taking off your lid?

[Dxun]

Ok i just read your last post thoroughly. With the slip on you should be in the ballpark. If at wide open throttle the bike is still responding well and you dont feel it kinda dropping off you should be fine. On the very top end if you are getting to much fuel it will almost feel like its bogging out on you. If thats the case, go get some jets from 160 and down and get it dialed in. My guess would be anywhere from 160-140 range. It's not going to be 140 but for 2 bux a jet its just better to have them all in case you need them in the future.