After break-in and first service from dealer I put a hmf sport series slip-on on my stock 2006 450er. Hmf recommends a 165 main jet and bigger pilot which i purchased from them with pipe. They also recommend 2 and 1/2 turns out on the mixture screw, but thats what mine was set at from dealer. After installing pipe and jets and removing air lid, 3/4 to full throttle produces sputtering and hesitation. I'm a newbie to jetting but from what I read this sounds lean??? I went to local dealer and picked up a hand full of different sized main jets 155, 160, 170, and 172 (they were out of 175), First tried 172 because hmf also told me it sounded like I was running lean, didn't really notice a difference. I ordered an adjustable needle after reading some threads about the non adjustable stock needle. I'm using a stock air filter, though I did just order a k&n filter and outerwear prefilter. I've read that some people with hrc kit or full pipe mods with different cams are using larger main jets 180-190, but friends and my local dealer say they find it hard to believe I would need anything bigger than 175. I know it's just a matter of fine tuning and finding the right set up, but I was hoping to get some info from other 06 450 owners. I plan on installing the new adjustable needle, 3rd clip from the top seems to be the rule of thumb. Going to pick up some bigger main jets (175-185?). Any suggestions? Thanks in advance for the help!

 

hey man i just bought an 06 trx 450 too and when they service it what all do they do and how long does it take them thanx

 

Have you checked your spark plug yet? I wouldn't mess with your needle yet. If you are right at 3/4 to full throttle and you are not running right, it is you main jet. Your needle is not a factor at 3/4 to full throttle. I am not saying you may not need a needle in the future but your main is obviously off. With the correct tools it is very easy to change out your main jet and solve this problem. How are you going about changing your main? What elevation do you live at? Did the issue get any better or worse (at all) when you changed out your main? With a full exhaust on mine, I have a 165 main in. I am thinking that you are getting too rich now but if HMF says lean I would simply just keep going up until it starts to run better or worse. Also, I think you are taking too big of steps when jetting. Only go one or two steps at a time (like from 172 to 175 or 178). Don't change any other factors until you get the right main jet in there. I would have though that you would be more in the 150's but it won't take long to find out. With the right selection of main jets you will have it figured out in a jiffy. Hope this helps.

 

Local dealer here in Ohio charged $145 for first tune up. They changed oil and oil filter, cleaned the air filter, topped any fluids off that needed it (break fluid, coolant etc), adjusted rear brakes (mine were barely grabbing), and last but not least they adjusted the valves. I wasn't thrilled about spending $145 for a tune up, but I didn't want to mess with the valves. I dropped my quad off on a wednesday, and they said they could have it back to me by that friday, but I told them to take their time, I didn't have any plans to ride that weekend.

I'm not sure what the elevation is here in Ohio, but I'm at the same elevation as HMF in Cleveland. I didn't think the needle was a factor in my 3/4 - full throttle problem either. I was taking my carb off the quad and taking the whole bowl off the bottom to get to the main jet till I realized I could just loosen the clamps, turn it and take off the little cap on the bowl just below the main jet, duh I'm an idiot. I could be wrong but I thought my problem was getting a tiny bit better with every bigger main jet. I know I should check my plug, but I haven't bothered looking at it cause I know I haven't found the right jet. This weekend I plan on getting it all worked out. I'll pick up some more jets and try them in smaller increments (thanks for the info dunefool). I'll start off with a new plug and be sure to check it every time now. I gotta also say I love the sound of my HMF and even though I haven't worked all the kinks out yet, I do notice a suprising difference in low to mid range. I'll be as happy as the day I got this quad when I get it running right again. Thanks for the help guys!

 

I've done my 06 and it's running great. If you put in the next size bigger pilot then 2 - 2 1/2 on the fuel screw is to much. Atleast it was for mine. The first thing I would do is install an adjustable fuel screw tha tway all you have to do is reach down and make your fine adjustments. You can get one at your dealer. MSR makes a good one. Mine was acting like your till I turned it in to about 3/4 turn. This is also telling me that a bigger pilot is not necessery. One more thing Did you take the lid off completely or did you cut it to match the HRC lid. take a look at this. http://www.trx450r.org/forum/index.php?showtopic=17874
Some say it needs part of the lid for a vacum.
I also installed the adjustable needle and the 3rd clip seems to be fine. Keep working on it and let us know how it comes out. Are you using geniue keihin jets or a kit like Dyno or jets that came with your K&n filter. Just remember the size is not the same. A 170 keihin is not the same a a 170 dyno. Use the keihin.

 

Just picked up an adjustable white bros fuel screw (dealer didn't have the scott t-handle or msr). I was running with no lid, but I will probably make an attempt to cut the lid like the hrc kit (thanks camokodiak450). I didn't get any more main jets, I'm fairly certain I have one that will work. HMF swears I should be using the 165. I didn't want to spend $40-$50 on a jet kit, but at $5 a piece I've almost spent that much picking up all these friggin jets, plus the adjustable needle, adjustable fuel screw and $3 a gallon for gas to the dealer 20 miles away lol. Thanks to great forums like this one, I already knew about the number/size difference in dyno and keihin jets and have been getting only keihin. I was going to work on it tonight, but Ohio weather sucks (cold and raining), plus wifey warned me already to not spend all weekend playing w/ my quad. So tomorrow or Sunday I'll put the new adjustable needle and adjustable fuel screw in w/ the 165 main and try a differnt setting on the fuel screw. I'll be sure to let you know how it turns out and what I finally ended up doing. Thanks again guys for the help. Cross your fingers.

 

No luck so far. I'm starting to think that perhaps my dealer isn't giving me 'geniune' keihin jets. I went as high as 180 and still no difference 3/4 - WOT. Plug is white as a ghost so..... I'm lean = go bigger main jet? Anyway I've noticed the jets I'm getting from my dealer don't have the little 'k' symbol on them. The 165 main I got from HMF with my pipe has it, but none of the ones from the dealer have it. My stock main jet was a 120 and it has the 'k' on it. What do you guys think? Think the jets from the dealer are dyno or something? Maybe I will try a different dealer. Also after my first service, I think I buzzed up and down the road once or twice, but didn't take it trail riding or anything. Since I'm grasping for solutions I thought perhaps the dealer did something valve wise that is causing me all this headache. A buddy suggested I put the factory pipe and jets back in and see if it is still doing it, so I think that will be my next thing to do. We have a big trip planned memorial day weekend so I got to get this fixed by then. I don't care if I have to go stock, just as long as I know it will run right. I don't want to be the guy sitting at the camp with a quad that won't run while every one is having fun tearing it up on the trails.

 

geez. thats almost grounds for suspecting an air leak......

 

man do you have the hrc kit. if you dont just drop the money and get the hrc kit, its comes with jets and cam and alot of other goodies. and you will see the diff. it is insane. if you need any help pm me i work at a honda dealer here in arizona and if i cant help you im sure i can ask a tech to help you out man. but next serivice have them throw in the hrc kit you will be happy. let me know man


Cooper

 

oh yea pics in the profile