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Dodjy

05 rich or lean question

11 posts in this topic

G'Day Guys, I'm having a few hassles getting my jetting perfect. I have looked at the jetting database and done a lot of jetting in the past but I reckon this may be better answered by someone who has been there before. It's an 05 WR450, needle from the spares kit supplied (not the single clip position needle), standard exhaust with the restrictor and spark arrestor removed and a larger diameter tail pipe replacing the standard pea shooter, 170 main, 48 pilot and the rest standard jets. I have the YZ throttle stop, done the air cut mod blocking the vacuum port, disconnected the grey wire and removed the intake snorkel. I've done a full throttle plug check and it looks perfect, the bike starts easily, warms up on the choke, then idles a little roughly without the choke about 2 - 3 minutes after starting. When it's fully warmed up, pulling the hot start raises the idle slightly (suggesting the pilot is rich). When hot it starts without the hot start (suggesting the pilot is lean). It backfires when I back off at medium to high speed (suggesting lean pilot), I need to adjust the fuel screw and idle speed often to get a stable idle and when at higher altitudes the idle is more unstable often hanging up high (suggesting the pilot is rich). The biggest problem is climbing slow, twisty, slippery , not so steep hills where you need constant but small (1/4 to 1/2) throttle openings. The bike surges making it tiresome to keep on track. It has no problem blasting up really steep hills at larger throttle openings. It feels lean to me but I was wondering if you guys have experienced this and how you fixed it. Usually surging and popping like this happens when a bike is lean but the higher idle when the hot start is pulled in and getting worse at higher altitudes stomped me. Wodyareckon?

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G'Day Guys, I'm having a few hassles getting my jetting perfect. I have looked at the jetting database and done a lot of jetting in the past but I reckon this may be better answered by someone who has been there before. It's an 05 WR450, needle from the spares kit supplied (not the single clip position needle), standard exhaust with the restrictor and spark arrestor removed and a larger diameter tail pipe replacing the standard pea shooter, 170 main, 48 pilot and the rest standard jets. I have the YZ throttle stop, done the air cut mod blocking the vacuum port, disconnected the grey wire and removed the intake snorkel. I've done a full throttle plug check and it looks perfect, the bike starts easily, warms up on the choke, then idles a little roughly without the choke about 2 - 3 minutes after starting. When it's fully warmed up, pulling the hot start raises the idle slightly (suggesting the pilot is rich). When hot it starts without the hot start (suggesting the pilot is lean). It backfires when I back off at medium to high speed (suggesting lean pilot), I need to adjust the fuel screw and idle speed often to get a stable idle and when at higher altitudes the idle is more unstable often hanging up high (suggesting the pilot is rich). The biggest problem is climbing slow, twisty, slippery , not so steep hills where you need constant but small (1/4 to 1/2) throttle openings. The bike surges making it tiresome to keep on track. It has no problem blasting up really steep hills at larger throttle openings. It feels lean to me but I was wondering if you guys have experienced this and how you fixed it. Usually surging and popping like this happens when a bike is lean but the higher idle when the hot start is pulled in and getting worse at higher altitudes stomped me. Wodyareckon?
Did your bike come with the ais smog crap ?? if it did , get the smog removal kit . you also may have the wrong needle in there, I had a big studder until I put the jd red needle in the bike..what is your fuel screw set at ?? :banghead:

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In OZ we don't get the AIS. The needle and 48 pilot jet is supplied to use for racing the bike when you have done all the free mods. The fuel screw is set at 1.5 turns out.

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I got the same problem mate!

I need to get a 50 pilot jet cause my fuel screw is way out.

Make sure your header is perfectly lined up and you may even need new exhaust

gasket.This can cause some wicked backfiring.

Us in Australia don't have to deal with that AIS crap.

The surges are probably your accelerator pump working with an unsteady hand.

I am on the 5th clip using a JD red needle, If you are on the 3rd clip, go to the 4th.

If you are rich, it will run rough, coughing and farting. Lean it will bog. I have changed

my needle position many a time, It doesn't take long at all.

I see you have done the air cut mod, I would put it back to standard as this richens it

when you back off so you don't get the lean effect.

Get a fuel screw off ballards if you don't have one, it is well worth the $50. This could

be your problem.

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Yep, I will get the screw but I made up a tool to set it and it isn't much of a problem. I did the air cut mod to try and get a stable AF ratio when on light throttle such as sliding through corners etc. I read the posts about the air cut valve fluttering in and out under those conditions changing the mixture. I'd prefer to keep it closed off if possible. I think moving the needle richer may be worth trying. As for the acc pump, I made a point of trying to keep the throttle in the same position and it was only 12 hours since the last drink so my hand was steady as. It definitely liked the throttle moving and not constant.

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well ... according to Clipstone Yamaha (Ringwood, Melbourne) the grey wire modification does not need to be done for the Australian market and they strongly recommend against it. I just got my 05 WR450F from them with all of the free mods done and over the 250k's i've put on it so far it runs SWEET AS!!!. Give their service dept a call to verify this and i think that you'll find them very helpful. The service manager (ANDY) is a wealth of information (03) 9870 9466

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Hey guys, i was just wondering (seeing as how there has been no confirmation or denial to my last thread) ... am i correct in my assumption that the Grey wire mod does not need to be done for the Australian market. As much as I'd like to think that I'm a genius (i already know where you can get 10/1 against that), I'd really appreciate some (positive?) feedback or at least some hard evidence to the contrary. Dodgy, did you have any luck since posting ?

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G'Day Pkof, I spoke to Jeff Taylor Yamaha in Dandenong and the guys said that disconnecting the throttle position sensor does the same thing (changes to YZ timing). I left my grey wire disconnected as it definitely idles better and I reckon it revs a bit more freely up high and I don't beleive disconnecting the tps changes the timing to YZ (I thought the ignition is mapped tps Vs rpm, so disconnecting the tps probably gives an incorrect advance curve). I still don't reckon it revs out as it should (I have never hit a rev limiter as heaps of guys on this forum have claimed to have done) but this is most likely the stock muffler. You really need to take what shops tell you with a grain of salt. My experience is that unless you can buy it and bolt it on, they really don't know much. When asking about the top end performance the guy was saying the power should keep increasing until you hit the limiter - mine drops off well before this, he then said "have you de-restricted it"? I said yep, airbox, tail pipe restrictor, grey wire, jets, then he told me there was a restrictor in the header pipe. Load of crap, I pulled it off and there's no restriction at all. With your grey wire I suggest you disconnect it and see what you think only takes a minute. There are some good articles on the grey wire on this forum, can't remember the author but he compares the two curves. I can't see a reason to change this part of the bike for OZ. Maybe we have a slightly less retarded WR curve but I beleive the YZ curve is there if you disconnect the wire. I pulled my muffler apart on the weekend and cut out the second main baffle so I'll see if this lets my bike rev better.

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Ok, thanks for the info Dodjy and please let me know on that last exhaust mod cause i was gonna try that next ... or get a FMF ? ($$$)

I'll try the grey wire mod this weekend !!

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Fixed the problem, the bike was way too lean on the pilot due to me loosing the tiny o-ring on the fuel screw. I also had the spring and washer around the wrong way. The correct orientation is not in the manual and is supposed to be spring on the needle first, then washer, then o-ring. Because I had no o-ring, air was being sucked into the pilot jet (past the fuel screw), hence all the popping, crappy idle and frequent adjustments. I also raised the clip on the needle to lean out the 1/3 to 2/3 throttle and thet seems to have fixed the mid throttle surging. The "hanging" idle is also fixed, when I replaced the o-ring, I had to back off the idle speed by about 1 to 1.5 full turns. I think that if you don't get the pilot circuit right, you end up compensating by opening the throttle more resulting in the idle hanging up high and being unstable.

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