Anyone know a good WR mech in SoCal?

Anyone know a good Yamaha mechanic in San Diego? I would really like to find someone that knows how to fix a problem with my WR450. I have just about given up.

Is this your carb problem? I was able to cure mine, and i'm not an expert. I'm up near LA, about 2 hours from you. But i have a spare carb that i can get cleaned up and let you try?

I don't think it is the carb. I think it is the CDI or TPS. I have cleaned out the carb and the hoses and it all looks good and runs great except 0- 1/8 throttle. If I run the the bike and disconnect the TPS = no difference; if I run the bike and try adjusting the TPS = no difference. No variation in the high idle.

Whats the jetting set to?

Whats the plug look like? Have you played with plug gap? Ever try a different coil? Different CDI? Disconnect the kill switch. Carb boots on tight. Leave the TPS disconnected for now. Sorry if you have tried all these things. How long ago did it run correctly for you?

Everything is cleaned, tight and the jetting has been tried for about 12 different combinations with the stock needle and the JD Kit needles. You name, I have tried it. Ran the best with the 165/45/Red #3 and 1 5/8 on the screw. Runs great from 1/4 to WOT. Snap the throttle and the bike takes off. Try slow speed, low RPM riding and the problems occur. So something in the transition from idle to 1/8 or the 0- 15 MPH. Bike starts and idles fine.


I think your 165/45 is way lean for Socal... I've had the best results with a 168/48 stock needle. Before you take it in try the 168/48 combo.. Change your spark plug! Also, make sure that your carbs slide plate is on correctly. The TPS shouldn't really matter, you should be able to unplug it and it should still run fine. Good luck

Try slow speed, low RPM riding and the problems occur. So something in the transition from idle to 1/8 or the 0- 15 MPH. Bike starts and idles fine.


Sounds like Mr.Pilot jet doesn't want to cooperate.....

Try slow speed, low RPM riding and the problems occur. So something in the transition from idle to 1/8 or the 0- 15 MPH. Bike starts and idles fine.


So what happens at 0-1/8 throttle? You haven't really shed any light on the problem. Is the response digital at these throttle openeings - on or off?

The problem: The bike stutters just off the throttle, if it was a 2-stroke I would say it is loading up, as the throttle is opened up, slowly or quickly, it runs like a champ. Constant low speed, it stutters. I have tried pilots of 42/45/48 combined with MJ of 170/168/165/162/160, used the stock needle and the JD needle (blue and red) from 2 to 5. The carb and vent hoses have been cleaned by myself and by the dealer. I have not removed the slide but the dealer probably did and I am assuming he installed it correctly. Regardless the bike runs the same as when I took it in.Two weeks at the dealer, with calls to Yamaha, and the problem remains. I am now focusing on the TPS or CDI but not sure about those since it runs great through the rest of the power band. The TPS resistance checks fine at the female side of the plug and fluctuates when I open the throttle. I tried checking the other side but the Multimeter leads might not have been long enough to connect, I didn't get a reading. I tried move the TPS adjustment from end to end without any change. Someone mentioned the Hot Start O-Ring. I will look at that. But in general this is all rather bizarre.

When I bought this, it ran fine at low RPM but would stutter when snap the throttle to WOT. I suspected lean jetting. It was 155/42/ stock #4 with TPS disconnected and gray wire connected. Airbox is open and bike has Pro Circuit 496 slip on exhaust. Once I changed the jetting, the midrange and top end was great but I lost the low speed-low RPM.

I have been working this issue for 2 months. Searching TT for answers, trying everyones recommendations. I have exchanged emails and phone calls with James Dean. I am going to give it one more shot this weekend, then I will return it back the way it was. We have owned 99 YZ400, 02 YZ426, and 06 YZ450 none have had this kind of problem. I am pretty disappointed in the whole thing. But I am betting it is something simple, something overlooked. I thought about the Vortex CDI but $400 is tough to spend when I don't really know if that is the problem.

I trust you have checked the accelerator pump timing? the constant low speed sputter makes this unlikly but should be checked anyway. How about a dyno test if you can make the problem happen regularlly then a dyno test may be worth the money. all the smog shops have a propane bottle with a hose and a button valve if you use this type of tool to inject propane into the intake while experiencing the problem this test will rule out a lean condition may rule out rich condition as well. I understand that this is alot of things to manage at one time please don't crash while attempting something like this. This is the kind of thing dynos were made for. also an exhaust gas analyzer may be helpfull for this type of troubleshooting. It seems like you need to gather more clues anyway you can.

Doc at Motoworld in El Cajon Service Dept. should be your last resort. He is verrry good.



That is exactly why I asked the original question about a good WR mechanic. But PBDBlue and I are getting together and try everything again including the accelerator pump and ACV. He volunteered to put another set of eyes on the problem. Saturday is the day. We will see.

Thanks Tim. I called and talked to him. He recommended many of the things we have already tried. But offerred to take a look at it tomorrow.


PBDBlue and I got together last weekend to figure this out. Removed the carb and checked:

-All the jets settled on 168/45 and JD Red #3

- blew out all jets and passages

- checked Accelerator pump

- checked ACV

Re-installed carb and still had a problem

Removed tank and seat and the dealer had re-inserted the grey wire so:

- punched out the grey wire

- punched out the neutral switch wire

- tested and adjusted the TPS

Re-assembled and (drum roll please) ta-da !! The stand test and street test checked out just fine. Waiting to get it out in the field but all indications we have it solved, well PBD Blue solved it. It appears the neutral switch was the culprit. Rather bizarre.

Many thanks to PBD Blue for helping me out on a Saturday morning.

Good One, Your reward for diligence. I am curious is the neutral switch shorted or open?

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