Rev Limiter or Exhaust Issue

7 replies to this topic

Posted October 30, 2001 - 07:07 AM


Prior to my temporary set back last Sunday, I had just Installed my new E-Series Exhaust. I had started my WR and warmed it up by riding it around the block a couple of times. Everything seemed normal. I ran it out of fuel before putting it on a friends trailer for a trip to the track and then to the ER...

Anyway when I got it off the trailer at the track and started it, it sounded funny. Kind of like it did when the Gray wire was installed. at full throttle I was getting that worrbling sound like hitting the rev limiter. Before the exhaust change the throttle snapped crisp. Other than full throttle the bike ran fine.

I'm really not in shape to go out wrenching on it right now, and couldn't kick it over if I had too. I'm thinking mabe I need to add more disks to the stack on the exhaust...Running 9 as recommended by the chart that came with the exhaust, or mabe raising the needle one notch in the clip.

any suggestions?


Bonzai :)

  • yzernie

Posted October 30, 2001 - 07:18 AM



Generally speaking, the jetting needs to be richened up after installation of an aftermarket pipe and/or muffler. Remember, each bike is a bit different. My buddy and I both got our 98 YZ400F's at the same time. We both put on the same aftermarket pipes and mufflers and he went one richer on his pilot and I had to go two richer on mine.

Use the info you get here as a guidline. There are sooooo many variables, altitude, pump gas vs race gas, air filter and filter oil used and most importantly......your riding style.


  • felixx

Posted October 30, 2001 - 02:49 PM


I have a 01 yzf . im not sure if it's going to be the same as the WR but mine had the same problem. The way i fixed it was put on all 12 discs lowered the clip on my needle one notch and bumped my air/fuel screw out till the bike ran fine. just some helpful info.....felixx..... Oh yeah i live in california....


Posted October 30, 2001 - 04:49 PM



Thats kind of what I was thinking....I put all 12 disks on earlier this afternoon. I plan on pulling the carb later in the week as my leg gets a little more strength. Right now I can't kick it over because of all the damage to my right leg....The plan makes sense though. Open up the pipe and lean her out a bit should do the trick.


Bonzai :)

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  • Taffy

Posted October 30, 2001 - 10:21 PM



i've only had one type of misfire at WOT and that's when it was lean. it would misfire every two or three seconds. mind you, the gearbox went the next week? now was that a misfire or a tooth missing off 5th gear?



Posted November 01, 2001 - 03:27 AM



It's not a tooth missing when it happens in Neutural. However I have had an issue lately where big blue has popped out of gear for no reason at all. A few of my maintenance inclined friends seem to think it is falling in between gears from time to time.

Ever heard of that?

Bonzai :)

  • Taffy

Posted November 01, 2001 - 03:46 AM


the dogs went on fifth gear-or was that fifth gear went to the dogs/ i can never remember.

when it was stripped the dogs in fifth had gone on the corners so it kept POPPING OUT OF GEAR, this was on top of the tooth missing making me think i had a misfire.

when we rebuilt the 'box the fork selectors were ******* huge!!! compared to what i pulled out. i bet yamaha don't advertise THAT mod too loadly do you?

like i said, it feels like a misfire ever two seconds/revlimiter. running it in fourth proved it HAD to be the gearbox.


  • armourbl

Posted November 01, 2001 - 12:55 PM


My bike made the same thing as your's Yama with the E series.

Seemed like I was hitting rev limiter early...

I eventually said to hell with the discs and now run the down spot with no discs.

At the time, I don't think you could say I was too lean on top because the bike had a 180 mj, stock needle in 3rd position from top, fuel screw 2 and 3/4 turns out, 42 pilot jet. If anything the bike was running too rich at WOT, if I'm correct.



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