bike missfire at 5k

[tz250racer]

Hi,I have a 1991 Fzr1000 to use as a track bike only.The bike has a jet kit and a yoshimura exhaust.The bike starts and idle great but when I slowly increase the rpm and reach 5k the motor start to missfire and few pops are heard from the exhaust and won't rev higher.It's like the motor hits the rev limiter at 5k but I am not sure if it has one.Coils,Cdi perhaps.I would not think a jet kit would cause this problem.Any help would be appreciate.Thanks

[apsolus]

some recient complaints just like yours ended up being the exup valve wasnt moving like it should. have you been through your carbs yet? might need a good inspection and cleaning

[rotortech]

Hell yes a jet kit will cause this problem. If your mains are too lean it will just quit around 5k. If you are running the EXUP take the advice from apsolus and check it out.

[tz250racer]

Hi,the bike has a not working exup.The yoshimura exhaust won't take the exup,cables where missing but the exup motor is still bolted to the motor and to the cdi but nothing else is attached.Does the cdi have a rev limiter or not?.Carbs where all cleaned.Thanks

[sweekster]

Have to agree with what both have just suggested here. My 1000 did the same thing and turned out I had a couple clogged main jets. Would not hurt to give the jets a good cleaning along with servicing the exup valve if you still have that header on the bike

[tz250racer]

The bike has a full yoshi exhaust and not the stock header.

[Ice Queen]

Almost certainly Exup motor related. Someone on the exup forum posted a thread showing a circuit board he had made up to "fool" the CDI unit into thinking that motor was still attached

[reelrazor]

Hey, you 1k geeks out there?

Could this be a low fuel switch issue?

[yamaha_george]

Almost certainly Exup motor related. Someone on the exup forum posted a thread showing a circuit board he had made up to "fool" the CDI unit into thinking that motor was still attached

IQ,
do you have a link for that "trick board "? would be useful to have it in the wiki

[DonTZ125]

http://www.exupworldwide.com/forum/view ... eliminator


Note that I have NOT checked these. Blowing up your TCI chip is at your own risk


I think you have to be registered & logged in to view it; here's the circuit for those somewhat interested. (I'm considering offering this as one of my products - yes, I'm going to be launching ANY DAY NOW )



The wires are I believe for a ('94 YZF750)'06 R6V; oddly, they do not match the manual I have for a '95 YZF750. Comparing manuals, the '95 YZF and all FZR1000s have the same EXUP wiring. Looking at the manuals, and comparing the graphic, I'm going to say the following is probably right: (graphic = YZF750 or any FZR1k)
B/R = B/R
B/G = B/Y
W/R = W/R
B/L = Y/L
L = W/B


TZ250racer - when you say the bike has a 'not working EXUP', do you mean the servo doesn't work, even though it isn't plugged in? If the servo works & is plugged in, even if the cables & valves aren't there the TCI will still be happy.

Edit - more digging, and I've found the bike these wires are for - a 2006 R6V.

[Ice Queen]

DonTZ125
Pretty sure that servo motor wiring for R and RU models are different. will have to spend bit more time looking.

[DonTZ125]

IQ - Dense moment here; the only 'RU' model I can think of is the FZR750, which was non-EXUP. Clarify?

Also, I'm looking at the service manuals for the FZR1000W (including A, B, & F), and the YZF750RE; their EXUP wiring all match what I've suggested above.

[Ice Queen]

The RU model is 1000 1991 onwards.

Just had a look at wiring diagrams and I THINK wiring is as follows:

R model 89-90 B/R; B/Y; W/B; W/R; Y/L

RU model 1991 onwards R/B; R/W; B/Y; W/B; Y/B

clear as mud isn't it !!!!!!!!!!!!!

[DonTZ125]

Sitting here with the FZR1000W ('89) manual open in front of me, which also includes the B ('91) and F ('94) wiring diagrams. I also have the YZF750RE ('93) in front of me. All show my colours.

I think that comes under the heading of 'caveat emptor', and "everything about these silly things is different!"

[yamaha_george]

Sitting here with the FZR1000W ('89) manual open in front of me, which also includes the B ('91) and F ('94) wiring diagrams. I also have the YZF750RE ('93) in front of me. All show my colours.

I think that comes under the heading of 'caveat emptor', and "everything about these silly things is different!"

Where the heck is SWEEKSTER when you need him to do the FZR historian bit .......................................