Uh oh, what did I do ? Bike keeps dying after recent upgrades.FIXED !


11 replies to this topic
  • still2smokin

Posted March 30, 2012 - 07:54 PM

#1

ARRGGH!!!!! My bike keeps dying and I don't know why.

Recently purchased 05 wr450 ran good on the street when I bought it 4 monthes ago,

What its doing- starts and idles great ( even for several min )

after it warms up alittle I give it 6000- 9000 rpms and on about the 3rd rev
it will cutout/stutter a couple times then slowly die then backfire and only restart sometimes if I pull
the hotstart and then if it does it only idles for a while then dieout again, die's even faster if I add throttle.

generally not restart till next day, then on the next day fire right up and run fine till I do the
same.

What I changed motor wise since it ran good-
was stock needle now JD red on 5th clip down
was 165 main now 168
was 45 pilot now 48
was 50 leak now 40
cleaned out carb really well withe brake cleaner with no problems found

Tusk fuel was 2 1/2 screws out now 1 1/2

Routed top two vent hoses up under tank

Adjusted accel pump timing, by eyeballing it so the squirt barely missed the slide and seemed about 1 second

Jumpered clutch switch to always closed.

Disconnected blue/white wire but now reconnected with no change.

Checked float level and was right at 8mm and needle looked brand new.

I did wire a trailtech vapor to the orange wire at the coil for rpm pickup but already disc that too.

New power bomb.

New gas.

Checked valves and were right in the middle.


I honestly cant tell if its starving for fuel or to rich .

I guess I am gonna pull the carb and look for any oopsies.

Any ideas guys ?

Edited by still2smokin, April 07, 2012 - 10:15 AM.


  • MANIAC998

Posted March 31, 2012 - 04:38 AM

#2

Could your needle clip have fallen off? This would mean that the second you opened the throttle, the bike would die because your letting in more air but no more fuel because the needle is not being lifted out of the main jet orifice. Maniac

  • Krannie McKranface

Posted March 31, 2012 - 04:51 AM

#3

Could your needle clip have fallen off? This would mean that the second you opened the throttle, the bike would die because your letting in more air but no more fuel because the needle is not being lifted out of the main jet orifice. Maniac


I agree.
... or a missing slide plate or slide plate seal.

  • still2smokin

Posted April 01, 2012 - 04:03 PM

#4

thanks for the replys...

I did not have time to take out the carb untill today and -

needle and clip were fine
float and needle looked good
accel pump looked good
took out all the jets and made sure nothing was clogged
I never pulled the slide out so as far as I know its all good

The one thing I did find was maybe I had the fuel screw washers and oring possibly out of order.
I did not pay attention how it was stacked upon first teardown. When I reasembled I found a pic at
rmatvmc and it showed screw-washer-spring-washer-o ring so thats the way I put it in.
Which way is right ?
http://s670.photobuc...rent=MOV016.mp4 vid bike dying
http://s670.photobuc...rent=MOV019.mp4 vid of accel pump squirt
Posted Image
Posted Image

Edited by still2smokin, April 01, 2012 - 11:32 PM.


  • L. Euler

Posted April 01, 2012 - 06:14 PM

#5

Almost sounds like the float bowl is draining. Do you have good flow from the tank? Float valve passage is clear? Tank Filter not Clogged?

  • still2smokin

Posted April 01, 2012 - 06:29 PM

#6

Actually I did check the petcock for 2 reasons.
It leaks a little on the outside and when this started happening I noticed almost every time
I would see an air bubble in the fuel line.
The flow looks good with tank off but I
already have a new petcock on the way.

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  • Leardriver

Posted April 02, 2012 - 12:43 AM

#7

When it won't start, take off your gas cap and see if it will start then. Your jetting is close enough for it to run fine. Your fuel starvation sounds like a plugged gas cap vent.

You have an extra washer on your fuel screw. The order of stacking is spring, metal washer, oring.

  • still2smokin

Posted April 02, 2012 - 07:20 AM

#8

Yup I made sure the gas cap was loose on the
last couple of start ups.

The tusk fuel screw comes with 2 washers from
what I see on product descriptions at retailers.
I did find a pic from when I tore it down showing
just what you said about spring- washer-0 ring.
and now remember the extra washer falling
out of the carb during cleaning as if maybe the extra washer was placed like screw-spring-washer-o ring- washer.
I am stumped.

  • Taxgod4u

Posted April 02, 2012 - 07:41 AM

#9

my 2 cents... i agree that is fuel starvation, look for something strange like a leaf in the tank, if carb is off blow through the fuel line and see if you get good flow down in teh bowl. replace fuel line, could be defective an collapsing at a bend. floats could be bent and not letting bowl fill completely or fast enough.

  • still2smokin

Posted April 07, 2012 - 09:35 AM

#10

FIXED !!! It turned out to be the fuel mixture screw was bad.

I tried going back to stock jetting --no luck

After trying my buddys carb off a 06 wr450 in it, it ran fine, so we compared them and my
Tusk fuel mixture wobbled around alot even when bottomed out. :thumbsup:
Put his Zip Ty screw in my carb and bam it ran great.

Tusk fuel screw $11.99 - I guess you get what you pay for.

Went looking for a Zip Ty screw at my local shop and instead found the
R&D flex/remote fuel mixture screw ! :thumbsup:

  • MANIAC998

Posted April 07, 2012 - 04:41 PM

#11

still2smokin, Thanks for the update! Glad to hear you got it figured out. And with you listing what finally fixed the issue, whenever someone does a search, they will come across this post which is completed. And that Sir, is priceless!!! Maniac

  • Krannie McKranface

Posted April 08, 2012 - 08:16 PM

#12

FIXED !!! It turned out to be the fuel mixture screw was bad.

I tried going back to stock jetting --no luck

After trying my buddys carb off a 06 wr450 in it, it ran fine, so we compared them and my
Tusk fuel mixture wobbled around alot even when bottomed out. :thumbsup:
Put his Zip Ty screw in my carb and bam it ran great.

Tusk fuel screw $11.99 - I guess you get what you pay for.

Went looking for a Zip Ty screw at my local shop and instead found the
R&D flex/remote fuel mixture screw ! :thumbsup:


NOTE: NEVER put an aluminum fuel screw in an FCR Carb! It will eventually corrode, and possibly break off inside the carb.

The Tusk is Aluminum. The R&D is Brass, just like the OEM.




 
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