won't rev up even full throttle

I'd simply answer that question by saying how quickly do you want to get moving? <!-- s --><img src="{SMILIES_PATH}/icon_smile.gif" alt="" title="Smile" /><!-- s -->

 

fellas!

I have a bike that i have manage to assemble from scratch, an fzr 250 2kr...about the reving problem i manage to fix it thru doing some synchro on the carbies and changing new batteries....with those solutions i have manage to run my bike at 160 kph....(it was a scrap bike when i bought it) <!-- s:lol: --><img src="{SMILIES_PATH}/icon_lol.gif" alt=":lol:" title="Laughing" /><!-- s:lol: --> and synchronize it by only aligning the butterflies in the carbies....don't have any vaccum guage here <!-- s --><img src="{SMILIES_PATH}/icon_redface.gif" alt="" title="Embarassed" /><!-- s -->

 

I have the same problem, I think the airbox is the issue

It looks like there's something missing




Is there meant to be a hose from the bottom left of the airbox into a T piece and connecting to those 2 hoses from the carbies?

 

I believe only found on the 2KR its a drain/air breather hose that threads along the frame going to a small inline air filter around an inch long, 15 mm diametre and then to the atmosphere under the bike around the rear shock, mine was blocked and after blowin the compressed air through it found the filter would break into particals on touch, refilled the filter with dacron and a small piece fine filter cut from the tip of a auto paint strainer (free from the auto paint suppliers)...

 

Took the fuel tank off last weekend.

Forgot to take some photos but I found some on ebay





For each pair of carbies there's a wide plastic "filter" on the hose (you can only see 1 in the ebay pics).

Both of mine just hang under the airbox, Are they meant to be connected to anything?

 

Ok I edited the ebay photos (sorry / thanks to who ever took the photo)..





What are these meant to be plumbed into??

 

I managed to take another look today, i'm guessing its because my 3LN is gravity fed and is missing the fuel pump.

I think I stall the bike, it floods the engine, the fuel bowls fill up, the floats rise to cut off the flow of fuel and the little fuel valves remain shut, the gravity fed fuel and weight of the floats isn't enough to convince the little fuel valves to open again.

I'll find a fuel pump and let you know how I go.

 

The fuel pump spec for the FZR250 are 10kPa / 1.5psi... Hopefully it will sort out you problem..

 

Thanks Dave, now I just need to track one down.

 

Hey Okibi, did you find a fuel pump?

My 3LN is also missing a fuel pump. I get occasional issues with flooding, difficulty starting. I'm learning the necessary nuances of throttle/cluch control, but it can be a real bugger at times - taking off from the line and having no power coz she's drowning.

Let us know whether the fuel pump made a difference?
Does anyone else know whether it's acceptable/irrelevant to run these things without a fuel pump?

cheers.

 

I was having a play yesterday getting her to stall up by overfueling (so no matter how much throttle it wouldn't start to rev), I then sprayed "start ya bastard" onto the slides and made no difference.

I'm thinking it's more a vacuum issue, not enough vacuum to pull the slides open.

So I guess the question remains WHY ...

 

when i got my bike i had the same problem, it is a carbie issue, i know that for sure.. to fix pull off your fairings so you can get to the back of the carbs. now you will see a little screw in the bottom of each carbie.. get a small screw driver and turn each screw gently all the way in to it stops... once all four have been screwed in... go back and turn them one full turn each outwards (anti clockwise). fixed my bike. good luck! let me know if it works <!-- s:biker4: --><img src="{SMILIES_PATH}/th_Biker_4.gif" alt=":biker4:" title="Biker 4" /><!-- s:biker4: -->

 

Sounds like the idle mixture screw is what you have adjusted.

 

it is... and if that doesnt fix the problem go to the wreckers and get some second hand carbs, they take less that 30 mins to r&r

 

mY 400 had the same type of problem. Turned out to be the fuel pump. Check you've got enough gas and that you don't need to
switch to reserve. The fuel pump should run for 2-3 seconds when you first turn the ignition on.

 

I've now been advised that the 250 doesn't even have a fuel pump! (anyone wanna confirm or debunk this?)
Anyway, paid ~ $300 for a full service by a guy who knows his stuff, and I can certainly tell the difference.
I still get the symptoms described here if I don't give it enough gas when trying to take off, IE low speed manuevres, in car parks and so forth, but I'm told it's just a "feature" of these beasts. You learn how to handle the throttle/clutch I guess. Just sounds like you're getting set for a take-off when tootling about.

 

My bike wasn't working right (air leak through the starter jet plungers) when I parked it for the winter, but even with my 230lb carcass athwart the saddle it most certainly didn't need clutch and throttle at parking lot speed. Having to taxi across the tarmac using 'launch' techniques is most certainly NOT a 'feature' of these bikes.

Whoever told you the 250s don't have fuel pumps was speaking from his nether regions. The lowest part of the tank is too low relative to the bowls to fill the carbs, and fuel stops flowing around half-tank. That said, a LACK of feed pressure will not cause a rich condition. Possible causes: your carbs are mis-jetted, your idle screws are too far in, your floats are mis-set, your floats are malfunctioning (perforated / cracked / porous floats fill with fuel and become 'sinks'), your float valves are shot, and don't stop the flow of fuel (particularly noticeable at slow running; the low fuel demand allows the leakage to overfill the bowls. At full honk, the float valve spends most of its time partially open anyway), your air filter is clogged, you airbox inlet is clogged.

Get a fuel pump from a wrecker, or one of the fellows parting out. Inspect the float needles (the viton coatings do wear out); set your floats to ~24mm; synch your carbs (these three points should have been part of the 'service' for which you just paid $300). If you're running that rich you probably don't have an air leak, the other common prob of these beasts.

 

Thanks for all the great replies, still haven't found a cheapish fuel pump for her but I hope to have some time this weekend to play with the idle settings.

 

The 2KR and 3LN both have fuel pumps. The 2KR won't be able to access all the contents of the tank without it, the 3LN tank bottom is higher than the carbs and will function without one, but it is best to have one to make sure there is an adequate supply to the carbs. The fzr fuel pump runs 10kpa, or 1.5psi