Balancing the carbs?

[magicmonkey]

I've decided to balance the carbs myself and I was wondering if there is anyone in the wellington area who might be kind enough to loan me a vacum meter? I know it's a bit of an ask but I thought I'd check before I start making my own out of bits of hose!

[t3mp0r4ry nzr]

make your own! all you need is 3/4 metres of 5mm clear plastic tube from plastic box - $5. insert 2 stroke oil. done. more sensitive than mercury manometre that will cost a bomb! takes 10 minutes to sync 4 carbs if you know what your doing with this setup

[CookMySock]

Yeah use the hose. Take a look how the carbs are ganged. If they are ganged 1,2-3,4 then sync 1 and 2, and then 3,4, and then use the linkage between the carbs to sync the two groups to each other.

You can't really use a single gauge and take a reading from each carb in turn - the pressure changes every few minutes, so all you get to do is chase the gauge around.

Steve

[Dodgyiti]

Mecury balancers are a delicate tool, advice above is correct- make your own. This will get you sorted;

http://www.youtube.com/watch?v=0nKaGEMLZjs

Then blance them up;



Go for it.

[Pixie]

Yeah use the hose. Take a look how the carbs are ganged. If they are ganged 1,2-3,4 then sync 1 and 2, and then 3,4, and then use the linkage between the carbs to sync the two groups to each other.

You can't really use a single gauge and take a reading from each carb in turn - the pressure changes every few minutes, so all you get to do is chase the gauge around.

Steve

You can use a single gauge with a 4 way valve arrangement

[CookMySock]

You can use a single gauge with a 4 way valve arrangementOIC. Is it worth it? I thought a single differential gauge (water tube manometer?) was much easier to "balance" something with, than a single switched gauge.

Bugger it, I'm gunna go make a tube manometer.

Steve

[Paul in NZ]

I have one you can borrow - we are up Kapiti way but I'm out of town a bit - Vickis usually lurking about the place (hey someone has to hide the bodies) - pm if you want to use it

[t3mp0r4ry nzr]

also google "$5 carb balancer" for further assistance!

[The Pastor]

Tbh in my experiance you need a real good balancing gauge. I use george from motorcycle doctors, hes really cheap

[racefactory]

You will find the trouble is not getting hold of thevacuum gauge, but getting to the fucking adjusting screws!! You need a fucking expensive 90 degree bevel screwdriver for your ZXR250. I suggest you first find one of those!

Another suggestion whilst you are working on the carbs is to adjust the pilot jet screws, it really makes a difference. My bike had an unsteady idle and hanged after blipping throttle, slowly returning down. I suspect a lot of ZXR's are like this... running lean on the pilot circuits. I just used trial and error taking off the carbs, adjusting them, refitting and eventually went from to 2.5 turns out (factory setting) to 3.5 (richer) and its got a nice pulsing idle and the revs drop nicely now!

[vifferman]

You will find the trouble is not getting hold of thevacuum gauge, but getting to the fucking adjusting screws!! You need a fucking expensive 90 degree bevel screwdriver for a ZXR250, I suggest you first find one of those!
How much room is there around the carbs on the ZXR250? The Bolt Shop in Glenfiled had some 90-degree ratchet screwdrivers that weren't as expensive as the carb ones.

[racefactory]

Simply put there is no room. I don't think a ratchet screwdriver is going to do the job. I thought an NC30 was hard enough, this thing is even more compact.

[magicmonkey]

Simply put there is no room. I don't think a ratchet screwdriver is going to do the job. I thought an NC30 was hard enough, this thing is even more compact.

surely you just move the radiator forwards and have a go at the screws from there, they're forward facing after all ...

[racefactory]

surely you just move the radiator forwards and have a go at the screws from there, they're forward facing after all ...

Just let me know how it goes eh!

[kwaka_crasher]

surely you just move the radiator forwards and have a go at the screws from there, they're forward facing after all ...

Radiator?

He is doing the synchronising with the airbox off, right?

[Pixie]

OIC. Is it worth it? I thought a single differential gauge (water tube manometer?) was much easier to "balance" something with, than a single switched gauge.

Bugger it, I'm gunna go make a tube manometer.

Steve

I had the gauge and valve in my junk box -taken off dead robots

[racefactory]

Radiator?

He is doing the synchronising with the airbox off, right?

You can't get to the screws from the airbox side, you can only put the vacuum meter tubes on from there.

[kwaka_crasher]

You can't get to the screws from the airbox side, you can only put the vacuum meter tubes on from there.

I don't believe that. There's nothing special about the carbs or the angle they're installed on. From the pictures I've found, a long screwdriver will reach the adjusters from the space above the frame crossbrace and a short one would probably even be fine from the normal position.


<img src="http://www.dirtygirlmotorracing.com/zxr/carbs-zxr-together-air-side.gif">

<img src="http://www.dirtygirlmotorracing.com/zxr/teardown-view-of-carbs.gif">

[magicmonkey]

I don't believe that. There's nothing special about the carbs or the angle they're installed on. From the pictures I've found, a long screwdriver will reach the adjusters from the space above the frame crossbrace and a short one would probably even be fine from the normal position.


<img src="http://www.dirtygirlmotorracing.com/zxr/carbs-zxr-together-air-side.gif">

<img src="http://www.dirtygirlmotorracing.com/zxr/teardown-view-of-carbs.gif">

yup, that's exactly what I thought when I looked at them on the bike, you can get straight to the screws once you move the radiator forwards

[kwaka_crasher]

Why can't you get to them under the frame brace without moving the radiator?

[magicmonkey]

Why can't you get to them under the frame brace without moving the radiator?

it's probably be possible but it's be a tight fit and make it much more fiddly. The radiator just needs the top 2 bolts un-done and the top of it tilting forwards, takes about 1 munite to do ...

[kwaka_crasher]

it's probably be possible but it's be a tight fit and make it much more fiddly. The radiator just needs the top 2 bolts un-done and the top of it tilting forwards, takes about 1 munite to do ...What isn't a tight fit on a bike!

Just seems bizzare... even more bizzare is why they didn't simply change the adjusters to be facing rearward so you can get at them no problem down between the carbs! And why the fuckers never make the drains accessible until you've actually got the carbs off and then don't need the drains anyway! (I know, I know - it's a production thing. But that doesn't make it any less annoying.)

[magicmonkey]

What isn't a tight fit on a bike!

Just seems bizzare... even more bizzare is why they didn't simply change the adjusters to be facing rearward so you can get at them no problem down between the carbs! And why the fuckers never make the drains accessible until you've actually got the carbs off and then don't need the drains anyway! (I know, I know - it's a production thing. But that doesn't make it any less annoying.)

well, the manual recons you should fit the vacum gauge and then put the airbox back on before balancing so it does kinda make sense to have them at the front. I think that's probably something that no-one actually does outside of a production line though...