ZXR250C carb help wanted

[Spoonrider]

Hey guys,

I have a 1994 ZXR250C and I am getting hesitation issues between 6-8k rpm, I am also told the bike is running very rich. The hesitation seems to come on as the bike warms up, it could be the richness fouls the plugs... but not sure. The bike has an aftermarket exhaust which I am told could be making the issue worse.

Just wondering if there is anyone in the Auckland area that is clued up on these bikes that doesn't mind giving up some of their time (for a box of beer) to help me remove the carbs and have a look at them to see if they are dirty or there is any other obvious sign as to what could be causing the issue?

Also, has anyone had experience with these http://www.ebay.com.au/itm/91-04-Kaw...ht_2524wt_1163 Given the needles aren't adjustable I was thinking of getting one of these to maybe help my issue?...

Any help would be very much appreciated :-)

[Haggis2]

Have you thought about gettign yourself a Haynes type manual? I consider myself reasonably clued up (sometimes) and have found mine invaluable with some things.

[Spoonrider]

Have you thought about gettign yourself a Haynes type manual? I consider myself reasonably clued up (sometimes) and have found mine invaluable with some things.

Yeah, have watched videos and have a service manual but always good having someone there who knows :-)

[FJRider]

A blocked / dirty air filter will make it run rich too ... give it a clean and see if it improves.

No filters (or small ones) will lean the mixture out a little. See if a short run with no filter makes any difference ...

[Spoonrider]

A blocked / dirty air filter will make it run rich too ... give it a clean and see if it improves.

No filters (or small ones) will lean the mixture out a little. See if a short run with no filter makes any difference ...

Thanks for the reply.

Air filter has been cleaned already so not that, o-rings between the airbox and carbs have been replaced too as they were poked. I was told it was running rich cos there was some black soot in the end of the tail pipe, so I am not certain if it is running rich or not...

[FJRider]

Thanks for the reply.

I was told it was running rich cos there was some black soot in the end of the tail pipe, so I am not certain if it is running rich or not...

The black soot is the result of our poor quality petrol. This is evident in most motorcycles since the introduction of unleaded petrol.

[Spoonrider]

The black soot is the result of our poor quality petrol. This is evident in most motorcycles since the introduction of unleaded petrol.

Ah, ok then.

So is there any easy way to tell if it is either running rich or running lean?

A lot of research that I have done points to it running lean and that I should try a couple of shims under the needles... It has a non-standard slip-on muffler as well which people say can play havoc with them too

[FJRider]

Ah, ok then.

So is there any easy way to tell if it is either running rich or running lean?

A lot of research that I have done points to it running lean and that I should try a couple of shims under the needles... It has a non-standard slip-on muffler as well which people say can play havoc with them too

Try the air filter stuff I suggested first. (easily done) Air filters can get dirty quite quickly ... especially in spring with all the pollen in the air. Dirty/dusty roads too ... (also a cheap quick fix you can do ... usually)

An aftermarket exhaust helps the engine breathe out ... what steps were made to help it breathe IN .. ???

What re-jetting has been done after the exhaust was fitted ... ???

[Spoonrider]

Try the air filter stuff I suggested first. (easily done) Air filters can get dirty quite quickly ... especially in spring with all the pollen in the air. Dirty/dusty roads too ... (also a cheap quick fix you can do ... usually)

An aftermarket exhaust helps the engine breathe out ... what steps were made to help it breathe IN .. ???

What re-jetting has been done after the exhaust was fitted ... ???

I am not sure what work was done after the muffler was added as I bought the bike with it already on. Will definitely try the air filter stuff first and see what happens but it was cleaned and oiled less than a month ago.

[FJRider]

I am not sure what work was done after the muffler was added as I bought the bike with it already on. Will definitely try the air filter stuff first and see what happens but it was cleaned and oiled less than a month ago.

Possibly no work done ... may need checked to see .... ???

When I had a 250 ... I cleaned it (air filter) weekly. It doesn't take much to affect small engines. (clean the plugs too)

If the filter is standard ... try an aftermarket one ..

[ducatilover]

It has an aftermarket pipe, it's lean.
Put .5mm washers under the needles and go ride it again, repeat 'till it's done.

Or, if you're near Tauranga, PM me and I'll do it for you

[Spoonrider]

It has an aftermarket pipe, it's lean.
Put .5mm washers under the needles and go ride it again, repeat 'till it's done.

Or, if you're near Tauranga, PM me and I'll do it for you

Thanks heaps for the advice ducatilover, I wish I was in Tauranga but I am in Auckland. I think if I take it slow I have watched enough videos and read enough manuals \ info to do it. Do you know where is a good place to get the washers from?

[ICE180]

j car have the type you need they are 0.2mm each if you get stuck let me know and i can get some when I go into work next on New years eve

[ducatilover]

j car have the type you need they are 0.2mm

Thanks heaps for the advice ducatilover, I wish I was in Tauranga but I am in Auckland. I think if I take it slow I have watched enough videos and read enough manuals \ info to do it. Do you know where is a good place to get the washers from?

What ICE180 said
It's not a very hard job to do.
ZXRworld.co.uk could help, they're mainly ZX400H/L but the process is the same and I think they'll have a few write ups there

Essentially you remove the tank and airbox, un-do the caps on top of the carbs, don't lose the springs
If you have a magnet on a pole you can lift the needles out without taking the slides/diaphragms out, but it's easy enough anyway
Then, put the washer under the needle, re-assemble and be careful not to over tighten the screws on the caps, I've seen a few crack
Also be careful with the diaphragms and make sure they're seated flat
One of the caps will have a little metal mount on the engine side (number 3 from memory) for the choke cable, try not to lose that either.

[Spoonrider]

Nice, thanks guys!

I didn't know you could do it without taking the carbs off the bike... I have taken the tank off heaps of times before and the airbox also so that isn't a problem.

Really appreciate your help.