Hey guys, Still having dramas with the zxr250 fueling. Bike runs and rides ok now but is unpredictable sometimes cuts out, and rpms seem to jump from idling all the way to 4k rpm when you slightly turn the throttle only for it to idle a bit at 4k and return to normal. Fuel level is set correctly, fuel screw is set at factory standard, and new idle jets/main jets have been put in. Upon doing some reading I saw mentions of a brass piece at the diaphragm, which I noticed was never in my slides. Could this be the cause of my problems, anyone willing to sell some spare or point me in the right direction? Part highlighted in image below:
If anyone has a working carb, or one that would just need a clean out/new jets and hasn't been messed with too much, they'd be willing to sell let me know.
That is the Air Bleed Jet (see below image). It is loose fitted (not pressed in) and can sometimes become clogged as it has a very small orifice. The small hole along the edge of your diaphragm goes over this part of the carb. If you misfit the diaphragm and cover the jet, it will cause problems. The Air Bleed jet does what it's name suggests and bleeds off air in the cavity between the rubber diaphragm and the carb cover. Not having that jet will obviously cause some problems, but without having a look, it's hard to diagnose. What part of Australia do you live in?
Yeah ok, I live in North Sydney. I'm half tempted to buy that kit that you've listed above, I got a dodgy one off eBay, which had jets, O-rings and the float needle. Made the bike run but has been doing all kinds of things.
Your symptoms describe an air leak (or multiple leaks). Those air bleeds are important, so acquire some. While you're working on and around the carbs - inlet manifolds, airbox seals, fuel and air t-piece o-rings will likely all need attention.
The Litetek kit(s), that greyimport posted a link to, will give you plenty of the pieces/bits that are hard to find and are high quality items. There are several carb rebuild kits depending on what you need to do. Here is a link to a cut-down kit. https://www.ebay.com.au/itm/255474455964 Also, this is a link to an old article for rebuilding ZXR carbs. It is not comprehensive, but gives you some idea. https://www.dirtygirlmotorracing.com/zxr/ZXR-Carburetors.html I think @TonyZXR lives on the Sydney Northside, so he might be able to lend you a hand. And lastly, have you (vacuum) balanced your carbs?
Thanks guys, I've purchased one of those carb kits with the brass piece, jet holder and jet needles. So I'll fit them for now, then balance carbs see how we go. At this stage I'll try to get it going properly with just that kit, but in future I'll certainly put a litetek seal kit through it. Thanks for your guidance, I'll update here hopefully sometime this week with how it went
Thanks for your guidance everyone. That seemed to make a massive difference. In terms of idling no longer randomly dying that kit made a huge difference. Feels much smoother as well under acceleration. I am encountering a new problem though which wasn't there before. Around about 12k rpm (particularly up hill or high load situations when rolling on into higher throttle) its hitting a wall. Seems to get worse the more throttle I roll on, but even if i slighly apply it in higher gears it'll hit a wall around that ballpark. I've just used the standard main jets that came in the kit: https://www.ebay.com.au/itm/255474455964 Any pointers?
Too much fuel. Those jets are huge for a ZXR250C engine. Normal jetting is 122;125:125:122 from Cylinder 1 to 4. You could probably go a bit lower as the Kawasaki's are always setup rich from the factory. What did you pull out of the carbs? I'd go with 120;122;122;120 or go with the standard jetting. You'll notice a difference. I didn't realise you were going to use all the parts in that kit. The right kit(s) for your engine (if you want to use the correct jetting) is the following one. The only real difference is the main jet size (& the cost). https://tinyurl.com/tk7zjw2v
Yeah I just figured may as well, whilst I'm there. These bits looked way nicer than what I put in their originally. I'll just swap back in the original jets then and give it a run. I did think they'd be a little big. Not too sure what i pulled out but I'll check and see.
Bit late to the party here but I wouldn't use any jets that come in those kits especially the needle which is probably more than likely your issue . I am located in South Sydney if you need a hand still.
