Right I need help with my ZXR250C. I know my carbs need new seals, going to buy a Litetek kit next chance I get. I need new float valves and seats, but I can't get the damn old ones out, they seem to be stuck, so I could do with some advice on that. But I noticed a serious problem earlier, that the left side of the block was heating up significantly faster than the right hand side and the valve cover, and I've got no bloody idea what could cause that to happen. There is a lot of things I need to fix on her (god damn PO's not looking after their bikes)
Can't agree more with the cursing of the previous owners!! As for the heating could it be a water blockage? Coolant flush wouldn't hurt. With the seats I used wd40 and pliers, with abit of a turn, if that doesn't work You can spray wd40 thru the fuel hose nozzle and hold carbs upside down. It might help.
I'll try that with the carbs, I'm gonna take them off because it seems to be running hot from being lean. Here are some photos of the plugs, these are about a month old, and they were darker before, but #1 was black (float was stuck open, hence why I need new float needles and seats), but since I last took the carbs off it's turned white #1 #2 #3 #4
Determining mixture from spark plugs is not done the way that most people think. The mixture ring is actually at the base of the porcelain, not at the top. A difference in temperature across the cylinders is usually caused by one or more cylinders not running correctly, so they are colder than the others. cheers Blair
Found out what was leaning it out: the float valve needle was stuck in the closed position, so very little fuel was flowing to the bowl. Does anyone have a link to where I can buy a set of new needles and seats?
http://www.motorcyclespareswarehous...roducts/khv-24l24-float-valve-needle-and-seat probably the cheapest brand new you'll find
Thanks for that Would you happen to know how I can separate the carbs? They're well and truly stuck together, and nothing seems to get the damn things apart
Use the start of this thread as guide to get them apart.. http://2fiftycc.com/index.php?threa...in-your-zxr250-keihin-cvk30-carburetors.2651/
I had to separate them so I could change all the O-rings and gaskets to the Litetek ones. It runs a lot better after changing them over, a bunch of the O-rings had perished and were leaking air. Now, it seems to misfire when cold on #3, if I grab the header it isn't heating up as fast as the others, but once the engine warms up it seems to start firing fine Soo, the bike is getting there, slowly but surely. (Also, my exhaust was full of petrol from the sticking float needle, and when i started it a jet of petrol shot out the exhaust )
Silly question, how do I check the valve clearances? I've only really done engine work on a little 2 stroke before, so I'm pretty new to 4 strokes.
take off radiator, fairings, fuel tank, airbox and carbs. take off the rocker cover and you will see the cams and the lobes on them that push open the valves which are covered by a bucket (directly under the cam lobes) you can then turn the crankshaft through the inspection plug (rhs on the clutch cover) and move the lobes off the valve buckets and measure that clearance. Dont turn the crankshaft the wrong way or you will mess up your timing chain. so once you have got the lobe of the camshaft off the valve bucket get a feeler gauge and check the space inbetween the cam and bucket. In the resources is the manual which tells you the proper way to do it (1st cyl at tdc check clearances of certain valves and 4th at tdc check the others) but it doesnt matter. As long as there is no part of the lobe on the bucket it is fine. inlet clearance is .15-.24 and ex is .2 - .29, if the clearances are tight you need to get the cams off (dont move crankshaft at this point), remove the bucket and there is a shim underneath which sets the clearance. Remove the shim and measure it and if your clearance is .1 for the inlet valve and your shim is a 180 you need to get a 190 to make the clearance .2. it will take you probably 2 days to do this if your clearances are out, watch this video as the process is exactly the same for the zxr's, the other 2 parts show how to take out the cams with the timing chain and put it back together again.
Sounds like I'm going to be busy in the near future with the valves! Also, it stumbled and wouldn't run properly (presumably not firing on #3), after I let it sit for a few minutes, it started working again, but did the same thing about 15 minutes later, same fix. Got it home and checked the charging system and it doesn't seem to work as well as it used to: at idle the voltage keeps dropping until it hits 12.4~12.6 volts at around 2,000 rpm (revs drop slowly to 1,500 rpm as the voltage plummets) but the voltage goes up to 14.6 at 6,000 rpm and goes down a bit when the revs rise some more.
voltage is good on the charging side of things, but something is f**ked on cylinder 3 then, did you check the leads and all that stuff?
The lead is conducting fine, the spark plug boot has a tear in it, but still conducts fine... I think I'll check if the plug sparks good in a moment
Just swapped #3 and #4 plugs, problem seems to have gone away for now. However, I was looking at my multimeter and the battery voltage, with the ignition just 'on' (so engine off, but lights etc. on), the battery loses a huge amount of power, dropping from 12.6 v to 12.1 v, then the problem occurs more. Just got a feeling that something is using up a lot more power than it should be and the bike can't get enough power to spark. I know my rectifier has a burnt connector but still conducts so I'm not sure if that would cause the problem.