Interesting, it's worth a check considering it's the original muffler and factor in the age. How do I check this?
Go out a quiet back road and take the muffler of and go for short ride. You will soon be able to tell if it was restricting the revs. Had this problem many years ago on a XC falcon. Engine would not rev over 3,200 rpm and would spit fuel back through carb. Rebuilt carb a couple of times, checked all the compressions, changed dizzy, even changed engine before discovering part of the pipe had collapsed and the poor old 5lt was trying to breath through about a 25mm hole.
Was so hoping you would say that. Good job for this arvo.... advantage of living on acreage with a convenient long back road.
there is a fuel overflow hose that leads nowhere and apparently if you get fuel into it you lose power and revs i will try and find the link
http://www.tecpeltier.com/viewtopic.php?f=16&t=61 3)After taking the carbs off the bike is Mega slow and sounds kind odd This is caused by getting fuel in the over flow tube (#23) . Now on a bike without a Air ram system the overflow would either be dumped on the road for go back to the air box. Now on the ZXR this is not the case and if you get fuel in this tube it reeks havoc with the fuel of this bike. Fuel can end up in this tube dew to incorrect float heights or because of how you removed the carbs on this bike.
Well I tried the exhaust off, besides from being the coolest thing I've ever heard it didn't fix it. Hmm I know the pipe it talks about huntsman. I've had fuel come out of it when the carbs come off from putting it on an angle. It's a C model diagram tho, on an A model it just goes to the airbox I assumed. Not sure what else to do/try on that point
I'm actually thinking of just throwing on another set ofcarbies simply to see if it makes any difference and rule them out for good. If anyone in brissy has a spare set of carbs I could borrow for a day or two maybe I'll try that too.
Could it be a sticky slide or a diaphram cap leak or something like that. How do you balance the carbies, although at full open throttle carb balance should be negligible unless their way way out & then they'd be awful down low. How are the inlet tubes between the head & carbs, if they suck air it'll lean out the mixture & no top end power, fuel = power ! I had a No.1 plug issue the same & I suspect the No1 carb was & maybe still is leaking past the needle & seat & filling the No1 inlet manifold as there's no way it can escape out the overflow tubes as they are 150mm higher than the bowls, so when upon start up she fires as there's a load of fuel there but it either semi fouls the plug or it runs richer on No.1 & eventually fouls later leaving you trying to run on 3 cylinders & these little buggers run sort of ok on 3 to the untrained ear. I removed the carbs for something & noticed the No.1 inlet full of fuel, it was soon after a carb rebuild & just thought it was a teething issue, she fouled the plug again so I checked straight away but all dry, fited a new set of plugs & all good till last sunday when she fouled again, cleaned the No.1 plug & all good so now I leave the tap off , I'll get a new set of needles & keep an eye on it. Did I read that you replaced the fuel inlet needles ?
Ahhhhhrrrrg leaking radiator pipe underneath carbies.... Can't say I'm surprised have taken the airbox off so many times and it gets a bit of a bump from that each time. ONE DAY BIKE... ONE DAY YOU'LL RUN WELL! In the meantime we'll add to the 100+ clocked hours of unpaid self maintenance
So thanks to some recent posts, some research and quite a lot of swearing it looks like I've narrowed down a year of problem solving and trouble shooting to one big oversight on the bike. Look like the ZXR A engine and ZXR C engine have different Bore x Stroke, hence different timing and I'm running the wrong CDI! From what I can see I think that if I am able to get a C model CDI on the bike it should fix the problem. Problem is there are extra connector pins on the C model CDI, so I need to figure out where they go, and if there is any difference with existing connections across the 2 CDI's. If anyone has thoughts/suggestions on doing this it would be greatly appreciated. Someone already mentioned a signal wheel swap, will I have to do this considering it's already a C engine?
G'day mate When you first embarked upon this project, my bet is you never imagined so many stumbling blocks along the way. Pleased that you have narrowed down to a single denominator and potentially there is light at the end of the tunnel. CDI's can be and are a pain at times, however with additional pins(connectors) how does one overcome this issue. We have many on the forum who have negotiated this trek and come out with perfectly running bikes, feel certain someone will put there hand up and assist. Could it be as simple as fitting an appropriate loom for the model? Wish you luck mate, hope that this issue can be resolved in a positive way without any further problems, lets face it, you are so close. Good luck.
Think of it this way, it won't leak on you when it's at the most inconvenient time somewhere in heavy traffic or in the middle of no where. You'll have a reliable unit that you'll be proud of at the end of your adventure
Hey Doug you'll get there mate! hooking up a cdi across models might be abit of a task I recall hanging369 explaining the difference in pins. please read this one if you haven't http://2fiftycc.com/index.php?threads/zxr250a-vs-zxr250c.1952/
So knuckling down and fixing this bike! Picked up a spare A model frame and engine today. Going to rip the C model engine out of the bike and go back to the original. Had a bit of a struggle this arvo getting the engine out of the parts bike's frame as it was bent, but a bit of handy leveraging and it came out looks like it's in good condition which is a plus. Plenty of work to go but excited to see results. p.s: If anyone has replaced a starter motor in the ZXR before I would love to hear from you.