Frustrated novice maintainer

[splitter]

Blurr, I am prepared to do the work myself, thanks for all of your suggestions and ideas. I will work through as time prevails and reply with the progress I am making.

Splitter

[dickfaber]

how many k's are on the carbies; and have they ever run without air filters?
the carbies on gpx and zzr 250's are almost consumables.
the butterfly valves on the throttle plates can and do float around, wearing an oval where there should be a round at the throttle plate, and chewing out the throttle shft bore. this causes an almost untunable engine. symptoms like high idle, then no idle, then idle hang, then no idle then no rev as the a/f mixture is changed everytime the throttle is moved.easy to check, hold up to the light, there should be an even gap all the way 'round, or if the idle stop screw has been taken out, no gap (no light) all the way round). snap the throttle a coupla times and check again. if not, carbies are rooted; get bran-new-second-hand ones. check them as well.

and dont bother trying to get fcr keihin's, yes they do make some that small, but not in pairs and it will cost more than the bike!


experiance of this? rebuilt at least 5 gpx250's and 2 zzr 250's

[splitter]

The bike has clocked up 52,000 ks and the carbies are original, air filter always fitted. However I will have a close look at butterfly valves on the throttle plates when I pull the carby out again soon.

Splitter

[Tack]

has it got a fuel filter? change that too.

[photomike666]

Common problem on these is the tank fouling a breather line.

We also had a simpler problem with my wife's zzr250. Turned out to be carbs. eventually they were soaked over night in a bucket of carb cleaner Ran better after that

[splitter]

The latest of my novice maintainer experiences is the carby may have been to culprit of my problems or so we all thought. After many individuals contributing to resolving the problem and thanks for your contributions.
After trying eveyones suggestions I resorted to having a qualified motor bike mechanic have a look at the bike. An hour later I received a phone call explaining that the issue had little to do with carbs, shock horror. His opinion that the top end pressure is reading 150psi and is low enough to prevent the engine idling when cold. He also mentioned that replacement of rings, boring, head gasket, oil, coolant plus labour will be required to fix the pressure problem and I quote that I was not prepared for.

Any thoughts, Splitter