Fucking bike. ZR250

[FROSTY:Me]

well that bike has me head fucked. with no load on itll (much to the owners dismay) rev clean to redline. Yet when he puts a load on the engine it wont rev out.

[James Deuce]

well that bike has me head fucked. with no load on itll (much to the owners dismay) rev clean to redline. Yet when he puts a load on the engine it wont rev out.

Assuming mechanically it's OK, that sounds like the stator needs rewinding.

[Devil]

Ah well. Ive given up. The trusty mechanic has it now!

[Zapf]

well that bike has me head fucked. with no load on itll (much to the owners dismay) rev clean to redline. Yet when he puts a load on the engine it wont rev out.

from a car background, its sounds like its missing under load. And usually that is spark related, when at higher load hence more petrol the spark is not strong enough to ignite the more dense air / fuel mixture. have you looked at the plugs / tried new ones. Or new spark plug leads depends on how old they are..... ermmm water / moisture in the leads?

my 2 cent

[badlieutenant]

while this forum will prove invaluble the best bet is to buy a manual. Youll learn heaps the simple and best way, finding out for yourself.

[Devil]

while this forum will prove invaluble the best bet is to buy a manual. Youll learn heaps the simple and best way, finding out for yourself.

I appreciate your advice, but if you can find a manual for a ZR250A you can have my first born son*.


*Disclaimer: Offer may be reconsidered on presentation of manual.

[That Guy]

Air filter clean? Check. (but sounds way too oily) Fuel breather not blocked? Check. Fuel supply not blocked? Check? if it revs with no load then won't under load then sounds to me like fuel starvation. The machine will use more fuel under load than it would for the same revs under no load. If the fuel lines and filters etc are all clear (and assuming its not electrical; coils, CDI, pick ups etc) I would suggest take the carbs apart, clean them, and check the float bowl height. The sympton of it getting to high revs when you only gently open the throttle but then it won't when you crack it open (and it won't get there under load) sounds to me like the float bowl is running dry - check the float bowl height, they can go out of adjustment sometimes. That is cheap to check (ie free! just your own time) so worth a check. If you are convinced that fuel supply is ok, I'd start with plugs, then plug cpas and leads, then coils, then either pick ups in the stator (like Jim says) or CDI. I'd do it in that order as I'd try the cheapest to replace bits first!

[Devil]

Air filter clean? Check. (but sounds way too oily) Fuel breather not blocked? Check. Fuel supply not blocked? Check? if it revs with no load then won't under load then sounds to me like fuel starvation. The machine will use more fuel under load than it would for the same revs under no load. If the fuel lines and filters etc are all clear (and assuming its not electrical; coils, CDI, pick ups etc) I would suggest take the carbs apart, clean them, and check the float bowl height. The sympton of it getting to high revs when you only gently open the throttle but then it won't when you crack it open (and it won't get there under load) sounds to me like the float bowl is running dry - check the float bowl height, they can go out of adjustment sometimes. That is cheap to check (ie free! just your own time) so worth a check. If you are convinced that fuel supply is ok, I'd start with plugs, then plug cpas and leads, then coils, then either pick ups in the stator (like Jim says) or CDI. I'd do it in that order as I'd try the cheapest to replace bits first!

Have checked:
Airfilter.
Breather
Fuel supply.
Plugs replaced in the last month.
Float level and mixture also adjusted to manual spec same time as plugs changed.
Uhm, havent been able to find another CDI to try.
I do think my leads/caps are slightly dodgy, but I think thats a side issue. Will probably replace anyway.

Its with the mechanic now anyway.
Cam chain has become noisy as well, could potentially throw the timing out by a couple of degrees.

[That Guy]

I do think my leads/caps are slightly dodgy, but I think thats a side issue.

Plug leads and caps can cause all sorts of mischief - they're cheap and easy to replace and given the pain the bike is putting you through and it sounds like they are pretty tired I'd put new ones in.

Try to borrow a CDI like you say to test before you buy one - I think it is more likely the coils or the pick ups though......

[FROSTY:Me]

hey devil--my 750 was running like a hairy bastard -turns out a lot of my hassles were caused by shit in the fuel.

[Slingshot]

[QUOTE=That Guy]Plug leads and caps can cause all sorts of mischief - they're cheap and easy to replace and given the pain the bike is putting you through and it sounds like they are pretty tired I'd put new ones in.[QUOTE]

My asre they're cheap.

I replaced the caps on my Suzuki GSXr250RR and it cost me over two hundy.

I had to get genuine one cause they had to be a funny resistance.

[Devil]

Update: Mechanic found dookie* in one of the carbs, blocking fuel completely.

Now she's hauling ass again. yay!

130km on 10 litres though. But I guess thats not too bad if you imagine a ZXR250 with no fairings/aerodynamics with a 90kg rider...

Next on my shopping list are progressive springs (mechanic thought it was jumping around a bit at 170km/h), and new leads and caps

*random sludge