ZZR400k - Carb problems. Anyone in the Manawatu?

[ducatilover]

I'm having some fun carb problems with my project ZZR400k, it's getting a bit silly for my relatively healthy knowledge of CV carbs.
It's acting like it has an air leak, but will not pull above 6000rpm very well at all (most 4cyl 250's will outrun it currently) when under 6000rpm it returns to idle very slowly, hence the air leak idea. It's fairly difficult to start, doesn't want to idle for a good 5 min after start up.
I've cleaned the carbs and payed extra attention to the jets, which are squeaky clean.
The air filter is nice and clean (foam element filter)
I have yet to sync the carbs and set the pilots, but, I've never seen such major problems with pilots/sync issues.
I couldn't find any splits or tears in the diaphragms at all, but I'm suspecting it's to do with the slides...
The rubbers on the engine side seem nice and happy.
Anyone able to pop around? I'm in Bunnythorpe, or any suggestions apart from hammers/matches would be greatly appreciated.
Cheers :yes:


Edit, it hunts/surges at idle when on the choke and the idle quality is shit anyway
I'll attempt to sync the carbs today, I think I've got everything I need here (I hate that part about moving house)

[kiwi cowboy]

I'm having some fun carb problems with my project ZZR400k, it's getting a bit silly for my relatively healthy knowledge of CV carbs.
It's acting like it has an air leak, but will not pull above 6000rpm very well at all (most 4cyl 250's will outrun it currently) when under 6000rpm it returns to idle very slowly, hence the air leak idea. It's fairly difficult to start, doesn't want to idle for a good 5 min after start up.
I've cleaned the carbs and payed extra attention to the jets, which are squeaky clean.
The air filter is nice and clean (foam element filter)
I have yet to sync the carbs and set the pilots, but, I've never seen such major problems with pilots/sync issues.
I couldn't find any splits or tears in the diaphragms at all, but I'm suspecting it's to do with the slides...
The rubbers on the engine side seem nice and happy.
Anyone able to pop around? I'm in Bunnythorpe, or any suggestions apart from hammers/matches would be greatly appreciated.
Cheers :yes:


Edit, it hunts/surges at idle when on the choke and the idle quality is shit anyway
I'll attempt to sync the carbs today, I think I've got everything I need here (I hate that part about moving house)

When you say it wont pull above 6 grand what does it do?.
If i try to free the air intake on my gsxr400 up by reducing the foam in the filter it wont rev out above 7 grand which is when the cv's are supposed to start to open.
Im wondering if the filter isnt right and its running lean giving a hard start and poor idle and wont create the suction to suck the slides up.
Would definatly sinc the carbs though they my be way out.

[ducatilover]

I got some compressed air going into the sides today, they were not too happy at all. Have cleaned them up again, re-cleaned the carbs completely, cleaned chokes and lubed cables. Carbs will be synced once I have sorted the air leak. Cyl 1,3 and 4 are leaking on the top left hand side of each intake rubber on the head side....coincidence? It starts and runs reasonably well, but, will get the air leak sorted now and carry on.
I cleaned the slides with a shit load of elbow grease and autosol, and the carbs themselves with CRC and 2k grit sandpaper.