GPZ stalling, little help?

[streets]

Last week the GPZ started playing up, suddenly hard to start, then impossible to start. After checking the fuel and spark about 10 times and cleaning the carbs, new plugs etc. I bit the bullet and did a compression test. 70 psi across the board. So off came the rocker cover and sure enough all 16 valves were tight. I adjusted the clearances and it fired up no probs only every time I try to crack the throttle it stalls. I haven't yet done a follow up comp test but would anyone have any suggstions as to the cause, other than burned valves?
Would burned valves cause this kind of behaviour?

[Large]

They prolly wont all burn together.

Have you checked/cleaned/replaced the fuel and air filters?

Have you been fiddling lately? (ie did you forget to tighten a carbie rubber or two?)

[cutcat]

Try giving it a bit more gas when taking off!!!

[streets]

Turns out the bike is only running on two cyl's. It suddenly cleand up this arvo and ran sweet for a minute then back to two cylinders again. I did another comp test and it's now 140 on every cylinder and they all appear to have spark and fuel. I'm lost.

[Benz]

Check the breathers to the float bowls, one may be blocked or twisted, happened to me. A damned wasp's nest in one stopped two carbs getting fuel flow. It would start and run, but broke down under any throttle.
Check the earths and terminals at your coils, check the sparkplug caps for rust, it only takes one crap cap to stop two cylinders.
Low battery voltage/ bad charge/shorted alternator leads may also give you the same problem.
May not be any of the above, but what have you got to loose now???

What in-line fuel filter are you running? If any then piss it off and try again. Not 100% sure on the air cooleds Benz, but the R's don't handle them.

[streets]

A bit more investigation shows me that the cyl 1 and 4 coil is dropping out as soon as the motor fires up. I can only assume that the coil is breaking down with any load? I don't have a spare but I was thinking of slotting a commodore coil in for testing purposes, any problem with trying that?

[streets]

I swapped the coils and the exact same problem rmained on the same cylinders. I checked the crank sensors and everything seems OK. The only idea I have left is maybe the ignitor? it runs this little fuji electric fella and it appears to have got a little hot by the tarnish marks? Or is that just age and wear?
http://www.streetfighters.com.au/forum/upload/63452054819679.JPG

http://www.streetfighters.com.au/forum/upload/63452054822943.JPG

[streets]

Fixed it this arvo, turned out to be hall sensor for cyls 1 and 4.

[Gix11]

Good news mate. Had many people question you about the bike since you finished it? Must get some looks hey?

[streets]

Yeah, I ride with a fairly large group and newbies that come along are alway's like "what the shit is that?". One guy asked if it was a buell. I wasn't sure whether to laugh or cry. Funnily enough the baffles were built by a harley exhaust guy and at idle it sounds quite buell like.