TOPIC:

Back at it. I bought a cheapo compression tester and all the cylinders are topping out at just under 180 cold.

I re synced the vm29's starting with #2 but when I mounted them up the #2 carb started to overflow out the air side. The bike is parked nose up on a pretty good incline so luckily it didn't go into the cylinder but I decided to take them off and put them on the back burner for now.
I picked up a set of 28mm pumpers with rebuild kits while I was away. I gave them a carb dip in the ulrasonic and blew them out with air. I replace the diaphragm, gaskets, o-rings and jets. The Jet needle and pilot screw's were different so I left the originals in. I had to make 3 of the little check valve retainer springs out of an old pilot screw spring and the carbs were missing their pilot screw plugs so I used some rubber screw nipples till replacements arrive. I i started with the pilot screw one turn out.
I mounted them hoping for a miracle but no luck. the bike started , At first they seemed to idle well at 1100rpm take off seemed sluggish and sounded like it was running rich but there was popping when I decelerated. Once throttle is more than half open the bike took off and felt great. I turned the screws in a half turn which got rid of the popping but Idle started sounding rougher and the bike started to stall on take off. I started to notice hiccups in the carbs while idling as well.
Does anybody have any experience running these on a similar setup? What's a typical setting for the screws on these? How about the Needle and jets? They are currently set to stock specs, Here's hoe they're set up (lifted fom the wiredgeorge pumper post)
air screws
ID Mark 120 _ 5
slide cut out 2.0 with extra long slides (won't fit any other bikes)
#102.5 main
#15 pilot
Service Fuel Level ~ 1/8"
Float Level ~24mm
Pump Arm Nut ~ 1/4" up from bottom
5CN29 - non adjustable jet needles
05 or 06 needle jets (memory)
Hoping to get these to work as I like the idea of the overflow valve on them

Ah, just found this thread. kzrider.com/forum/3-carburetor/325136-78...line-hookup?start=20

I'm going to try capping the vacuum line and see what happens
.....

I set the pumpers up properly and while overall they seem close I'm noticing a familiar problem. While all the other plugs look pretty uniform it only takes going around the block a couple times before the #4 is black. I'm starting to think the problem isn't in the carbs at all. I switched the #1 and #4 wires and there was no change so I'm assuming it would be in the valves or cylinder if anything. Trouble is I just spent a bunch of time and money rebuilding the top end to try and get rid of this problem and it's still haunting me. Where do I go from here?

Pic of the plugs?
Steve

Here are some pictures of the plugs. This is just after taking it around the neighborhood, only getting into second gear briefly on one of the bigger roads. Starts up easy and seems to have pretty good power all things considered but I can here it misfiring in the one cylinder as I ride longer. When I pulled the plugs it looks wet inside cylinder #4

Here are a couple pictures of the plugs after taking around the neighborhood once or twice and getting into second briefly on a bigger road. The bike starts easily and seems to have good power but as I ride longer I think I can hear that cylinder start to misfire ( this is a 5 min or 10 min ride tops) When I took the plugs out cylinder 4 looks wet

Would assure correct valve clearances, especially on #4 cylinder.

Acceptable compression in relatively cool engine may be lost as the engine reaches normal operating temperature, which can result from a too tight valve clearance.

A too tight valve may allow full seating with complete closure while the engine is at less than normal operating temperature.
But as the engine attains normal operating temperature, the too tight valve prevents full seating of the supposedly closed valve (i.e., the supposedly closed valve is leaking at normal operating temperature and causing loss of compression).

Good Fortune!

Are these with the 28's or 29's? How old are the valve guide seals? They can make them appear rich and I had to go down one full step on the pilots to get them to burn. Rode like that for a year until I could redo my head.
Steve

these are the 28s. I replaced the valve guide seals with viton ones when I redid the top end a couple months ago. The whole head is different from before the rebuild since I bought a new one that wasn't helacoiled for a fresh start.
I'm curious about something though. If I'm running aftermarket cams are the marks on the timing plate still applicable to setting the proper timing? I'm running a gpz 750 intake cam / kz 750 exhaust and degree'd them into their respective specs. Afterwards I set the timing statically and with a timing light. Is it possible for the timing to just throw off one cylinder or would I be noticing similar issues in #1 as well?

Checked using the Kawasaki method this time and the Valves are all within spec. I'm going to double check where I have the cams degree'd to while the valve cover is off

Not sure if the adjustable sprockets had slipped or I didn't do it correctly last time but the cams were not degree'd properly. I set them and quadruple checked everything. Took the bike on a ride, It felt like it had tons more power but when I checked the plugs the #4 was sooty black once again. I tried backing the air screw out to 2.5 turns on that carb, rode it around and still got sooty black!

If not already done, would clear tube test #4 carb and assure fuel level is correct.
And assure valve clearances in #4 are within specs.

Good Fortune!