'89 DT75 dropping a cyl at speed

[Flatsboy]

Checked the parts diagram and I don't see the disks nor does the service manual mention them. Exactly where are they located? Thanks SM

[Flatsboy]

Just tried a known working fuel pump from same year DT75, same result. Next step is to rebuilt carbs again, double check float levels, replace reeds. Need to get 2nd pair of hands to pull spark plug leads one at a time once it limps to isolate which cyl is misbehaving.

[Solarman]

Can use a timing light on each plug lead to see if the light flashes normally, or is skipping during times it is missing.

Post back what you find out.

[Sealfie]

I haven't timed it exactly but I seem to remember it's random, not exactly 10 secs. I'll get it on the lake and document. I noticed yesterday after warming it up idling about 5 minutes, I took off at full throttle (about 4,700 rpm) and it cut back well before it did when I ran it up from the same spot and took it to 3,800 or so several other times. That made me think it may be overheat related but I've replaced both heat sensors (puck and duckbill) with new.

I haven't used a Suzuki gauge. From what I see it warns of over-rev, temp and low oil, correct? Or does it also warn of oil flow? I can see where this might help direct a search but won't pinpoint failed components.

I haven't read all thread but this problem really sounds like a classic lack of fuel problem. You say you have rebuilt fuel pump, thats good. My concern is within the fuel lines and connections. I think you have an airleak somewhere even though you replaced the fuel lines. If you have an airleak the pump will partly pump air instead of fuel. I strongly recommend that you try with another portable fuel tank, preferably with a friends fuel tank including fuel lines and connections that you know is OK before you do anything else becuase this is so easy to check. You can also try to push fuel forward manually (with the bulb) while you drive, could make a difference, wont help enough if the leak is severe though.