YPVS Loses Position(?)

[2steve]

Extended test ride today in 77 degrees F. Still more manageable with the gnarly needle, (it's not bent, just "chewed").
That still points me to new carbs.

However, riding 21 toward Rock Hill I noticed that going downhill and pulling in the clutch, the engine would stop. Obviously, I had felt the need to do that.
Turned around to go back and it stopped under power. Pulled over, had to turn off the key, then restarted.
I'm gonna change out the new Yambits coil to the original RZ one that I thankfully kept. It's ugly, but might just work better.

[automan]

 

[Kawtriplefreak]

I am concerned about my dual outlet RD400 petcock flowing enough fuel to feed the PWK 35s on the 421. So I will be ordering the 660 Raptor petcock and modifying it for dual outlet. I considered a Pingel but I want to keep a reserve feature and am also worried that the lever on the petcock won't clear the RZ side cover.

[2steve]

If it's really the carbs, and it could be, I might have a fuel feed problem after all. Last time I had it out, it was lurching some when slowly dying on the open road.

My petcock flow passage (recommended by Mark) looks generous, but I also bought a genuine RZ unit with plans to put in a second outlet. Besides that, I would be able to turn it to reserve while riding under duress.

Wondering too about bowl filling inside the carbs through the needles and seats.

These ponderings would go better if Chuck Q were to jump in. Your concerns especially.

[m in sc]

not petcock issue

[2steve]

I see genuine PWK 28's on eBay that must have come from Sudco - new in box.
Are any of those ok for the RZ, or do they have to be a certain part number?

Assuming they are not drilled/tapped for an oil passage which could be added later.

[m in sc]

dont assume. even the knockoffs are ok though.

you need a jjh needle, roughly a 142 main150 and a 38-42 pilot should be damn close. or just try a set of vm28s

[2steve]

$100 each for genuine and $30 for knockoffs painted black with red highlights.

I'm okay with $30, but life lessons make me a little nervous about getting 2 actual good carbs at that price.

Not gonna argue if there is assurance that they are fine.

[m in sc]

some knockoff are good. some aren't . just depends.  keep in mind the y boot will no longer fit, you need to deal with cables,  etc. did you get the coil swapped etc?

[2steve]

Coil swapped but had a stoppage. Didn't have enough evidence to blame on the swapped coil. Could have been low fuel in the tank and couldn't reach in that RZ side cover hole to change to reserve while underway. It did lurch a little as it was dying out.

Figuring best to go with carbs next.

Economy for throttle cable, I see.
I need to get angled adjusters(?)
And you are offering printed Y boots that would work?

[m in sc]

.. no im not . get unis but honestly,  get the ign test sorted. if you want we can throw some vm28s on to test before spending the money on carbs. just need the cable

[RDnuTZ]

this may have been covered already in the past 19 pages... but has the top end ever been off this motor?

[m in sc]

yes.  it was rebuilt, ran great for a while, then this suddenly came put of nowhere

[2steve]

yes.  it was rebuilt, ran great for a while, then this suddenly came put of nowhere

There's about 300 miles on a very well rebuilt engine with new Yamaha crank. mnein did it right.

I hear you Mark. Will work on acquiring the cable set up.
Maybe even steal the still-fresh VMs off the 7,700 mile RD400 in the garage.

[m in sc]

not a bad idea.  Will be good for a test