YPVS Loses Position(?)

[m in sc]

I usually run a redundant ground,  won't hurt

[1976RD400C]

A video of how it runs may help 

[automan]

Geez, 16 pages of PV or something flatlining the thing.

Maybe I read the whole post and weed out muffler bearings.

cliff

[2steve]

Yeah, don't read the whole thing. Time is too precious. You won't get it back.
Maybe read the 1st post and then know that the stator and control electronics are all new now, carbs & YPVS checked out good but it's still exactly the same.

[automan]

Time to waste, I am retired.

I have read the whole thing.

I have H1's and a DT250.

I am not privy to the RZ bikes as to how the exhaust is mounted to the Jugs.
Nor am I knowing the exhaust system, is it US or CAN? Paint suggests CAN with zero cats.

Crank seal leak-down done? both left/right and l/r to each other?

c

[m in sc]

has nothing to do w any of that. its a basic rz setup w aftermarket pipes. motor is fresh. it idles perfect and runs up high perfect. this rules out:
crank seals
reeds
air leaks
worn rings
etc.

its all midrange. we verified the pv position and operation. 
it -feels- like carburetor but it did it to me at 1/4 throttle And wide open. it follows rpm only.

rpm specific issues regardless of throttle position point towards electrical. 

as does the fact that it ran fine,  then suddenly just didn't.   after the motorvwas refreshed, and had some mileage on it.

if it was MY bike, id get a set of individual carbs and a splitter type cable to eliminate the stock carbs . and.. honestly,  they work better.

its a us model fwiw.

[2steve]

I'm with you, Mark. Just one thing blocking me - besides the dollars: I would be hating life if I got new carbs, or a splitter cable so you could help, and then find out that's not the problem. Thus possible wasting your time (again). If someone has a loaner set of known good RZ stockers, that might be a thing as well.

Still haunted by the possibility that the on-highway random shut downs are related to this problem and it's not lack of fuel feed. There's a teachable moment there, but I'm a retarded student.

Gonna run an extra ground pipeline today and I have determined that the original coil mount that I copied with the new one was needing to be turned. I have no hope that this will change anything. Just makes me feel better 

Thank you for hanging in with this thread, Automan. The pipes are Toomeys and were the bomb back in the day. Finding an RZ with factory pipes is not very desirable and it would also be very rare.

[m in sc]

I have individual carbs we can test with if you had the cable setup. I don't think that's it but it eliminates a possible cause. we're down to elimination.

its not a bother, I offered. if I don't want to do it,  I won't   

[automan]

It

has nothing to do w any of that. its a basic rz setup w aftermarket pipes. motor is fresh. it idles perfect and runs up high perfect. this rules out:
crank seals
reeds
air leaks
worn rings
etc.

its all midrange. we verified the pv position and operation. 
it -feels- like carburetor but it did it to me at 1/4 throttle And wide open. it follows rpm only.

rpm specific issues regardless of throttle position point towards electrical. 

as does the fact that it ran fine,  then suddenly just didn't.   after the motorvwas refreshed, and had some mileage on it.

if it was MY bike, id get a set of individual carbs and a splitter type cable to eliminate the stock carbs . and.. honestly,  they work better.

its a us model fwiw.

So why chase carburation?

How about collapsed baffle(s) in aftermarket pipe(s)
Pipes that were good suddenly flat regardless of throttle sounds like pipes out of tune with engine.

i.e. Factory Pipe Product on my H1 has the flatspot at 5-5800rpm regardless of throttle.
They are tuned for 9200. They have zero baffles. Stock exhaust no flatspot.

cliff

[m in sc]

if it was a collapsed baffle it wouldn't rev high. i had one in an FPP kill a piston years ago.  i get it. 

Not chasing carbs, i feel its electrical. Process of elimination, though, has its value here as well. Ive never had one do this, and i thought i had it sussed till i rode it, i've honestly never felt one do quite what this is doing.  Hence why i reached out to chuck q.

[automan]

gotcha

cliff

[teazer]

We may have covered this a few pages back, but have you tried swapping a different set of pipes - just to see if the problem goes away?  If you were closer, I would offer my RZ350 as a test mule for swapping parts. IS there anyone closer with an RZ that you can borrow parts off to do back to back testing of swapped parts?

[m in sc]

that makes no sense as they worked fine before.  theres no collapsed baffle so..?

[1976RD400C]

Can we review the carb set up? Stock needle jets and needles? Stock pilot? Does the needle jet seem to fit in the carb body ok? Does the main jet and washer fit ok with a snug fit to the needle jet and carb body?

[m in sc]

all is good there,I went thru them myself as well, and they were fine. I was hoping for a smoking gun there, nope. had a toomey kit as far as I know. I was looking for clogged air jets, etc, none of that.