YPVS Loses Position(?)

[2steve]

Rewound stator is in. The problem is 30 - 40% better, but still there. Wondering about plugs and jetting, since the coil has been replaced with new.

OK to run non-resistor plugs AND non-resistor caps with the stock cdi?

Neighbor stopped me offering to buy it last night.

[m in sc]

yes you can do that. same thing Josh ran knto.. reset jetting to where it was and spot on

[2steve]

The pilot now is one size bigger than Toomey says. I agree with that, since the air screw can just be opened up to 1.5 turns to make it right, but maybe I'll go with their size 20 at 1/2 turn out. They did all the research after all. Maybe drop the needles 1/2 to one step.
Just rebuilt, so rich was ok, but might be a problem now.

I'll get new non-resistor caps and new non-resistor plugs.

... and do everything at once, so if it improves, I won't know why.

[1976RD400C]

Here's what I learned messing around with mine for 3 years. If you change the pipes and air filter, they develop a bad flat spot at 5000-6000 rpm. You can hear it through the exhaust and intake tract. Jetting doesn't help it. I did pretty much fix it by installing UFO inserts in the carb slides. That required machining on the bottom of the slide to get them to fit in there even though they said they were for a RZ. Mine has resistor caps and spark plugs. I tried non resistor plugs, no noticeable difference. I switched from K&N and Y boot to individual foam filters, better top end power. I have the Dynojet needles and 410 mains. Didn't notice any difference from 360 mains. My PCDI-10VT is programmed same as a stock CDI, 27.5* at 3500 going to 17.5* at 9000 and 9* at 10000. If the power valve sticks and won't open up, it still runs ok but the top end power is not there. Those UFO inserts on this bike and my RD make a huge difference in throttle response, especially in low throttle openings.

[2steve]

^^^That's a help. I noticed that flat spot. It was ok enough, then it got worse. The thought was that it's a YPVS transition problem, when it was partly/mostly(?) the stator.

Assuming, like the RD400, you put UFO's in and you're pilot size MUST go down. With a 400 and boost bottle, way down.

Do you have size 20 pilots, or smaller with UFO's?

All good info. Thanks! I have UFO's that might fit:

[1976RD400C]

For the RZ I have 15 pilots with the air screw at 2 1/2 turns. That feels right. I'm experimenting now with adusting when the power valve moves using the Zeel.

[m in sc]

heres my advice: you did a repair. set the bike up how it was before and see if its back 'to normal' if its not, you still have something else to address repair wise. get your baseline tuning on the carbs back to where it was, period,. . don't change stuff now or it will never get diagnosed.
get the plugs sorted out, set the carbs back up they way they were. assess from there. ( and no, resistor plugs and caps or lack thereof shouldn't change anything.  IF you have to run resistor plugs, run non resistor caps. they do have them. )

Id still be leery of the cdi box or coil. the " '30-40' percent better" tells me you haven't completely fixed it yet, and ufos aren't going to fix that. 

[2steve]

Yeah, gotta think on that. Carbs really are where they were, just don't know if being a little rich pilot/air screw/needle is a factor in this. It did run very well with this same setup previously (with that 5 - 6k flat spot that it would push through ok).

It has the same lower rpm symptoms to a lesser degree, but is no longer lighting up consistently at 6k or so. Just acts congested, then overcomes it in a less predictable way now.

Would be nice to be able to health check the cdi.

[m in sc]

replace it.

[2steve]

John @ Economy has a Zeel stock RZ replacement. Might not be too much to handle. I'll just need to be a wiring boy with cool new tools.

RegulatorRectifier might have too.

Plugging in a known good one to check would be convenient.

I know the original 52Y cdi's are 40 yrs old, but are they known to be failing?

[m in sc]

get the cdi and powervalve controller unit in one.

[mnein]

Steve - the 52Y's were obviously the good ones, the other part number cdi failed within the first 5 or 10 years of new. Unfortunately I don't know anyone that can determine the health of your cdi, maybe impossible, so I suppose you're doomed to replacing electronics until you find what's wrong. Working on a car right now that has intermittent starting problems so I sympathize a little with your pain.

[m in sc]

yup. my 84s cdi died in like 09 or so. if you plan on keeping the bike just replace it.

[2steve]

Planning to keep the RZ till someone has to pry it from my cold, dead hands 

Mark, seems you did better than most if it wasn't till 2009.

Presuming I can use the Zeel that has both controllers inside with the stock stator and stock coil?

Matt, if you are stumped, do what I did and call three-finger Bill, (Shari's cell number). That boy knows everything.
In my case, the '90s Chev pickup needed a new ignig switch.

Glad I got a quarterly commission check recently 

[m in sc]

yes you can wire it in with stock stuff.  get a new dyna coil as well