power valve connector

[davewills4]

Hi all, how much freeplay do you have on the power valve connector when you wiggle it with your finger? As the connector on my 250 1KT has a fair bit of movement to the point where it may affect the performance. As I was riding back from Oulton park the engine was really labouring just as it approached 6000 revs where the powervalves tend to start operating 

[tzar250]

Hi. I believe Yamaha state that the PV cables should be adjusted until tight, then each backed off a quarter turn.  I read this recently in a manual.  It might even have been for a RD350ypvs but will apply equally to a TZR.  So not a huge amount of rotation should be evident.

Hope that helps.

[davewills4]

Hi tzar250, yes I believe the cables to be adjusted to spec, it's just the actual pv connector moves alot when you push it with your fingers, and the cables don't move when you move the connector up and down.  I changed the connector with  an old one I had and seemed to improve but still had some free play. Dave

[oldiggy]

Try taking the pipes off then operating ignition while watching the power valves to see what's going on. The ends of the power valves might be worn,or the rubber pad might be missing on the connector. I spent years messing around with that connector so got rid of it.

[biggz]

You mean the two-piece connector that sits between the cylinders, which makes the L/H powervalve the master and the R/H the slave? If yes, I aim for zero play, test by slackening the cables from the servo, take off the cap over the end of the R/H valve and rotate the pulley with one hand and feel the end of the R/H valve with the other. I want any movement of the pulley to transmit to the R/H valve. Sounds like you have more play than zero... If you leave it like that I would expect the flats on the inner ends of the powervalves will wear and make it difficult to sync the valves.

Hope that's what you were asking.

Good luck

Laurie

[davewills4]

Cheers for the replies,  so oldiggy when you say you got rid of the connector how did you join the two power valves together?

Yes Biggz that is the one the actual power valves were  brand new 5 years ago as the power valves that were in the bike when I bought it were very worn. Also bought a new connector from yambits seems to be a problem with these connectors not being a really tight fit when fitted the 2 Allen bolts are as tight as I can physically get them without shearing them off

[anadr0id]

When I was a poor student and couldn't afford a new connector (or powervalves, for that matter), I inserted tiny soda can strips to get a really tight fit.

[oldiggy]

 I bought a connector years ago from yambits it didn't have the rubber inserts on both parts so never used it, it's in the project section I made my own valves and  got rid of bushes and connector as I got fed up with those parts wearing out. If that connector is a tight fit which you need it places more pressure on the valves and bushes.

[biggz]

I agree with oldiggy about getting the connector good and tight and then the valves start to feel like they're binding... Getting twitchy about burning the servo, I went so far as to buy a spare, and compromised on "tight-ish". (oldiggy's solution is way beyond my abilities.)

anadr0id has a good scheme for eliminating slack in the connector - I'd thought of buying a cheap set of feelers and carving them into slivers to get the same result. If you wanted to get flash and sync the valves perfectly, you could lay half slivers on the opposing flats of the P/Vs, if you see what I mean.

Laurie

[teezer250]

Hi Dave
I would buy a genuine yamaha pv connector and check the condition of valves ends where it joins them for any wear.
Before fitting I would also check that the valves move freely by hand and not sticking.
I once had the cables partially seized so I bought new genuine yamaha ones to make sure everything is turning freely.