Reed Valves 4L0 / 1V0

[steven]

Hi,
As stated in the Haynes manual, the reed valves changed from 4L0 to 1V0 reed valves during the production run.
How do we distinguish between the two different types?
Was it just the "petals" that changed, or was it the actual "cages" as well?
Iv looked over my various reed valves, and petals, and can see no distinguishing marks or numbers.
On speaking to Granby the other day, when I ordered four new petals, I was told that there is now a third reed valve/petal.
The part number for the petals is 345 136 137 00, and they are £10 plus EACH...

[Norbo]

you would have been better of getting some racing reeds from me £25 a set and they are all so gen yam .

The reed blocks were the same it was a small mod to the bottom of the reed pettle they changed thats all .

[steven]

Hi Norbo, thanks for the reply and info.
I bought some Hy-Tech fiber racing reeds a few months back, from eBay. After reading horror story's of steel reed valves breaking and being sucked into the engine.
The only problem was, no matter what I did, I could not get the fibre petals to seal/seat properly. There was always a very slight gap between the petal and the rubber of the cage.
With good reeds, When I blow through them, they make a nice "quack" or rasping sound, almost a musical note.
With the Hy-Tech fibre ones, as they would not seal, no matter what way round I fitted them, there was always a small gap, and on blowing through them there was no "quack" or rasping sound, as the air was just going strait through them, due to the petals not sealing properly against the rubber of the cage.
I bit the bullet the other day and ordered 4 new genuine Yamaha ones, and these seal perfectly.
I was just intrigued as to what the differences were between the 4L0 ones and the 1V0 ones,,,, then Granby when the bloke at Granby threw a spanner in the works, by telling me there was a third one now???
On closer inspection of the various petals I have, it does appear that I have three different types.
As the pictures show, there are very slight differences between these three petals, as you say it is at the bottom end, where the screw holes are.
Thanks again for the info.
Steven.

[Tone]

The orignal LC petals are the ones in the middle of the three in your photo which according to an old Yamaha Technical bulletin I have say's were fitted to machines from engine number 4LO-000101 to 4LO-004668 along with #25 pilot jets.
The 1VO petals which are the ones on the left were fitted as standard to machines from 4LO-004669 along with #27.5 pilot jets.
The 1VO petals were also fitted to some of the earlier bikes under warranty to try and cure the midrange flat spot.
Tone

[steven]

Hi Tone,
Thanks very much for the info.
Regards,
Steven.