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Post by verbotten on Oct 1, 2022 14:01:31 GMT 1
Can someone tell me if the reed petals should be 100% closed on the 4L0 reed valve assembly? I sat the assembly on a torch and can see some light at the side of the petals and at the top of 1 petal (using feeler gauge the largest petal gap is around 0.3mm). I have swapped them round / over and does not matter what combo I try there is still a tiny bit of light. I'm happy to replace them but it might be pointless if a small gap is okay. Thanks
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Post by chrisg on Oct 1, 2022 14:05:28 GMT 1
Normally they are closed but when there is any back pressure, they will close fully.
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Post by 4l04ever on Oct 3, 2022 20:13:27 GMT 1
Try blowing and sucking through them. They usually make a duck quacking noise one way :@)
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Post by steven on Oct 4, 2022 8:15:56 GMT 1
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Post by chrisg on Oct 4, 2022 10:33:53 GMT 1
Ive assumed that the reeds are std. and not fibre. If there is a small gap, the minute there is any back pressure they will snap shut and seal. As previously stated, try sucking through them. The link talks about fibre reeds not sealing when shut. |
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Post by dougw on Oct 4, 2022 13:06:22 GMT 1
I`m running Showe Dual Stage reeds in YPVS reed blocks in my 4L0.
The standard steel reeds closed completely , no gap.
The Showe reeds did not close completely from new, small gap.
It runs fine with the Showe reeds, better low end running and transition from 4.5 to 6K revs , the previous minor hesitation gone.
It's possible it may have lost some top end at 8.5 K plus, but I`m not fussed about that on this one, it's my go to work bike.
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Post by verbotten on Oct 4, 2022 16:18:52 GMT 1
Yes, the reeds are standard stainless steel, I have ordered a new set to replace as I want them to close fully for piece of mind.
The bike had been running fine but recently developed a stutter around 5-6K which was not there before, it then backfired badly a few times on the RH cylinder and struggled to idle without cutting out. I checked for continuity on the run switch, checked the spark / HT leads and swapped them around to make sure they were okay and they are. Spark plugs are okay and I swapped over the CDI (VAPE system fitted) as part of fault elimination.
Issue was still there so I have removed the RH carb for cleaning and the RH reed valve so am now trying to work out if the issue is carb/reed related.
Not sure where to go after that if the issue persists...most probably back to Dave (Mutts Nutts) but I realise he is well booked up and I would like to fix myself if possible:)
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Post by tony2stroke on Oct 4, 2022 17:37:26 GMT 1
Something I have noticed over the years, people bend the reed stops to open them up and or fit fibre reeds, if you bend the reed stops as they are fitted, they can disturb the reed seating, ie the reeds can lift up at the front, over tightening the reed stops can do the same thing, this pushes the reeds into the rubber and stops them seating correctly too, I have noticed that some can leave an impression in the rubber over time as some have mentioned, this too will stop the reeds seating correctly, unless reeds are fitted within the raised bits (if you follow me)
If the reed stops have been bent open you will know by measuring reed stop tip height, if they have been bent open you may be able to bend them back down to correct height, sometimes this is enough to correct the issue.
A small gap is OK, as long as it will seal when pressure is raised in crankcases, at low RPM with bad sealing I have noticed bad tick over (very fluffy is my description at very low revs too) but I very much doubt your mid range problem is the reeds not seating, I would think carb myself, but saying that, normally if problem at certain rev range then not carb something else, but if at certain throttle opening, then carb.
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