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Post by jon on Feb 28, 2024 20:18:07 GMT 1
Hi all,
IIRC reed spacers are generally expected to uncover the boost port if placed between the cylinders and reeds, or increase bottom to midrange power at the expense of top end if placed between the reeds and reed rubbers?
In practice I seem to recall they make little difference?
Has anyone tried both?
Jon
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Post by charles13 on Feb 28, 2024 20:48:08 GMT 1
Hi all, IIRC reed spacers are generally expected to uncover the boost port if placed between the cylinders and reeds, or increase bottom to midrange power at the expense of top end if placed between the reeds and reed rubbers? In practice I seem to recall they make little difference? Has anyone tried both? Jon I wonder how they would work with a 2-1 manifold as wasn’t that supposed to accomplish the same thing, or where the reed spacers supposed to get rid of the 6k flat spot? |
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Post by midlifecrisisrd on Feb 28, 2024 21:08:30 GMT 1
When fitted between barrels and reeds they also increase crankcase volume
Steve
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Post by jon on Feb 29, 2024 8:12:12 GMT 1
Has anyone done any dyno tests of various setups and thicknesses?
Jon
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Post by Tobyjugs on Feb 29, 2024 9:15:55 GMT 1
Yes on 50cc Freetech race bikes. It's all tiny gains towards different needs of the racers.
I've also done similar on my engines but not really seen any big gains.
The reed spacer worked best on a 4L0 engine fitted with YPVS reeds. I think the YPVS reeds interfere with the middle transfer duct a little.
6mm gave possibly 2pk in the midrange and there was no extra gain with a 10mm spacer fitted.
I would say good to use for a specific engine goal.
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Post by dougw on Feb 29, 2024 10:05:53 GMT 1
Yes on 50cc Freetech race bikes. It's all tiny gains towards different needs of the racers. I've also done similar on my engines but not really seen any big gains. The reed spacer worked best on a 4L0 engine fitted with YPVS reeds. I think the YPVS reeds interfere with the middle transfer duct a little. 6mm gave possibly 2pk in the midrange and there was no extra gain with a 10mm spacer fitted. I would say good to use for a specific engine goal. Interesting. I was running some 6mm 3D printed plastic spacers between the barrels and YPVS dual stage carbon reeds on my 4L0. When stripping it after one of the reeds broke I noticed the plastic spacer was being deformed by the smaller gasket surface that resulted from the barrels being carved out to fit the YPVS reeds. So it got rebuilt with new oem yam steel reeds and no spacers. I cannot really say I noticed any loss of performance, but I don`t know how long the dual stage reed had been playing up for before one failed completely , one outer petal being sucked through the dual reed window. Its running nicely now, but I have some NOS LEDAR nozzles to try , then I may try some alloy 6mm spacers. I`m not sure my "Arse Dyno" is sensitive enough to pick up small, 2HP, changes though ! |
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Post by Tobyjugs on Feb 29, 2024 12:29:24 GMT 1
Yes on 50cc Freetech race bikes. It's all tiny gains towards different needs of the racers. I've also done similar on my engines but not really seen any big gains. The reed spacer worked best on a 4L0 engine fitted with YPVS reeds. I think the YPVS reeds interfere with the middle transfer duct a little. 6mm gave possibly 2pk in the midrange and there was no extra gain with a 10mm spacer fitted. I would say good to use for a specific engine goal. Interesting. I was running some 6mm 3D printed plastic spacers between the barrels and YPVS dual stage carbon reeds on my 4L0. When stripping it after one of the reeds broke I noticed the plastic spacer was being deformed by the smaller gasket surface that resulted from the barrels being carved out to fit the YPVS reeds. So it got rebuilt with new oem yam steel reeds and no spacers. I cannot really say I noticed any loss of performance, but I don`t know how long the dual stage reed had been playing up for before one failed completely , one outer petal being sucked through the dual reed window. Its running nicely now, but I have some NOS LEDAR nozzles to try , then I may try some alloy 6mm spacers. I`m not sure my "Arse Dyno" is sensitive enough to pick up small, 2HP, changes though ! I would also like to try both the ledar nozzles and the dual stage reeds. People give the reeds a bad reputation for not performing, but i think they probably will work well for the midrange gang. That's exactly what I'm trying to say about the spacers unless it's part of a plan you won't notice much unless you are measuring on a dyno. |
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Post by headcoats on Feb 29, 2024 12:32:16 GMT 1
You will all have to talk nicely to Mutts Nutts 😛
When I changed from V3 to V4 Reed blocks, the V4 had a thicker built in spacer,maybe the reeds were longer ?
Didn't really measure anything
They did put the Reed stops back in though
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