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VForce V384A reeds

Started by Hawaii-Mike, February 11, 2019, 02:23:42 PM

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teazer

That's a great question.  I'd speculate that most guys there run stock or mildly modified bikes and that the stock reeds may well be adequate for a mild or stock motor.  A high performance motor is probably restricted in the reed area and a bike with large carbs can probably benefit from better flowing reeds, but small stock carbs on a mild motor probably don't need more reed area.

Some years ago Performance Bikes tested a bunch of different reeds and cages on an LC cylinder and the difference in HP and flow was barely measurable.  That may have been on a fully tuned 250 though.  I can't remember and it's too cold outside in the shop to go and dig it out.

So the question that raises is at what HP or airflow level do the reeds become the limiting factor?

m in sc

in my experience, by feel, anything OVER 30mm carbs that the motor actually needs will benefit from larger reeds in a notable way. its not as much about total flow volume, persay,  as it is about the volume over time affecting the ability for the reed to close back up between intake strokes. more reed area = more cfm per mm of reed lift. IF the reed opens a shorter distance, it can close faster. by giving more reed area, this is achieved. this definitely helps in responsiveness and crispness as you aren't blowing mixture back out the reed waiting for it to close when the piston starts to move back down. this is why the steel reeds, IMHO, work well on stock to mild motors with 26-28mm carbs. they snap back faster. single petal or ported reeds with YZ petals seem to work well up to 30-32 mm carbs depending on state of tune of the porting and how much is flowing through them (with a direct affect on how far the petal has to move).  therefore, with double the reed tip are as on a v force type, it only has to open, in theory, 1/2 the distance to equal the same flow, therefore closing 2x as fast (again in theory) which gives better rideability on bigger carbed motors.  im sure it will help the crispness down low on even a stock ported motor to some degree, but probably not enough to even feel.

:tellit:   :twocents: :dawg:

SUPERTUNE

I'm with Mark, The VF reed will have better response and do help HP #'s when using bigger carbs on the RD's. On mild builds I use the YZ125 fiberglass oem reeds as they do respond faster than the stock metal reed petals.
Yes, I have made 74HP RD400 with my Harry Barlow F-500 engine he did for me in 2001 on ported stock cages with custom TDR reeds, VM36 Mikuni's and Harry's pipes, this was on a dynojet 150 with upgrades.

Back then the rules stated we had to use a stock cage, but could do anything we wanted to them and reed petals.

These pics were from Paul's STG 2 build with TM34's on pump gas and made almost 62HP with the VF YZ 85 reeds.
Chuck
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

e30 gangsta

Guess I need to send my cylinders back out to you to get the Paul Special port done on my Stg 2 cylinders lol

mcboomport


I did put in some Banshee 350 V-Force reed cages in my Yellow Screamer street bike, but are even bigger than the YZ85 reeds and need to epoxy the outsides of the cylinders as they do break through the stock RD400 castings on the cylinders.
Chuck
[/quote]

^X2  I have a set of RD400 cylinders set up for Banshee V-Force III reeds.  The metal got extremely thin so we epoxied the cylinders too. Also had to use spacers.. I don't remember the thickness off the top of my head.

Organicjedi

#20
A Britt was trying to tell me that stock reeds are best and was talking about 70hp with them. He even showed me a dyno chart. It was clearly a race bike though as there was no power below 7 or 8k.

The V force reeds really helped the low and mids and also throttle response on my 400. That's what counts for me.

EE

Alright I should probably clear this up. Here's my webpage on reeds & reedcages: http://erlenbachracing.co/reedcages%20mods.htm
The 70hp through stock reedcages gets quoted a lot so here's "The rest of the story..."
Around 2000ish I'd developed my landspeed RD400 and set the 3 world records and moved on to running an RD400 roadracing program  http://erlenbachracing.co/roadracing.htm  , well I got the bike pretty darn well developed and we're going to the dyno and I think I've always wondered just how much hp you can squeeze through a stock unmodified set of cages, then modified, then RZ so I take a box of reedcages. We dyno the bike with the modified RZ reedcages it had in it and then I throw in a set of stock unmodified reedcages (with fiber reeds I won't run steel.. to much money in these motors to risk it and zero real proof (dyno proof) I've ever seen to say they even work "as well" as fiber reeds..), and i'm thinking this will really choke the hp down! Nope... it pulled the same peak hp, Now to be fair the dyno guy couldn't print anything out so I don't have two charts to lay on top of each other but I am 100% sure where you would see the difference is in off peak and throttle response. There's some amazing things happening at peak hp and as this test proved to me way back then was something I thought I'd been seeing anyway (Ahrma limited us to RD reedcages and we would never see much if any of a drop in lap times when we would switch from modified RZ to modified RD BUT a good Roadracing rider can compensate for a lot of variables..) which was that a well developed engine and properly designed expansion chamber could overcome a slightly less than optimal reedcage size. Translated it means that most people put in more reedcage than they need.. the rule of thumb is only increase a restriction in an engine to the size needed or just "slightly" above or you lose velocity.. In my builds these days I try to use YZ85 reedcages or YZ85 vforce cages in everything for the street and  entry level roadracing even. I have no problem getting them in any RD cylinder (with a little patience) without "busting through" or "hitting air" as we say and they have plenty of airflow. Then for all out I switch to RZ or Banshee vforce. 

Hawaii-Mike

Ed thanks for your input!  For us streetbike guys, what pipes and carbs do you recommend to match the reeds?

SUPERTUNE

Can't go wrong with Gary's off the shelf F1 pipes(spec 2)
For street package as long as we can still get them.
They make more usable street power than any for the $$
I have great dyno results even making 35 ft -lbs of torque which is hard to do and still make over 58 HP on a pump gas street 400.
I need to make more time to come here and post these results.
Guillermo had me build his RD400 a year and a half ago, and he ripped out 7600 miles on it doing nothing but new plugs and fix a broken throttle cable 3 way splitter. Went to Roebing Road races and dynoed it by just adding a 3/4 gallon of 110 race gas with 50:1 to his half of tank pump 93, put in some new br9iex plugs and right to the dyno...(this is riding it to the track 18 miles from his home)
This is very good results in my book.
Chuck
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

Hawaii-Mike

Good to know, thanks Chuck!

I have three RD400 projects and three sets of pipes.  Spec2 classic, Bassani and Jim Lomas street retro.  One set of ported cylinders by Ed, done a couple of years ago and waiting for me to put a bike together.  For carbs I have stock VM28's, PWK28's and VM34's.

I don't intend to go all out on all of these bikes due to $$$ and I have several other bikes (Kawi triples, RD350 etc).  Recommendations on pipe/carb combinations will be appreciated. 

SUPERTUNE

My take is use them 34's on Eds cylinders and the classics first!
Save the stock vm28 for the Bassani's, then the pwk with retro's last.
C
RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

Hawaii-Mike

Thanks Chuck, I'm working on the '76 now.  I may put the Bassani's and VM28's on it.  I'm saving the best parts for the '78.

SUPERTUNE

#27
Crystal Silver '78's are the best looking for me!!

Here's Guillermo's '77 STG 2 ported with the V-Force V382A reeds using TM34's and F1's.

This was when I was taking it out at night for break in right after I got it together in August 2017



Here's the dyno run last month after Guillermo putting 7600 miles on it...(ok , yes the chain was a bit loose, G just loves to ride it!)

https://imageevent.com/supertune/guillermosrd400videos?p=100&n=1&m=14&c=2&l=0&w=4&s=0&z=4

Torque and power curve is very broad and makes this 2 stroke a beast to ride on pump gas on the street.
35 FT-LBS of torque and 58 HP



Chuck

RD machine work, boring, porting, cranks and engine building.


Chuck 'SUPERTUNE' Quenzler III
Team Scream Racing LLC
1920 Sherwood St. STE A
Clearwater, FL. 33765
cqsupertune@tampabay.rr.com

pdxjim

#28
I'm getting back to work on my LC, so digging up an old thread here.

After reading this thru a few times, it seems the bottom line is:

If your cylinders are off, and you are good opening up the reed boxes (or paying someone else to do it), the bigger Vforce3 V382A YZ85 reeds are the way to go. 

If your cylinders are on the bike and/or you don't want to modify them, go with the smaller V384A for the RM100 because they drop right in.

Is this correct?

In my case, I'll be using bigger/more modern carbs and tuning the cyls/head as well.  Does this change the optimal reed choice?

... and as a side note, Garrett opened up the reed boxes (and opened the intake ports a little) on the Kart Track Racer RD350 cyls, and we fit VM30's with the Vforce3 V382A reeds and it rips.  Pulls stronger up top than any RD I've ridden.
Wasting time on 2T forums since the dawn of the internet. '89 TDR250, '13 300xcw, '19 690smcr, '56 Porsche 356A

m in sc

im pulling 34s thru the RM100 reeds, no issues there, they will more than handle 30s IMHO  :twocents: