Vforce reed valve?

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Kawakaare
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Vforce reed valve?

Post by Kawakaare » Tue Feb 12, 2019 11:31 pm

Hello, im new to the forum. Quick info about me: 25 years old, motofanatic, Professional Mechanic, former motocross racer, currently passenger in my brothers sidecar, and recently aquired a Kr250b1 which had been sat in a hen house for 8+ years.
Im fairly seasoned in the world of engine tuning and motorsport, but this is my first Solo Road racing bike. And I thought what better way to start than an old 2stroke :lol:
After a complete tear down of the engine, cylinders, piston, gearbox and clutch. Where in mint condition (except maybe for 12 year old mineral oil). But a crank rebuild, new bearings, ultra sound for the carburetor + rebuild Kit, and a thorough cleaning of the engine. Reassembled and started up i 2. Kick.
Now it pulls fantastic, but floods the engine if left in idle to long, and sputters when the engine is loaded at 8000+ rpm.
Now the reed cages are bad, like new petals cannot, get Them to close. So i figured i might aswell mount some vforce reeds. Any experience, on fitting vforce reed on the kr1 is much apreciated.
From what info ive gathered the kdx 200, kx 125, and even a polaris water ski, should fit, anyone can confirm this? and which has the best flow for std. 28mm carbs?

Sorry for the long post Hope to get some respons from you.

Greetings from Denmark
Kåre Jensen
"fear allows you to feel your body better, it makes you act like a wild animal."

-Dani Pedrosa

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Re: Vforce reed valve?

Post by KR-1R » Wed Feb 13, 2019 12:10 am

Hi Kåre

welcome to the Forum, great to have worldwide visitors.
post some pictures of your bike(s) if you like - or anything interesting (racing)

below is a forum topic in the KR-kive section (our reference topics section), on the V-Force reeds...

I think V313C (KX125) is more suitable than V313A (KDX200/220)...
VFORCE3 REEDS for KR-1

keep in mind that information is now 10 years old (prices etc)
.
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Re: Vforce reed valve?

Post by Luders » Wed Feb 13, 2019 8:01 am

Welcome to the forum. You will find all the information you need to restore your B1 here.

Upload some pics for us.

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Re: Vforce reed valve?

Post by 500bernie » Wed Feb 13, 2019 8:18 am

Welcome to the forum.
As Ben said, we all like to see photos.
The Vforce3s will be an improvement on your old tired reeds.
The reed bodies are thicker than the standard ones, so you will need to screw out the reed body mounting studs about 6-8mm (so you can get a full nut on them).
Cheers
Bernie 8)
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Re: Vforce reed valve?

Post by Kawakaare » Wed Feb 13, 2019 10:24 am

Thanks for the replys, ill probably go go with the V313C. Ive made my own, intakes for the carbs in aluminium. So ill can customise the flow to best suit the vforce. Ill post a topic in show me yours later today, with photos of the bike, rebuild, and my homemade intakes :mrgreen:
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Re: Vforce reed valve?

Post by Luders » Wed Feb 13, 2019 8:17 pm

I too made my own aluminium intakes for my race bike, but had little choice running 38mm carbs. I don't suppose the pics are still active on my build thread, but if you want me to unearth some I probably could.

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Re: Vforce reed valve?

Post by Kawakaare » Wed Feb 13, 2019 10:23 pm

A picture would be very much appreciated, curious if i can make mine a better way.
What kind of gains do see with the 38mm? And do you have to port the barrels, and change ignition to take advantages of Them?

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Re: Vforce reed valve?

Post by Luders » Thu Feb 14, 2019 7:40 am

Mine have powerjets and I run a PDCI-25V Zeeltronic. Main advantage is it allows the motor to breathe, but the powerjets really help dial in the fuelling. I increased the PJ size and it cleaned up all the low end roughness and I was able to adjust them back at the top end at WOT.

I stroked my engine and run a single ring Cagiva Mito SP piston. The transfers are opened as far round as you could go.

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Re: Vforce reed valve?

Post by Kawakaare » Thu Feb 14, 2019 12:40 pm

Sounds like one hell of a machine 👍 Had a quick look thru your race bike thread, and YouTube videos. Absolutely astonishing work. Looks like you got a pretty wide powerband on that bike.

I was looking at bigger powerjets carbs and little bit of porting, but for now its just gonna be the vforce, and some jetting then the engine should be ready to go. And my time and money is needed elsewhere. Ill probably be better off spending money on some decent tyres, and getting some track time.

Ill might get it on the dyno and try retarding for a little more top end. We'll see, many ideas, little time, little money 😂
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Re: Vforce reed valve?

Post by KR-1R » Thu Feb 14, 2019 7:56 pm

mgtkr1 wrote:
Sun Jul 22, 2007 3:33 pm
ive also thought about making some carb mounts out of ali and having a bolt on type rubber for the carbs, similar to the type used on tz 350's/old brit bikes etc then this allows the carbs to be swapped to a smaller size by just undoing 2 screws and swapping the rubber but the idea put me off as the stuffers will be wrong without changing but i reckon an ali setup like the way mentioned would still be do-able in yer shed, and will have a go at doin some when i eventually get some 35mm carbs. elf had made some using old rubbers off a kr mated to the manifold type as described in 35mm bore size using some very effective rubber bond, if i can get some this will be another way ive considered getting round the problem of oe kr1r rubbers (and std) been nla. falconman, do you have a piccy of the ones you made?
falconman wrote:
Wed Jun 11, 2008 11:25 pm

I made manifold plates out of 1/4 inch thick aluminum and used a standard mikuni type manifold that fit the PWK 35's. It fit ok but had to grind about 2-3 mm off of the float at the overflow boss.

Here is a pic of the manifold plates I made. It took a little over an hour to make them. I had to use longer studs and bolts due to the reeds and plates being a bit thicker than the original setup. Also in the pic the 8mm allen bolts on the rubber manifolds were replaced with button head allens for clamp clearance.

Thank you. They are not hard to make. Just scribe the outline of
the gasket on the plate then I used a scroll saw to cut to the line and drilled the holes. I would definately use a separate plate for each carb size. Using a plate for a 35mm carb with 28's would increase the reed box volume a bit too much. Also if you want to keep the injection just drill a hole in the manifold for the nozzles.


Thanks! The rubber part is the manifold. I use Mikuni p/n VM34-200 for the 35mm carbs. I get my stuff from here - http://www.sudco.com/ there are other manifolds that will work but they usually have a different bolt pattern.

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Re: Vforce reed valve?

Post by Luders » Thu Feb 14, 2019 10:36 pm

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Re: Vforce reed valve?

Post by Kawakaare » Fri Feb 15, 2019 12:32 am

Thought about the plate with bolt on intake rubbers. Probably go for that design when i (eventually) upgrade the carbs, but i found a block of aluminum and two 28mm carb-intake rubbers. 1,5 hour later at the milling machine, and some final touches with the air grinder i was done.
I like your idea of displacing the carbs Ben. Are you running without reedblocks/funnels, or customised some?

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Re: Vforce reed valve?

Post by Luders » Fri Feb 15, 2019 8:12 am

The reedblocks are customised to suit. In my experience running without doesn't really work well. The space is so tight and carb so big, I had to off-set them slightly to accommodate the airbox.

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Re: Vforce reed valve?

Post by Kawakaare » Fri Feb 15, 2019 5:05 pm

Figured as much, im guessing there could develop some turbulence restricting the airflow.
Thanks for the replies, vforce v313c ordered today. Marked as non-stock item however, hopefully i wont have to wait too long.
"fear allows you to feel your body better, it makes you act like a wild animal."

-Dani Pedrosa

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