Mainfold problem...

[tellan]

I'm going to build my own mainfold, in stainless steel.

But I have a problem... The mainfold is supposed to be as short as possible, and be arround 42-43 degrees. But when i cut the steelpipe I'm goign to have as the mainfold the bottom area of that pipe become much bigger than the area of the reedblock and the whole engineblock. And the area of the reedblock is a rectangle and the pipe is round, I saw this mainfold,

but dont know if that will work either.

I've made a pic to make it easier to understand.

And the carb cannot be to close to the backtyre either.. so I havent really figgured out how to solve this so I wonder if someone here have any Idea. And please tell me if you dont understand the question

One idea is to cut the pipe in two parts and then weld them together again, but If there are a better way I would prefer it.
I might seem a bit confuzed, but I really dont know how to do

Greetz tellan

 

[Mekai]

I'm going to build my own mainfold, in stainless steel.

But I have a problem... The mainfold is supposed to be as short as possible, and be arround 42-43 degrees. But when i cut the steelpipe I'm goign to have as the mainfold the bottom area of that pipe become much bigger than the area of the reedblock and the whole engineblock. And the area of the reedblock is a rectangle and the pipe is round, I saw this mainfold,

http://files.upl.silentwhisper.net/upload8/Glasblast_blok_og_studser_014.jpg but dont know if that will work either.

I've made a pic to make it easier to understand.

http://files.upl.silentwhisper.net/upload1/insuget.JPG

And the carb cannot be to close to the backtyre either.. so I havent really figgured out how to solve this so I wonder if someone here have any Idea. And please tell me if you dont understand the question

One idea is to cut the pipe in two parts and then weld them together again, but If there are a better way I would prefer it.
I might seem a bit confuzed, but I really dont know how to do

Greetz tellan

I had made an angle as i have ilustrated at the picture bellow.

/Mekai

 

[Swobber]

The best way to deal with this is either to modify your reed valve, or making a smooth transition from a round hole to a square hole.
You could also make mixture of both solutions.

The inlets on the picture is'nt ready - I know you've taken the pictures from MJS's project.

/Swobber

 

[tellan]

The best way to deal with this is either to modify your reed valve, or making a smooth transition from a round hole to a square hole.
You could also make mixture of both solutions.

The inlets on the picture is'nt ready - I know you've taken the pictures from MJS's project.

/Swobber

Mekai: Yea thank you Ill try to make the mainfold like that and se how it works.

Swobber: Yea I have thought about something like that... yeye thank you, and yes I know the mainfold I posted isnt ready yet.

/tellan

 

[ruud.]

u can also weld it together like this, and fil it with a metal epoxy. Than u can make a good flow to!

 

[Big B NRG]

Btw, don't forget that steel expands when it heat's up...

Block heating up = manifold heating up (because steel conducts the heat)

 

[Mexicano]

Why don't you just buy this one from Scooter-Center:

Product Nr.: HR7000801

 

[tellan]

Why don't you just buy this one from Scooter-Center:

Product Nr.: HR7000801

Probably that mainfold just fits the regualar Keihin/pwk carbs, the Koso carb is much bigger and thats why I have made a new mainfold, but I tried to make a better flow to.

But I've done like the mainfold I posted in my first post, from the MJS project, and then I'm going to fill it up with a kneedable steel which Bram is going to send me.

Bram: will there be any probs with the steel mainfold? If it expands to much.. will it be able to brake? Does alu work the same way as steel to when its heatended up?

 

[Big B NRG]

Bram: will there be any probs with the steel mainfold? If it expands to much.. will it be able to brake? Does alu work the same way as steel to when its heatended up?

The problem is that your carb could drop out of the steel manifold and become stuck between the wheel and the carter.

The manifold won't brake. An alu manifold will even conduct more heat then steel (that's why racing cylinders are made of alu).
Another point of having a non rubber manifold is that it does not absord any shocks comming from the block, during driving. And if you carb begins to shake, gas inside the carb will become foam and that will be the end of your cylinder

It's better to have a malossi short neck and make the inlet of the carb a bit smaller. You can boil your shortnect manifold in hot water and then push it on the carb. That will work.

Just take a dremel and a sandpaper rol and go around the inlet of the carb (set the dremel on high speed). That will do the trick.

Still If you want, I can send you some kneable steel.

 

[tellan]

The problem is that your carb could drop out of the steel manifold and become stuck between the wheel and the carter.

The manifold won't brake. An alu manifold will even conduct more heat then steel (that's why racing cylinders are made of alu).
Another point of having a non rubber manifold is that it does not absord any shocks comming from the block, during driving. And if you carb begins to shake, gas inside the carb will become foam and that will be the end of your cylinder

It's better to have a malossi short neck and make the inlet of the carb a bit smaller. You can boil your shortnect manifold in hot water and then push it on the carb. That will work.

Just take a dremel and a sandpaper rol and go around the inlet of the carb (set the dremel on high speed). That will do the trick.

Still If you want, I can send you some kneable steel.

Hehe okey, doesnt sound to good. For the moment I'm using a Stage 6 mainfold.

Here is a picture of the carb and the pipe which I've made a mainfold of.

As you see I have made a trace where the mainfold precisly fits in, so I dont think it will drop of. But what you say about the steel not absorbing any shocks may be a problem. I tried to set up på carb in the lathe, and then try to mill the big egdes down, but that didnt work very well. Do you have any picture of the Koso carb you modified for Freddan?

If there is to much problems with having the mainfold in steel I just have to boil the rubbermainfold I used before or mill down the egdes of the carb.

 

[Swobber]

You could also fill it up with a CO2 welder, and then grind it afterwards.

Alu and steel does not ekspand the same.

/Swobber

 

[Big B NRG]

Hehe okey, doesnt sound to good. For the moment I'm using a Stage 6 mainfold.

Here is a picture of the carb and the pipe which I've made a mainfold of.
*pic*

As you see I have made a trace where the mainfold precisly fits in, so I dont think it will drop of. But what you say about the steel not absorbing any shocks may be a problem. I tried to set up på carb in the lathe, and then try to mill the big egdes down, but that didnt work very well. Do you have any picture of the Koso carb you modified for Freddan?

If there is to much problems with having the mainfold in steel I just have to boil the rubbermainfold I used before or mill down the egdes of the carb.

Hmm, I had pics of that carb, but I cannot find them, aks Fredrik on msn.
I sended him pics.

 

[tiba_karotsu]

good thing MRD made a big manifold for Minarelli engines that can use KOSO 32mm carbs with no porting at all, MikkoR has one & i've seen it & i'm gonna get it from him along with a 30mm KOSO carb, time to see what this set-up can do with a bigger carb.

 

[Big B NRG]

good thing MRD made a big manifold for Minarelli engines that can use KOSO 32mm carbs with no porting at all, MikkoR has one & i've seen it & i'm gonna get it from him along with a 30mm KOSO carb, time to see what this set-up can do with a bigger carb.

Is the MRD manifold a short neck model?

 

[tiba_karotsu]

nope it isn't like the MHR manifold it's part aluminum & part rubber, the rubber part you can twist to direct the carb at any direction, i was surprised when i saw it i have been looking for that kind of manifold to replace my KOSO manifold, it's simply maxed out for a 28mm carb there's only a thin wall left so fitting a 30mm carb & match porting the runner isn't a good idea.

when i get my hands on it i'll post a pic of it asap.

 

[tellan]

Okey, I'll ask Freddan.

But will there be any serious troubles with the steelmainfold or will I be able to use it without damaging the engine? I mean... I've seen lots of other people using mainfolds made in steel or alu, and their scoots have worked fine.

If its to risky in any way, I'll have to mill down the egdes of the Koso and put it in to my Stage 6 mainfold, and use it untill I buy a MHR shortneck.

 

[Big B NRG]

Okey, I'll ask Freddan.

But will there be any serious troubles with the steelmainfold or will I be able to use it without damaging the engine? I mean... I've seen lots of other people using mainfolds made in steel or alu, and their scoots have worked fine.

If its to risky in any way, I'll have to mill down the egdes of the Koso and put it in to my Stage 6 mainfold, and use it untill I buy a MHR shortneck.

You could fix this problem buy using some absorping material under the manifold.

But to be hounest, I would buy a shortneck manifold.

 

[tiba_karotsu]

save yourself the trouble just get the MHR shortneck manifold.