Pocketbike Forum banner
1 - 20 of 123 Posts

·
Registered
Joined
·
186 Posts
Discussion Starter · #1 ·
Hey guys. I'm working on a new project.I have a motor that I pulled from a chainsaw, it has a very small exhaust its 2inches long and only 3/4 of an inch wide. I'm either adding pics or links to a photobucket page so you can see what I mean.

So I'm wanting to increase flow by increasing the size of the exhaust.

I have a exhaust manifold from a somewhat similar 2stroke motor, the part would bolt right up if the fins I the head weren't in the way. So what I want to do is very nicely cut back the fins until the manifold will fit in and bolt up, then I can as a pipe from there. The exhaust I am wanting to as also has fins on it. So I was thinking.g that might make up for the lost fins
 

Attachments

·
Registered
Joined
·
186 Posts
Discussion Starter · #3 ·
Yes its a bigger manifold, would porting the exhaust to match it ruin power at all? Or does it matter and is it something that absolutely needs to be done

I'm nervous on porting, I here several different warnings about it, like angle of port being super crucial, going too big loses power, and a few other reasons why I shouldn't do it... have you done much porting?

Has anybody done a reasonable amount of porting and have any input?



Oh I picked up a saw for parts, it had a but different exhaust so I tried to copy one and am working on doing another style hopefully a straight pipe or maybe a slightly angled pipe, depends on how it fits.

Also what about a manifold? Could I make one of I can get a small block of aluminum, one that I mark each peace on each end then cut it out to taper from large to small? With a little but larger of a tunnel and each piece bored out a bit.
 

Attachments

·
Registered
Joined
·
186 Posts
Discussion Starter · #4 ·
I realize my next idea might possibly be the stupidest yet, but honestly I have set that bar extremely high.

Would lead work?

Of not for exhaust I. Wondering.g would lead work so that I can make a custom intake manifold.

about ths exhaust manifold, of I used the metal sleeve type things for the a screws so that I wouldn't bend the lead when tightening it. Just not sure of it could take the heat for exhaust or intake purposes
 

·
Registered
Joined
·
638 Posts
Lead probably wouldnt work in this situation, the exhaust would run the risk of melting it, and on the intake side, i think lead would be too soft to reliably hold up a carb, and you would run the risk of it cracking, and running your engine lean... Maybe it would work, would have to get input from the gurus on that....
 

·
Banned
Joined
·
21,742 Posts
I realize my next idea might possibly be the stupidest yet, but honestly I have set that bar extremely high.

Would lead work?

Of not for exhaust I. Wondering.g would lead work so that I can make a custom intake manifold.

about ths exhaust manifold, of I used the metal sleeve type things for the a screws so that I wouldn't bend the lead when tightening it. Just not sure of it could take the heat for exhaust or intake purposes
A lead intake would work but not too well without a plastic isolator between the engineblock and the intake itself...Once the intake starts to absorb heat itll start vaporizing the fuel..........Thats why intakes are either plastic or aluminum w/plastic isolator.............

I cant believe you cant get a stock exhaust can and modify it.........
 

·
Registered
Joined
·
186 Posts
Discussion Starter · #7 ·
A lead intake would work but not too well without a plastic isolator between the engineblock and the intake itself...Once the intake starts to absorb heat itll start vaporizing the fuel..........Thats why intakes are either plastic or aluminum w/plastic isolator.............

I cant believe you cant get a stock exhaust can and modify it.........
could you show me a pic of what you mean, sorry man i know you have show me several ways i could make my own, but since i have gotten the welder all the ideas and ways to do them have been forgotten and i could really a refresher.

if you could show me another pic, now that i have the welder and can go out and do it now or next time my kiddo falls asleep i can do the stuff now.

WHAT IS THAT MOTOR IN YOUR PIC,
 

·
Banned
Joined
·
21,742 Posts
could you show me a pic of what you mean, sorry man i know you have show me several ways i could make my own, but since i have gotten the welder all the ideas and ways to do them have been forgotten and i could really a refresher.

if you could show me another pic, now that i have the welder and can go out and do it now or next time my kiddo falls asleep i can do the stuff now.

WHAT IS THAT MOTOR IN YOUR PIC,
The engine is a Mazda rotary engine going into a CX7 sleeper SUV.........Its gonna be a Turbo Porsche Cayenne killer.........LOL







 

·
Banned
Joined
·
21,742 Posts
That motor, the rotary one looked bad a$$

I like the razor trike too, what kind of speeds do you get on that thing?
Thanks..In the car its gonna feel bad azz....LOL..The trikes going a tick over 50mph flat out on alchohol......Its a Techumseh TC300 w blueprinting aswell as powerporting and a Hi-Fire ignition module that eliminates the points......
 

·
Registered
Joined
·
186 Posts
Discussion Starter · #11 ·
Was wondering of this exhaust would work well for my conversion?

It came off one of them mini pocketbikes, the one I got for like $35

I was gonna cut it somewhere do that it would come off the motor and exit towards the rear of the minibike. I need it to fit the small size chainsaw exhaust pictured in the beginning of the thread

Well here is a pic of what I have and what I need to make it fit

Of anybody has any ideas on how to make the transition, I'd be greatful for any advice.
Cam2 I remember you showing me how you did one but I cannot find it again, been looking all say. Maybe you could show me again.

Thanks guys
 

Attachments

·
Banned
Joined
·
21,742 Posts
Was wondering of this exhaust would work well for my conversion?

It came off one of them mini pocketbikes, the one I got for like $35

I was gonna cut it somewhere do that it would come off the motor and exit towards the rear of the minibike. I need it to fit the small size chainsaw exhaust pictured in the beginning of the thread

Well here is a pic of what I have and what I need to make it fit

Of anybody has any ideas on how to make the transition, I'd be greatful for any advice.
Cam2 I remember you showing me how you did one but I cannot find it again, been looking all say. Maybe you could show me again.

Thanks guys
You need MC Culloch headder # 48609..In case you didnt know ..Not all engines get exhaust systems...The Mcculloch benefits from an open headder..Some add oval cans running across the end like a Tee welded to the end of the headder pipe..


If you want a quieter engine...Go back to the pics posted in post #8 and look how I mounted my exhaust pipes....I have no clearer pics of the process...Those mods were done back in 08 and I had a severe harddrive crash in 09........

Its not hard to take the exhaust apart,,make a flat steel sandwich plate,,cut an hole to match the pipe and drill 2 that youll use to bolt the pipe to the outter exhaust case half.........then assemble the outter half of the muffler without baffle plate to the part bolted to the engine with the two or 3 tiny screws holding it together...youll also need to make a good exhaust bracket..........

You first need to post the kind of exhaust can you have in order to get clearer instructions.......................

http://vintagepowersport.com/wp-content/plugins/page-flip-image-gallery/popup.php?book_id=6
 

·
Registered
Joined
·
186 Posts
Discussion Starter · #14 ·
Did you make that header Cam2??? or is that the part # you mentioned. I am surely gonna buy the part number you posted, but im also gonna try to make one eventually , if my skills ever increase ;)

I may have a line on one for a good price, waiting to hear back from the guy.




This is how your headder should look like when done............



 

·
Registered
Joined
·
186 Posts
Discussion Starter · #17 · (Edited)
Right on, thanks for the links cam2 saved me some hunting

I made a chain guard for my hopefully mini torque converter + mc49clone combo. Of they work together with what I'm planning to do.

The bottom is not done, its gonna be a bracket to take some stress off the motor (at least I hope, and that's the plan)

I'm also gonna weld the chainguard to the box I'm using and made that mounts the converter to the motor. I'm hoping that will keep it from breaking loose of my crappy welds, the more the merry is the idea I'm using :D

Here should be a pic

Also was hoping of someone could tell me of that part that the clutch goes into has been cleaned enough or should it look new in there? Would it be better to take a steel brush in there?


Also i just bought the 3rd link you posted i think, the one that was $20 with $5 shipping the nos exhaust header. thanks again Cam2 that was awefully nice of you to take the time to find those for me man.


 

Attachments

·
Banned
Joined
·
21,742 Posts
No problem at all......As far as the transmission ...the clutchbell drum can be a lil cleaner but the rust will just add grab.............

In case you dont know it........The output sprocket spins opposite of the clutchbell therefore for the vehicle to go forwards with the CVT mounted like that the engine must spin backwards...........

Youre also gonna have to weld the hole in the CVT fill nut and drill a tiny hole in the drainplug

Look at how I have my Engine w/CVT mounted on my Goped.....Theres plenty of room behind the CVT variator for nuts......





 

·
Registered
Joined
·
186 Posts
Discussion Starter · #19 ·
Cool, o think I can swing some welds and brackets like that, thanks for the pics. That clears a lot of questions up .

Hoping to get back out in my shed soon so i can work on something but the cold and price of kerosene is too much for me
 

·
Banned
Joined
·
21,742 Posts
:mad:
Cool, o think I can swing some welds and brackets like that, thanks for the pics. That clears a lot of questions up .

Hoping to get back out in my shed soon so i can work on something but the cold and price of kerosene is too much for me

Those cheap $10 electric heaters from Home depot work pretty good......Thats why I like having my hobby room......I get lots of things done without freezing......



I got bored sitting in the house today because of icy rain and sub-frigid temps so I decided to get my Ducati Cag ready to ride..........When the time comes the stage 2 will either be cut off so I can shoehorn in a Blata aircooled bottomend w/80cc PW80 0r 80cc Minarelli Jog topend engine build I plan on throwing in it after I finish working out the details,,order the parts and build the engine.........

In the meantime I added some pretty indestructable and beefy front forks......I also got rid of the crappy wheel bearings and added a bulletproof set of triple clamps thatll handle speeds of over 70mph and give the rest of the beefy trellis frame the finishing touch....I still have to drill the axle holes and then make-up a front caliper bracket......




Next week the temps are supposed to go back up into the 40's.........Ill be able to definately get some welding done needed to tie it all in together then......

Have fun with your projects and hope they turn out as planned........
 
1 - 20 of 123 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top