inverted intake manifold?

peteyb · Apr 11, 2011

I have very limited space in my custom made bike frame. i have to resort to relying on a heater hose extension hose to connect the intake manifold and the carburetor. this also means that i may have to invert and hack off a bit of (approximately where the red marker is) the air intake manifold. is this going to anyhow affect the performance of the engine in any negative way, shape, or form?

thanks.

Bikeguy Joe · Apr 11, 2011

You should be just fine, just try to keep the hose length to a minimum.

"the prussian" Shop Dogs · Apr 11, 2011

How are you going to attach carb to bike? Just wondering about vibration and bowl being level? You may need to make a sleve to fit into carb then attach that to frame via a brackett .

"the prussian" Shop Dogs · Apr 11, 2011

Just a quick after thought , it's sitting kinda high in frame ? Is that for ext. Pipe Room ?

peteyb · Apr 12, 2011

i used a ladies bike, and modified it into a mens frame... thus the frame is very small and tight. i will take more pictures of it later to show you how the engine is sitting as of now.
the intake manifold will connect to the carburetor via a car heater hose. it has been done before, and apparently somehow adds some torque to the engine as well.

here is a link to how its supposed to work:

"the prussian" Shop Dogs · Apr 12, 2011

Ah... That's why it looked funny in frame . I only brought that up cuz it's a lot easyer to bend ext. Then mod. Carb. Inlet.
Very cool idea , just use caution following any course of mods. , it does look like he did a good job looking at all the angles.
I feel sometimes guys push proformance in one area and have trouble with something else, not throwing any stones , it's just you rarley hear about the failures.
It's to bad you can't run stock then mod to see diff.
I have one frame with a ton of room behind engine and it's a dead mule on hills , so i may try this mod myself . Prob use stock inlet and weld on ext.
Good luck ,keep us updated on ypur progress.

"the prussian" Shop Dogs · Apr 12, 2011

Check out handle bar ext. Thread , venice has pic of nice intake man.

breno · Apr 12, 2011

I had a similar issue with a tight fit on my 1st build.
At 1st I used the heater hose but I had the intake facing the normal way and just cut it earlier in the piece.
Fitted the heater hose on which was an akward angle then used the bit i cut off in the other end of the heater hose and fitted that into the carb and cable tied carby to the frame.
It was ok for a while but the look of it was dodgy so i made up a new intake.
Doesn't take too long but it can be a little finicky trying to get it as close as possible to the frame once its out.
I had to actually drill a hole in the top tube for the excess screw of the carby clamp fitting to go through.

peteyb · Apr 12, 2011

thats a really sweet mod, breno! you dont happen to have that intake extension just lying around somewhere would you? lol

breno · Apr 12, 2011

Thanks bud it wasnt too hard to get together. I guess your biggest problem might be not having a welder handy.
If I knew where that pipe was I'd be happy to give it to ya. My garage is abit of a mess atm junk is everywhere...lol

peteyb · Apr 12, 2011

thats cool... if you do happen to come across it though, shoot me an email, will yah? hahaha

[email protected]

thanks!

i'll post some more pics of my engine/frame configuration by the end of the week... promise!

i am also having a fun time trying to mount my expansion and exhaust pipe around this tight little frame...with the help of some good old copper piping! i will post some pics of that too as soon as i find a way to manage it.

breno · Apr 12, 2011

can do mate.. hopefully it all works out for ya.
What pipe are you planing on fitting up?
Theres nothin wrong with a compact set up it can be a bit of a bugger to set up initially but when its done you'll look at it and be happy you made it work.
The lower centre of gravity can be good for cornering too..
Here is my 1st build complete from a while ago so I feel your pain with trying to make it all work. Good luck.

peteyb · Apr 12, 2011

thanks for the encouragement (i am definitely going to need it

). your picture got me pondering... my gas tank will be just slightly above (almost level) to my carb, almost indentical to yours... how was your fuel flow?

breno · Apr 12, 2011

No problems mate only issue I had was the clearance from the front tire to the zorst.
If it didn't have front suspension it wouldn't have been an issue.
I had to pull the suspension apart to fit some fuel line over the bolt that goes through the spring to minimize the tyre rub but that ended up putting too much strain on the extended shock and caused it to bend the forks back only making it worse.
Had the choice of gettin new forks with no suspension or a dif bike.

So I guess theres a lesson learnt make sure ya check ya clearances between the tire n the zorst when fabbin up ya zorst last thing ya wanna do is jump on the brake n rub ya tyre so ya cant turn.

corgi1 · Apr 12, 2011

I believe there is a thread on here that says adding a certain amount to the length of the manifold improved the power

peteyb · Apr 18, 2011

corgi1 said:
I believe there is a thread on here that says adding a certain amount to the length of the manifold improved the power

yup, there sure is!

i think this is the page that you're refering to?

Intake Extension for More Low RPM Power

peteyb · Apr 18, 2011

these are the most up-to-date photos of my project.

i am currently in the process of mounting a custom exhaust system with expansion pipe and muffler. i am also trying to mount my carb, connect all the cables, fuel lines, tighten all the bolts, attach turn signals/headlamp, and then she should be road worthy!

EDIT: i almost forgot about the chain too!

corgi1 · Apr 18, 2011

What is the Gray looking stuff on the top tube at ,and on the seat post?

peteyb · Apr 20, 2011

i believe you are talking about the white paint? its to prevent from rust from inhibiting the bike frame after i had my bike converted into a mens frame. we had to grind the paint off a bit to expose some bare metal to have the frame re-welded. one of my good friends did the welding for me at work. i work at a machine/welding shop so i have easy access to mig, tig and arc welders.

corgi1 · Apr 20, 2011

Ok ,it looks like that this morning,I was seeing bigger blob amounts before your last post and thinking terrible JB weld or something connections(sorry),eyes are going too I guess,grttin' old aint all that great,lol

inverted intake manifold?

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