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Long Intake Manifolds - Rough

Started by junior varsity, March 23, 2010, 01:59:55 PM

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junior varsity

March 23, 2010, 01:59:55 PM
I spent some time searching but could not come up with an answer,

I've got my bike apart currently, diagnosing bits and pieces. While I'm aware that max power and RPM are limited by the long intake tracts, I'm not going to split singles on this Monster. I am, however, curious as to whether there are benefits to cleaning up the stock castings of the intake manifolds. They are pretty rough, and looks like they could benefit from a polishing.

Any thoughts, experiences, or links to information that I have missed?

junior varsity

#1
March 23, 2010, 02:02:38 PM
I think Koko64 has done this. Wondering if others have, and if so, are there places that do the necessary polishing that I could send 'em to?

ducpainter

#2
March 23, 2010, 02:09:22 PM
My understanding is while you want to match openings and remove obvious ridges polishing is not the best thing.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


junior varsity

#3
March 23, 2010, 02:15:04 PM
I thought that the roughness helped the fuel atomize, giving a more homogenous mixture, however I recall reading about having them polished and "swirled" which would accomplish the atomization while increasing flow.

ducpainter

#4
March 23, 2010, 02:41:14 PM
Quote from: ato memphis on March 23, 2010, 02:15:04 PM
I thought that the roughness helped the fuel atomize, giving a more homogenous mixture, however I recall reading about having them polished and "swirled" which would accomplish the atomization while increasing flow.
Don't know about polished and swirled.

There is a phenomenon/physical property called laminar flow which affects atomization in the intake past the carb/throttle body.

Smooth surfaces actually hurt the process...

from my understanding
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


krista

#5
March 23, 2010, 02:42:52 PM
Ultimately as long as the 620/750/800/900 intake ports are under said manifolds, any work done is like tweezing short weeds in an overgrown field with 6 foot tall grass...
Krista Kelley ... autist formerly known as chris
official nerd for ca-cycleworks.com

junior varsity

#6
March 23, 2010, 02:52:46 PM
Fair enough. I had pulled them to inspect the gaskets underneath and replace - and was going to have the ceramic coater who is doing my headers do the intakes to match, thought I ought to see if there is much I can do while they are off before hand.

Good stuff. Thanks for the input nate & chris

greenmonster

#7
March 23, 2010, 03:33:03 PM
I smoothened the 1mm threshold & shortened the screws that were too long.
Made it run a bit smoother but no big difference.

Why not do it to know you made all as optimized as possible,
even if it is a minor improvement?
Just my 2c.
M900 -97 
MTS 1100s  -07

junior varsity

#8
March 23, 2010, 03:56:40 PM
I think I'll try to smooth out the huge casting seams and maybe call it a day. What threshold are you describing?

ducpainter

#9
March 23, 2010, 03:58:42 PM
Quote from: ato memphis on March 23, 2010, 03:56:40 PM
I think I'll try to smooth out the huge casting seams and maybe call it a day. What threshold are you describing?
I believe he's referring to the diameter differences of the manifold and intake port.

If you clean up that 'step' or 'threshold' it can't hurt.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


junior varsity

#10
March 23, 2010, 04:00:24 PM Last Edit: March 23, 2010, 04:02:38 PM by ato memphis
I'll certainly give that an eyeballing in the daylight. One of these days I'm going to send them there heads off for testarossa work. But I think I'd rather go with testa - nero - get some cool fancified black painted heads.

ducpainter

#11
March 23, 2010, 04:03:27 PM
Quote from: ato memphis on March 23, 2010, 04:00:24 PM
I'll certainly give that an eyeballing in the daylight. One of these days I'm going to send them there heads off for testarossa work. But I think I'd rather go with testa - nero - get some cool fancified black painted heads.
Also check the rubber boot to manifold joint.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."


junior varsity

#12
March 23, 2010, 04:05:15 PM
Not sure what I can do there - it seems to seat well around the manifold. Curious as to whether I should throw some liquid gasket in between during reassembly, before tightening down the clamps, to keep 'em as air-tight as possible.

Duck-Stew

#13
March 23, 2010, 06:04:21 PM
Quote from: greenmonster on March 23, 2010, 03:33:03 PM
I smoothened the 1mm threshold & shortened the screws that were too long.
Made it run a bit smoother but no big difference.

+1 to a 750 I did ages ago.  Same results.
Bike-less Portuguese immigrant enjoying life.

MotoCreations

#14
March 23, 2010, 07:14:06 PM
On a M900 I had with FCR's (long manifolds) -- did a quick cleanup (5+hrs) of the intakes and rode the bike for awhile.  No difference that I could tell.

Ceramic coated the (above) intakes and no other changes.  I swear the on/off throttle response was better.  I had someone comment the same who rode the bike.  36hrs between swap and same weather conditions.

I know a few dirt track racers here in the Northwest who ceramic coat the intakes of their sprint cars.  One driver can tell the difference between them not knowing which ones are installed.  (covered by a bodywork)  He said he can tell by the on/off throttle response within 2 turns.  He has seven manifolds and although almost all look identical, they all have slightly difference thottle responses. (thus he will swap depending upon track conditions) Guy is good -- wins on a regular basis.

Biggest difference I noticed is the intake manifolds don't get as hot as a non-ceramic version.
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