I have a 91 GS , and I'm primed to kick up the power some . I don't thought too much for the port design , the floor looks awfully low . I can do my own valve job , has anyone see much improvement from port work and a nice triple angle ? I've be reading some about the 332 cam I believe it is , any thoughts roughly the viability of this cam surrounded by a lower compression engine , sans the big carbs and valves ? I used to flow head and am confident I can improve low hoist flow , any suggestions or observations appreciated .
I'm also not safisfied with the carb jetting , anyone come upon a syringe and jet combo that works honest for them ?
Answers: 336 cam ?
Those are interesting.
It's one of a Few "Old Fashioned" cams which was "Track Developed",,,and so all right developed that modern technology cannot really surpass it.
.A Decent Port and Valve Job never hurt anything.
Compression IS an issue.
It's kinda the KrAcK of Hop-Up efforts,,,a Cheap Easy High.
But even within the most responsible approaches,,
Ya still gotta have some sort of "minimum" to receive decent overall conduct.
BMW's aren't real glorious CR motors to begin near.
Especially not GS's
.
Anytime you put an extended duration camshaft,,,
Intake Vacuum is gonna drop at low speeds,
and Cranking PSI is gonna drop.
Which makes for some pretty dismal low closing stages power,,,
with thoroughly soggy throttle response,,,,
and can create an engine More sensitive to carb tuning and gearing.
So even though you may not want to raise CR a short time ago for CR's sake,,,
You really should sort of at least try to preserve up with the CAM,,,surrounded by terms of Cranking PSI
Which probably requires nearly a full 1 point increase in static CR....at minimum
R100/s have 9.5 :1 CR
A 336 cam in even those things suggests a raise CR to about 10:1
It's a Very Late closing cam,,,55* ABDC....
that's nearing "valid race cam" nouns.
I'm sure You'd find your motor Terribly weak running near stock GS C/R (a) 8.5:1
And I say that , Realizing that You are NOT trying to build a Super Power Drag Racer,etc
Here's some articles/info I found while poking around.
You may already own this stuff.
This one has several interesting points,,,,but also address some "Valve Job" Prep tips
http://garnet.acns.fsu.edu/~jroche/road_...
This one is not so great,,but worth reading
http://www.ibmwr.org/r-tech/airheads/336...
This one has a relation in the page to some Details on the Cam,,,and a moment or two about diverse other relevant dimensions
http://moragafalconers.org/BMW_336_Cam/
...............................
I'd shoot for 9.5~10:1 range,,,especially next to that particular camshaft
Good luck next to your project,hope it comes out nice
Try to get a hold of a set of 34mm Delorto's. Just getting away from the CV/Bings is an increase. These are squirters! Then after you freshen up your ports, cam it, don't forget to double plug the heads. These are proven HP mods that work in good health and do not hurt the reliability of your GS!
I'm also not safisfied with the carb jetting , anyone come upon a syringe and jet combo that works honest for them ?
On cold sodden days, after starting up...
Answers: 336 cam ?
Those are interesting.
It's one of a Few "Old Fashioned" cams which was "Track Developed",,,and so all right developed that modern technology cannot really surpass it.
.A Decent Port and Valve Job never hurt anything.
Compression IS an issue.
It's kinda the KrAcK of Hop-Up efforts,,,a Cheap Easy High.
But even within the most responsible approaches,,
Ya still gotta have some sort of "minimum" to receive decent overall conduct.
BMW's aren't real glorious CR motors to begin near.
Especially not GS's
.
Anytime you put an extended duration camshaft,,,
Intake Vacuum is gonna drop at low speeds,
and Cranking PSI is gonna drop.
Which makes for some pretty dismal low closing stages power,,,
with thoroughly soggy throttle response,,,,
and can create an engine More sensitive to carb tuning and gearing.
So even though you may not want to raise CR a short time ago for CR's sake,,,
You really should sort of at least try to preserve up with the CAM,,,surrounded by terms of Cranking PSI
Which probably requires nearly a full 1 point increase in static CR....at minimum
R100/s have 9.5 :1 CR
A 336 cam in even those things suggests a raise CR to about 10:1
It's a Very Late closing cam,,,55* ABDC....
that's nearing "valid race cam" nouns.
I'm sure You'd find your motor Terribly weak running near stock GS C/R (a) 8.5:1
And I say that , Realizing that You are NOT trying to build a Super Power Drag Racer,etc
Here's some articles/info I found while poking around.
You may already own this stuff.
This one has several interesting points,,,,but also address some "Valve Job" Prep tips
http://garnet.acns.fsu.edu/~jroche/road_...
This one is not so great,,but worth reading
http://www.ibmwr.org/r-tech/airheads/336...
This one has a relation in the page to some Details on the Cam,,,and a moment or two about diverse other relevant dimensions
http://moragafalconers.org/BMW_336_Cam/
...............................
I'd shoot for 9.5~10:1 range,,,especially next to that particular camshaft
Good luck next to your project,hope it comes out nice
Try to get a hold of a set of 34mm Delorto's. Just getting away from the CV/Bings is an increase. These are squirters! Then after you freshen up your ports, cam it, don't forget to double plug the heads. These are proven HP mods that work in good health and do not hurt the reliability of your GS!
Resolved Questions
- Should I move out my dirt bike...
- Suzuki t-shirt?
- Hi, Im looking to introduction a Motorcycle...
- Turning the fuel sour on a motorbike,...
- Biker anthems, biker songs what comes into...
- Dirt Bike Riders CLICK HERE??
- There's a flip side to that coin!?
- Which scooter, Buddy 125 or Vino 125?
- Engine not easy to turn over?
- Stalling Dirt Bike?