B pipe manifold diameter

WAB

WAB

salty nuts
Location
coastal GA
Ha, I was just measuring my new/old yama 650 FP manifold last night. This was with a cheapo Harbor Freight dig caliper so they are not exact.
It measured approx 44mm I.D. at the top. My brand new 701 FP headpipe is at approx 45mm or so. I was told it would be fine to go to 46/47 on the manifold and headpipe without making waterjacket walls to thin. :biggthumpup:

What about the ports that face the cylinder? I measured those to be 43mm wide and 44mm tall on this older 650 style manifold. What are they on the newer manifolds??
 
WaveDemon

WaveDemon

Not Dead - Notable Member
Location
Hell, Florida
FL-cracker said:
Wow! was that recomended to you, or did a engine builder bore it to that?
Click to expand...

that motor was built by watercraft factory. it hit real hard. this motor is why I tell people there full of crap when they say you have to run dual carbs for big power. this motor hits harder than any other big bore I've ridden and it's built on x cases.

I need to put that motor in my sj and feel how good it is in there.
 
jetskier79

jetskier79

I'm goin' for two
Location
San Diego, CA
my head would explode if I took this much time to build an engine. Slap parts together and ride.

Someone who knows what they are doing should build me an engine.
 
WaveDemon

WaveDemon

Not Dead - Notable Member
Location
Hell, Florida
TXJFrosty said:
Whoa... 50mm??? are you kidding me??? holy crap dude!!!

OK... so next question... when is the ID of the headpipe/manifold too big for a specific engine?
Click to expand...
don't know but mine is about 790 cc's. Id think a 1 or 2 mm bigger than your intake isn't a bad Idea on a single carb motor.
 
F

FL-cracker

X-H2O
Location
old exit 72 Melbourne
WaveDemon said:
that motor was built by watercraft factory. it hit real hard. this motor is why I tell people there full of crap when they say you have to run dual carbs for big power. this motor hits harder than any other big bore I've ridden and it's built on x cases.

I need to put that motor in my sj and feel how good it is in there.
Click to expand...

WOW! Thats realy saying something!
 
jetskier79

jetskier79

I'm goin' for two
Location
San Diego, CA
WaveDemon said:
I need to put that motor in my sj and feel how good it is in there.
Click to expand...

Probably would feel reaaaal nice. I'm running my old X case blaster motor in my SJ. It wasn't anything special in the blaster.....runs good in the SJ. Thing could probably stand to be propped better.....but it runs good.
 
WaveDemon

WaveDemon

Not Dead - Notable Member
Location
Hell, Florida
jetskier79 said:
Probably would feel reaaaal nice. I'm running my old X case blaster motor in my SJ. It wasn't anything special in the blaster.....runs good in the SJ. Thing could probably stand to be propped better.....but it runs good.
Click to expand...
thats what I'm thinking. if it's good in a blaster it mush be even better in an sj.
 
SkiDaddy

SkiDaddy

Just Havin' Fun!
Location
Orange City, FL
Dome size was 33cc.

My headpipe to manifold diameter was 42.7 - 43.7. Not even round.

Yamasaki has the right idea w/inscribing diameters, since these parts will float around for years to come....
 
WaveDemon

WaveDemon

Not Dead - Notable Member
Location
Hell, Florida
yamasaki said:
who did the actual machine work on that manifold? steve or ron?

i know ron@powersports does/did alot of machine work locally for alot of shops/people.
Click to expand...
I don't know the history of who did what. You probably know better than me since it was jetrock who had the work done. WF did the porting and I've heard conflicting info on who assembled it.
 
WaveDemon

WaveDemon

Not Dead - Notable Member
Location
Hell, Florida
well someone buggered up the girdle bolts on that thing and I don't know who. crackrock said it was stoyer. stricky said it was crackrock.
 
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