motorcycle head porting

victoRR · 07-08-2004, 6:29 AM

For the 929.

I landed a very good job with Dell Computers (who knows how long it'll last though) and I figured why not take up a project with my bike now.

I am quite confident that the bottom end is still very up to par and after having a valve/cct mishap in January the bike has since been fixed with new valves (2 intake valves) and a new CCT. I ported the exhaust ports while it was off for a not-so-noticable gain.

With a fully ported head, I am looking at *possibly* some aftermarket cams and hardware (valves,springs,shims), full race system (possibly Hindle if I can find a good one used) and a PC3.

What are the true benefits? Who from here has done it? Would I be better off with a 954 swap?

I wanted to, but never got around to track days. My main use for the bike is for enjoyment and the occasional straight line race at the track. *sorry guys, I said it, I drag race my bike*

input?
Would you do it? I'd do the work myself since i've already torn into it.

abtech · 07-08-2004, 11:09 AM

Originally Posted by victoRR

For the 929.

I landed a very good job with Dell Computers (who knows how long it'll last though) and I figured why not take up a project with my bike now.

I am quite confident that the bottom end is still very up to par and after having a valve/cct mishap in January the bike has since been fixed with new valves (2 intake valves) and a new CCT. I ported the exhaust ports while it was off for a not-so-noticable gain.

With a fully ported head, I am looking at *possibly* some aftermarket cams and hardware (valves,springs,shims), full race system (possibly Hindle if I can find a good one used) and a PC3.

What are the true benefits? Who from here has done it? Would I be better off with a 954 swap?

I wanted to, but never got around to track days. My main use for the bike is for enjoyment and the occasional straight line race at the track. *sorry guys, I said it, I drag race my bike*

input?
Would you do it? I'd do the work myself since i've already torn into it.

You are going to do the porting? Not a good idea unless you have a flow bench and a couple of decades of porting experience under your belt. I have seen nice bikes destroyed with a die grinder in the wrong hands . . .

figment · 07-08-2004, 12:26 PM

Originally Posted by abtech

I have seen nice bikes destroyed with a die grinder in the wrong hands . . .

What about a drimel tool with a cratex (sp) tip just to smooth the edges off a bit?

abtech · 07-08-2004, 1:45 PM

Originally Posted by figment

What about a drimel tool with a cratex (sp) tip just to smooth the edges off a bit?

Still not a good idea unless you have all of the pertinent info regarding flow rates before and after. There are several modeling programs available to predict the consequences of "smoothing the edges off a bit", but all require a full topographical run with a laser of the example port. Most "casual tweakers" would be better off going with a Serdi or full round valve job and leaving the internal port surfaces untouched.

I'm certainly not against porting cylinder heads, but advise having a pro with an outstanding track record do the work. If you are serious about having some head work done, I would recommend Superbike Mike Engineering in Ft Lauderdale, Florida.

stegen · 07-08-2004, 3:50 PM

or how about a 1000rr with some mods?

Baketech · 07-08-2004, 5:46 PM

I've seen MANY cylinder heads flow worse than stock after someone "smoothed" the edges....I've also flowed heads after welding (before being ground...ie smaller ports) that performed better than stock....go figure.....

Although many a backyard engineer with a Dumore can look at a head or a manifold and "see" areas for "improvement"...in my experience porting is not an intuitive process. Except for a few gifted wizards, it is at best an empirical game based almost entirely on iteration and documentation....

The key to porting is either have an expert do it.....or have about 20 cylinder heads laying around to experiment with....

I would never touch a head with anything more aggressive than a scotchbrite without flowing it first....

abtech · 07-08-2004, 6:18 PM

Originally Posted by Baketech

I've seen MANY cylinder heads flow worse than stock after someone "smoothed" the edges....I've also flowed heads after welding (before being ground...ie smaller ports) that performed better than stock....go figure.....

Although many a backyard engineer with a Dumore can look at a head or a manifold and "see" areas for "improvement"...in my experience porting is not an intuitive process. Except for a few gifted wizards, it is at best an empirical game based almost entirely on iteration and documentation....

The key to porting is either have an expert do it.....or have about 20 cylinder heads laying around to experiment with....

I would never touch a head with anything more aggressive than a scotchbrite without flowing it first....

Well put

Machinist · 07-08-2004, 11:50 PM

Porting and Polishing works well as long as the Job is done by a qualified person, I have done this job to my 954, and it has really made the engine perform well ( Allows it to revv up a lot Quicker)I work in the Aircraft Industry
in a Turbine Engine overhaul shop so I have acess to a flow bench etc, without the proper know how and equipment you can definitly do harm

I also had a custom map made to get the best out of the porting job, So it does work

But have it done by a qualified person.

victoRR · 07-09-2004, 12:40 AM

I will not be doing the porting myself. I will however be removing the head and doing the labor to assemble everything myself. I will be sending the head off to a qualified individual for porting and flow bench testing.

I needed to know first hand if this is actually worth it. I wouldn't mind tearing into the engine first and foremost. I don't really want to do a power adder (nitrous or turbo). Naturally aspirated works best for me.

I will be looking for spare heads so mess around with. (bare of course)

Just an idea that ive had for some time and wanted some first hand experience feedback.

Ported head, cams, tuning.
or
954 complete engine. (low mileage)

Cowboy1600 · 07-09-2004, 3:43 AM

Originally Posted by victoRR

Ported head, cams, tuning.
or
954 complete engine. (low mileage)

I dont think you'll be able to slot a 954 motor into a 929 frame....i think you'll be looking at a whole new bike if you want 954 power. They are 2 different bikes, not an evolution.

abtech · 07-09-2004, 7:06 AM

Originally Posted by Cowboy1600

I dont think you'll be able to slot a 954 motor into a 929 frame....i think you'll be looking at a whole new bike if you want 954 power. They are 2 different bikes, not an evolution.

Not so. Your namesake (Cowboy on this forum) grafted a 954 motor into his 929 last year (as have a few others) without much drama.

Jungleboy · 07-09-2004, 7:21 AM

Originally Posted by Cowboy1600

I dont think you'll be able to slot a 954 motor into a 929 frame....i think you'll be looking at a whole new bike if you want 954 power. They are 2 different bikes, not an evolution.

Actually they "are" an evoulution and are very similar, the engines being almost identical from the outside, Both have the same stroke the 954 has 1mm bigger pistons, bigger throttle bodies etc etc

Baketech · 07-09-2004, 8:42 AM

Originally Posted by victoRR

I will be looking for spare heads so mess around with. (bare of course)

FYI, you will still have to assemble the head to do any effective bench work.....

victoRR · 07-09-2004, 7:23 PM

Originally Posted by Baketech

FYI, you will still have to assemble the head to do any effective bench work.....

Understood. I've had experiences with head porting on my old cars (Fox Body Mustangs 79-93 models) as well as the 99 GT I had recently. I saw good gains from doing the work myself and having them put on a flow bench.

The bike is something I don't wanna take soo lightly though. (not that the cars were for that matter).

CBR929RE · 07-09-2004, 7:39 PM

I've read that the 54 engine was just a bored out 29 so it should be dimensionally the same on the outside. as for the porting I also recommend having a good pro due it and get a good multi angle valve job too. my friend had his heads and upper and lower intake ported and polished on his 347 stroker in his mustang (he has since put on another intake, the one he shoulda bought when he built the engine had he followed the buildup I had given him) he did that and the guy who did it always does a multi angle valve job when he does the port and polish. he also put in a bigger cam at the same time and when he first fired it up this winter after doing it we could just hear how much more power it was making. so in conclusion I say do the 54 swap and port and polish that head.