Performance Head Stuff.

[Guest]

Since this is the performance section, Can any experts give me a idea on who makes the fastest heads period? NO star billet heads. Im talking old school porters. Hear cooper heads just rock. My buddy ran one low low 8 s no n os and Lazer Heads really rock!! Man they are expensive, It hurts being a poor drag bike racer, ha ha Later Mike

[nickp]

Star Racing in my opinion...1570 gs1150 ran 7.11 back in 2000 with fred collis riding....nothing fancy, biggish valves and proper porting!

[nastyjones]

Mike Law, Dorchester Ontario owner of Raceworks Canada. Close enough for pick up, save shipping costs

[rapidray]

I used to be in R&D at Vance & Hines. That was fun. I also learned a LOT from Nigel Patrick. Nigel is STILL one of the smartest cylinder head guys out there! I have no problem getting heads to flow the #s I want them to, AND keep good velocity. The air speed is a LOT more important than the actual CFM numbers. A lot of people think they can just make ports bigger but end up trashing heads beyond repair this way. George Bryce knows a thing or 2 about cylinder heads also!
Ray.

[DohcBikes]

I used to be in R&D at Vance & Hines. That was fun. I also learned a LOT from Nigel Patrick. Nigel is STILL one of the smartest cylinder head guys out there! I have no problem getting heads to flow the #s I want them to, AND keep good velocity. The air speed is a LOT more important than the actual CFM numbers. A lot of people think they can just make ports bigger but end up trashing heads beyond repair this way. George Bryce knows a thing or 2 about cylinder heads also!
Ray.

Funny you should say that.

http://www.thegsresources.com/_forum/showthread.php?237360-Did-I-hone-too-much

Those intake ports HAVE been enlarged. And smoothed. And the bridge is not straight.

Increasing velocity is the way to gain power on those heads.

From what I can see there it is fairly evident that you will lose velocity. The flushing of the valve guides aided in this. And it WILL make your stems wear faster. For no gain.

Raising the floor of the port as should have been done would negate the need for the guide work.

Katana 750 ports are widely known by racers to be too large to create the velocity neccessary to make peak power.

There is a reason the manufacturers do this kind of thing. (leave the ports too big)

Yoshimura fills their Katana 750 intake ports with epoxy. Their engines are built quite well, from what I have heard.

Do you think yoshimura spends much time below 8k rpm?

And do you think if they did, they would want to see a loss in power in that range?

You don't have to trust me. Email Yoshi and ask them about it.

90% of power that is gained through port work is gained within one inch of the valve seat, including the seat itself.

One of the best ways to guarantee a power gain on almost any head that is bolted to an otherwise mostly stock engine is to have a 5 angle valve job done and backcut the valves. This way you increase flow without losing velocity.

I will add that I have completed over 300 dyno runs as rider and the operator of the dyno to compare the effects of air intake requirements on many different engines. We also had a flow bench to correlate flow gained from porting techniques to gains or losses in power.

[trippivot]

poor drag biker

george bryce .jpg

you disqualified George Bryce right off the bat - and he posted this yesterday on facebook.

Tom Klemme made me a 100 cfm 1150 head as a gift and it screams!- I posted photos of it already.

Good head work is not cheap - cheap head work is not good - any reputable performance upgrades should be measured before and after on a flow bench and dynometer - yes plenty of us do not go that extra inch but if you want to get what you pay for - or want to prove you give what you advertise -

my flow bench will be installed and running this summer - and the boss is looking into a dyno to fill the local demand - so needless to say redline is growing.

[rapidray]

Contrary to the posting above, cutting down the guides DOES increase airflow and has a MINIMAL effect on guide life. I can't tell what you did in the bowls from those pictures but, from what I can see, you did NOTHING wrong to that head! I use 40 grit rolls to finish intake ports to keep them rough & help atomization. You could go a rougher finish in your ports to help there. What Jeff said above here IS true! Cheap, fast or good, choose 2!!! LOL!!
Ray.

[DohcBikes]

Contrary to the posting above, cutting down the guides DOES increase airflow and has a MINIMAL effect on guide life. I can't tell what you did in the bowls from those pictures but, from what I can see, you did NOTHING wrong to that head! I use 40 grit rolls to finish intake ports to keep them rough & help atomization. You could go a rougher finish in your ports to help there. What Jeff said above here IS true! Cheap, fast or good, choose 2!!! LOL!!
Ray.

Show me where the posting above says that cutting the guides reduces flow. It doesn't. Volume and velocity must be discussed individually.

The Katana ports are already in need of high speed porting. Increasing the volume of the chamber in that area does nothing to increase air speed. In fact it will very likely slow the incoming air down. When you raise the floor of the port it greatly reduces the need to cut the guides down.

Increased guide and stem wear is unavoidable. Shorter guides of the same material wear parts faster. Especially in the presence of high lift cams and performance springs. To argue otherwise is just wrong.

[rapidray]

Whatever you say. What do I know? I've only been porting heads & building racing engines for 41 years. I've been using flow benches for the same amount of time. My Dad built his first one with 6 Electrolux vacuum cleaner motors & bought the second SuperFlow flow bench they ever sold. He also upgraded every time SuperFlow released a new model. I have spent a LOT of time in airflow study & know what works, what doesn't & what causes problems. Will cutting down the guides wear them any quicker? Maybe, but NOT noticably. Do you OWN a flow bench? If not, go away. If you DO own one, try this little experiment: put some clay in front of a guide & taper it to make a nice shape that will flow well. Measure the airflow & write it down. Now, REMOVE that clay & put it BEHIND the guide, shape it the same & measure the airflow again. What does that tell you? They will flow the same amout of air both ways. Harold Bettis was the lead engineer at Superflow & friends with my Dad & I got to spend a lot of time with him. He is also a friend of Warren Johnson's & a VERY smart guy.
Ray.

[DohcBikes]

Whatever you say. What do I know? I've only been porting heads & building racing engines for 41 years. I've been using flow benches for the same amount of time. My Dad built his first one with 6 Electrolux vacuum cleaner motors & bought the second SuperFlow flow bench they ever sold. He also upgraded every time SuperFlow released a new model. I have spent a LOT of time in airflow study & know what works, what doesn't & what causes problems.

That's neat.

Will cutting down the guides wear them any quicker? Maybe

Oh? I thought that's what I said too.

put some clay in front of a guide & taper it to make a nice shape that will flow well. Measure the airflow & write it down. Now, REMOVE that clay & put it BEHIND the guide, shape it the same & measure the airflow again. What does that tell you? They will flow the same amout of air both ways.

Neat. Do this experiment:

Buy a Katana 750. Dyno it. Take the head off. Raise the floor of the intake ports with epoxy. (If you ever have before, not sure what the old timers are still doing) Remember that when doing this, it covers much of the guide, reducing the need for cutting. Flushing the guides after the proper high velocity chamber shape is achieved will maximize the flow. Dyno it again. Marvel at the wonders of intake velocity and its realtion to power output in a motorcycle engine.

Harold Bettis was the lead engineer at Superflow & friends with my Dad & I got to spend a lot of time with him. He is also a friend of Warren Johnson's & a VERY smart guy.
Ray.

Also some very neat stuff.

What was it I said specifically that you disagree with?

[stetracer]

That's neat.

Oh? I thought that's what I said too.

Neat. Do this experiment:

Buy a Katana 750. Dyno it. Take the head off. Raise the floor of the intake ports with epoxy. (If you ever have before, not sure what the old timers are still doing) Remember that when doing this, it covers much of the guide, reducing the need for cutting.

just curious arnt the guilds on the ceiling of the port not the floors?
IMO. You should port differently for street riding or drag racing or road racing.
The Busa head nothing small about those ports. I personally like to cut the valve guides down flush
You can ask ten different engine builders how to port a head and you will get five different answers.
Some of the katana's had large ports with small valves and some did not.

[rapidray]

I've been welding & epoxying heads since the 70s, it's nothing new. How does epoxy on the floor cover the guide? Are you porting upside down or just talking about something you don't have experience at & just read somewhere?
Ray.

[rapidray]

All you said is a fact JD. Heads & cams are designed to the engine AND the application.
Ray.

[madmikeracing]

Surprising what the Internet has inside. I remember reading something years ago and the Name Nigel Patrick reminded me of something. Well Here's the Link. I found it interesting and funny ha ha . Buyer again beware!!

https://www.rbracing-rsr.com/patrickracing.htm

and alowww.rbracing-rsr.com/eat****.htm

Posted for entertainment reading only,!!