turbo time....

I don't really agree on the "don't worry about the intake ports" theory. Boost is a measurement of resistance. I can give you 30# of boost thru a straw or 5# of boost thru a fire hose and the fire hose is going to flow more air. I agree a 100% on doing a GOOD valve job without all the stainless valves using GOOD springs. I've learned the biggest thing with a turbo is getting enough fuel in to match the air, easier said than done when big power comes into play.
That old pink turbo still had the Zenith carb too. In 92 those bikes were only 4 years old! So the collectability of them wasn't reconised. If I only knew then what I know now. :blush:

Les

les holt wrote: I don't really agree on the "don't worry about the intake ports" theory. Boost is a measurement of resistance. I can give you 30# of boost thru a straw or 5# of boost thru a fire hose and the fire hose is going to flow more air. I agree a 100% on doing a GOOD valve job without all the stainless valves using GOOD springs. I've learned the biggest thing with a turbo is getting enough fuel in to match the air, easier said than done when big power comes into play.
That old pink turbo still had the Zenith carb too. In 92 those bikes were only 4 years old! So the collectability of them wasn't reconised. If I only knew then what I know now. :blush:

Les

That j-head hes looking at getting has more than enough potential in stock form to keep up with a small turbo motor,I say to concentrate on the exhuast side because in my experiance anyway the intake side needs little more than mild beburring to knock the rough spots off of the ports since its being force fed as much air/fuel as that little motor could possibly handle at normal streetable rpms.
The exhuast on the other hand will act like a big cork holding it back.
The more efficiantly you can spin that turbo,the more power youll make.

This is how I do the intakes on a j/early gpz style head for a big inch carbed motor,the only way to move a lot of air through them is a lot of smoothing/cleaning while trying to keep port velocity high which is a real pain in the ass in my experiance.
The turbo on the other hand doesnt need as perfect of conditions to make same if not more power.

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The exhuast port on every head Ive done in last 10 years or so gets the same shape d-port just like the big block chevy hp heads of late 60s-70s,flatter/wider on short side and nice and curved on long side to try and even things up through the port,i do the same exhuast on carbed or turbo motors while the intake depends on purpose of motor.
On the older z1/kz style heads I actually do the d-port on the exhuast with a 1 size over exhuast valve with the intakes just cleaned up on the intake side.
I dont own a flow bench,hell i wouldnt know how to use one if I did! :sick: :woohoo:
Im just a dumb ol farm boy/plumbing electrical contractor whos learned by breaking/blowing up stuff over the years! :laugh:

les holt wrote: I don't really agree on the "don't worry about the intake ports" theory. Boost is a measurement of resistance. I can give you 30# of boost thru a straw or 5# of boost thru a fire hose and the fire hose is going to flow more air. I agree a 100% on doing a GOOD valve job without all the stainless valves using GOOD springs. I've learned the biggest thing with a turbo is getting enough fuel in to match the air, easier said than done when big power comes into play.
That old pink turbo still had the Zenith carb too. In 92 those bikes were only 4 years old! So the collectability of them wasn't reconised. If I only knew then what I know now. :blush:

Les

That j-head hes looking at getting has more than enough potential in stock form to keep up with a small turbo motor,I say to concentrate on the exhuast side because in my experiance anyway the intake side needs little more than mild beburring to knock the rough spots off of the ports since its being force fed as much air/fuel as that little motor could possibly handle at normal streetable rpms.
The exhuast on the other hand will act like a big cork holding it back.
The more efficiantly you can spin that turbo,the more power youll make.

This is how I do the intakes on a j/early gpz style head for a big inch carbed motor,the only way to move a lot of air through them is a lot of smoothing/cleaning while trying to keep port velocity high which is a real pain in the ass in my experiance.
The turbo on the other hand doesnt need as perfect of conditions to make same if not more power.


The exhuast port on every head Ive done in last 10 years or so gets the same shape d-port just like the big block chevy hp heads of late 60s-70s,flatter/wider on short side and nice and curved on long side to try and even things up through the port,i do the same exhuast on carbed or turbo motors while the intake depends on purpose of motor.
On the older z1/kz style heads I actually do the d-port on the exhuast with a 1 size over exhuast valve with the intakes just cleaned up on the intake side.
I dont own a flow bench,hell i wouldnt know how to use one if I did! :sick: :woohoo:
Im just a dumb ol farm boy/plumbing electrical contractor whos learned by breaking/blowing up stuff over the years! :laugh:

thank you all for sharing. more more more pics and info!!!!!

Theres plenty of ways to get the same result,use what what works best for you and your situation.
The most important thing I cannot say enough is to remember most of these bikes were having a tough enough time with stopping/steering in stock form with 70hp at the rear wheel,when you start bolting that much more power in there you need to build the rest of the bike to handle it.
The other thing to remember is if it doesnt scare the shit out of you everytime you crack the throttle its time to reevaluate your situation,because those reality checks at 100mph really suck! :sick:
All my major issues have been caused by an excessive hp to brain cell ratio! :woohoo:

my stock front brakes are ok for now, after the turbo ill make adapters to modern multi piston calipers and radial master cyl. and i cant afford to build a corner carver like id want so im just gonna stick with straight line sprints. my daughter wouldnt be well off without me lol. any more pics or tips everyone is welcome to contribute!

A few things...cam timing works best with 110I/113E on these Kawi motors. Lift is your friend but not duration. That's why the stock cams work so good...not much duration. Turbo cams can be had with .340 lift and there is a .418 lift cam. Both have more lift but not much more duration. Good cams are the GPZ .375 cams from the 83-84 yr. model. You want to open the valve quickly and higher but not too long so you trap the boost in the cylinder. Long duration with a turbo will blow the fuel mixture out through the exhaust. Like mentioned earlier you want to seal the motor good...HD studs, head nuts, maybe o-ring the cylinder if you are going to turn the knobs up later. Basically, over-build it for the turbo. Timing needs to be retarded also. Trick is this...more intial makes bike easier to drive on the street but limits the HP at rpm and vice-versa. Have a set-up to retard the timing if you plan on making much boost. I was told to set intial stock but retard once boost starts. Say...back to 30* on boost...Turbo's like higher gearing. Makes them sluggish on the street but the higher gearing will load the turbo more to create boost. It depends on what you plan to use it for so plan it ahead of time so you can put the right pieces in place. Also...if you plumb a 100 shot of NOS in there it will help cool the fuel charge...if it holds together! lol :evil:

just a hundred shot? lmao. thanks for your input. whats your setup?

i have a few shots of my gas turbo nitrous 1428 pro-mod set-up.i'm changing over to an alcohol efi blowthru setup this winter,less chance of burning up cylinders and running too rich as well causing the cylinders to wash down, draw thru carbed can work well but blow thru has much better fuel distribution to the cylinders. and when your dealing 30 plus psi boost you definitly don't want lean cylinders.

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sorry the pictures didn't go i'll try again

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sorry the pictures didn't go i'll try again

1977 KZ turbo...old ATP turbo system, 1200cc, stretched 6" over, .340 cams, HSR42 carb....here are a couple pictures...