Topic: CB 836cc f1 turbo - spoked kickstart street turbo

[Ilja]

Alrighty then, on with the project!

Bought some K7 intake boots, and they fit nicely onto the F2 head and onto my carbs. The K7 boots are 34mm on the head side and 38-39 on the carb side.
They go very tight onto the head as the heads spigots are 36mm outside. But pretty loose on the carbs as the carbs are 37-38mm.

The F2 head's intake channels are 31mm on the inside and my carbs are 32.5mm.. so that fits perfectly sizewise..

What's not so nice is that I have to re-arrange the carbs on the rack as spacing is way off... and modify my plenum.
The Keihin 32 CVK carbs which I'm using have to be spaced further apart between pairs and closer togheter in the center...

I noticed my Mikuni BS34 carbs of my z1000 have the right spacing between left two and right two, but would need to be brought closer togheter in the middle.
But... I think I'll stay with the Keihin CVK ones as they are already jetted perfectly and the BS34 carbs also dont have athmosferic ports for the pitot boost reference tubes.

So, installing the new pistons again at the moment and hopefully I can close the engine this weekend.

[Ilja]

Cruzinimage pistons have changed a little bit..
Thicker top ring land and directional rings.

[Ilja]

So my new compression ratio with the f2 head will be 7.8:1....
Just like the kawasaki gpz turbos were like from factory. Pretty good... 

[MessnerMoto]

Just to say that I am following this thread closely. Please continue

[Ilja]

Just to say that I am following this thread closely. Please continue

I will... :-)

When I first rebuild the topend I installed a new cam chain..
Im wondering if I need to replace it again withe the f2 chain because of the stronger valve springs in the f2 head.....
Hmz... think I should. :|

[MessnerMoto]

http://www.ebay.de/itm/CATENA-DISTRIBUZIONE-DID-219FTH-94-M-HONDA-350-CB-K4-SUPER-SPORT-1972-1972-/371469604573?hash=item567d5056dd:g:-EgAAOSw14xWKLQX

hd cam chain for 28eu

[Ilja]

I heard of rhe 219T and 219H.... but not the 219FTH???
Got the 219T in the engine atm..

Are you sure about the 219fth? Would be perfect!

The original f2 chain would also be fine, but its endless.... and not easy to put back togheter and center punch the pins on the engine.

[MessnerMoto]

Yep 219fth is stronger then 219t and 219h... it is similar to "audi" HD chain. Straight side plates, etc... have one for me. I also have technical specification for all DID 219 chains.

http://forums.sohc4.net/index.php?action=dlattach;topic=150140.0;attach=314622;image

I did my research part

[Ilja]

GREAT!! Thanks a lot... gonna order it right away!

[Ilja]

 

[Ilja]

And if using mls.... watch out for the rivets between cylinders and head!!!! I drilled 2 holes so they dont get squashed in between and potentially cause the head not to seal..

[754]

I wonder how much HP  Nitro Hunters turbo 750  made back when he made a 10.08 quarter mile back in the day..stock pistons, and rods I think..

[Ilja]

I dont know that bike..... but for 10sec pass it should be considerable! Any pics or movies around?

Heads on! Hopefully the mls will seal correctly... torqued it down with 28nm... but might go up to 35 as 8mm 10.9 should be 35nm..

I can still see through the gasket on the sides if I hold a light behind it!!!! Apparently it does not compress the embossed beads completely flat, and leaves a minimal gap at the areas around them. 

[NitroHunter]

I wonder how much HP  Nitro Hunters turbo 750  made back when he made a 10.08 quarter mile back in the day..stock pistons, and rods I think..

Yes Frank it was stock 736cc pistons and rods with a copper head gasket, required to scale at 675 lbs with rider, and when I won the Dragbike USA Northwest Nationals it ran 10.00 @ 143mph. Holley red fuel pump, 30+ lbs boost (30 psi gauge was pegged), ERC 118 fuel, 26* timing in the mag. 5 base gaskets shimmed up the barrels for a 6.9:1 CR. A real dog off the line.
Make no mistake, it was a rolling time bomb. In this configuration with the big wastegate spring, the fuze was lit everytime it ran.
Based on some Hot Rod Magazine graphs of the day using weight and speed, we 'loosely' came up with 165hp.
But that may have been optimistic... 

[TurboD]

Nitro I would say those numbers are close.

[Ilja]

Awesome! 6.9:1 is really low indeed.... and 30psi!!!! Jesis thats insane... gotta love race fuel!

In my previous setup I could only get 1mm extra gasket at the base gasket because the cam chain didnt allow more... too tight. And it screwed up the squish.

Now with the F2 head im at 7.8:1 - 8:1... and 1.25mm squish should be acceptable offboost.

[754]

Nitro, what year was that around 1986 or so ?
 Thanks for the pics, bike looked much like that at that race in Kent  WA we were all at.
 I was on the road with Jean Beauregard this weekend, he just sold his red front engine dragster this month..aka The ChevHarley...

[BPellerine]

Nitro, what year was that around 1986 or so ?
 Thanks for the pics, bike looked much like that at that race in Kent  WA we were all at.
 I was on the road with Jean Beauregard this weekend, he just sold his red front engine dragster this month..aka The ChevHarley...

any pics of that bike frank?bill

[754]

Same bike as the pics, maybe not yet raked..did not run tens yet when we met him.

[Lostboy Steve]

I wonder how much HP  Nitro Hunters turbo 750  made back when he made a 10.08 quarter mile back in the day..stock pistons, and rods I think..

Yes Frank it was stock 736cc pistons and rods with a copper head gasket, required to scale at 675 lbs with rider, and when I won the Dragbike USA Northwest Nationals it ran 10.00 @ 143mph. Holley red fuel pump, 30+ lbs boost (30 psi gauge was pegged), ERC 118 fuel, 26* timing in the mag. 5 base gaskets shimmed up the barrels for a 6.9:1 CR. A real dog off the line.
Make no mistake, it was a rolling time bomb. In this configuration with the big wastegate spring, the fuze was lit everytime it ran.
Based on some Hot Rod Magazine graphs of the day using weight and speed, we 'loosely' came up with 165hp.
But that may have been optimistic...

That's wicked. Any videos of that setup. I'd like to hear that thing.

[NitroHunter]

Talk about squish, my pistons were about an 1/8" down in the hole, and yes the cam chain was really tight. Revving the daylights out of it was necessarily the standard launch procedure. Guys would ask me how high I twisted it and my standard reply was I don't know, the tach only goes to 12 grand...
I've often wondered just how much boost it really made but who would have thought a 30lb gauge would be pegged. I think mostly it just beat up the air and and heated the intake, there was no porting or pocket work done.
The E40 Rayjay was way too much for 44cid, a little B25 would have been a far better match. Earlier boost - like before 3rd gear - would probably have produced 9 second runs.

[754]

What year did you set the record ?

[Bill/BentON Racing]

Robbie,  not sure on the 40, but 18- 20 avg max on a B25! Your times were sure impressive, Bill

[NitroHunter]

Frank, the record run was 1987.
Over the '86 winter I raked the frame, installed the air shifter, and changed the POS anemic fuel delivery system - from petcock to carb - and like magic it quit tearing up pistons and sleeves and finally ran worth a damn, ending several years of frustration.
With the #15 lb wastegate spring, I ran the entire early bracket season on ERC 110 gas that I got from the sprint car guys. The ERC guys had seen my bike on display at a winter car show and we had quite the informative sitdown secession on fuels, and I never again ran any other brand.
That year the bike ran in the low 11's a hundred passes with no issues, and I never whinged it up to 10 grand. I had already lived through enough carnage that I just wanted to have fun with what I had left and could cobble together. But the Dragbike USA race was coming up, and the class record was only 11.30 and I'd been consistently dialed at 11.20 every Wednesday night, so in went the #30 lb spring. I made a call to California to the ERC guys, fortunately they remembered the bike and our conversations, and viola, a jug of record-ready 'ERC 118' shows up and off we went to Spokane - to light the fuse on the ticking time bomb.

Ya know Bill, maybe a hybrid B turbine / E compressor... with a 50lb gauge.
On YOUR motor. 

[754]

I think we must have seen it in 86.... Sept nationals at Kent..
You brought the record down by a second! Pretty impressive..
How much over was the swi garm, and what did you rake it to?...and how did the rake make it feel ?