Topic: Bike scrap yard sell. Hot head! I should have bought it?

[bwaller]

Crap, i wish i had that extreme head for my F model. Just my luck its not here in the states.

Crap....you could put on small Lectrons Frank.

Yeap, some 34's might work just right. I'd better stick with what i've got for now. You guys on this forum will make a person go broke on these old bikes stepping them up and we'd still not be fast enough to beat the newer bikes straight off the showroom floor. lol

you don't need to tell me about spending money Frank
you would have a heart attack if I told you how much i had in my turbo
and I try not to think about it

Its too bad we can't sell our projects to recoup the exact amount of money we've put into them.

We'd all be retired kicking it in the Caribbean right now Frank. 

[/b]


Yeah and trying to build a faster catamaran or some damn thing! 

[dragracer]

Crap, i wish i had that extreme head for my F model. Just my luck its not here in the states.

Crap....you could put on small Lectrons Frank.

Yeap, some 34's might work just right. I'd better stick with what i've got for now. You guys on this forum will make a person go broke on these old bikes stepping them up and we'd still not be fast enough to beat the newer bikes straight off the showroom floor. lol

you don't need to tell me about spending money Frank
you would have a heart attack if I told you how much i had in my turbo
and I try not to think about it

Its too bad we can't sell our projects to recoup the exact amount of money we've put into them.

We'd all be retired kicking it in the Caribbean right now Frank. 

[/b]


Yeah and trying to build a faster catamaran or some damn thing! 

Looks like i just saved myself some money. Got an email that the head was sold to someone in Denmark. Hopefully i was an SOHC forum member who will document his build on this site so we all can share his excitement.

[RAFster122s]

Don't call them boat anchors for nothing, or euphemistically refer to a money pit as a boat anchor.  Known guys chasing speed on boats spend gobs of money on props, etc. Hull modifications to reduce wetted area are not unheard of... sails that claim to produce better performance...

Hobbies are what we spend our free money (hopefully not going into deep debt to do it) upon. Be it golf, cars, motorcycles, tennis, sports events, radio control planes/helicopters/cars/boats, electronic devices, video or sound systems, gaming systems, books, art supplies, etc.

Crap, i wish i had that extreme head for my F model. Just my luck its not here in the states.

Crap....you could put on small Lectrons Frank.

Yeap, some 34's might work just right. I'd better stick with what i've got for now. You guys on this forum will make a person go broke on these old bikes stepping them up and we'd still not be fast enough to beat the newer bikes straight off the showroom floor. lol

you don't need to tell me about spending money Frank
you would have a heart attack if I told you how much i had in my turbo
and I try not to think about it

Its too bad we can't sell our projects to recoup the exact amount of money we've put into them.

We'd all be retired kicking it in the Caribbean right now Frank. 

[/b]
Yeah and trying to build a faster catamaran or some damn thing! 

[PeWe]

AHA, The danish guy bought it... The guy told that someone in Denmark that was interested.
It's easy to create new projects....
- I need to take out the engine again to verify some small details like the small o-rings under the cam towers, the no hole ones, seal end of oil lines.
- Replace the other HD cyl studs when I snapped one. Bought a new set and used only one. Should have replaced all when they had been torqued equal. Or replace all with Kibblewhite studs.
I need to get it out from my mind, another one might snap while driving.

I'll console myself with a new tank and side covers in same color as my bike should have and had when I bought it 34 years ago. Then continue to collect parts for another engine.... $$$$ + $$$$ 

[RAZZ]

Hallo

Just found this thread..

IM the one who bought the “hot” head.. I did not think much before I took it, I have being looking for a ported head forever, and stuff like this is so seldom for sale (especially in Europe) – so I just called the guy who had it and said, I take it.. I guess a new engine project is born 
 
Just bought a 67 mm cylinder, but I think it will be too hard to find new pistons to fit, so it will proberly end with a new 67,5 mm bore and a set of Wiseco/ CycleX pistons

Future plans for a hot street engine is taking form, at the moment the wish list looks like this:
Lightened APE crank with Super rods
New cam ( torque over high end power)
Under cut trans, new bearings, new chains + more

Mukuni RS 34 carbs –> I have some carb questions, 1: the Carb inlets on the head are welded and have a outside dia. at 40 mm / boots are inside 40 mm - witch carbs should I go for, that will  fit ? 2: does anyone have some good suggestions how to fit CB spaced carbs..

If anyone have some goodies from the list they want to sell for reasonable money PM me, (IM on a budget)

PeWe do you know from witch Suzuki the carb boots are from ?

[Jerry Rxman Griffin aka MuthaF'er]

Ahhh, the Danish guy    Welcome Razz. No info for you though on the intake spigots. Get in touch with MRieck, our head guru. I'm thinking he just installed RS34's.

[cbr954]

If you are going with APE for the crank, rods and undercut tranny, I would suggest having them set you up with pistons. 

[dragracer]

Hallo

Just found this thread..

IM the one who bought the “hot” head.. I did not think much before I took it, I have being looking for a ported head forever, and stuff like this is so seldom for sale (especially in Europe) – so I just called the guy who had it and said, I take it.. I guess a new engine project is born 
 
Just bought a 67 mm cylinder, but I think it will be too hard to find new pistons to fit, so it will proberly end with a new 67,5 mm bore and a set of Wiseco/ CycleX pistons

Future plans for a hot street engine is taking form, at the moment the wish list looks like this:
Lightened APE crank with Super rods
New cam ( torque over high end power)
Under cut trans, new bearings, new chains + more

Mukuni RS 34 carbs –> I have some carb questions, 1: the Carb inlets on the head are welded and have a outside dia. at 40 mm / boots are inside 40 mm - witch carbs should I go for, that will  fit ? 2: does anyone have some good suggestions how to fit CB spaced carbs..

If anyone have some goodies from the list they want to sell for reasonable money PM me, (IM on a budget)

PeWe do you know from witch Suzuki the carb boots are from ?

Regarding the carbs; you will likely not find a racked set of carbs to fit the current port spacing. I would however suggest that you measure the width of the spigots( c/l to c/l) from cylinder #1 to #4 and then the c/l between 1-2, 2-3 and 3-4. I think Mikuni has a spec sheet on their website listing the dimensions of  the various racked carb set per application. Try to find something as close as possible. Regarding the boots, you will need to use radiator hose cut to length. Most of us use Dayco hose as it is more rigid and has nylon strands bonded in the rubber. You will need narrow hose clamps also. If you can't find a set of racked carbs with the correct dimensions, your options are narrowed to individual carbs like the Mikuni VMs or Lectron carbs. The drawback to Lectrons are they are not made for the street- they are designed for idle or full throttle only. It has no low speed jet. They are venturi type carbs for race only. The VMs do have slow speed jets but i'm not sure how streetable they are.  I might have missed another brand of individual carbs that may work for you- some other member is likely to charm in to help beyond the opinion i expressed.

[jweeks]

     Carbs can be respaced. The Honda head spacing is usually narrower than most other (aka newer) heads and manufacturers. I've done it for the CV carbs from a Suzuki that Sam's motor is now running. The machinist bill was a little over a hundred dollars US. We'll install oversize valve seats, blend ports to the new seats, insert different valve guides for smaller diameter stems, shave weight off of rocker arms, slot cam gears, but are afraid to narrow carb fuel tubes, rack mounts, and linkages??
     The true restriction is the OD of both the head intake and the OD of the carb expelling the fuel/air mixture. If you can't get something flexible and relatively immune to the fuels passing through it to mount the two together, it won't matter what the spacing. That's why you don't see 40mm carbs mounted to stock size 750 intake ports. Even if you can figure out the intake manifolds, the big carb size is wasted on a too small intake port. Rewelded drag head intakes allow a bigger carb, but usually mount Lectrons which mount individually. Big ports with a small motor are a bad match as shown by the stock F heads on our 750 size motors. Velocity through the intakes needs to stay high for the throttle response that we all love on the street.
      Find some used carbs that you can afford and modify as needed to fit. If you can find some Mikuni carbs that are near to the spacing that you need, just hope that you can afford them. There will be some tuning to be done after mounting whatever you get. Getting the right fuel/air ratio across the rpm range that you run the motor is what will make the setup a success.
     If you get too far outside the "size" box, consider fuel injection. Not cheap, but relatively easy to mount to any head. Megasquirts to control it and using junkyard bike throttle bodies and fuel pumps aren't that expensive. About the same cost as a good set of aftermarket carbs that "fit" the stock Honda head spacing.
     Just my opinion.

[RAZZ]

Hi

thanks all the good answers ( keep them comming  ) I forgot to tell a have the old Suzuki carb boots in ok condition and the plan is to reuse them, I was just curious to know more from PeWe, maybe I can use the Carbs from the Suzuki..( its a place to start..) I know fuel / air mix i everything, for making it run good, when I get this project engine put together and running, I will use a dualband Lambda sensor to do the jetting right, it is quite time consuming, but is Works..

[BPellerine]

would webers work on the head with silicone hose?

[KayOne]

Sorry to hijack the thread.......

" Big ports with a small motor are a bad match as shown by the stock F heads on our 750 size motors. Velocity through the intakes needs to stay high for the throttle response that we all love on the street. "

Are F2/3 heads properly sized for an 836 cc SOHC, or are even larger displacements required? Any information or experience with the big valve/port late F head would be appreciated.

Thanks
     

[jweeks]

Just my personal opinion, but no on the 836 cc. The F heads need about 1,000 cc to match the ports to motor air demand. The K heads with some porting work better in the smaller displacements. The F heads make some top end power but not much below that in the smaller displacements.

                             

[KayOne]

Thanks!

[PeWe]

Hi

thanks all the good answers ( keep them comming  ) I forgot to tell a have the old Suzuki carb boots in ok condition and the plan is to reuse them, I was just curious to know more from PeWe, maybe I can use the Carbs from the Suzuki..( its a place to start..) I know fuel / air mix i everything, for making it run good, when I get this project engine put together and running, I will use a dualband Lambda sensor to do the jetting right, it is quite time consuming, but is Works..

Hi,
Fine that you found this thread.
About the carb boots. I got the information from Thomas at Spinning Wheel selling the head. I saw all CB750 stuff when visiting him when I live 30 minutes away by car.
It was a pile of old CB750 stuff left for auction from an old biker that had passed away.

[PeWe]

Yes, carbs can be respaced. I dit that with my old Mikuni VM29 used only one summer 1984. Almost like new.
I saw that the difference were not that much. The distance between 1-2 and 3-4 were almost like CB750 OEM carbs. The biggest difference was distance between 2-3. I saw that it was possible to cut 10mm and just hope for the best. I got it done (cut and welded together) end of 80's but stopped by the throttle axis. My bike went into the long sleep after fall 90......
I got the idea to use the Mikuni throttle axis spring 2013. Just drill 3 more holes and cut the axis after 4:th carb. (hole for throttle mechanism and carb 3, 4 all displaced 10mm)

I had to do some other adaptations. Trickiest was the t-pipe for petrol feeding carb 2-3. Cut 5mm on each side loosing 1 o-ring on each side.  It leaked fuel here....
I had to use thicker o-rings and place 2:nd o-rings outer the normal outer with no dedicated groove. I got it sealed and tight.

One thing I did not think about was clearance to bike frame. I'm lucky that the carbs could be squeezed in. Throttle wire very close to frame and need some force to mount when the frame is very close. Carbs are clear from frame too.
http://forums.sohc4.net/index.php?topic=119335.0

[POPS 911]

On my CB750A Hondamatic drag bike I mounted YAMAHA XJ750R SECA CV CARBS with new F boots from GEORGE [ e-bay ] in FLORDIA , these Hitachi carbs with a little STP on inside of the rubber slide right in with just a little pushing. Just what I needed to hold rear brake and screw open the throttle full open[ I cheated with a 2-step to hold RPM,s under the creep] = like a slider.  So far this year I have bought 4 sets of these simple carbs [ XJ750 SECA or Maxim ] 1981 thru 1983 years. In 1981 Yamaha made a XSJ750RH SECA but I never found out what carbs this bike had on it from JAPAN. Put bike on dyno and had better numbers than F-CARBS. I wish I could mount the HONDA CB750 CV carbs I have from a NIGHTHAWK but the spread was to great = DOHC to a SOHC spacing off 3/4" between 2-3 mounts. 29's Mikuni off 1/2" between 2-3. I have about 20 sets of different carbs from HONDA,KAWASAKI, and YAMAHA and have tried the BLUE, RED and BLACK hose but always had a hard fit or bends. On e-bay a few years ago A person was selling 4 cast Aluminium straight adapter than bolted on to the manifold spigots, wish I would have bought them and had some made by a casting company.

POPS BK911

[dragracer]

On my CB750A Hondamatic drag bike I mounted YAMAHA XJ750R SECA CV CARBS with new F boots from GEORGE [ e-bay ] in FLORDIA , these Hitachi carbs with a little STP on inside of the rubber slide right in with just a little pushing. Just what I needed to hold rear brake and screw open the throttle full open[ I cheated with a 2-step to hold RPM,s under the creep] = like a slider.  So far this year I have bought 4 sets of these simple carbs [ XJ750 SECA or Maxim ] 1981 thru 1983 years. In 1981 Yamaha made a XSJ750RH SECA but I never found out what carbs this bike had on it from JAPAN. Put bike on dyno and had better numbers than F-CARBS. I wish I could mount the HONDA CB750 CV carbs I have from a NIGHTHAWK but the spread was to great = DOHC to a SOHC spacing off 3/4" between 2-3 mounts. 29's Mikuni off 1/2" between 2-3. I have about 20 sets of different carbs from HONDA,KAWASAKI, and YAMAHA and have tried the BLUE, RED and BLACK hose but always had a hard fit or bends. On e-bay a few years ago A person was selling 4 cast Aluminium straight adapter than bolted on to the manifold spigots, wish I would have bought them and had some made by a casting company.

POPS BK911

Hey Pops,

Where've you been??

[POPS 911]

FRANK: Winning races against BUSA'S, 1400 KZ, 1000PLUS KZ [ BRUCE SAUER POWERED ] 750-1000 SUZUKI'S, another 400cc Hondamatic that won $2500 at a INDY RACE in 2013 and I winning the " KING OF COLUMBUS RACE " with 17 bikes in the lane and a PERFECT RUN FINAL " DEAD ON THE NUMBER " in the finals against the TRACK CHAMPION. Not bad for a 1981 CM400A with 28 horsepower and a 71 year old rider [ that TRACK CHAMP is 21 ] so I got 50 years on him.............. You know the BAD BOYZ and GIRLS of OHIO are deadly on the 1320'. Got my 750 Matic ready for 2014. I Will not go to a race that they buy back two rounds !!!!!!!! MAN CUP,NHRO even Scooter was not that money hunger. I have a 1982 CB900F SUPER SPORT BOL D'OR to race but with 15mm wrist pins stock why break this rare bikes motor ?

POPS BK911

[Bill/BentON Racing]

Good news POPS!  Tell us more about your 750A! Pics please, Bill

[POPS 911]

 I have 6 complete CB750A'S but only 2 drag bikes of these type bikes. Both are stock with CV CARBS , Open exhaust, Dyna's systems, one w/ F rear brakes [ left handelbar brake that goes to rear  F/type brake hyd. brake system ] = like the same system we put on many BUSA DRAG BIKES with a slider. The other is a stock rear drum brake with a CM400A Left front handlebar cable system to hold rear drum brake and open throttle all the way open. I have use this set up on my CM400A for 10 years with .01 to .09 lights on the tree. You can build a bigger motor but in STREET ET they do-not pay more for a bigger number = MPH.................  For years I worked on PRO-MODS and PRO-STOCK, SG,TG and these are MONEY LOSERS !!!!!   My $800 cost, 1981 CM400A " TURTLE " has many wins over high dollar, high horsepower, high MPH bikes on the 1320' = it's a BRACKET RACE = RUN YOUR DIAL IN,    "GET DAT WIN TICKET " a quote from Keith SHINE Dennis to me for 25 years.

POPS BK911
PS: I'm running 77 mph at the big end when they come by at 142 mph [ CARS 177 MPH ] = for their breakouts trying to catch the " TURTLE "