Topic: Anyone out there have bored factory carbs?

[MRieck]

I'd ask Jay if he would do a set for you. Try to get a 3 or 4 sets together to make the set up worthwhile for him. He is a reasonable fella.

[gschuld]

Mike,

     I reached out to him about this a few days ago but he hasn't been online here since the 25th.  So perhaps he has a life or something

Question for you...  What is your feeling about whether bored K0 carbs would suit my RC1000 motor well or not?  Would you feel comfortable with being able to tune them properly?

George

[MRieck]

Mike,

     I reached out to him about this a few days ago but he hasn't been online here since the 25th.  So perhaps he has a life or something

Question for you...  What is your feeling about whether bored K0 carbs would suit my RC1000 motor well or not?  Would you feel comfortable with being able to tune them properly?

George

George...any carb is tunable unless it is incredibly to small or large for the application. There are plenty of jetting options available BUT your needle profile is very limited with stock carbs. That would be my only complaints as even the slide cut away could be machined. I know you are a purist but for the dough the RS-34's are the way to go with a larger engine. Like I said you are a purist and I appreciate that.

[754]

 There is a member on here from Winnipeg was set up to do carbs, think he specializes in 550,s or 400,s.

[bwaller]

www.denoonsp.com Not sure he's set for all carbs, but maybe worth a contact.

[joe p]

The carbs that Frank has are some I ran on a 1000cc with an RC head. It had a KH F cam. It ran OK, but like was previously mentioned, a set of RS would be nice.
joe p

[Greg H]

Does anyone here have any first hand experience with Monty Campbell's carb boring service?   http://www.x-pipe.com/motorcycle.html  He's been around since the mid 70s doing it, but I haven't heard any reports of his work. 

George

This is very intersting , the bored out smoothbore 29mil Mikunis he does sound good .

[gschuld]

Thanks for the replies.

Mike,

      I'm very happy that my period correct "purist" stance hasn't turned you away from my quest, ...yet .
I'm reluctant to admit that I am a VERY stubborn person at times.  The Mikunis are great carbs I'm sure, but alas my silly needs will not allow "modern" carbs on this old 69.  I'm just difficult sometimes....

Frank and Bwaller, thanks for the info. I'll check them out.

Joe P,

By your comment did you mean that the very SAME carbs that Frank has were the ones you owned and ran on an RC1000 motor with a Kenny Harmon F grind cam?  Could you tell me more about how it ran?  Where in the rpm range did you feel the carbs were particularly lacking?  Have you ever swapped them out with another type of carbs to compare them?  About what was your functional redline with that F grind cam?

Actually, I'd like to hear any info on the RC motor itself. When it was built, what RC parts were used/not used, etc.  Do you still have the motor?

George 

[joe p]

gschuld I send you a PM.

[POPS 911]

gschuld: I sent you 2 PM's ON CB SOHC 750  RC CARBS bored out to 28.9 old style with racing velocity stacks and rubber boots. These are bored factory carbs that you are asking for purist.

POPS BK911

[gschuld]

Pops,

     I believe that I sent you a reply PM as soon as I got yours .  I believe that I gave you my e-mail address that you asked for so you can send me some photos.  I didn't get a reply.  If my PM didn't make it through to you, I apologize.  My e-mail again is gschuld@hotmail.com

Do you know what these carbs were specifically modified for.  Road racing, drag racing, modified street motor.  I believe that the intended purpose of the modification to the carbs makes a difference. 

Thanks,

George

[Big Jay]

We did hundreds of them before the 29 Mikuni smoothbores came out.

Jay, are you still set up to bore a set of Early 750 factory carbs?  Interested?  Price? 



George

Positively not.

[Retro Rocket]

Just a heads up, some PM's are NOT getting through, there are some small bugs in the forum after moving servers..... Better off discussing things in the thread.. {some people get the sh1ts far too easy}   

[MRieck]

We did hundreds of them before the 29 Mikuni smoothbores came out.

Jay, are you still set up to bore a set of Early 750 factory carbs?  Interested?  Price? 



George

Positively not.

That's funny Jay.

[gschuld]

First one I saw do this was Eraldo Ferracci. Then we did it. We used an end mill slightly smaller than the slide. Took material off the top and then the floor.   Width stayed the same.

Jay,

   Thanks for getting back to me. Back when you bored the sohc carbs, did you alter the fuel metering system in any way?  Such as enlarged pilot holes like Frank(754) found in his bored round top drag carbs?

I'm very intent on learning what exactly gets altered besides the physical opening.  I have a nice Bridgeport milling machine and all the end mills and atachments to make any opening I would want.  I could blend the cuts into the in/out ends with precision.  No problem... I'd be happy to experiment on a set of my non K0 round top carbs.  I just want to make sure that whatever I end up with is geared toward a street driven bike, not some all out modification that is only good for the track with full throttle airflow and mixture as the only real consideration.  The carbs would be going on an RC Engineering built "hot street" style motor: 11/69 K0 1000cc, 10:1 pistons, Super rods, RC cylinders, RC "race" ported head and full top end (likely going to a RC#315 cam), while retaining the factory starter system and non lightened factory alternator.  It's going back into an 11/69 K0 frame with vintage speed parts.  Basically a fun street bike motor, just as I intend to use it.

Any help would be greatly appreciated.

George
 



 

 

[754]

Why dont you want to lighten the alternator?

[gschuld]

Frank,

      It's not that I don't want to lighten the alternator.  It's just that when RC built this motor, he didn't lighten the alternator or remove the electric start as he did with the Cobra motors.  I know this a loaded question, but do you have an extra RC modified alternator(the version cut to retain the starter ring) on the shelf?

George

[754]

I think i cut mine myself.. I dont run starters.. At least use a 73 or later without the lip.

[Big Jay]

First one I saw do this was Eraldo Ferracci. Then we did it. We used an end mill slightly smaller than the slide. Took material off the top and then the floor.   Width stayed the same.

Jay,

   Thanks for getting back to me. Back when you bored the sohc carbs, did you alter the fuel metering system in any way?  Such as enlarged pilot holes like Frank(754) found in his bored round top drag carbs?

I'm very intent on learning what exactly gets altered besides the physical opening.  I have a nice Bridgeport milling machine and all the end mills and atachments to make any opening I would want.  I could blend the cuts into the in/out ends with precision.  No problem... I'd be happy to experiment on a set of my non K0 round top carbs.  I just want to make sure that whatever I end up with is geared toward a street driven bike, not some all out modification that is only good for the track with full throttle airflow and mixture as the only real consideration.  The carbs would be going on an RC Engineering built "hot street" style motor: 11/69 K0 1000cc, 10:1 pistons, Super rods, RC cylinders, RC "race" ported head and full top end (likely going to a RC#315 cam), while retaining the factory starter system and non lightened factory alternator.  It's going back into an 11/69 K0 frame with vintage speed parts.  Basically a fun street bike motor, just as I intend to use it.

Any help would be greatly appreciated.

George
 



 

 

That was 30+ years ago. I only remembert that we did it. We did way more dirt bik carbs for dragbikes. I remember more of that than the Honda deal.

[gschuld]

That was 30+ years ago. I only remembert that we did it. We did way more dirt bik carbs for dragbikes. I remember more of that than the Honda deal.

Jay,

    Fair enough.  I know that would have been a long drive down memory lane.  If you don't mind, what kind of reputation did Monty Campbell have with his "maxi-bore" bored carbs?

George

[MRieck]

Sucked if I remumber right

[gschuld]

Mike,

     Great...   Funny as he is the only guy out there still offering his boring services for these carbs.

Side note:  I have a early RC exhaust and a vintage #315 cam coming for the RC motor.  Still working towards the rebuild....

George

 

[754]

He is not Denoon can maybe do them . If you got a mill do them yourself..

[gschuld]

Frank,

   I'd be happy to mill them myself.  That part doesn't concern me at all.  I'm more concerned with messing up the fuel metering system with the change.  If opening up the throats at the top and bottom and blending them before and after the cuts are all that is required, I'm all set...

Isn't there more to it than that?

George

[bwaller]

Nothing like this comes easy. Find a dyno and work out the fine tuning. Or just buy a set of Mic smoothbores that are close to period correct, since that's what is important. Unfortunately, I think you're at the end of the road of good information you're looking for.