Topic: Anyone out there have bored factory carbs?

[gschuld]

Good news!  Your the man with the plan...

George

[POPS 911]

With where you live at DA BELOW SEA LEVEL some days [ like Englishtowns raceway I had  -325' on my dial in computer ] you might need a bigger main jet then BILLS Georgia setting , like you said ask MIKE REICK as he is a head builder and lives in your neck of the DA. Flip that bail off and use your jet wrench and make 4 changes in about 10 minutes with those stacks = if you run a stock air box hope you can get those rubbers back on easy, use a little STP ON THE LIPS TO SLIDE BACK IN, or on any o-ring.

POPS BK911

[Magpie]

My carbs aren't bored, they're just tired of waiting around for me to use them................. Sorry, I couldn't help myself. Cliff.

[pencil9]

A few years back I had a mid '70's with 836 kit and kenny harmon 'D' grind cam, had an aggrevating flat spot taking off from a complete stop.   Don't remember where I found this trick but I took the slides out of the carbs and had 0.010 machined off the bottom of 'em to give 'em less cutaway, and bingo !     Fixed, no more hesitation there!!!   I don't remember doing anything different with the idle jets either.    Maybe this would help someone here.
*cheers*

[POPS 911]

GEORGE :   I owe you some change and will send it thru the US MAIL. That extra fuel system that the guy who wanted $500 to bore out your carbs could be a simple DIAL A JET KIT # DJ-102 cost $121.95  which I had [ still have a few ] alot of these kits and could fit many to 1970-80 lean factory carb bikes for a simple screwdriver twist for more fuel. Had a 1982 YAMAHA XV920RJ [ chain drive ] VIRAGO w/dial jet kit that I rode all over the USA = sea level to 10,000 feet no problems.

POPS BK911

[MRieck]

A few years back I had a mid '70's with 836 kit and kenny harmon 'D' grind cam, had an aggrevating flat spot taking off from a complete stop.   Don't remember where I found this trick but I took the slides out of the carbs and had 0.010 machined off the bottom of 'em to give 'em less cutaway, and bingo !     Fixed, no more hesitation there!!!   I don't remember doing anything different with the idle jets either.    Maybe this would help someone here.
*cheers*

My stock 75 750f carbs had a big flat spot when trying to leave the line hard. Rev, rev, rev....drop the clutch and absolutely nothing. Close the throttle a bit and Holy $hit.....hang on. It sucked. Motorcycle mags ( at that time) noted the same thing. I got a different set of carbs.

[POPS 911]

GEORGE: How are the bored out carbs working for you ? I told you they looked like new inside and out and those stacks are only ones I have ever seen on any carbs [ well made ] could not use on my matic as I needed CV's for the auto trans stall. When you go bigger and need round or flat slides I got many sets.

POPS BK911

[gschuld]

Pops911,

PM sent

[Bill/BentON Racing]

George,POPS didn't respond to my PM's,not sure he reads them.Wish he would have! POPS,read your PM's please! Thanks,your friend,Bill

[brandEn]

A few years back I had a mid '70's with 836 kit and kenny harmon 'D' grind cam, had an aggrevating flat spot taking off from a complete stop.   Don't remember where I found this trick but I took the slides out of the carbs and had 0.010 machined off the bottom of 'em to give 'em less cutaway, and bingo !     Fixed, no more hesitation there!!!   I don't remember doing anything different with the idle jets either.    Maybe this would help someone here.
*cheers*

Cycle X recommends this in their tips and tricks section.

[POPS 911]

GEO: Did you get the RIGHT CARBS YET ?  I know you are trying for that perfect match  of stock looking with extra power for that big motor you are building.  Talked to a great HONDA MOTOR wrench spinner at the track this past weekend and he gave me many facts about weak spots in HONDA MOTORS = wrist pins 15mm. stock and cam chains.   But I know you will have all after market stronger parts in your big motor.

POPS BK911

[KRONUS0100]

where are the pics of the bored out cabs?

[gschuld]

Sorry for not updating.  I was going to let this go until I had some testing done on these to share, but since you asked .  I ended up custom boring a set of carbs from my stash using the dimensions from Frank's(754) vintage bored set as a guide(thanks Frank).  I didn't go quite as radical as Frank's set, but these carbs are intended to be more street friendly.

The factory carb actually measure out to an equivalent of 27.7mm throat, and my bored carbs measure out to 29.4mm(Frank's set was 30.4mm!).  Bill Benton has an interest in testing them and comparing them to factory stock carbs, so at some point we might be able to gather some useful data and see how they compare back to back on the same engine.  He currently has them.  Bill has a full racing schedule, the Tiger to work on, and plenty of other things going on, so it may be a while before this experimental side project gets going.  No rush here...

I'm not sure where this will all end up.  I'm thinking of it as a fun experiment.  No more, no less.  I have no expectations that these bored factory carbs will be the next hot ticket or anything.  Hopefully they will show an improvement over stock carbs on engines powerful enough to benefit from an increase in throat area and not mess things up at the low/midrange end of things... 

We'll see.

George

[gschuld]

George

[KRONUS0100]

thanks.  carbs i have are only done on the head side of carbs............thinking they are basically smoothed out and not actually bored out.  they seem to work ok............have had them on 3 motors, now residing on my new 750F3 motor.