stock carbs on a rephased 750

[ClarkSN95]

First post!

So I've got a 1980 Special I'm doing a café racer build on and I've got a question about the carbs. IIRC the stock carbs are the Mikuni VS34's?

Pardon my ignorance but this is my first carb vehicle, up until now its been EFI sportbikes and cars...

Plans for the engine are:
Mikes 750 kit (9.0:1) compression
Hughs 277* rephase, stock 1980 cam rephased
Mikes 2-1 headpipe
K&N pod filters
Pamco ignition
PMA (kickstart only with a capacitor)

Best plan for jetting the stockers? Or would I be better off getting something like Lectrons?

Thanks in advance guys!

 

[XSLeo]

Well the stock carbs are BS34 not VS34. If those carbs were well tuned on it as a 650 then they will be just fine on it as a 750. It may need some tuning if the air filters or exhaust were altered.
Test them as they are. The carb guide has a section on "Tuning For Mods" Just test, make any changes according to the test results, test, adjust One thing at a time till it runs it's best.
Leo
Leo

 

[ClarkSN95]

I imagine they worked fine at some point, the thing was sitting for god knows how long before I picked it up a few weeks ago. I'll just rebuild them and go from there, probably the cheapest route

 

[XSLeo]

Well, not always. Without doing a few tests and running it you don't know what you have. It may have been just fine, without spending much, much less than a rebuild cost.
Leo

 

[itsnotlevel]

I imagine they worked fine at some point, the thing was sitting for god knows how long before I picked it up a few weeks ago. I'll just rebuild them and go from there, probably the cheapest route

You cant use stock carbs on a rephased motor....they have to be separated, they cant be linked together.
I know its late, just figured Id put that out there for completion of a forum post.

 

[gggGary]

You cant use stock carbs on a rephased motor....they have to be separated, they cant be linked together.
I know its late, just figured Id put that out there for completion of a forum post.

Yeah and the Fimbler rods must be decoupled after a rephase and get a transplitter shim for the idle trim pot.



you got it out there for sure.

 

[ClarkSN95]

I swear to god I lost brain cells just now...

 

[ippytattoo]

There is no issue with running stock carbs on a rephrase motor. Ignition is a different story.

 

[ClarkSN95]

I know, I'm running a 277* Pamco

 

[arcticXS]

Yes, the carbs have to be 270 or 277 degrees out of sync, in order to work on a rephased engine. As we all know, on Honda twing with 180 degree crank, one carb opens while the other closes, and vice versa........
Hahahahaha
Someone sure have access to some good stuff.......

 

[TwoManyXS1Bs]

I thought you had to mount one of them sideways. ..?

 

[itsnotlevel]

ippy....did you do your rephase yourself?

 

[itsnotlevel]

There is no issue with running stock carbs on a rephrase motor. Ignition is a different story.

ippy....did you do your rephase?

 

[DIRTY DOG]

yes the bs34 will work on a big bore rephase eng.I'm running a set on my 680 cc 277 repahse ( I rephased my own crank's )

 

[itsnotlevel]

yes the bs34 will work on a big bore rephase eng.I'm running a set on my 680 cc 277 repahse ( I rephased my own crank's )

A video would be nice....crank, ride, idle?

 

[ippytattoo]

On the rephased motor I had HHB did the crank and MrRiggs did the cam. I ran bs34's on it and it ran fine.

 

[itsnotlevel]

so you no longer run the stock carbs on it? Why?

 

[650Skull]

You cant use stock carbs on a rephased motor....they have to be separated, they cant be linked together.
I know its late, just figured Id put that out there for completion of a forum post.

ippy....did you do your rephase yourself?

ippy....did you do your rephase?

A video would be nice....crank, ride, idle?

so you no longer run the stock carbs on it? Why?

Troll???????

 

[itsnotlevel]

No, just dont believe any of them. Nobody wants to step up and show anything...I know first hand the stock 650 carbs...attached...dont work on a rephase...not well. Its mechanically impossible....air and pistons just dont work that way.

 

[itsnotlevel]

Troll???????

So am I only allowed so many posts per hour? All my posts are in english and without the typical spammer hyperlinks....still think im a troll?