Oil in CV Carbs Trick ?

[Hellbilly429]

My cousin races flat track and my grandfather has always helped him with his bikes, and he keeps talking about the CV carbs from the Harley motors they raced, he said they would put oil in the tops of the CV carbs in order to smooth out the acceleration. Anybody have any knowledge or experience with this? Would it be a possible solution to the problem the CV carbs have with high-flow filters?

[LukeM]

Interesting.  The oil on top of the diaphragm would slow down the movement, thereby smoothing out the action of the needle in that section of carb.  I'm not sure how tolerant that thin membrane would be after exposure to oil for that length of time, and I do know that the diaphragms for the CV Honda carbs are getting rare and expensive.

Thinking further, it's possible that it may alleviate the vacuum provided by the airbox.  But I think Honda would have thought of this during the design/testing phase. There is probably a good reason why they went the route they did. Maybe the diaphragm needs to be more flexible to improve throttle response? Quicker acceleration?

Thanks for chiming in.
Luke M

[Re-run]

I don't think this would help our carbs much. I am hazarding a guess that the large vacuum created by the much bigger harley pistons really yanked on the diaphragm. The oil helped slow that down and made things smoother by doing so. Since our pistons do not pull so hard, this might not be an issue. Just a thought. I suppose it could be tried and if no change, the oil removed right away.

[sgtslag]

A great many things which work for racing (engines are usually torn down, and rebuilt after every race...) are not safe, or advisable, on a street machine.  The racing tricks may shave off small bits of time, but at what cost to the engine?  On a street bike, I try to look at the long haul, not the short gains.  My bike is 33 years old, and it runs like it is only two -- I like that!  YMMV.  Cheers!

[Hellbilly429]

Well thanks for explaining that one, he had mentioned it many times to me because he knew the bike had CV carbs before I did.... The bigger piston theory makes sense to me though re-run, much more compression with the Harley's.... And I am sure this trick has never been used for longer than the length of a race before they tore everything down again.... still might try it for shits and giggles later down the road, just to see what it does....

[shinyribs]

Everything is always worth a shot...at least once.

[LukeM]

Sometimes twice...depends on what sort of success/failure you had the first time around.
Luke M

[shinyribs]

LOL.Very true! Well put man

[Hellbilly429]

Yeah, I talked to him more about it today and he said it would just make the bikes pull instead of spin, and that they liked using the CV carbs for racing cars too because they could use this trick to keep them from spinning on the take-off and out of the corners, like a cheap traction-control system.

[Lucky 1]

This thread has gotten way off course.

What the person was talking about is oil dampened carbs like the SU carbs.
Some were fitted to Harleys.
There is a knob on top of the vacuum cover and that knob is
attached to a short rod attached to a small piston that sits in the top of the larger slide.
That is where the oil drops were placed.
Many brittish cars used that style of carb.
See the brass knob on top?
What the dampening did was to stop the fluttering up and down of the slide piston at idle.

[Hellbilly429]

Huh, think I'll have to show him those pictures and see if that makes more sense to him, I know it's been a while since he has dealt with that kind of stuff

[shinyribs]

I dont understand everything that has been said here....but THAT is the prettiest dang carburetor I have ever seen! Id love to have one just to hang on the wall.





Well,maybe minus the two lightning bolts

[Hellbilly429]

Is it cause of the SS Nazi symbol? Don't lie to me Shiny, lol. I am very confused here myself, my grandfather is one of those guys who explains by showing you, and if he can't show you he will tell you a story about it that will be vague and brief...

[slownugly007]

ditto! that things cool as hell!

[shinyribs]

Yes. Twin lightning bolts is the symbol for "white power". At least it got adopted by those types somewhere along the line,or whatever. Cools carb,bad lightning bolts.

I bought a '71 C10 that had those twin lightning bolts HUGE in the back window. Reached top to bottom. I was clueless what they meant. I thought they looked cool and left them. I went to pick up a girl from my science class and she QUICKLY let me know what they were She was black so it was kinda akwardI felt bad about driving into her neighborhood with them.LOL. Oh well,live and learn.

The guy I bought the truck off of was in his late 20's and not a hair on his head...shoulda been a clue.

[cdaiscool]

Twin lightning bolts was the symbol for the SS, their Secret Service if you will. They were... nasty.

[Hellbilly429]

Lol, slightly akward, if she was Jewish I think you would've never seen her again.... I do have to say that the one thing those guys do right is their designs, ever see the bike on The Walking Dead? Love that bike...

[Lucky 1]

Many young men do not understand what the symbols mean.
Like when you are at a party and someone says." I would never let MY kids
serve in the military,they could get killed." and you are a vet listening to it.

[shinyribs]

Oh,I admit I dont know what most of them mean. I learned what those mean,though.

LOL.Jewish?...couldn't afford to date her








                                                                             sorry

[Hellbilly429]

eh-hem.... right, prob should leave it at that..... although I am sure if you had some coupons.... No, Bad Hellbilly!