how much are flat side carbs.?

[one2dmax]

You can also fool the engine a little bit into thinking it has an equal length system by having various diameter pipes (see the gen 2 for a good example of this).

 

[rebeltaz83]

You can also fool the engine a little bit into thinking it has an equal length system by having various diameter pipes (see the gen 2 for a good example of this).

haha, now thats something i didn't think of, but i can see how that could work.

 

[thor_eyerdhal]

I am not sure equal length headers are the best choice for street use...
Tuned headers have a narrowed powerband that give more power at a given RPM.
For street use, a wider powerband with a lower peak power is better.

 

[texas-ss-tornado]

So I've got a set of 39 flatsides on my latest VMAX, and the daggum thing runs GREAT, and pulls like a freight train, but will not START for crap! When it's cold, unless I shoot a bit of carb cleaner into the velocity stacks, it will not start and keep running? I know these carb setups don't have chokes on them, any "tricks" to getting them to start easily??? Any help would be greatly appreciated!

 

[Itgoes]

Are they UFOs version of flatsides and manifolds have their intakes on the side?

I used Uni foam filters and could just push the filter flat to choke the engine when it would be stubborn.

 

[texas-ss-tornado]

Are they UFOs version of flatsides and manifolds have their intakes on the side?

I used Uni foam filters and could just push the filter flat to choke the engine when it would be stubborn.

Yes, UFOs version with the velocity stacks sticking out the side. They are open with no filters at the moment, sounds like I need to come up with some kind of "starting filters"??? That's almost as bad as having to spray ether in there! LOL! Fires right up when it's hot though! unk:

 

[Itgoes]

Yes, UFOs version with the velocity stacks sticking out the side. They are open with no filters at the moment, sounds like I need to come up with some kind of "starting filters"??? That's almost as bad as having to spray ether in there! LOL! Fires right up when it's hot though! unk:

Just close one stack with your hand that may be enough......I was able to smoosh 2 filters flat on one side and that worked every time.

 

[Rusty McNeil]

Just richen the idle setting. I know that's not ideal though.
How high is the idle set?
Maybe lowering the idle more would get the slides closed more and let them act "chokey" since I'm pretty sure the idle fuel holes are downstream of the slides.
The Vgas I put on a friends bike didn't require any help starting.

 

[one2dmax]

Keep in mind there is no choke. BUT, they have an accelerator pump. So, pump it twice then crank it a bit. If needed after cranking and if it fires but doesn't stay running then repeat it.

 

[texas-ss-tornado]

Keep in mind there is no choke. BUT, they have an accelerator pump. So, pump it twice then crank it a bit. If needed after cranking and if it fires but doesn't stay running then repeat it.

Yea, I've tried this, to no avail. The "normal" tricks don't seem to be working here! I'm gonna look into fashioning some filters of sorts............unk:

 

[one2dmax]

Filters kill most of the benefit of flatslides AND cause a potential fire hazard. The way the carbs mist above the mouth of the carb tends to saturate the filters which almost immediately catch fire even with one backfire. If you track back through the history of flats on the vmax you'll find more then one person this happened to.

Gary Spradley had a custom aluminum box made on his set to add a filter too. Was a very nice setup but lost almost as much power as it had gained.

 

[texas-ss-tornado]

I stuffed a couple rags down each one and it started right up. Gotta figure out how to make a log term solution for this issue! unk:

 

[rebeltaz83]

can you put your hand over one or 2 of the stacks?? or maybe make yourself something small made of rubber that you can carry with you to put over the openings....... rags are not a good thing, debri gets down into the valve openings it would be bad news..... ive seen a busted valve and torn up walls from a spark plug coming apart.

 

[Itgoes]

Filters kill most of the benefit of flatslides AND cause a potential fire hazard. The way the carbs mist above the mouth of the carb tends to saturate the filters which almost immediately catch fire even with one backfire. If you track back through the history of flats on the vmax you'll find more then one person this happened to.

Gary Spradley had a custom aluminum box made on his set to add a filter too. Was a very nice setup but lost almost as much power as it had gained.

Yeah I agree Sean....I had a 5 HP loss with the filters on. 123 vs 128. I ran Uni's for several years though without a problem....but have heard about the fires. I'm pretty sure none of those were UFO setups though, they were all flat sides that were up under the lid. I think with the filters out in the air there is much less of a problem because the vapors are not trapped. If I had a set now I would be looking at individual K&N's because they flow much better than the UNI's. I would never run without filters.....but that's just me. Even if you lose some top end the flat-sides still give you awesome mid range TQ that you can't get with std. carbs.........my bike made 80 lbs.

 

[texas-ss-tornado]

Well, I've got some ideas for filters, thanks for all the suggestions! unk:

 

[asherc]

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