Shortneck/rail cut, do or don't do????

[Stevo80]

Ok guys, I'm getting close to the point of short-necking and cutting the rails on my bike. I know why it's done, but my question is, is there any reason I wouldn't want to do it? Other than obvious reasons of course. My bike is a committed drag bike at this point too. I know this subject has been talked about a hundred times all over the net, just trying to get some last second opinions. lol
One thing I'm not certain on is this.... Is there enough clamping area on the forks for the clamps without having them machined down so the clamps can go down farther?
The bike is not being setup for any kind of "class" racing either.
If wheelbase is not a concern and the front is low enough with internally cut forks and stock offset clamps is there any reason to shortneck?

Thanks for your .02!

 

[Dennis]

Good questions, I'm interested. Seems to me without a wheelbase restriction there isn't much motivation for shortneck. Cut frame rails will help you get low which seems like a no-brainer, but I believe it moves you forward which reduces weight on the rear wheel. I'd be concerned at the tracks around here about getting hooked consistently.

 

[Stevo80]

Good thoughts Dennis. I had not thought of the fact that my rather heavy butt would be sitting quite a bit further forward. Hmm... Being 6'3" I would definitely like to sit more "in the bike" instead of on it. The good tracks around here usually have it pretty good and traction isn't an issue. There are a couple of tracks around that you will never see me at again. lol Once was enough. I might just do the rail mod and keep my money and not do the short neck. I am planning to pull the motor and get everything powder coated,etc and hate not to do something while it's all apart too. :/ Decisions decisions.

 

[Dennis]

Here is my theory on short neck. I may be wrong.

It is done to get the bike lower and shorter in front. Lower is good to a point, but with my stock fairings I can get low enough now. The motorcycle drag guy at JRI shocks tells me that some guys work to hard to get low in the front and that makes getting weight transfer harder, potentially causing spinning (one of the problems I've been dealing with). Shorter wheelbase is good if you put it back on the rear and can make it stick. I can't imagine there is any other purpose of short necking. The perfect launch has your front tire about 1" off the track, so at that point the front suspension has no play in the performance of the bike, so the arguments about putting more weight on the front tire are meaningless. I know the prostreet guys all do it, so maybe there is more to it that I'm missing.

 

[Stevo80]

All good points and I would agree mostly. The whole weight over the front is true even though the bike might be in the air, there is still more weight toward that side of the "fulcrum" if that makes sense. It might be just enough difference on the perfect run to keep the front where you want..?/ IDK Pro street I would guess is mostly because of such high hp and wb limitations.
Am I wrong in thinking that wb won't be changed much unless you go to offset clamps though right? Short-necking itself just gets the bike lower correct? Unless I'm missing something? I am only running a 3/4 fairing, flat pan, sidewinder etc, so low is good.

 

[Dennis]

I think it depends on what you hold constant. If you have a 12 over arm there is no "weight on the front tire" advantage (actually a slight disadvantage). Different argument if you keep the wheelbase the same in either case.

I'm certainly not the chassis expert, still trying to get mine to work like I want. The Prostreet guys get low, but I don't know what other things need to be tuned to make low work. I do know that the guys I know with short neck comment that the bike does not handle the same ... a bit sketchy down track.

 

[Stevo80]

Well after looking at my bike and how low it is, etc. and based on all the research I can find, I don't think I will move forward with the short neck, rail cut, yes.

Hey Dennis, and I say Dennis, because you are the only one responding, lol, ever use any off set triples? Thinking of running some 1/2" from someone. Supposedly another 3lb or so loss getting rid of the factory Busa top clamp too. haha

 

[Dennis]

I haven't used them. Isn't it another case of only the only point being reducing wheelbase for a length limit class?