Today I switched out my Mikuni air horns for longer ones from EFI Hardware. From what I have read on here, the consensus is generally that the longer intake manifolds perform better on the street. I am running the short Mikuni manifold, but would rather not part with it, or go through the expense of buying a different one and waste time reworking the linkages. This seems like an easier solution to try.
DSC04313 by ryant67, on Flickr
DSC04312 by ryant67, on Flickr
DSC04311 by ryant67, on Flickr
DSC04310 by ryant67, on Flickr
DSC04315 by ryant67, on Flickr
DSC04316 by ryant67, on Flickr
DSC04317 by ryant67, on Flickr
DSC04318 by ryant67, on Flickr
The air horns are currently untrimmed, and are 105mm long, 48mm ID at the base, and 89mm at the mouth. They can be trimmed down to a minimum of 68mm. I might trim them down to 90mm, just to give just that little extra clearance from the master cylinder.
DSC04319 by ryant67, on Flickr
I cheaped out and cut the baseplate myself from some spare 6061 aluminum sheet I had. I didn't want to hack up the old one, and enlarging the holes would be more difficult than just cutting new ones in a blank.
DSC04289 by ryant67, on Flickr
Good old Wiss tin snips, a file, and a dremel did a decent enough job. An 83mm hole saw cut the openings, and ITG grommets hold the air horns in place. This allows 40mm clearance over the mouths inside the air filter, whereas the old setup I had only had 15mm, which would very likely have been disrupting air flow.
There seems to be a very noticeable gain in low end power/torque, and the rear wheels break loose a lot more readily when I get on the throttle now. Much louder induction roar too, which I don't mind at all. Very pleased.
Now I just need to finish up making my new carb heatshield.
Edited by ryant67, 13 April 2015 - 06:42 PM.