KZ400 with loads of class... (FINAL STAGES!!!)

[jsnabbs]

Thanks guys! The exhaust is stock headers with a pair of seamless Norton style peashooters welded on. Dime City has them

Oh sorry, i meant the exhaust from page 1&2 of this post, i see you've changed back to 1-1

im looking for the 2-1 system, check the link i posted in previous post

 

[valvesprung]

Ah, the 2-1 from the begining of the thread is the stock system. This bike being a "S" model was the stripped model.

 

[Mike Lawless]

Mikuni VM30's is what comes up for a Honda CL360 on DCC. Helloooo eBay! Would love to hear how a bike runs with Mikuni/pods if anyone has done it.

I just bought the whole enchilada from DCC. VM30s designed as a kit for the 350 honda. I have them on a 300 Suzuki. It's their "Pre Jetted" kit. Came with pod air filters. The filters are listed as "K&N Type" but do not have a K&N logo on the top. I'd imagine they are a generic brand, but the are of much better quality than the $10 pod filters. I also got the 2 into 1 throttle cable adapter. This had to be cut and fitted. A little fiddly, but it worked out good. I'd imagine there are many people wouldn't have the skills and tools to do that part.

At any rate, I was in the same boat. Stock BS style Mikunis that ran and idled OK (barring the igniton problems I was having) but way lean up top. Parts were hard to find and they did not lend themselves easily to tuning. My inclination, based in the automotive world, is to ditch the stock stuff in favor on tunable race oriented stuff one can easily get parts for. The VM 30s filled the bill on that count.

The bike pretty much fired right up and idled nicely right out of the box with the "as supplied" jetting. After putting some time on it, I need to make some minor adjustments, but I am very pleased with how the bike runs.

Now, if I had it to do over again, I think for this smaller engine, I would have gone with 28s, maybe even a tad smaller. The larger size really isn't gonna help until you get near max rpm and throttle.

This is just an observation since my experience is automotive related.
I have a good amount of experience with individual runner style intakes on high winding race motors, (one carb throat per cylinder) and there is a phenomenon called "Intake Pulse Reversion" that comes along with IR type systems, such as motorcycles.

To "tune" this, the intake tract is lengthened or shortened to put the powerband where it does the most good. A longer tract will boost bottom end and midrange performance because it better contains the fuel "stand-off" (the pulse that reverses direction and actually pushes fuel mist out the top of the carb. You can actually see this with the motor running). With a motorcycle carb being attached directly to the head, it makes for a very, very short tract. Having the reversion contained within an air box is most likely why the stock bike runs better with the box than without. It would be interesting to try making the intake length below the throttle blade or slide about 6 to 12 inches long to see what happens. Of course this would put the carbs way back by the back tire, so not really practical.

There is a program called "pipemax" that, given a set of parameters, can calculate the ideal intake tract length, throttle blade to intake valve. On my VW drag racer, I ended up with about 10 inches from throttle blade to intake valve. with another 4" stack length on top of that.