Winter Build Thread

DING DING DING
DAILY DOUBLE

hahaha

I actually got in an argument with some guy on the ZX7R Facebook page over that thing. I left the group shortly after because I realized most of the guys on there already know so much more than me I have nothing to offer the group. </sarcasm>

The flo commander does exactly what I wanted it to do, exactly as well as It was advertised to do it. It doesn't claim to add any special element to the main circuit.

What it does do is let you fine tune the main jet mixture with the turn of a single knob on the outside of the carbs. The less air that comes in the main air jet, the richer the mixture from the main circuit is. Its the same as adding a larger main fuel jet.(disregard any minor fuel atomization differences). Dynojet used to send plugs in their jet kits to restrict or block off the main air jet so that you wouldn't have to run 230 mains on a tuned zx9. The thing is that most people claim its just "snake oil" because they don't understand how it could be beneficial to other people.

I swapped this motor, and with my relatively unique airbox, filter, carb setup, big bore etc.. I was having a really hard time finding which direction I needed to go on the main jet and by how much. It sounds easy when you read about tuning carbs, but sometimes lean feels rich, rich feels lean, and lean feels like timing issues, and it's all just a mess.

I got the FC to help me tune the carbs from basically scratch, and as soon as I got it on the bike, in an hour or so I knew within 2 or 3 jet sizes where I needed to be without changing any main jets. Thats me tuning on a backroad though.

There are plenty of reasons most people wouldn't ever need one. And honestly they're the majority. Most people install a jet kit on a mostly stock bike and the kit gives them instructions on how to do it and what jets to put in. There is no reason for those people to run a FC on their main circuit.

Other people do the kind of engine work I did and then they bring it to a dyno and use an AFR gauge to tell them how far off it is, and it doesn't take long for a dyno operator get the right jets in. (Turbo might disagree. lol) There isn't really a reason for those people to run a FC on their main circuit either unless they are fine tuning so much they are trying to move between jet sizes.

New exhaust what

I took enough pictures that it kinda speaks for itself. But I have been wanting to change my exhaust for a while. Also at the track one time someone said "I thought your bike would be louder" with the last setup, and that was enough on it's own to change it up.

The small midpipe cut down on power and sound and I have been wanting to get back to a side mounted exhaust instead of the stubby outlet one. You can see the comparison between the old and the new pipes a little further down.

But I bought a buncha 2.5" (63mm) mandrel bent pipe after seeing a lot of ZX7RR and newer superbikes with the full sized pipes (not just 52mm). and cut and welded them together. I'd never done any custom tubing before but it was actually pretty easy to get it to go where I wanted.

Its hard to tell from the pictures but this is is really big and it's gonne be crazy loud.

Special shoutout to CCMHUNT for the trick exhaust hanger that started this whole thing. I know he's gonna hate the sacrilegious modern style silencer i hung from it, but I really like it! So thanks again man!


IMG_1069 by MxJoel165, on Flickr

IMG_1070 by MxJoel165, on Flickr

IMG_1071 by MxJoel165, on Flickr

IMG_1072 by MxJoel165, on Flickr

IMG_1074 by MxJoel165, on Flickr

IMG_1076 by MxJoel165, on Flickr

IMG_1078 by MxJoel165, on Flickr

IMG_1077 by MxJoel165, on Flickr

IMG_1081 by MxJoel165, on Flickr

IMG_1086 by MxJoel165, on Flickr

IMG_1080 by MxJoel165, on Flickr

Here's my inspiration BTW if you cared.

Thanks, Sorry that update was kinda brief last night. I was pretty tired. I haven't posted here much lately, mostly because this thing has been sitting in the corner of the garage for a while. I've still been lurking though and it looks like there is still plenty of great stuff going on!

The old pipe kept the mid range super solid and linear, but it was a little lacking up top. So I'm hoping this will open up better at high rpm. And sound meaner..

http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/

This is the website I kinda used for reference. I had a 2" pipe crush bent after the collector so that necked it down to an even smaller cross section. That says 1.75" is only capable of supporting ~108hp per pipe. Most aftermarket stuff is 2" (52mm) with nice bends, and that is capable of ~144hp according to that site. So plenty for a stock-ish 750cc motor.

I made 138 at the wheel, so I was obviously pushing past that for engine power. 2.5" is arguable a little big (capable of supporting ~232hp) and I expect to lose a little velocity down low. Usually you want the smallest pipe you get use without it becoming a restriction to keep velocity as high as possible. 2.25" would have probably been the ideal choice, but the silencer I got had the full 2.5" inlet so I just went for it.

Track day bro

New exhaust worked great and was for sure the loudest pipe out there. ha So i guess that's good?

That's my buddy on the DRZ. This track is small and is perfect for a supermoto, so my bike is kinda a handful and is exhausting to try to stay attached to it for the whole day, but i made it out alive.

IMG_1131 by MxJoel165, on Flickr

IMG_1130 by MxJoel165, on Flickr

IMG_1133 by MxJoel165, on Flickr
IMG_1137 by MxJoel165, on Flickr

IMG_1135 by MxJoel165, on Flickr