[heloego]

Ever since I fitted the sidecar to my C5 it's run like sh*t. Even after pulling the sidecar off it's run like sh*t. New plug didn't help. Fresh gas didn't help. New NGK plug cap didn't help. New coil assembly didn't help.I may have found the issue...Got a new insulator, so we'll see what happens.

[wildbill]

you could be onto something there. I fitted one the wrong way on my previous bike and it didn't go too well at all...lol

[Narada]

Just found my vacuum leak! 

I had relieved a bit of material on the other side of insulator for "improved" injector spray. 
Unfortunately, this undermined the o-ring groove. 

[Bert Remington]

I made my own intake insulator from 10mm/0.4in thick phenolic.  I didn't cut a groove because I think the thicker phenolic is stiff enough to use Hylomar or similar sealant to be used instead of an O-ring.

I attached pictures of GHG's insulator.

[Narada]

Ah...nice pictures Bert! GHG told me he made his own, but I hadn't seen it. 

I figured I'd need an o-ring groove and don't have a milling machine, so I just ordered a new one...actually I ordered two since they seem so weak and crappy, might need another at any time, lol! 

How does everything fit upstream of that thicker insulator? Kind of tight isn't it? 

Btw, I also found a rubber breather tube / hose that had many cracks on a 90 degree bend at the air box. 
 
Ordered one of those too. A little surprising being a low mile 2015...maybe crappy rubber?