Monday, 24 July 2017

The XS Triple Sidecar - sync'ing and rejetting and rejetting and...

Good things sometimes take a while and with the VM36-carbs on the XS Triple sidecar it was no different...

Let's talk about jetting carbs. First step after soldering the cables was to make a base-setup of the carbs. This requires a bit of experience and lots of jets. Depending on what the carbs come from, it can quite easily be, that you slap them on and fire the bike and see what's going on. As these VM36s came off a two-stroke Skidoo both the pilots and mains had to be swapped out.

Next set the throttle-slide-stops (i.e. the idle adjustment) to the same level. A rather crude way to do it is to simply slide in a drill under the throttle slide cutout and then set all three of them so they just touch it.

Then the next step is to fire the bike up and see what happens. If you're lucky it will fire up and you will have to work the throttle and the air- or mix-screws a bit to make it start, run and finally idle. Be aware that just because a bike idles means absolutely nothing in terms of how well it is set up. (Spot the missing mainjet in this picture... yes it came loose and lay around in the float chamber, still the bike idled.)

Next you try to sync the carbs (assuming you have both idle and at least midrange) - I did this with my trust vacuum clocks, but you can of course also just do it via the cables.

As you might have noticed, the pictures look a bit different than usual, that's because I've been using my trusty old DSLR instead of my normal camera, so it would have been rude not to play around a bit.

Some backfire through the #1 carb

Once sync'ed and rejetted a few times, it started to sound more like this...

So are those VM36s are simple install and why isn't everybody doing them? Well firstly they are an incredibly tight fit as you can see in the pictures below, I had to remove some of the breather tubes as the carbs were touching each other.

... and then there's this thing with the cable splitter under the tank, which is huge and there's no off-the-shelf solution for. But is it worth it (after a testride): Hell yeah, she's a gas guzzling, fire-breathing, two-wheeled hoodlum that will reward exactly one-smile per mile, because it goes all the way!


  1. Replies
    1. Cheers! Much appreciated. Finally progressing at a serious rate of knots with the sidecar.