Metering Rods...

[Guest]

I am working with a 78 GS 750 and I am going to be running pods and a 4 into 1exhaust.

My question is when it comes to the clip on the metering rod I read that I want to move it down 2 slots. This put it at the bottom slot on my carbs (VM26's).

Is this the norm?

[tkent02]

There is no norm. Are you talking about the jet needle? The bottom slot is probably about right, for a starting point. Might be too far. Depends a lot on the pods, and the pipe, and a bunch of other factors. What are you using for jets? Which jet needle are you using?

[born2lose]

Stock needle, 117.5 jets (have 120's on stand by), HCI foam pods, MAC 4 into 1 no baffle.

[tkent02]

Stock main for that bike is 105 or 102.5 I think? Is the 120 going to be big enough? Don't know about those pods, haven't tuned a MAC pipe in a while, sure try it all the way down at the bottom clip position.

[born2lose]

I was going off the Oh God! Pods! Write up in the mega welcome section

[dorkburger]

Metering rods? Now you sound like a car guy.....

[born2lose]

Metering rods? Now you sound like a car guy.....

Lol.... yeah I know force of habit

[born2lose]

VM – Disco Never Died

With hipster VM carbs, don’t be too smug. Sure we have more game with the ladies, but there's good news and bad news for us as well. Our needles usually (but not always) are adjustable, so we are not slaves to the DynoJet cult and can spend that money on bell-bottoms and lava lamps as God intended. OTOH, we get no short cuts or pre-packaged kits to launch our jetting adventure.

BTW – if another person tells me to "just get a Stage 3 Kit" for my 1978 VM26s, I will not be responsible for the ensuing bloodbath.

So we have even more trial-and-error to work through. Based on your mods, figure out roughly how many sizes up you need that main jet to go. That linked guide suggests +6 sizes for pods and pipes. My GS750 stock mains were 100, and I am running 117.5 now, but stay tuned for changes.

With a target size in mind, order main jets at -1/0/+1 of the target size – so if you think my jetting might work for you (I wish it worked for me) – order 115, 117.5 and 120 mains.

For pods and pipe, you need to raise the needle usually around 2 notches – i.e., move the clip 2 slots down.

For the pilot, you might be OK with the stock size, with just some re-balancing of the pilot screws to shift towards more fuel. If not, you may have to increase the pilot size one step, or even two.

See... basically when I popped the carbs off and tore into them the JET NEEDLE () had the clip in the middle groove so I moved it 2 slots down.

I have yet to get the bike running since I rebuilt the carbs in January, but in the shop free revving at WOT it would stall out.

Middle throttle it revved just fine.

Didn't dig into it much since the bike was about to be torn down for brightening.

Just curious if the clip ended up on the bottom grove typically for a 78 750 with pods and 4 into 1.


Rest of the engine is stock.

Carbs bench synced at the time only

No other adjustments were made ( it was subzero outside )