Carburetor upgrade

[SussexSlammer]

So, I'm currently running some poorly tuned stock carbs. New jets are in order for next weekend, as well as a good thorough poke 'n prod cleaning. I was planning on upgrading the carbs over winter to those mikesxs knock offs, but haven't mulled any other options over. Are there any other upgrade possibilities for this? I think I still have a set of carbs left over from an old 76 rd250, but I'm not sure if those would work? There's a slew of options out there, and I don't know where to start.

 

[Wolfe_11B]

Get a set of VMs with parts already installed for a 4stroke 400. You need to buy a set with the parts installed or you'll be fighting trying to get them right, and it will end up costing more trying to buy all the parts on your own. The VMs have a ton of parts that affect fuel delivery. But once they are right they are good to go. Run far away from the Mike's XS carbs. If you really want the PWK knock offs, just buy them elsewhere. But trust me on this, buy real carbs. You'll end up spending less.

 

[SussexSlammer]

Get a set of VMs with parts already installed for a 4stroke 400. You need to buy a set with the parts installed or you'll be fighting trying to get them right, and it will end up costing more trying to buy all the parts on your own. The VMs have a ton of parts that affect fuel delivery. But once they are right they are good to go. Run far away from the Mike's XS carbs. If you really want the PWK knock offs, just buy them elsewhere. But trust me on this, buy real carbs. You'll end up spending less.

Okay, so the 2 stroker carbs are out of the question then. I'll try and stick with actual PWK carbs then, I just have no clue where to start. Maybe flatsides? What even is a flat side in comparison to a constant velocity. I have literally no experience with motorcycle carburetors. The carbs on our bike are 34mm something (I think?) now is that inlet/outlet diameter?

 

[Wolfe_11B]

Just be warned that flat slides like TM's and PWK's are very tricky to use unless you plan on being WOT all the time. You cant open and close the throttle quick unless you have a pumper system. They were designed for 2 strokes and race bikes. I would stick to a VM round slide setup. Since you seem to be new to the carb thing, the best recommendation would be to stick with the stock carbs, especially on a street bike.

Don't get caught up in the sizes listed for carbs. It's irrelevant to go by them unless you know how the flow works on each specific carb model.

 

[SussexSlammer]

Good to know! I appreciate all the solid advice. Looks like a some jets and rebuild kits are in order.

Also. I did order a couple of jets already. I have a set of 137.5 main jets and 45 pilot jets. Is that a good place to start? Or should I get a couple different sizes?