TOPIC:

Interesting subject this one.

I too have noticed after completely stripping & rebuilding carbs that on occasion one or two slides have less slip than others........when off the bike.

What you do need to take into account is that they will perform a little different when HOT on the bike. The carbs do actually get quite warm from the inlet track & the heat coming from the expanse of metal on the engine below. Thats why the fuel in the float bowl evaporates so quickly when left to stand.
The only way to be sure is to get the bike to running temp then switch engine off, then remove top rear airbox section as quickly as possible & test the slides from the rear of the throat with your fingers.........you will find they move a lot better.....as carb bodies expand.

VENTURA,
Try running your 1300 with pods fitted on STANDARD 110 main jets before changing anything.
The standard 1300 airbox is a massive restriction on the carbs, so by fitting pods you actually find it runs a lot better as it can breath a lot better & balances out.
This is why most 1300's with standard airboxes run rich plugs.
Try removing the standard air filter element & top plastic cover under seat & running your 1300.........you will be amazed how much better it runs as it can breath. Look at the tiny trumpet inlet from the standard airbox..........all 3 twin vent carbs are trying to suck thru that !!!!!

My current 1300 & four previous ones have all been fitted with K&N pod filters & ran perfectly well on the 110 jets.

Pete F

Hey thanks Pete- I've got a Dynojet kit in these carbs right now but I have a few sets of stock carbs around so I can try out the stock mains.

I hear you on the operating temperature factoring into the function of the carbs - the diaphragms become a lot more flexible when warm. I think I'll set up a couple of carb sets to make experimenting an easy swap. It will be very nice not to deal with that clunky airbox again.

Bill:

Over the years I've seen a few sets of these BSW32 carbs. I've also run into sticking CV pistons, either a single piston or both. Here is what I have noticed over the years.

1: Varnish deposits on the bore walls or on the pistons. (All three bores.) As you know a good cleaning will usually take care of this. Sometimes the varnish can be quite stubborn. One mistake I have seen is when others take an abrasive cleaner or tool, to clean this area of the carb. It cannot tolerate any Vacuum leaks in this area. So no damage or galling of the cylinder walls.


2: Improperly installed hardware, or missing parts. I have made this mistake in the past, by me not FULLY seating the circlip on top of that plastic piston holder. (I currently have a set on the bench now, and last night I gave this portion of the carb build close attention. It helps to 1: make sure the pistons are surgically clean, 2: Jet Needle, clip, spacers, and plastic piston holder are fully seated on the piston. And lastly, spending extra time to make sure the circlip is fully seated in the clip grove. It also helps to have a circlip compression tool that reaches deep down in the bore of the piston. (Make this task much easier)

3: Regarding the experimental return spring. I too have wondered the same, if installing a CV Piston Spring would help with the surge and lag that can occur on sudden throttle changes. My bike acts like it has Turbo Lag (Without the Turbo) when I suddenly roll off the throttle, in a delayed reaction. Even with my carbs in tune, and synchronized, this lag has persisted over the years. I don't think one would need to modify or change the weight of the piston. If you have ever noticed those springs. They are very light with a low compression rate. With this current set I have on the bench. I'll go to my local bike salvage yard and see if I cannot come up with three springs to experiment with. Once I obtain those results, I'll report back.

Hope this helps.

Todd.

Haha nice! I'm excited to see something actually progress with this idea .

Pete's got a point with the heat expansion. Since the slides are brass and the carb is I think aluminum the heat might affect them differently making the slides easier to move.

The thought of the spring adding weight might not be an issue since they're lightweight like Todd says.

I still think it might be worthwhile to take a postal scale and measure the compressed rate of the spring and see if it actually does make any difference . The most harm it could do would be to make acceleration a bit more sluggish but it might not even be anything perceptible.

By the way, I've been wanting to get some pods as well but they're no longer available as far as I can tell. Where have you guys been getting the pods?

There is a photo somewhere in a post here of a really good modification for pods, they used the top of the air box and plated the bottom of it and put on 3 round pod filters on the plate facing down, terrific idea, easier to get round pods than oval ones, and it gets rid of most of the air box