Broken carb piston diaphram clip?

Anyone know how to fix this with out damaging the diaphram? What would be the consequences of not fixing this?

P.S. - Image borrowed from MiCarl!

 

You mean you want it to look like this?

P.S. - Image borrowed from MiCarl!



Here is what I did. I gently clamped the ring to close the gap down. Then I cocked it at an angle so something dripping would drop into the gap next to the piston.

I then lit a heavy nylon wire tie and dripped the melting nylon into the gap.

The challenge is the drips are flaming. If I had it to do over again I would have covered the portion of the ring I wasn't working on with a damp cloth. You can see some blisters to the right of the patch where the little ribs on top caught fire. Didn't seem to harm function though.

Then I cleaned it up with a file - paying attention to being smooth underneath so there would be nothing to tear the diaphragm.

It has held up just fine for over a year and 3k miles.

 

{{{{shudders at the sight of this}}}}

I'm working on a replacement ring........every last one of these is like that. Even many brand new, in-the-box pistons. Beautiful factory design and engineering.

On mikuni's, every last one of the rings is PERFECT.

Industrial espionage has it's place and time.........

 

So if I leave it cracked like that, will I see or notice a degredation in performance?

 

It's probably been that way for 25 years.

I did mine because I was concerned the sharp edges would damage the diaphragm.

 

Re: Broken carb piston diaphragm clip?

I just found one of these when I opened the #2 carb. All the others are good. Here's what mine looks like:


I would prefer to just leave it than try to repair. I'm sure MiCarl is a more than capable mechanic and a fine craftsman, but, his repair here looks a little less than desirable. The whole flaming bits of plastic deal is worrisome.

The carbs seemed to be working fine as they were, I just took them apart for some winter cleaning.

Are many of you running diaphragms that look like this?

 

who cares what it looks like, as long as it does the job... unless I missed something, there are no carb slide pageants. and who would pass up a chance to play with fire? :twisted: :mrgreen:

 

I had one like that as well, got it professionally plastic welded by much the same process as is used on dashboards, I expect. Turned out so good you can hardly tell the join. Only cost a couple of dollars. I have no idea how this assembly comes apart or is put back together but I would think it requires some kind of special press tooling.

 

Mine all have the gap - I thought it was normal. Anyway I have seen no I'll effects

 

i got the identical width gaps on three out of four.

 

Must be a Hitachi disease; I have FOUR racks of carbs (2 on the bikes and 2 spares) for a total of 16 and NONE are like that. Mikuni must have done something different?

 

Len how does it come off? Seems it could be repaired f it is removable

 

Re: Broken carb piston diaphragm clip?

Thanks for the replies, all.

So, you're saying I should fix it because I can, or because I should? And don't get me wrong, I enjoy playing with fire, just not around a delicate (and expensive) part like this diaphragm.

I'm just wondering if I have to fix it. If it's not causing problems, I like to let sleeping dogs lie.

Where did you get this done?

 

All of mine on my Max are cracked just the same with no discernible problems. "If'n it don't stink, don't stir it" a wise fellow told me once. If you are not experiencing any problems, it is more likely a cosmetic thing and should be left alone. Although plastic welding is a nice idea. Let us know what you end up with will you?

 

I had decided to just let it ride. After all, the bike was running fine. But, I ended up buying a used set of carbs off eBay. I needed to replace one of my slider/diaphragm assemblies due to a tear in the diaphragm that happened when I was cleaning them, so I gambled on a cheep used set. I got them for about $40 shipped. The gamble paid off. The outside of the carbs looked like hell, but the insides are in surprisingly good shape. All four diaphragms look almost new! No tears, no dried out/hard spots and all of the plastic rings are INTACT.

All of the float bowl drain screws are seized, though... :roll:

 

I had mine apart a few weeks ago. They all had the crack in them. It looked so clean I thought they were suppose to be there. Bike runs fine