Choke plunger - xs360 76' - pads are shot

[bochnak]

Guys,

I was able to get this bike running and been having an intermittent high idle. I checked for vacuum leaks and found the starter plunger the culprit. The rubber pads are hard and indented, so they need to be replaced.

Here is my issue. The fiche states the PN is 584-14171-00-00:

http://www.boats.net/parts/search/Yamaha/Motorcycle/1976/XS360C/CARBURETOR/parts.html


Here is a pic of part pulled from carb:

While here are pics of 584-14171-00-00 from mike's xs and ebay:

http://www.mikesxs.net/products-35.html#products PN 48-2012

ebay

http://www.ebay.com/itm/200653639033?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649


Clearly they are different. Can anyone help sourcing the correct part?

Has anyone been able to change the pads out? I have plenty of rubber stock and punches at work. I might have to make my own.

Thanks,
Matt

 

[bochnak]

I decided to try and replace the rubber pad.


Here is the plunger with the pad removed:

I used a 1/4" punch and ~.085" THK rubber. I would guesstimate duro to be 50-60. This rubber material is probably not ideal for carb use, but I want to see if the concept will work. McMaster sells Viton in rod and sheet form.

New pad installed. I think I'll use a drop of super glue.

Stay tuned, we'll see if this takes care of the issue.

 

[OliverB]

Neat idea. Yeah, not certain how the adhesive and rubber will hold up to gas long term but, as you indicated, it is an experiment.

 

[Shaun Chandler]

Good idea. When I saw your post earlier I didn't make the connection with the pad on the end there. I was probably drinking.

Good idea. Viton would be great. I'm also not sure about the adhesive. How were they held in before you removed them? Probably just pressed in would work well. If you can't get the exact right punch you could make one easy enough. Just drill a hole in a solid piece of bar and bevel the outside edge with a grinder. Won't hold an edge for long but it should work. Would help if ya had a lathe .

Shaun

 

[bochnak]

Thanks guys. The material I had laying around at work is neoprene. Not the greatest compatibility with gasoline.

I ordered Buna-N rubber from McMaster. PN 8635K543. 3/32" THK, 50 duro. They also have Viton, except the duro was 75, too hard IMHO.

There is a ridge on the end of the plunger that holds the pad in place quite well. I will also use glue as extra insurance. The old material seemed as if it was molded in place. Hard to tell.

Material comes in Monday.

 

[bochnak]

Would help if ya had a lathe

We have lathes at work

The ridge ID is .220", while the punch is .250", so the pad fits perfect.

 

[bcware]

If it's a temporary mock setup I'd try grip glue over super glue. I would think the superglue won't bond to metal well, but grip glue is designed to bond rubber to metal while being non-hardening. Plus, you might have some lying around.

That new slightly different looking part might fit. If the only difference is the length of the tail. I've never seen a replacement plunger anywhere else.

 

[xschris]

Does your choke use a thumb lever on a cable? That looks like a set up on the 82 xs400 and the 82-84 xs650 carbs. I have had a few sets of these carbs. Do you have any pics of the carbs?

 

[bochnak]

If it's a temporary mock setup I'd try grip glue over super glue. I would think the superglue won't bond to metal well, but grip glue is designed to bond rubber to metal while being non-hardening. Plus, you might have some lying around.

That new slightly different looking part might fit. If the only difference is the length of the tail. I've never seen a replacement plunger anywhere else.

I don't think the glue is needed. The ridge holds the pad in place. I have to use a pick to remove it.

I don't have any grip glue. However, we use this adhesive all day long at work bonding metal and rubber/plastic:

http://www.permabondllc.com/TDS/102_TDS.pdf


I'm not sure if the new plunger would work. The plastic "dumbbell" (look at the large OD) accepts the fork that lifts and lowers the plunger.

 

[bochnak]

Does your choke use a thumb lever on a cable? That looks like a set up on the 82 xs400 and the 82-84 xs650 carbs. I have a a few sets of these carbs. Do you have any pics of the carbs?

Yes, thumb choke lever.

 

[xschris]

Not the same carbs but the choke plunger with the plastic spool on it does look the same. The 82-84 xs650 used these type.

 

[xschris]

http://www.ebay.com/itm/YAMAHA-XS65...Parts_Accessories&vxp=mtr&hash=item45fa936d71 Looking at a pic I guess it is different yours don't have the pin in the middle.

 

[bochnak]

Well, the Buna material came in. I superglued the pad in place and tested the plunger in the the choke body with some compressed air. Zero air leaks! I confirmed that the old pad was bypassing some air.

This did not resolve my high idle issue, however. The high idle issue was the RH cylinder not firing. The idle speed screw was turned in far enough to make only one cylinder idle properly, and when the RH would fire intermittently, RPM's would increase.

In any case, I think new plungers or this mod was in order.

 

[bochnak]

I recently started a blog on MC repair.

I've added all this information on the following post:

How-To: Choke Plunger Pad Replacement

I'm hoping it helps people beyond this forum

 

[Drewcifer]

he's got an xs 360 guys, same as me. Different mechanism, same function. You can even see the tooling on the outside of the xs400 carb is the same, just uses a plunger instead.