Rubber plugs in carb

[lhaolpa]

In rebuilding my carbs on my xs400 rj seca,I noticed that they sell rubber plugs for the pilot jets.My question is:Why would one close off the pilot jet ? Question # 2 is : should I get some and install them?I would guess that the 650 uses the same carbs as our more diminutive versions.My carb is Bs 34 ss,and I have been looking for a kit for it for some time.The earlier models seem to be better supported as far as parts are concerned.If anyone has any insight into the use of these plugs,please enlighten. lha

 

[HoughMade]

There is a passage from the main jet to the pilot jet and the pilot jet gets its gas through there. Older carbs (mine) had a screw blocking that passage. I would have a tendency to return it to stock...whatever that was.

 

[lhaolpa]

There is a passage from the main jet to the pilot jet and the pilot jet gets its gas through there. Older carbs (mine) had a screw blocking that passage. I would have a tendency to return it to stock...whatever that was.

Therein lies the problem,who the heck knows what stock is.Mine had no plugs or screws either so what does one do? To plug or not to plug,that is the question. lha

 

[hmusket]

I think you'll need the rubber plugs, I know my carbs, from an '81 have them. Copied this from the carb guide, page 9 of the PDF file

In BS34 carbs the pilot jet is under a rubber
plug at the end of the smaller vertical tubular casting in the carburetor body; the plug
must seal correctly.

Mike's XS has them.
http://www.mikesxs.net/products-39.html#products
Z1enterprises, sold in a set of 4
http://www.z1enterprises.com/Carb-Rubber-Passage-Plug-4-Suzuki-Yamaha-1962.aspx
I didn't check Parts Unlimited

 

[lhaolpa]

I think you'll need the rubber plugs, I know my carbs, from an '81 have them. Copied this from the carb guide, page 9 of the PDF file
Mike's XS has them.
http://www.mikesxs.net/products-39.html#products
Z1enterprises, sold in a set of 4
http://www.z1enterprises.com/Carb-Rubber-Passage-Plug-4-Suzuki-Yamaha-1962.aspx
I didn't check Parts Unlimited

In the pdf manual,there's a drawing depicting the fuel flow and the passages where it passes.In this drawing,it shows the fuel flowing from the fuel bowl into the pilot jet,no plugs.This is an'82 seca DOHC that I'm referring to.Maybe the seca has a different setup than the earlier models.The drawings don't show the plugs in the carburetor diagrams either. lha

 

[hmusket]

I checked the parts PDF at Yamaha ( http://www.starmotorcycles.com/partviewer/default.aspx?ls=star ),
for the carbs http://www.starmotorcycles.com/part..._(1982_MOTORCYCLE)/CARBURETOR_(XS400J_-_1982) and for the DOHC there is no reference to any type of screw or plug, that you find in the older models.

 

[lhaolpa]

I checked the parts PDF at Yamaha ( http://www.starmotorcycles.com/partviewer/default.aspx?ls=star ),
for the carbs http://www.starmotorcycles.com/part..._(1982_MOTORCYCLE)/CARBURETOR_(XS400J_-_1982) and for the DOHC there is no reference to any type of screw or plug, that you find in the older models.

That's what I found,nothing about the plugs,nor are they in any drawings. Thanks lha

 

[Shaun Chandler]

If I'm not mistaken they had plugs from 80 to 83. I only know because I was rebuilding my 1978 carbs this week only to discover that someone had swaped the engine and carbs on my 78 for an 81. I used the cmsnl site looking at the fiche from yamaha to figure out which carb I had. I didn't want to rely on the motor serial incase they were mismatched. I bought new plugs because mine were rotten, got them from sirius consolidated in cambridge ontario. Luckily I live close so I don't have to mail order I think I was six bucks for 4 plugs.

 

[lhaolpa]

If I'm not mistaken they had plugs from 80 to 83. I only know because I was rebuilding my 1978 carbs this week only to discover that someone had swaped the engine and carbs on my 78 for an 81. I used the cmsnl site looking at the fiche from yamaha to figure out which carb I had. I didn't want to rely on the motor serial incase they were mismatched. I bought new plugs because mine were rotten, got them from sirius consolidated in cambridge ontario. Luckily I live close so I don't have to mail order I think I was six bucks for 4 plugs.

'81,'82 two different animals OHC & DOHC are different. lha