100% Canadian 1980 BS34 Jetting Specs please?

[Vincenthdfan]

Hey all,
I'm trying to ascertain the 100% factory jetting specs for the 1980 Canadian BS34 carbs please.

I have bits and pieces by search function and bookmarked discussions from the past, but would like an honest to goodness 100% breakdown if anyone has one off the top of their heads?

Thanks in advance!

 

[jpdevol]

Courtesy of Skull & translated from Japanese (Oceana, Canada, etc)

 

[jetmechmarty]

Mine is U.S. I'm not sure it makes a difference. My XS650SJ factory service manual has two, depending upon where in the book I'm looking.

Pilot 42.5
Pilot air jet 135
Main jet 132.5 and 135

Above is factory. Below are my two stock Specials.

XS650SK:
Pilot 42.5
Pilot air 132.5
Main 135

XS650SH:
Pilot 42.5
Pilot air 130
Main 137.5

My only measurable deviation from stock is the aftermarket filters in the airboxes.

 

[Vincenthdfan]

What I'm trying to get away from here is the stringent USA EPA specs for both of my 1980 Specials that are all stock (filters, boxes, etc.).

Do we have the Air Jet spec (#46 on diagram), I believe I read in the past it was a 130?

 

[Vincenthdfan]

Mine is U.S. I'm not sure it makes a difference. My XS650SJ factory service manual has two, depending upon where in the book I'm looking.

Pilot 42.5
Pilot air jet 135
Main jet 132.5 and 135

Above is factory. Below are my two stock Specials.

XS650SK:
Pilot 42.5
Pilot air 132.5
Main 135

XS650SH:
Pilot 42.5
Pilot air 130
Main 137.5

My only measurable deviation from stock is the aftermarket filters in the airboxes.

Have you done anything with your needles and needle jets?

 

[jetmechmarty]

What I'm trying to get away from here is the stringent USA EPA specs for both of my 1980 Specials that are all stock (filters, boxes, etc.).

Do we have the Air Jet spec (#46 on diagram), I believe I read in the past it was a 130?

Factory pilot air jet is 135.

 

[Vincenthdfan]

Factory pilot air jet is 135.

Canadian too though? I believe Canadian was 130, but want to confirm.

 

[jpdevol]

Just switching from the 270-Y-0/5HX12 NJ/needle combo to the 336-Y-0/51X11 accomplishes richer throughout (effects pilot circuit less, mid & main more). And, you get adjustability with the 51X11 - but start @ #3. I'm guessing you'll end-up one (maybe two) steps leaner on the main vs US spec

 

[jetmechmarty]

Have you done anything with your needles and needle jets?

My needles and needle jets are clean. Nothing more. Factory set.

 

[jetmechmarty]

I'm guessing you'll end-up one (maybe two) steps leaner on the main vs US spec

Did you mean richer (larger)?

 

[jpdevol]

Did you mean richer (larger)?

If switching to Non-US NJ/needle, it'll likely be now too rich on the main, so need leaner. My experience is ~2 sizes all else equal. Stock US BS34 jetting is typically very lean to ~ 3/4 throttle and the non-US bikes better jetted

 

[jetmechmarty]

If switching to Non-US NJ/needle, it'll likely be now too rich on the main, so need leaner. My experience is ~2 sizes all else equal. Stock US BS34 jetting is typically very lean to ~ 3/4 throttle and the non-US bikes better jetted

Interesting! Thanks.

 

[jetmechmarty]

I’m sorry I misunderstood the intent of this thread and polluted it a bit.

 

[jpdevol]

Not at all; you helped flesh-out the discussion and explain why all those jet numbers "those geeks" are tossing around matter

BTW, I learned all that minutia here (not before), so credit goes to Skull, 5twins et al

 

[Twenty2]

I have a Canadian '80 Special and it came with 135 air jets, I have no reason not to believe that they are stock but I guess it is possible.

 

[5twins]

I've never seen any Canadian BS34 jetting specs in print anywhere. The "world" model specs that 650Skull posted are all I've ever seen besides U.S. specs. I think I've seen several Canadian members post about finding 132.5 mains. But, I don't think anyone knows for sure what came in there, lol. We need more Canadian members with totally stock and unmolested BS34 equipped bikes to chime in.

Also, I've never seen any spec on the factory needle setting for that 5IX11 needle. 650Skull has reported finding his in the #4 slot (from the top), but who knows if that is where the factory set it. He posted a pic and the needle looks pretty crusty and beat up, so it could very well have had it's setting changed. Set in it's middle #3 slot, which is often a factory setting, the 5IX11 needle is 2mm shorter than the U.S. spec 5HX12. That's equivalent to two clip positions, and that's a big change for a needle. Set like Skull found his would add another MM to the difference and be richer still.

 

[650Skull]

Never stated the set up I found in my carbs was stock. Only stated that was was the way they were set up. The jets had obviously been played with due to the condition of their heads

I literally spent hours converting the Japanese BS34 carb diagram to english. Cross referenced from the manuals from 650cafe, biker.net and online parts semantics from the Yamaha dealers you regularly reference. And those parts lists have discrepancies as well. These are Yamaha dealers mistakes

Your welcome by the way. It was after Imade up and posted the parts list for BS34's with the pilot screw part no your search managed to find a replacement from another model.

Again I never said my carb set up was factory

 

[jpdevol]

I literally spent hours converting the Japanese BS34 carb diagram to english. Cross referenced from

And kudos to you for that, and the model history in Tech, and....

 

[5twins]

Skull, I'm afraid your translated BS34 diagram had nothing to do with my search for a mix screw replacement. I found pics with measurements on eBay and that's how I found it. And the part number listed for the mix screw in your translated diagram (3L1-14923-00) is no where close to the part number of the replacement I discovered .....

But, thanks for that translated drawing, it is helpful.

 

[jpdevol]

Part numbers change......the original 3L1-14923-00 (fuel screw only) is now 11J-14105-00 (screw kit)
https://www.cmsnl.com/products/pilot-screw-set_11j1410500/