XJ750 with XJ650 carbs

Hey guys - so back in November I posted on here asking if anyone had an xj750 carburetor and I got a bite and the guy offered me a carburetor for an xj650. He did say they were compatible. I have slowly started putting everything back together. Can anyone tell me if I will be ok with the 650 carb set or did I get tricked?

 

https://www.xjbikes.com/forums/threads/xj-parts-catalog-section-c-fuel-system.44642/

It looks like the answer is yes, maybe.
XJ650 Maxim, Midnight Maxim, XJ650RJ Seca (non-turbo), XJ650 Euro all use HSC32 carbs (various versions)
XJ750 all USA 1981-83 models use HSC32 version 5G200 (Seca) and 15R00 (Maxim and Midnight Maxim)

It also looks like your question was answered here:
https://www.xjbikes.com/forums/threads/newbie-with-carb-question.126339/

 

Thanks mate, didn’t even see that.

 

no . the carbs are the same body and set up but jetted different you would need to do a complete rejetting from slide needles , air jets and fuel jets
http://xjbikes.wikidot.com/carb-specs

Years & Models: 1982-3 XJ650 Maxim USA models
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 5N800
Main FUEL Jet Size: #110
Pilot FUEL Jet Size: #40
Main AIR Jet Size: #50
Pilot AIR Jet Size: #205
AIR COMPENSATOR Jet Size: #36
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-10

Years & Models: 1981-3 XJ750 Maxim, Midnight Maxim, and Seca Canadian models
Carb Manufacturer: Hitachi
Carb Series: HSC32
Carb Model ID: 15T00 (Maxim, Midnight Maxim)
Carb Model ID: 5H200 (Seca)
Main FUEL Jet Size: #120
Pilot FUEL Jet Size: #43
Main AIR Jet Size: #80
Pilot AIR Jet Size: #195
AIR COMPENSATOR Jet Size: #36
Starter FUEL Jet Size: #40 (non-replaceable, in float bowl)
Main jet NEEDLE ID: #Y-14

 

Without the internal changes not going to work the way you want it to. Find the correct carbs from someone on here for a good price.

 

Thanks timbox

 

Buddy north of you in Toronto has similar problem. Has a 650 and has a set of 750 carbs you should do a swap

 

Could you give me info on that?

 

Sorry he doesn’t have a 750 set to swap. He was going to get a 750 set and rejet to fit his 650. I do have a 750 maxim set that has been to church including new diaphragms , throttle shaft seals that I could sell to you. PM me if you’re interested. Maybe he will buy your 650 set.

 

Pm sent

 

I PM’d you - let me know if you got it.

 

Hello everyone ! I know this thread is a couple years old now but i'm trying to get my bike together and am having similar issues. I have a 1982 xj650 with carbs that are filthy, I'm picking up a 81 xj750 seca that hit a curb for a parts bike this coming weekend and am curious on if I could make the xj750 seca carbs work on the xj650. the owner states the engine ran great before the accident. I do have the xj650 carbs complete if I need to steal a jet or 2. Any help would be great ! thanks

 

Yes, they should work, as far as I know. Both used the Hitachi HSC32 carbs. Jetting is another story.

All the data for jetting can be found here: https://www.xjbikes.com/forums/threads/xj-parts-catalog-section-c-fuel-system.44642/

Note that there are several variants for US/Canada/Europe, so it gets a little hairy.

 

Thanks for the quick response ! sounds like I'll just have to slap em on and play around with it see what works for me. I don't have much for specialty tools to work on these bikes as i'm only $200 into the bike so going to trying to keep my costs low as possible lol and thanks for the link it is definitely going to be useful with my trial and errors i'm sure I will face.

 

750 caebs on a 650 should start and run may be rich

you could swap the air jets and fuel jets from your 650 carbs

 

Just swap literally everything:Jets, needles, etc...... the carb bodies and rails are the same.

 

Awesome thanks for the suggestions ! I'm hopeful to find a decent middle ground between the 650 and 750 carbs lol. i will keep everyone updated on my progress!

 

There’s not a middle ground.

the bodies are the same. The jetting/internals are the differences.