Carb Swap

Has anybody tried or got any opinions on swapping the hittachi carbs on an 82 xj650 for a set of mikuni carbs of the later 89 xj600. Does anyone think it might work cos they are a lot easier to find, and it could be cheaper buying a second hand set of ebay than replacing diaphrams etc.

 

Even if the Carbs bolted straight-on, the orientation would probably be a problem not easily overcome.

Those Carbs wouldn't come Close to mating-up with the Airbox and you'd be doing some Re-Jetting for awhile until you got them anywhere close to feeding gas like the ones that belong on it.

 

Tried the carbs of the 89 xj600(pre divi) and they are a straight fit, and looking at the airbox rubbers its looks like they will also fit without a problem, i had pushed them into the airbox to remove old carbs. All cables fit as they should. As for orientation not sure what you mean, you may be thinking of the diversion with its inclined engine which my 600 is not. So if i can find a cheap set i think i will give them a go.

 

I looked at a set of XJ600 Carbs on eBay. Those Carbs are oriented differently. The Fuel Bowls and Floats are tucked-up under the Carbs.

The Carbs are Down-draft Carbs ... not Side-draft, like on the Bike you have now.

To make them work, and I doubt you can ... the Intakes are going to need room for plumbing or Intake Air hook-up.

Although I'm just guessing ... my best guess is that they might bolt-on ... its what you need to do after getting them bolted-on that will provide the insurmountable problem of getting them to fit and use on your bike.

 

Not sure what you mean by side draught and down draught, have heard the term but never really new the difference. As for the carbs, after stripping both sets to clean they are virtually identical, i am thinking you have these mixed up with the XJ600 Diversion which i think is different and i think it also uses a fuel pump.
About the only thing i can find that is different is the choke, on the 650 it has a lever on the hand controls, on the 600 it is just a knob on the side of the carbs, pull on - push off.

Also cant see where the extra plumbing would be needed as the setup is the same on both bikes.

 

I must have looked at the wrong year bike. If they are identical, the only other possible set-back would be the Jetting.

You might wind-up bringing-over the former Jets if the Jet sizes are not the same.

Other than that, I guess you are good to go!

 

Will update this post in the future to let you know if it worked or not, for the moment i am concentrating on the 600, but to my mind it could be very useful to know if these carbs will work with maybe just slight jetting changes as over here at least you can pick up a full bank of these carbs for less than the price of a new diaphram.