YICS vs non-YICS?

are there pros and cons for each? I have an 82 650RJ non YICS and am happy to not build the block off tool and no doughnuts to order for the valve cover. how bout performance affects?

 

Someone would have to do a very accurate gas mileage run, then be brave enough to block the passage and repeat the run, hoping that whatever blocked the YICS doesn't get stuck due to heat.
{drive with an 8 OZ bottle on a clear road until the bike dies}

Then we would at least have a gas mileage comparison, proof that YICS works.

 

oh, so then syncing a non YICS motor is the same as syncing a YICS motor w/ out the blocking tool???

 

Yes- - don't tell me you didn't sync yet??

 

haha yes yes, but I have bigger problem than that. I asked that question becuase I seen so many threads on 'dont' sync your non YICS without the tool bla bla bla', meanwhile, us non YICS owners have no choice. I thought the casting of the heads were different somehow in the sense that it was naturally blocked off. guess not though. thanks

 

The non-YICS motors HAVE NO YICS passages in the head to block off.

The castings are different; whether or not YICS was truly any sort of an improvement remains to be seen.

 

What if some were to replace the yics carbs with non yics carbs like edelbrock32x34s or kenhin32CRs? Would any harm be done, besides a minute mileage difference? I'm getting tired of the high maintenance and endless fiddling with these Mitsubishi MCA-jet throwbacks.

 

I would think a good match for an XJ would be an off-road Weber that would go on a sand rail, connected to a shared intake manifold.

"replace the yics carbs with non yics carbs "
They are the same anyway. Minor jetting difference.

 

You're getting the two engineering concepts entangled; they aren't really related.

YICS is/was a set of passages cast into the head that pushed a charge out into the intake stream just above the intake valve, swirling the incoming mixture.

The carburetors fitted to the XJs, both YICS and non-YICS, are CV carburetors.

CV carbs have nothing to do with whether or not it's a YICS motor and vice-versa.