'82 XJ650 Seca Without YICS?

My brother just brought home an '82 650 but it doesn't have the YICS on it. Did Yamaha not put YICS on all the bikes or is this a different engine? Looks to be nearly identical to my 900 engine aside from the YICS. Please shed some light on the situation! Thanks!

 

Yamaha did NOT use YICS on all the XJ family.

Lifted from Len's excellent YICS article.

 

So Fitz, s YICS a good thing, a bad thing or just a thing? It would seem no YICS at least simplifies carb sync.

 

The YICS system adds swirl and vaporization to the incoming air/fuel charge. Whatever air/fuel that goes thru the ports has enough time to completely vaporize, and a spinning air/fuel charge in the cylinder adds to the blending, giving a better burn. The system works more aggresively at part throttle, such as cruising speeds.

 

The YICS was pretty much just a sales gimmic in my opinion. If it were the cats meow, it would still be used in other engines. When engine manufacturers come up with something that works better or makes the engine perform better, others will copy it or do their best to without using the same patent. So far I didn't see any other engine use the YICS idea as far as I have noticed.
I've had Suzukis that had a "gear indicator" on them, which was another sales gimmic. (If you don't know what gear your in, you shouldn't be riding). I always thought it was a joke to even have it.
There have been other screwy ideas thru the years to make bikes stand apart from the crowd, but usually fall by the wayside after a year or two if it doesn't help sell the bike. Just a thought.

 

YICS makes it a pain to tune carbs. It's easier without it. I agree PainterD, its a sales gimmic.My XS without it tunes easies and runs better.

 

Thanks for the replies!!! That really clears things up.

 

Didn't Suzuki have that Twin Swirl Combustion Chamber? Isn't that basically the same thing?

Still used too....see SV650

 

I think the YICS bikes get better fuel economy.