Yamaha YICS? Or xj400? Is it the same?

Hello all, is the 80s yamaha yics in america basically the same bike as the 80s yamaha xj400 in japan? Reason i ask because i grew up in japan and seen them alot but now in america and i stumbled across a 80s Yamaha yics and looked very similar to the xj400 and first time seeing one here in the states and wondering if they were the same bike?? First pic is the yics here in the states, 2nd pic xj400 in japan

 

Welcome to the forum Herb I don't know the answer to your question but someone will.

 

Ok lol

 

Sorry ment to say is the xj400 in japan basically the seca550 here in the states?

 

That's pretty much the same bike smaller motor. You'll find a Japanese bike has dual-disc oil cooler and probably linkage for the shifter, for the sake of 550 does not. Yamaha had to meet price points to sell the bike in the United States so they could not afford the extra whistles and bells. As far as how to work on the bike it's identical
It probably has a lot of common parts.

 

Dang really thats a bummer for sure So is the frame smaller to? The bike kind of looks small compared to the Japanese version

 

https://www.xjbikes.com/forums/threads/tech-topic-model-id-and-vins.14577/
If you go to the above link, way down at the bottom it talks about the xj400 it says it is the same bike as the 550 seca with just a smaller motor and of course you have the dual front disc on the xj400 oil cooler.

 

Ok hey man thanks alot, i have a opportunity to buy it for 300 and mite be the closest thing to the real thing

 

Ok so i was kind of right on those models being the same but the styling and muffles with different motors, so the xj had the 400cc and the seca yics has the 389cc ? What can be done to get to a 400cc or better?

 

XJ550 Seca models (North America) have 528cc motors. The XJ400 models are basically identical to the rest-of-the-world's 550 models, with some minor exceptions as XJ550H pointed out previously.

 

But North America motors wasn't as powerful as the japan motors?

 

Sure they were, basically the same design, engineering, quality. North American (and many European) engines of this era had CARBS that were de-tuned (leaned out) to meet emission requirements, but otherwise it's all basically the same. Carbs can be re-jetted or have their mixture screws adjusted for more power in certain rpm ranges, but be aware there is almost always a trade-off: you'll get more power, say, at high rpm's, but it may become a bit of a dog at lower rpms, which is not what you want if you do mostly "city" operating, as you're really dependent on low-end torque in stop-and-go ("city") riding.

 

Ok i see thanks for the info, and was keep seing something about a yics tool? So this must be done if have a yics motor?

 

And another question is would the Japanese xj00 side panels fit the seca550

 

What are you aiming to do ? Make a US spec 550 look like a Jap 400??

 

Yes basically with the typical upgrades as far as beet side faring, tail wing, shocks upgrade, exhaust upgrade etc

 

Something along these lines

 

.

 

The YICS tool is needed to block the YICS passages between cylinders for carb syncing. There’s threads on here about making them.

 

Hmm that one is interesting - twin pot calipers and box rear swinger. Can't quite make ot the wheels - maybe original.