Help - YICS Plug Threads Broke

Hey guys,

I was just finishing up tuning the carbs with the YICS tool. Got everything slapped together and began putting the YICS plugs back in on the cylinder block.

As soon as they started to tighten, the threading basically just crumbled and I'm left with what you see in the pictures... It happened to both sides.

I know the YICS helps to improve fuel efficiency and what not, but at this point I REALLY don't want to replace the cylinder block..

Is there any way that I can just close off the YICS passages and just seal it off? If so, the carbs would just be independent from each other and as long as they're synced/tuned, should run just fine.. less a few mpg... right?

Any and all ideas are welcome as I really don't know what I'm going to do at this point..

1982 xj650

 

The porta can be blocked, but you have to pull the head to do that. I'd strongly recommend consulting a machine shop about a repair in-situ. I've never seeen or heard of the plugs cracking the main gallery. Very odd.

On second look I don't think it can be repaired in place, or repaired economically anyway. Degrease thoroughly, remove that one o-ring that's visible, and stuff the gallery full of a good 2-part epoxy. That'll give you time to find a replacement set of cylinders and pistons (or a spare engine).

 

Well, if it has to be done then so be it.. I found a cylinder block with Pistons on eBay for $70.

I'm not overly familiar with this engine.. but I have the Haynes manual and am a pretty patient and meticulous person. Do you think it's feasible to replace it myself?

I'd there anything else I should look at replacing while it's pulled apart?

Again, any insight is appreciated!

 

With the book and some patience yes you can replace the jugs. Make sure that when you do it to replace the gaskets if need be, and use the correct ones. XJ4ever in the top right corner has all of them. Just don't hesitate to ask questions if you have them. Have fun and good luck.

 

Yes. It's an easy engin to work on. The top end comes off with the engine in the frame. The gaskets, spcial o-rings, and spcial crush washers will set you back a fair amount though. The hayns should be sufficient for that job, but you should look for a Yamaha manual as well. Neither one covers evrything in enough detail, but the two together do.

+1 on ordering from Chacal. There are a few gasket kits that are just plain wrong despite being sold as being correct. Chacal won't sell you one of those.

 

Just as an update for anyone that ever reads this... I ended up buying a "YICS Eliminator Tool", removed the o-rings, degreased the exposed sections thoroughly, installed the eliminator tool and filled it in with an epoxy called "QuickSteel" by blue magic (1300c max temp); ended up doing 2 coats. Let it sit/dry for roughly 2 days. I've put about 100 miles on the bike since (both inner city and highway speeds) and it seems to be holding well.

 

How did you break the case ?.....did you over-tighten the YICS port bolts.....

Wow...... both sides cracked......

Sorry that happen to you......ouch

 

I'm thinking a solution involving jb-weld to get the casting back together. and a threaded rod with washers and nuts through the entire passage. The nuts clamp the hole thing together vs relying on threads in the casting.

 

I have an aftermarket aluminum engine case in my 71 Super Beetle ...very expensive ...the oil sending unit boss cracked ..fixed it with liquid steel 2 part putty and JB weld a little over kill but does not leak and has been in place for 3 years . I could fix it by tig welding, but would require engine tear down so not something I want to do. From the look of this I suspect that at some point your YICS ports were over tightened and possible the tool was forced in but who knows . If your repair works run with it , better than pulling the head and replacing . I have never pulled the plugs on my 750 Seca and do not intend to I synched my carbs without the tool with no problem.