YICS Fix! It really works!

[YellowJacket!]

OK, I've been rebuilding my YICS - and a few others - for several years.  For the most part, I followed Lucky's instructions on his website and split the YICS in hald, sanded down the edges, and resealed it with a rubber/fiber gasket and red RTV.  For the most part it works and I've had a few last longer than a year.

It seems that the most common failure though is an INTERNAL leak between both chambers on the repaired YICS.  I've been experimenting with the ways that I repair them and never really could find a good way to reseal the inner septum (the thing that divides the two chambers).  I've even thought of sanding the insides of the chambers clean, resealing it and using a syringe to inject some POR-15 inside and coating the inner chamers with it.

Aside from finding someone with a CNC machine and the willingness to work for free, I decided rather to "think outside the box".  I found that on several of my failed seals that exerting just a little bit of pressure in the septum would stop the leak.  While it is not practical to squeeze my YICS while I'm riding, I decided to try the next best thing.

I drilled through each chamber and used a long bolt with two washers and a locknut to gently squeeze the chambers back together and it worked!  I tightened it just enough to make the leak go away but still preserved the bit of flexibility that a few of us feel makes these things work.  Its a bit ugly so I'll call it my prototype 1.  Also, the bolts stick up too far to allow me to use the chrome cover so I'll be driving around with a naked YICS fully exposed.  Oh well, its in the name of progress...

Anyway, after a bit of pressure testing and no leaks at all, its ready to go back on YJ for some field trials.  If I can conclude that it works, then I'll work on a better way of bolting the halves together and still be able to use the chrome cover.

Here's some pics of the fruits of my labor.







And here it is mounted on YJ:



David

[spectre]

Cool! I think my YICS might be leaking, I hope not... but I'm all for function over form if it'll fix the problem.  :)

[fret not]

I would think a single bolt of smaller size as close to the septum as possible would do to close the internal gap.  That would not take much force at all.

[Extent]

If you really do think that the "flexing" of the case has any effect on it at all then this will be just as bad, the large pressure will have a massive damping effect on any sort of vibration you may get on the two most flexible faces of the chamber. 

Personally I'd be much much much more worried about the volume that the bolts take up inside.  The rear chamber is only a few CC's smaller than the front, that must be intentional, and in my mind shows how sensitive the design must be to volume changes.

I think you may be better off trying to build up the height of the septum internally so that it will naturally be under more pressure when the sides of the case are clamped and glued.

[supervision]

  I made a pair of replacement cambers from 2 small WD40 spray cans. I was concerned of all the heat, collapsing hose, and plastic. These are thin aluminum. The connection of the rear intake port is very short. For the front cly I short coupled a piece of 3/8" copper tubing, bent to clear the throttle linkage. They seam to work, and are lasting.   

[Lucky]

Jürgen Lorenzen, who has been a member here, made some out of stainless steel. he put pics up of them on the XZ550 Facebook page.  he indicated that they were made for him & may be available for sale...

the volume is the same, & he says they work great.  i assume they don't 'flex'...

not sure if the link wil work but i'll try:
http://www.facebook.com/photo.php?fbid=229964463697373&set=o.32575026241&type=1&ref=nf

[kev10104]

I think that looks awesome.

[Lucky]

I think you may be better off trying to build up the height of the septum internally so that it will naturally be under more pressure when the sides of the case are clamped and glued.

I just did Spectre's & when we opened it , found that the "wall" in the center divider is gone (pics on the XZ550 Facebook page) I cut a new wall from galvanized sheet & cut a slot for the new wall to sit in.  Dirco'ed it all in & it's sitting clamped now.  should work great for the next 30 years...

[supervision]

 That's cool looking, with the logo scripted in.

[Raj1988]

To me, in all honesty, its just not worth the hassle, But then again... 

[YellowJacket!]

Ridden the bike quite a bit over the last few days with mostly around town riding and here ae a couple observations since I bolted the YICS together.

ALways ran great with the YICS on and just sealed up with the gasket and RTV but was usually a bit difficult to start.

Now starts easier than ever.  Idle is rock solid and steady at about 900rpm.  I think I need to adjust it though as I seem to remember the manual saying it should be around 1200 to 1300.

The only thing that seems new is a slight "bog" which I think may be related to the fact that the YICS is less expandable now due to the bolts.  A little finesse of the wrist fixes that though.  I need to check the vacuum line to the flapper actuator though.

I think I may try Lucky's fix that he did for Spectre and compare the two.

Could be all in my head though as I've done a bunch of other stuff to the bike too so it could be a combination of things.  However, I was able to tell when the YICS was leaking as the idle was all over the place, she was hard to start and ran funny.

David

[PeteXS/GS/CB/XZ]

However all this turns out, and whether a Vision starts, idles, and runs better with or without a functioning YICS, I sure wish Yamaha had designed and manufactured this part better. It's just a headache waiting to happen.

[jasonm.]

If you really do think that the "flexing" of the case has any effect on it at all then this will be just as bad, the large pressure will have a massive damping effect on any sort of vibration you may get on the two most flexible faces of the chamber. 

Personally I'd be much much much more worried about the volume that the bolts take up inside.  The rear chamber is only a few CC's smaller than the front, that must be intentional, and in my mind shows how sensitive the design must be to volume changes.

I think you may be better off trying to build up the height of the septum internally so that it will naturally be under more pressure when the sides of the case are clamped and glued.

FYI- the '83 chanbers are the same size. Yes, I know I had both an 82 and 83 apart. Also, when ypou use the incorrect sealer...it will not hold. RTV is not rated for gasoline. Thus you had to install bolts. Had you used a "plastic welding epoxy" Permatex has a good one at Advance Auto,  or maybe Yamabond4.  I have used both and neither has failed. But if you have sanded the ridges off then You must use the "plastic welder epoxy". Folow the directions, clean, sand, mix(use popcicle stick), apply. Sets in 5 minutes. Fully hard in a few hours or less.

[Extent]

FYI- the '83 chanbers are the same size.

Very interesting, do you know if they're both same size as the bigger or smaller 82 chamber?  I'm currently only running half of a YICS, and I could defenately tell the difference between it and the full size.  If I ever get to a dyno I'd be really curious to try different chamber sizes to see what's going on, but I haven't thought of a good way to make an adjustable chamber.

[lexx790]

FYI- the '83 chanbers are the same size.

Very interesting, do you know if they're both same size as the bigger or smaller 82 chamber?  I'm currently only running half of a YICS, and I could defenately tell the difference between it and the full size.  If I ever get to a dyno I'd be really curious to try different chamber sizes to see what's going on, but I haven't thought of a good way to make an adjustable chamber.

Try using a bicycle tyre pump, swap the tyre pump tube for something a little bigger to get the flow.
Does anyone know the exact cc of a YICS ?

[YellowJacket!]

FYI- the '83 chanbers are the same size.

Very interesting, do you know if they're both same size as the bigger or smaller 82 chamber?  I'm currently only running half of a YICS, and I could defenately tell the difference between it and the full size.  If I ever get to a dyno I'd be really curious to try different chamber sizes to see what's going on, but I haven't thought of a good way to make an adjustable chamber.

Try using a bicycle tyre pump, swap the tyre pump tube for something a little bigger to get the flow.
Does anyone know the exact cc of a YICS ?

I'm just about to crack another one open.  I'll see if I can dig up a syringe and make the appropriate measurements and post them.

David

[YellowJacket!]

Seen some talk about leaking YICS lately so I thought I'd revive this thread for some of the newer members.

YJ's bolted YICS is still working great with no leaks.

David

[Rick G]

Don Minor mentioned to me, that he runs the YIKS hose to the ports on the  intake manifolds. Says it works great.!!

[sunburnedaz]

Has anyone tried making a gasket for this?

[Rikugun]

Has anyone tried making a gasket for this?

Read the first paragraph of YellowJackets post. If you can make it to the second sentence you'll find your answer!  :P  :laugh: