Demon Valves! Updated 3/27

Alrighty, I've had an incredibly terrible time getting my syncing/colortuning to work after a carb overhaul, but before this can happen, the valves obviously need to be in spec. I've put them into spec FOUR times over the last week - every time I measure them, the numbers change enough for me to need to change 1-3 shims.

I'm using metric feeler gauges with the engine at 24 hr cold temps. Checked the clearances on all 8 valves, and a couple were out of spec. Replaced those shims, hand rolled the engine over about 4 times, and then remeasured all 8 - one was out, rinse and repeat until finally all 8 were in spec after rolling it over.

Started the bike, got it synced relatively close, but still sounded odd. Re-checked valve clearances again, and 3 were out of spec!

What the F*** is going on!!?

 

Re: Demon valves!

Are the same shims measuring out of spec or different shims each time?

 

Re: Demon valves!

The only way valve clearances change like that (and I assume yours keep getting tighter when they change) is that the valves are sticking/not closing properly when measured; and then after running for a while they seat better and the clearance changes.

This can be caused by a damaged or bent valve, a "burnt" valve, or excessive carbon deposits that are breaking loose and preventing the valves from seating.

Exactly what is happening? Which valves keep changing, and what is happening to the clearances?

The other explanation is that you're not getting them fully seated until you run the motor.

Give us some specifics. Something's going on. Are you using the bucket holding tool, or the "zip tie trick" to hold the valves open?

What is the history of this motor and your history with it?

Have you run a compression test at any point?

What happened with the YICS eliminator tool?

 

Re: Demon valves!

They are actually getting loser, aka needing a thicker shim. They've been all over, but usually it's 2 and 3, both intake and exhaust.
I've been using the bucket holder tool, not a zip tie.

The motor has 9500 miles on it, i've had it since 7k, when i put the valves in spec before putting a season on it.
The last time i ran compression, they were within 2psi of each other, all solid number.

Im going to order a yics tools from len, but before that will be needed, these valves should be sorted out.

 

Re: Demon valves!

Soo... what happened to the YICS eliminator?

I'm beginning to wonder if glops of melted o-ring are being pulled in behind the valve seats (where the YICS passages go) preventing the valves from closing properly.

Too loose means the clearance suddenly increased. The only way that can happen is if the valve isn't closing properly, for whatever reason. The valve didn't get shorter.

Either that, or the shims weren't in place when you measured them, and when they seated the clearance increased.

The only other possibility would be what I said before; bent/burnt/damaged valves or broken valve springs.

Get them as in spec as you can; roll the motor over, forward only, about 8 times by hand. Then unplug the TCI and spin it with the starter for a few cranks, and re-check. If the clearances held, run a compression test and post results.

 

Re: Demon valves!

1. Did you set the lobes in the same positions for each read? Ensure proper lobe alignment. Take a picture of the lobe position for each measure... Reference pics when performing repeat measure. Share problem cyl pics before and after with us
2. Did you loosen cam journals or measure journal clearances to ensure you're in spec (not suggesting you must do this but am wondering if you removed journals or removed cam?). Might not hurt to check journal clearance to make sure they're not too wide
3. Buckets are well oiled and are not hanging?
4. I think temp of the block is supposed to be "room temp" are you in a 50 degree or colder garage?
5. Make sure no dirt or debris or excessive oil on shin bottom side which will crush out on turning over the motor
6. Make sure shims are seating before measuring they should actually rotate in place once they are snapped in

Hope any of this helps

 

Re: Demon valves!

1) Same lobe position every time, 180 degrees off the buckets; dead oposite the top of shim.
2) Don't know anything about Journal clearances - no cam work has been done on this bike besides chain tensioning.
3) Fresh oil, flowly freely on all buckets.
4) 60 degree shop, always waited 24 hours after engine use to measure clearances.
5) Fresh oil. Hand rolled the engine 5 times and remeasured installed shims just to prevent this.
6) They go *click* when removing the bucket holder tool.

Greatly appreciate your reply - I will have to get a compression test afer quadruple checking the clearances.

 

Re: Demon valves!

What is source of replacement shin - new or used... If used they may be thinner than stamped... Did you measure them

 

Re: Demon valves!

Sounds like a valve is bent. What was your very first set of clearances to begin with?

Also, did you happen to loosen any of the cam clamps? If so, make sure they are all tight again.

Yup, give us a compression reading.

dave

 

Re: Demon valves!

All but 2 are used. I used a digital caliper to confirm all their measurements, and all were within .01mm of their indicated, like 2.55 was 2.54. And actually a couple I got from chacal were .02mm off indicated thickness, but still usable to get me within spec.

Here is my initial thread when I started doing valves.

 

Re: Demon valves!

Alrighty - fresh compression numbers:
130PSI across all 4 cylinders after cranking for 5 seconds on each.

I would still like to re-check the clearances again, but in the mean time, what else do you guys think could be going on here?

I'm certainly clueless and steadily approaching a state of discouragement.

 

Re: Demon Valves! Updated W/ Compression Numbers.

Healthy. When you get this puppy right, it's gonna haul.

Re-check the clearances.

You never did answer as to exactly what happened to the YICS eliminator tool. If that things all melted and broken up in the YICS passages, it could explain a lot.

While you're waiting for a proper YICS block-off tool, clean out the passage. Pull the bolts out of both ends, get a strong flashlight and be sure the YICS gallery is clear.

 

Re: Demon Valves! Updated W/ Compression Numbers.

Hey, thanks again.

Glad to know my compression numbers are encouraging.

Forgot to mention the YICS eliminator - removed it and all accompanying o-rings came out clean and clear. Will have to wait for the proper tool - Len wants a fair amount, but I'm crazy for this bike, so it is what it is.

 

Re: Demon Valves! Updated W/ Compression Numbers.

The YICS Passage is easily Cleaned.

Use a Hardwood Dowel or a section of Fiberglass Driveway Marker Pole.
Cut BOTH end Flat.

Remove BOTH Plugs from the Right and Left side YICS Tunnel.
Cut-out Squares of Cloth or Terrycloth -- 1-1/2" X 1-1/2" Square.

Soak the Cloths in Carb Cleaner
Push them into the YICS Chamber.
Poke them through the Chamber.

Tab the Rod or Dowel with a Rubber Mallet.
Let the Patch fall-out the other side.
Keep send Patches through the Chamber UNTIL the Patches fall-out as Clean as they are going-in.

FREE YICS Tool

http://xjbikes.com/Forums/viewtopic/t=4 ... =yics.html

 

Re: Demon Valves! Updated W/ Compression Numbers.

The YICS Passage is easily Cleaned.

Use a Hardwood Dowel or a section of Fiberglass Driveway Marker Pole.
Cut BOTH end Flat.

Remove BOTH Plugs from the Right and Left side YICS Tunnel.
Cut-out Squares of Cloth or Terrycloth -- 1-1/2" X 1-1/2" Square.

Soak the Cloths in Carb Cleaner
Push them into the YICS Chamber.
Poke them through the Chamber.

Tab the Rod or Dowel with a Rubber Mallet.
Let the Patch fall-out the other side.
Keep send Patches through the Chamber UNTIL the Patches fall-out as Clean as they are going-in.

 

I'm pretty much at my wits end on this pig and don't know what to do :evil:

I checked the clearances over 10 times yesterday, with some changes in their numbers throughout the process. In particular, #3 exhaust would be .15mm, I rolled the motor over by hand about 4 times, then electronically about 15 more. Remeasured, and it was .18mm. Without changing shims, rolled it again by hand and then electronically, it was .20mm. Rolled it more, then .18mm again. #3 intake, and #4 intake also changed, were reshimmed and stayed in spec thereafter.

The last three clearance checks were all within spec, although a few of the numbers changed by .01 or so (to be expected i guess, that's pretty slight).

My compression numbers were all great at 130psi on all 4.

After some bourbon and sleepin' on the work, I checked them all one more time today, and they were still in-spec. Blocked the YICS with rick's olive oil and tee-shirt strips, and it synced fairly well - that's never been my issue though. Took it for a little ride, and it sounds pretty terrible. It sounds like a valve issue, like in THIS VIDEO.
It makes the same clacky sound with poor power until maybe 6k RPM, and then WOT gets about 7.5k RPM regardless of the gear. Neutral sounds amazing and redlines nice and crisp.

Where do I go next, besides the local bike shop with a fat stack of cash? (Honestly doesn't sound terrible, unlike this bike).

 

Someone will pitch in you've gotten out of my league but clearly that head has gotta come off something is (stating the obvious) not ok with one or more valves... Get em out and inspect roll em on glass to see what's going on...