Carbs suck ..... in more than one way.

Been gettin a lot of carb help from here on XJBikes, thanks. But not yet done as you can see from the subject line.

Got it to lite-up but have had nothing but problems with running smooth and color-tune / YICS tool. Using homegrown YICS too was able to get good color out of #3 & 4. Number 2 was all over the map and #1 showed nothing but a white color.

Oh God help me! Removed YICS and after several sequences of idle mix screw was finally able to blue color on #1 at about 1/4 turn from bottom. Okay, opened back up YICS ports and tried tool again, no blue, basically all white and hard to even keep my darlings heart running.

Anybody want my YICS tool?

Any thoughts, helpful or humerous?

 

Couldn't help it, had to feel it out of the garage and under load. It ran worse that is sounded during tuning. Missing, jerking under low rpm, good for a second under 5K rpm then missing again and losing power. Was trying for 4 mile round trip .... headed back home for 2mi round trip, I really didn't want to walk farther that that.

Bike ran really smooth prior to full carb job (float bowl leaking started this), don't know were to go with this, junk yard keeps coming to mind.

 

oh yea, and after making sure valve clearances are in spec (shanged 3 shims) it sounds like I have a valve that wants to escape the head!

 

You don't use the YICS tool when adjusting for mixture; it's only to be used during a running carb synch.

 

Thanks, that differs from my understanding of another thread post. I'm trying everything so I'll go this direction. Checked plugs after most recent ride (so to speak) and both #1 & #3 plugs are carboned up real good.

Obviously rich, so I'll continue from here.

Thanks again!

 

Did you get a good bench sync then a good vac sync?

If so, you're done with the YICS tool. Shouldn't be used when doing colortune.

 

Re-do your Bench Sync.
Use strips of 3X5 Card.
Before you reinstall the Carbs; smoosh some RTV on the Manifold to Head Joints.

Install the Tool.
ColorTune for Idle.
Blue is good Idle, ... But you need a bit more richness to get out-of-the-hole.

Get the Blue.
TWEAK --> Out ... Until the BLUE fades due to the additional richness.

From there you should be able to Vac Sync OK.

 

Yep, used 3X5 card strips for my bench sync. Vacuum sync took a few times but ended very consistant (with YICS tool).

First attempt at color-tune was terrible (no YICS tool) and would get no color regardless of where I turned the idle mix screw ...... just white flash, no blue, no orange, no yellow. Thought it was not getting fuel, checked bowl level ..... perfect. Went back to Yics tool, getting some orange, okay, went back to NO YICS finally got blue color. Took quick ride (thought I would have to walk home) #1 plug seriously carboned up.

I get blue but doesn't matter where I turn mix screw to ....... it's still blue but idle sure changes.

driving me crazy and don't want to pull the carbs again!

 

Check for air leaks.

Check that AIR Jets are correctly placed.


Remove Pilot Mix Screws.
Inspect for Flattened O-ring at bottom.
Assure O-ring and Tiny Flat Washer NOT "Flipped-over"
(O-ring above Flat)
Flush top to lower passages.
Pilot AIR through Pilot FUEL
Block Pilot Fuel orifice.
Flush Pilot AIR thru Mix Screw orifice.

 

Your valves should have a nice rhythmic tapping at idle. It should be an equal amount (sound wise) of this coming from any one of them. It isn't loud but it isn't quiet either. Anything different and something isn't right. If you have a valve that is too loose it will be really loud, too tight and you won't hear it at all until it's too late.

You might have had a shim riding above the bucket when you measured and it settled in after to go REAL loose-I'd go back in and check clearances before you mess with the carbs again. Once my shims are back in I drizzle them with oil and crank the mill over several times to 'bed' them in before I do the final measurement.

By all means don't give up. A bike that is running at all is ALWAYS worth saving....that is unless it's a rusty old nighthawk 250!

 

IF the Valves are IN Spec, ... then HEARING them is GOOD!!!

The Valves are Closing real tightly, ... transferring Heat to the Seat for Cooling.

I fuss to have the Valve train .004 on Intakes and .005 or .006 on Exhaust.

 

Not so. Mixture tuning using the ColorTune is our "visual substitute" for the EGA that Yamaha used for mixture tuning. Yamaha specifies the blocking of YICS for the EGA procedures (mixture tuning) as well as for sync.

The reason for this is that with YICS not blocked, you're "reading" a combination of the cylinder you're working with PLUS the other 3, via the YICS passages. With it blocked, you've isolated the cylinders from each other. So if you're seeing an issue with one particular cylinder with it blocked, then that carb (or cylinder) does indeed still have some sort of issue. Possibly a vacuum leak.

 

You are correct. I mis-remembered the procedure.

 

Thanks all .... I'm still not convinced my YICS tool (homemade) is actually blocking ports. So until I have confidence everything else, it seems, have several confounding factors which introduces unknown results in this carb sync.

What I do know is that the unrelated from YICS tool is the valve noise. I only modified 3 valve shims. *no. 2 intake *no. 3 exhaust and *no. 4 exhaust. The noise seems to be originating on the left side the. So no.2 intake change is where I start my exam.

 

Just go back and re-check all of your clearances.

 

With any carb issue, valve clearances always are questioned. I would recommend re-checking your clearances just to rule that out. Just an FYI, valve ticking or fluttering sounds are happy sounds.

After that, I'd take a look at that homemade YICS tool....

 

I love that normal valve ticking ..... but this is out there. So yea, off comes the valve cover again.

For me to have any confidence in YICS tool I'm going to need to buy one. Shipping costs are terrible for one item purchases.

 

From Len???

 

Actually costs are good from Len ..... But going back is another story. Sent SS brake lines back and that was bad (still compaining). Will get YICS tool from him, hope it is fool-proof cause it seems this fool will find it if there is a fault.

Just finished re-check of valve shim clearance ..... all still within spec. Maybe valve noise because fuel mix is so rich and piston skipping a beat?

 

Off topic, but how dis you ship back? Just use priority mail flat rate boxes

 

UPS wont ship to PO Box so had to go USPS. Brake lines don't fit in any of their standard anything fits box so had to use normal process. $15.