Messing with Carbs

xsjohn · Posted: July 11, 2007, 9:32 pm Post subject: Messing with Carbs

I have a hotter right cylinder on my 80....Anyone else..????Left the black rubber plug off the right by accident and it cooled down.....Misses a high rpm's ...........Tells me the right needs more fuel....

John

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

No, No, No, that 34mm carb was designed to run with that rubber plug. If you remove it, it'll run too rich. This carb was designed to draw it's pilot mixture from the side, off of the main jet area, not directly from the float bowl like most.

xsjohn · Last edited by xsjohn on September 21, 2007, 7:59 pm; edited 4 times in total

5twins......You are right.....But his lets me know the right needs more fuel.......
John

xsjohn · Last edited by xsjohn on July 13, 2007, 9:35 am; edited 1 time in total

5twins.......Still looking for a better solution.....

John

hesredbird

Are you talking about the vacuum line plug? I don't know any other rubber plug. I am also an idiot.

xsjohn · Last edited by xsjohn on August 21, 2007, 11:56 am; edited 2 times in total

Don't know a better solution than to run the right a bit richer with a hotter plug to keep the plug clean.....Can you imagine explaining this.....I opened a bag of worms for sure.......Should have stuck with the earth is flat and the earth is also the center of the universe........But being an idiot I had to open my mouth....

Before I dicked with this situation on mine I was seeing 260 and more degree cylinder temps and now 225-240 depend onthe ambient.......

John

Xumi

So in your opinion, John, is this a better solution than raising the needle on the right side? (I'm on a '79, so it shouldn't matter to me.. but I'm curious).

xsjohn · Last edited by xsjohn on September 25, 2007, 11:16 pm; edited 4 times in total

Xumi.....Got the right combination now........Have to work the slopes too>>>

John

jimdi · 650Rider Supporter Joined: Oct 27, 2005 Posts: 512

Ok John - you got me again -
Why does the plug effect the right cylinder and not the left?

(2 carbs - 2 plugs - 2 cylinders)

Jim

INXS650 · 650Rider Supporter Joined: Mar 22, 2007 Posts: 645

Why not just get a set of 34mm VMs, and call it a day? Oh wait, I have problems with my VM's too. Get a fuel injection kit I say. Anyone know where to get one?

xsjohn · Last edited by xsjohn on July 17, 2007, 8:26 am; edited 1 time in total

Jimdi.....I was an idiot.....my right cylinder has always run real hot compard to the left.....Took the plug out of the right in desperation trying to cool the right cylinder......It cooled it but misses on the top end...

John

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Try some 5Z1 needles from a late '70s XS400. They're pretty much the same taper as the stocker but are adjustable. With the clip in the center slot, they're about 1.5mm shorter than your originals so they'll run richer. You can raise them 2 more slots if you want and make them even richer.

xsjohn · Last edited by xsjohn on September 21, 2007, 7:00 pm; edited 4 times in total

5twins.....found the correct solution......

John

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

I'll have to check my temp there. The hotter spot I've found so far on the right is just in front of the plug (20-30' hotter). Other spots (behind plug, cylinders, head pipes at head) run about the same on both sides.

Xumi

Trying to think about John's mystery hot cyl.. talking about the basics of a motor - if the fuel mix is equal both sides, and the compression is same both sides, that leaves timing, valve clearance, exhaust backpressure, and excess friction (scored sleeve/piston/rings) as primary other factors that could affect performance and temp.. did I miss anything?

Timing - he's electronic. I doubt it would be an issue.

Valve clearance - John knows what he's doing and watches this, and keeps maintained.

Exhaust... John, have you checked for exhaust leaks?

y guess is that if everything else checks out, you may have a problem inside that cyl.

xsjohn · Last edited by xsjohn on May 29, 2008, 7:55 pm; edited 4 times in total

Xumi....Not a mystery to me any more....right lide runs 25-30 degrees hotter which makes it leaner.........probably because of the drive side and the heat disapates less than the left which is above a air space on the stator side.......

Thanks John

Xumi

John,

Well - I guess if it runs good and strong.. I wouldn't lose anymore sleep over it. Sure is curious though!

Now I just had a vision of you leaning over the side with your laser thermometer to check temps while riding down the freeway... That sounds like fun!

xsjohn · Last edited by xsjohn on September 21, 2007, 7:02 pm; edited 4 times in total

Bet if you used a thermometer you would find the right cylinder on yours a bunch hotter that the left........Thinnk the problem is in the head ........

ANY ONE ELSE OUT THERE WITH A INFRARED THERMOMETER LET ME KNOW WHAT YOU FIND ---THANKS---

Thanks John

tracker79

I ran a fairly hopped up snowmobile a couple of years ago and after a couple of melt downs i put exhaust tempature probes and a gauge on it. After that you could tune down to a knats ass, end of problems. You could see exactly where you was, lean/fat from mid range to wot. To keep even egt`s both carbs were set different. Had about $85 in the probes and gauge, well worth it.

xsjohn · Last edited by xsjohn on January 29, 2008, 5:51 pm; edited 2 times in total

The right side rukns quite a bit hotter....?

John

tracker79

A buddy of mine has one of those things, i`ll see what mine reads. Thinking about what Xumi said about checking while riding, the right side may be alittle tricky....no beer untill tests are complete

xsjohn · Last edited by xsjohn on September 29, 2007, 6:10 pm; edited 5 times in total

tracker79 .......Seems the most important measurment is the plyg (4)

Also been mearuring the cylinders (5) but I am beginning the feel the the plug is a more accurate reading........

John

INXS650 · 650Rider Supporter Joined: Mar 22, 2007 Posts: 645

John come on out to Greenville, and you can test temps on mine all you want. See what mine measures with the 36mm on her and no cooler.

xsjohn · Last edited by xsjohn on July 14, 2007, 8:11 am; edited 1 time in total

If you are getting 38 to the gallon there would be no way yours could be getting hot..........You might have something there......

John

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