Cold #1 exhaust

[crazy steve]

The last mile before home is uphill at a good angle. I dropped into 4th and revved it hard till home. I then let it idle and I grabbed the thermal laser gage and looking at the top of the exhaust pipes coming out of the motor. The #1 and #4 were like 325° and the #2 and #3 were 265°. I thought that the two center cylinder would be much hotter? What’s up with that?

You might want to check your coils; if the 2/3 coil is weak, that could be the issue. Don't forget to check the resistor caps...

[fredintoon]

- - - I grabbed the thermal laser gage and looking at the top of the exhaust pipes coming out of the motor. The #1 and #4 were like 325° and the #2 and #3 were 265°. I thought that the two center cylinder would be much hotter? What’s up with that? - - -

Hi Bartman,
try swapping the coils so they run the other pair of cylinders. Swap #1 & #4 plug wires onto the #2 & #3 plugs and vice-versa. Swap the Orange & Green wires to the coils. Test ride. Temperature check. If the temperature difference reverses with the coil swap it's ignition. If it stays the same it's carbs.

[Bartman]

Thanks guys. I am just now reading and will check into the coils vs carbs later.

But for tonight I moved the throttle cable up on top of the bars under the tank. I like things nice and tidy and this is something that doesn't need to be tight. Also I had oiled up my old cable but the other week when I swapped cables I was in a hurry and didn't think to oil this one. As Phil said I have it running good and then put the cable on.

I rode it up the road and it is much better than yesterday. But I really don't like the 30 year old lights! It is also dripping oil out of the chain tensioner, I will be getting an auto chain tensioner soon.

Coming back down the road in third I opened it up and it moved real good and around 6k it then felt like passing gear was kicking in. Is this about right for pulling power?

[Bartman]

What, no comments on Bullit and the sound of the XS11?

[bikerphil]

Coming back down the road in third I opened it up and it moved real good and around 6k it then felt like passing gear was kicking in. Is this about right for pulling power?

Sounds like you're getting it dialed in, these things will pull hard from 6K up to redline, sounds about right.

[Bartman]

Here is what I have been working on. Not painted yet.

http://s1339.beta.photobucket.com/us...38367166251378

[Petersg_99]

You know, at first I didn't think I liked the standard tank at all, but with the stripes, it's kind of growing on me, but I think for my taste, I'd like to see a little something on the sides too.

Here is what I have been working on. Not painted yet.

http://s1339.beta.photobucket.com/us...38367166251378

[clcorbin]

After changing my handlebars to something shorter, I had the same problem. Nothing I did would get the cable in it's "happy" place where turning the bars didn't rev the engine.

Until I took a large black ziptie and firmly secured the throttle cable to the frame. Never been a problem sense. The ziptie is far enough back that it doesn't interfere with pulling the carbs, so I have almost forgotten about it.

[Bartman]

The tank with stripes is from Chris (Yamahansolo). He had his friend paint these for him and he decided that he would keep his old blue one.

The burgundy rear and seat trim is from my second project bike. The fairing is one that I purchased on Craigs list.

When I put the second “keeper” bike together I will try my hand at painting. Maybe by then I will have what I want figured out.

[Bartman]

I swapped the coils and the center two exhaust are still cooler. I tightened the coils ground double connector and ohmed the grey and orange wires back to the ignition box. Every thing is tight and clean. I then swapped the ignition box with my next bike and still cooler.

I put it back to original and have turned the idle screws on 2&3 in about 1/4 turn and still don't see any change. Hooked the sync Gage's up one more time and every thing is good. It is idling at 1100 very smoothly with no trouble revving. If I didn't have a laser temp gage I would think nothing is wrong. I don't think the exhaust pipes are different thickness which might effect transferring heat?

So how do I cool #'s 1&4 and heat up #s 2&3? What temps do any of you's guys see at the top bend of your headers?

[crazy steve]

You might check your exhaust valve clearances. Tighter would mean less time on the seat and possibly higher temps....

[TopCatGr58]

This is a long thread now, and I didn't bother trying to look thru it, so I don't know if you commented on your carbs...what jets you have in them...mains mainly? IIRC, this was still when Yamaha was using the different emulsion tubes(main needle Jet) for the inner 2 carbs to run richer to help in keeping those cylinders a little cooler than the outer since the inner would run hotter if jetted equally due to the reduced air cooling surface exposure! JAT!?

T.C.

[Harley Steve]

I know this thread is concerning the cold exhaust but you did mention it and you also commented about it Sunday when you stopped by.Might want to start a new thread after you get this sorted out.
You had both calipers completely apart, if I remember, and you had some pitting,etc New parts went back in?
Next time out, touch each rotor and see if one is hotter than the other. Don`t know about Yamaha`s but pads need to be compatible to rotors.You`ve only been 50 miles, might not be seated in yet. Your rotors looked like they had had those bad boy sintered pads.Steve

Oh, no one saw you with those Harley chaps on, huh?

[Bartman]

I figured that I would let the brakes work a little bit before looking at them. They are stopping well.

As far as the HD chaps you let me use….I went by everyone to fast for them to get a good look. You don’t mind if I cover the HD up with duct tape or should I put a Yamaha patch over the HD emblem?

I am going to start another thread about the different temps of the motor.

[IIININIII]

Cold Pipe

Hi Bart, I know I am late to the party but I had the same problem on my fixer upper last month. For mine, cylinder #3 seemed to run fine on the road but would idle poorly with the pipe colder than the rest.

Tested compression, fuel, and spark, and had already been in the carbs and knew they were clean and floats were to spec. All good. A real head scratcher.

However, by luck I noticed that compression was very low when NOT opening the throttle. That led me to suspect the throttle plates. Sure enough, at idle, 3 throttle plates were open and #3 was closed. It was very difficult to see by eye so I used shims to confirm. Since #3 is the main off the throttle, I set it at .001 (by shimming against the port wall just under the throttle plate), then adjusted all of the other plates until they matched. They were not aligned with each other.

Put the carb back on, set the idle screw, and the problem went away immediately.

Hope this helps anyone else who may encounter this problem.