The XL600 thread

[Carter Pewterschmidt]

I rebuilt my stock wheels, which turned out pretty nice, but I really want to build a 17" supermoto set to try on this bike.

[MAXNX]

Originally Posted by Carter Pewterschmidt

I will have to politely decline my friend. I have so many parts laying around here that it's becoming a nuisance. In fact I've been trying to pass some of them off to Crobox. I do appreciate the offer so if you ever need something in the future let me know. I have various odds and ends and carb parts galore.

I would however make room for a spare set of stock wheel hubs.

Can I get a hold of you if I need little things here and there? I am right down the road from you.

[Dracus124]

Do i need to adjust anything when I take the snorkel out? it sounds little more beefy now

[m2h]

Originally Posted by joexr

I did this. 1/8'' or #30 drill bit.

Thanks for that. Will have a look at doing it while the motor is in bits.
M2H

[m2h]

Originally Posted by mcma111

Your still limited by the hole size in the cam. The two banjo bolts have different size holes. The top one is smaller so buy another bottom one for the top. That's about all you can do.

Thanks Steve. Another option to look at.

[m2h]

Originally Posted by joexr

Its limited by the size of the oil line. There are 5 holes in the cam.

Yeah wondered about that too. Don't matter how big the exit is if the door in is smaller!

Thanks again
M2H

[sw3dl1]

Originally Posted by Carter Pewterschmidt

I'm always trying to buy an NOS 86 tank for my bike, so I routinly search ebay for XL tanks, but I never saw one of those before. A very cool find indeed, the "desert" decals really make it and Acerbis is a good brand. All around a hot piece of old XL bling. If it were white instead of red I might have went after it myself.

Make sure to do a little write up and take some pics of the install.

You looking for a red, white and blue 86 XL600r tank? If so, I have an 87 that is almost perfect. It was taken off when new by a friend to use an aftermarket tank. Been setting on a shelf for almost 27 years. NO RUST INSIDE. I was going to use it but I found a Red tank to go with red framed bike I'm building. I doubt I will use it. If intereted shoot me a PM and we will work out a price.

[Carter Pewterschmidt]

Originally Posted by MAXNX

Can I get a hold of you if I need little things here and there? I am right down the road from you.

Sure man, send me a PM whenever.

[MAXNX]

Originally Posted by Carter Pewterschmidt

Sure man, send me a PM whenever.

PM Sent

[crobox]

Originally Posted by davek181

I hope I answered some of your questions or cleared things up a little. If not please feel free to ask more.

So I've been thinking more about how carbs work, since your great explanation, Dave. I do have a few more questions....

Regarding the air mixture screw, this regulates the amount of air that gets mixed in with the fuel in the low/pilot jet, right? So it only applies to idle, right? And I guess the more you screw it in, the leaner the idle mix...

And second question... mostly just our of curiosity.... The bottom of the main jet sits a little lower than the bottom of the pilot jet. Are both of these actually submerged in the float bowl fuel? Or is the main jet submerged and the pilot jet just above the level of the fuel?

Just thinking about it all and trying to understand how it works...

Cheers,
Christian

[crobox]

Oh, and also....

Not long after starting to ride my XL600 around, I had the distinct feeling that
A) I want to get better at riding off-road; more confident, more skillful
B) I don't really want to do it on the XL, because it's a bit heavy and also it's so damn beautiful (which is to say that I want to ride something for a while that I don't mind dropping.)

So I started talking to various friends about it (turns out I have a lot of friends around here who ride dirt bikes), and one guy said "Hey, my wife has an NX250 she doesn't want."

I bought it for $250, did a bunch of basic work on it, realized it has a problem with one of it's valves, decided to ignore that problem, got it started, stripped a bunch of plastic parts off it, mounted my old XL600 front fender, and started riding it. And it's fun! Here it is:



I've been posting more technical questions and stuff over in the NX250 thread. I know it's a bit off-topic so I'll leave it at that.

But I gotta say it.... electric start is nice!

-Christian

[m2h]

Am considering trying to add an oil cooler to my '86 while I have the motor out. Has anyone tried or heard of fitting a later model XR400 cooler? Don't really know the dimensions but read on Thumper Talk of one or two xl600 owners who have done it but gave no real description of how.
Wondering how much cooling it would provide as it don't look very big!
Read about using coolers from JC Whitney etc. but at 11" X 6" X 3/4" might be a mission to fit in.
Interesting discussion maybe?

[doc.heckle]

Pilot jet, screw in richer out leaner, it alters the amount of air not fuel.

[joexr]

If the screw is on the cylinder side of the carb its a fuel screw . In would be leaner. If its on the airbox side its an air screw. Out would be leaner. 2strokes usually have air screws and 4strokes usually have fuel screws.

[davek181]

Originally Posted by crobox

So I've been thinking more about how carbs work, since your great explanation, Dave. I do have a few more questions....

Regarding the air mixture screw, this regulates the amount of air that gets mixed in with the fuel in the low/pilot jet, right? So it only applies to idle, right? And I guess the more you screw it in, the leaner the idle mix...

And second question... mostly just our of curiosity.... The bottom of the main jet sits a little lower than the bottom of the pilot jet. Are both of these actually submerged in the float bowl fuel? Or is the main jet submerged and the pilot jet just above the level of the fuel?

Just thinking about it all and trying to understand how it works...

Cheers,
Christian

Regarding the pilot jet/ slow jet, fuel mixture screw and circuit. As you can see there are several names for it but that is not unknown in the mechanical world. The mixture screw can be either an air or fuel mixture screw depending on where it is placed in the idle circuit. Usually if it is in front of the slide, down wind side or nearer the engine it is a fuel screw. if it is ahead of the slide on the air cleaner side it is an air screw. It works on the same principal as the needle jet/main jet where it limits the flow of fuel or air in the idle circuit. It is also a tapered rod that you either retract or push into a fixed orifice by screwing it in or out. Understanding that concept it is easy to see that if it is an air screw, screwing it in richens the mixture by limiting air mixed with the fuel. The opposite is true with a fuel screw obviously.

The pilot jet mainly affects idle, and is adjustable for best idle purposes. There is a little bleed over effect into the low speed range as with any circuit of the carburetor. It takes care of duties when the main circuit is closed down due to the needle for the main circuit and low venturi effect essentially shutting it if. So for a very brief period of throttle opening the slow circuit helps transition to the main circuit as the needle is pulled out of the main jet. There are other factors involved there too such as slide cutaway which is used to promote venturi action for the main circuit, and some carbs have accelerator pumps too (pumper carbs they are commonly called) for the off idle transition.

Both main and slow jets are submerged in fuel all the time, I do not know why the slow jet is shorter officially but I suspect it is to keep it above the flow of the main jet and out of potential crud in the bottom of the float bowl since it is smaller than the main jet and will plug easier. They could in theory put a slow jet in a place where it could use the main jet circuit as a source of fuel drawing though the main jet and metering the mix at idle with the mixture screw. I can see potential transition issues that way so I think they are separate for a good reason. You do see jet sharing sometimes in CV carbs where they use a rubber plug to seal the passage after you put the jet in and it draws it's fuel then through a larger jet but that is a whole different kind of carburetor.