Trading Cams, one mans opinion. Do you smell that?

[81xsproject]

Everyone has heard the expression about opinions, but here is mine.

I just got home from my first substantial ride on my '81 w/ '79 cams. Well, if you didn't listen to the guru's, you should . When it comes down to it, I wont be keeping the cams in. I wish I could afford to Dyno it, but sorry too poor. The thing is, when it comes to all around ridability the older cams have nothing on the ones that were made to be there. Here is what I can tell you... Under 2krpm it feels like the bigest dog I ever sat on. From 2-4k is alright, but still doesn't pull like the old cams. From 4-5k it feels pretty good, but just not like it should. And then it happens; all at once like some invisible switch inside is turned to "ON." The thing takes off like you can't believe. Even in 5th gear at 70mph, it just gets up and pulls hard and smooth like I am on some other bike. Don't get me wroing, my old cams pulled hardest at high rpm's, but not like this. It is a VERY noticable difference, and not just in feel. The way is sounded was... was... AWESOME!!! It sounded like a racecar, or bike, or I don't know, just awesome.

This made the decision of what cams to keep VERY difficult. When it comes to ridability, the 80's cams win hands down. When it comes to pure fun, it's the 70's cams.

In the end, I wish I had 2 11's. Both 80's, one with each set of cams. Then again, I have never gripped and ripped a 70's bike.

A couple things I did notice... with the older cams on, my idle dropped WAY down. It also felt like it had lost some of that "I don't need no stinking brakes" negative compression that it had with the newer cams.

Since I don't have 2 11's, I am going back to the original 80's cams. If I was a hardcore drager like Bandit of DragXS, I would be running the older cams for sure. The fact is, I am only above 5k when I am really stretching the bikes legs. It was said earlier, "DOWN SHIFT." But, I don't want to shift all the time. I want to crack the throttle and take off like a rocket, not shift or wait for 5k to come. If only we could have our cake and eat it too .

[GNEPIG]

.. the more i mess with these things the more i'm getting the hint.
i hear ya on what you are saying with the old cams and if you like the way the power delivery was with the original cams go ahead and switch them back. but it sounds like to me that you could make your low end better with some jetting and or timimg changes/adjustments. you have went through the trouble to put them in there and you know they work for the better, you know you can adjust to make the low end better and still have the big top end.
one of the trade offs of a bigger topend is less lowend power.
my ugly black bike has an 80 motor in it, i really like the power it makes also.. if you live some place were there are no straight aways [all corners, twistys] then the newer cams are for you

[81xsproject]

One of the things I have to remember is that the engineers who designed one of the finest bikes of all time (the 11's, obviously) are the same engineers that put those cams in there, and in the end they are a whole lot smarter than me

[trbig]

This is something that has me interested also. "IF" I can finally get this thing running right and charging, I'm going to just ride it this year and try to quit working on it for a while. Then this fall, I will put the XJ cams back in and see how it feels. I have an XJ with a '78 XS motor, '82 XJ Head, and the '78 XS cams. I didn't really get to ride it with the XS cams in the XS head (before I bent the valves up really nice) to be able to compare it to now. I also have the stock jetting in the carbs for an XJ going to this motor.

As stated, you can do some jetting things and get more bottom end. Mine isn't terribly impressive, but when I threw in some main jets that were obviously too big for it, to try to compensate for the pod filters, I got on it in 2nd and 3rd. As the RPM's went up past 4 grand.... so did the front end... in both gears. I have never had it even try to do a wheelie from just acceleration. You also had to keep an eye on the RPM's because it would pull hard way into the red-line. It went like crazy even from the start, but yeah... was like turbo kicked in a little higher up. But alas..... it didn't run worth a crap at any other time besides wide open, so I put the originals back in.

Tod

PS

"Procrastination is a lot like masturbation; Both are fun, and both are fu@*ing yourself."

Why do today what you can put off until tomorrow?? And also... NOBODY loves me like ME!!!

[Dennyz]

Interesting comparison, 81xsproject.

I own both an '80 and '79 Special in stock form with very similar mileage on them (around 20k). They are both fitted with K&N filters, drilled air boxes and appropriate jetting. They both have the same ignition system also. The '79 has stock exhaust and the '80 has the MAC 4:2 (criss-cross pipes).

The '79 is hands down faster off the line. Both bike are very close, but the '79 jumps a half a bikes length or so, and holds it. We switched riders and got the same results.

I was surprised to read your results of the cam change. I suspect matching a set of '78-'79 carbs to your early cams could yield a little different results.

[81xsproject]

Well, there is a good chance that my bike isn't tuned as good as it could be. I am no carb expert. I definately burnt a lot more fuel on the trip than I would have. The whole time I felt like I had my wrist in it more than I would normally need. It showed at the pumps too getting from 30-36 on a 50-60mph ride.

[Dennyz]

81xsproject,

Another thread on the topic, brought to mind cam timing. Your results sound a lot like a cam timing issue. Is that possible?

[Burly1]

My '79 is most definitely quick off the line, but the powerband, as described in the original post, is best at 5500-6500 rpm and above. This is the way the bikes were designed to be, exactly as you described. They pull like a freight train at 5000 rpm and above. This is why the XS Eleven's are the most versatile motorcycle's ever produced! With a few modifications in the suspension, they handle like a sport bike. For carrying heavy loads, they can't be beat. For cruising around town and country, they are easy on the butt, and you need to shift much less than almost anything out there. Keeping them in top running form is the only trick, and the help you can receive here is as good as it gets. Know why you see very few XS Eleven riders using stereo's? They like to hear 'em run, that's why! Blue pipes? Hell, if they're not blue, you aren't running hard enough. Go ahead and take another bite on that throttle. She ain't even breathing hard yet. If you want to putt, buy a Handy Davidson. Burl