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Prolink High RPM Performance

Posted: Thu Jul 05, 2012 8:35 am
by panteradave
I have a low mileage, all stock '82 that doesn't seem to have the 6-10k performance kick that I was sort of expecting. The engine appears to be in excellent shape with very good compression on all cylinders, and exhaust header temps are even all the way across after a hard run. The plugs show a nice clean burn though are perhaps very slightly on the leanish side. Ignition timing and components are good. The intake and exhaust systems are completely stock and the carbs were recently totally rebuilt by Mike Nixon.

Don't get me wrong, the bike runs great and the engine revs very willingly to redline with no flat spots, but the performance is dead linear throughout the rev range (or at least above 3500 rpm or so). There is no noticable power surge at higher rpm. I realize the prolinks have different cam profiles and are also heavier with all the extra plastic bits and so shouldn't be on par with the earlier pre-prolink CBXs, but I'll admit that I'm a little disappointed at the moment.

It's very possible that my performance expectations may have been naive and not based on actual reality. Also, my CBX performance sampling consistists of only two bikes, my '82 and another '82 (which I did not push to redline), so I probably don't really know what a CBX should feel like.

So my question is: is the linear engine response to redline just the nature of the prolinks, or should it pop a little bit above 6k or so? If the later, where should I head to figure it out?

Thanks,

Re: Prolink High RPM Performance

Posted: Thu Jul 05, 2012 12:46 pm
by cbx6ss
The fairing and luggage on my 81 were hiding the cbx spirit within mine. I discovered a new and much more exciting bike when I stripped the fairing and luggage off.
/r
Brad

Re: Prolink High RPM Performance

Posted: Thu Jul 05, 2012 2:28 pm
by EMS
After 30 years and a lot of development in motorcycle technology and performance, a CBX may indeed feel a little underpowered. I am not drag-racing my bike, but I am able to keep up with my riding buddies on their newer bikes when I ride my 81 CBX. And I am riding two-up. Sure, when I compare it to my new BMW K1600GT, there are worlds in between, but I don't own a CBX to have the fastest bike on the planet.
If your 82 does not show any distinct signs of malfunction, you may expect a little too much from the old lady. After all, it has "only" about 100 horsepower.....at the crank!

Re: Prolink High RPM Performance

Posted: Thu Jul 05, 2012 2:47 pm
by Larry Zimmer
I'd say that's about right, Dave. Sounds very similar to my '82. From about 4500 to 6000 it gets better. From 6000 to 9000 it just continues similarly with maybe a touch more oomph. But not a lot of difference. Just kinda keeps going. But, not the 'hit' that some others might seem to have above 6000/7000. As Mike said, it has 'only' 100 at the crank, with about 60 lbs-ft torque in a fairly linear curve.

Re: Prolink High RPM Performance

Posted: Thu Jul 05, 2012 4:28 pm
by cbx6ss
I'll bet most bikes feel like a moped after the K16!! Wonder what THAT bike would feel like naked...

Re: Prolink High RPM Performance

Posted: Thu Jul 05, 2012 8:31 pm
by steve murdoch icoa #5322
Over the years i have seen the phrase "linear power" in reference to the Pro-Link.
No power peaks, just a nice curve.
A dyno-run article from the archives. http://www.cbxclub.com/protect/xcerpts/dynolie.pdf

Re: Prolink High RPM Performance

Posted: Thu Jul 05, 2012 9:14 pm
by panteradave
It sounds like linear response is prolink normal. My most direct but still seat-of-the-pants performance comparison to the CBX has been my ST1300, which is really not a fair comparison. While the CBX is definitely no acceleration sloach, the 125 hp ST1300 (like K1600GT mentioned above) is a whole other world of technology and perfomance. On the flip side, the V-4 ST blatty exhaust can't touch 10000 rpm music of the CBX six, technology or no.

The '82 dyno comparison is very interesting. I guess a big-bore kit combined with a 6-2 Kerker exhaust would add some definite spice. Something to think about.

Thanks for all the replies and info.

Re: Prolink High RPM Performance

Posted: Thu Jul 05, 2012 11:50 pm
by bikeymikey748
Dave, I just plugged a big bore & 6-1 onto my '82. Admittedly,there's a LOT less on it than when I began. For comparison sake, I've owned a bunch of other bikes. I've only just begun to sample it, but it pulls with authority! The revs seem to jump at 5-6,000 ( didn't try this too much....still breaking it in). The front end,definitely, gets light when you accelerate with any sort of friskyness.Very entertaining!

Re: Prolink High RPM Performance

Posted: Fri Jul 06, 2012 12:24 am
by panteradave
Just curious, which big bore kit and 6-1 did you install?

Re: Prolink High RPM Performance

Posted: Sat Jul 07, 2012 11:01 pm
by bikeymikey748
Just curious, which big bore kit and 6-1 did you install?
Dave, I put in one of the inexpensive kits, I picked up on e-Bay ( the one frm Japan, for $250.00). Happy surprise? The machinist, who did the boring, said it was a good quality kit. I went with a DG 6-1, the resonator was swapped for one from a Yosh, with a larger I.D.
Are you going to make the changes ?

Re: Prolink High RPM Performance

Posted: Mon Jul 09, 2012 11:41 pm
by panteradave
I'm definitely thinking about it. I'd like to hear more after you've gotten it broken in.

Dave

Re: Prolink High RPM Performance

Posted: Tue Jul 10, 2012 7:37 am
by Jeff Bennetts
Well Dave, how about posting up a couple pics if you don't mind. :handgestures-fingerscrossed:

One of the few body designs that looks great in yellow, well except for that Italian car with the dancing horses badge.

Have you done anything to bump the compression back up to the 71's spec?

Re: Prolink High RPM Performance

Posted: Tue Jul 10, 2012 11:01 am
by Larry Zimmer
This old goat missed something, Jeff. Which '71 are you talking about? I couldn't find one mentioned anywhere above.

Re: Prolink High RPM Performance

Posted: Tue Jul 10, 2012 2:33 pm
by NobleHops
Dave Bell has a 72 Pantera - I think Jeff is referring to the specs of the prior model year.

N.

Re: Prolink High RPM Performance

Posted: Tue Jul 10, 2012 2:54 pm
by Jeff Bennetts
NobleHops wrote:Dave Bell has a 72 Pantera - I think Jeff is referring to the specs of the prior model year.

N.
Yes, the 72's compression went down to the mid 8's for the American market, I believe they compensated with a hotter cam, with the aftermarket so huge for the 351 Cleveland it's not that hard to get the compression back up but with the shit gas we have nowadays 11:1 is considered high and maybe Dave is more concerned about originality anyway.