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IN/EX cam swap?

Old 08-13-2011, 07:39 PM
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IN/EX cam swap?

I have read in a few places that swapping the EX cam with the IN cams gives you some performance boosts because the EX is a higher degree cam similar to an AFM cam grind, so that is to say, running 2 exhaust cams in the same head.


Has anyone attempted this and if so some pointers on doing so?


I just got some new cams because it was a deal I just couldn't pass up =)

I might end up getting them reground to yoshimura specs but I dunno quite what I want to do yet because I could also do Kent or Mori.
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Old 08-13-2011, 08:48 PM
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I'm running four exhaust cams! And I too was looking for some advice before doing this and came up with little or nothing. So I figured "what the hell, let's give it a shot." I may have even been the first.

I don't have any hard facts for comparison as I haven't gotten around to re-dynoing yet. I really should get on that. But my seat of the pants feeling is good so I haven't really been terribly concerned with the actual numbers.

At the same time as swapping cams I did a few other things as well that would have helped alter the behavior. Port and polish, and I degreed them slightly for more overlap. Just slotted the stock gears and went 1-1/2 to 2 degrees on all cams. From listed specs, not actual values of my engine. As these were slightly different.

The bike is on it's way to becoming a track only machine, so my goals were to get the engine to live a little higher in the rpm range. I feel this has been accomplished to some degree. I'm sure reground or other aftermarket cams would have a little more to offer. But I had to draw the line somewhere when it comes to tossing money at this thing.

Oh yeah... it does seem down on low end torque. My dad has a bone stock, low mileage SuperHawk that I often use as a comparison to mine. His definitely has more of that tractor like pull. But I expected this. There's no free lunch, right?
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Old 08-17-2011, 11:04 AM
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well IMO to get the low end torque just regear final drive... but of course your going to sacrifice top end but im sure with power and torque boost you can find a happy medium.

I would however like to see some dyno results because I am in the process of planning a somewhat "budget" high performance/compression build and if I could save a little and use 4 exhaust cams instead of paying $500-$600 on aftermarket cams or a rigrind that would be great... of course later on when money allows I will get some aftermarket ones but doing this and getting closer to aftermarket will save me money now.
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Old 08-17-2011, 07:52 PM
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Originally Posted by scottiemann View Post
well IMO to get the low end torque just regear final drive... but of course your going to sacrifice top end but im sure with power and torque boost you can find a happy medium.

I would however like to see some dyno results because I am in the process of planning a somewhat "budget" high performance/compression build and if I could save a little and use 4 exhaust cams instead of paying $500-$600 on aftermarket cams or a rigrind that would be great... of course later on when money allows I will get some aftermarket ones but doing this and getting closer to aftermarket will save me money now.
I think that the only difference between the IN/EX cams are the fact that the EX cam has a slightly higher lobe, but not a longer duration or anything. So I think that the power gains you'd see would be somewhat less than an aftermarket cam.


Once I get my carbs dialed in I'll swap the cams and get some definitive evidence because I changed too many things on my last go around and now I'm trying to hunt down the problem

And I'm already regeared, I'd like to go back to stock with the same grunt.
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Old 08-17-2011, 09:38 PM
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Use the search function. There is a thread in the Knowledge Base about this.
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Old 08-18-2011, 12:03 AM
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Originally Posted by msethhunter View Post
Use the search function. There is a thread in the Knowledge Base about this.
Originally Posted by bass4dude View Post
I have read in a few places that swapping the EX cam with the IN cams gives you some performance boosts because the EX is a higher degree cam similar to an AFM cam grind, so that is to say, running 2 exhaust cams in the same head.


I did, and I didn't get very many returns. It has been on my mind since thinking about getting my cams reground (pre purchasing cams) and I was searching for quite a while.

And on a side note, I did browse through most of the knowledge base and I didn't see one.

I'm not saying there isn't one there, but I didn't see it.

I like the search function just as much as the next person and I have no particular desire to start needless threads. There's already too many to read through as is. And if you look at the guy below my first post, he also said he looked and to no avail did he find info.


You're jumping down the wrong persons throat here, bud.
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