Twin cam problems
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Road Master
Joined: Nov 2010
Posts: 1,156
Likes: 1
From: Nebraska
Twin cam problems
So its been a few months since I did my hydraulic tensioner conversion, cams, and 2 into 1 exhaust. Even with the new map in the PC something has been a little off about this set up. I felt the ignition curve was a bit off so I had my go to guy when I have questions ride it tonight. He confermed that the curve seem to be more a straight line than a curve and said i needed to do some work on the laptop. He also checked cylinder temps and found that the front was 180 and rear was 218 degrees sitting still. This is quite a difference for no air moving across them. He seems to think its an injector problem and told me to ohm them out to be sure. Thats not the most disturbing part......he hates MM fuel injection systems as do most people with any knowledge of FI in general...it has a dual manifold meaning basically one intake per cylinder where a delphi is a single intake that y's off to each head. Here is the problem with that....when you put a 2 into 1 header on this it cant scavenge like it should so youll never get the most out of your pipe. It will run just fine but youll never see the big numbers that its capable of. So here is our solution. We are gonna hog the intake out! Completely remove the divider down the center. Gonna try that and see what happens.
Road Master
Joined: Sep 2009
Posts: 1,169
Likes: 9
From: Southern Illinois
I also have the MM injection and am thinking Axtell 97" kit with bigger cams and a 2 into 1 system so will be curious as to how " gutting" the center divider works. Been told that with the MM system best i can hope for is 100 hp and 100 tq.
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Road Master
Joined: Nov 2010
Posts: 1,156
Likes: 1
From: Nebraska
Its still better than a carb in my book. Hopefully the injectors cure my temp difference. I wonder if the sensor on the front head would have anything to do with the lower temp? Its not showing any codes.
Road Warrior
Joined: Jan 2006
Posts: 1,798
Likes: 1,189
As far as gutting (or modding) the center divider works, I'd advise against it. I know a few cases where it was done, and no case where it made anything better. Most ended up replacing the throttle body afterwards.
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Road Master
Joined: Nov 2010
Posts: 1,156
Likes: 1
From: Nebraska
i pulled the induction module off this weekend and checked the injectors...both injectors ohmed out at 14.5 so that wasnt the problem. I swapped the injectors positions around and put it back together. Still no difference in temps. Loaded a knowingly rich map and it brought the front cylinders temp up within maybe 10 degrees of the rear.
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Outstanding HDF Member
Joined: Jan 2010
Posts: 2,916
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From: earth
Yes. The rear is likely leaner than the front. If you are running a canned map, it is probably a basic map, meaning 1 table controlling both cylinders, or an averaged map for both cylinders which typically causes an AFR imbalance between cylinders, in your case the rear is lean, or the front is rich. As opposed to an advanced map that has seperate tables for each cylinder, and requires exhaust gas analysis feed back to individually tune front and rear. If you do have an advanced map and you paid someone to tune it, they messed up. Not sure where or how you measured temp, if it was a laser, surface emissivisty issues make it hard to use accurately. Try reading on or near the plugs, bare metal preferably, same spot on both cylinders. Actual temp may be a little off but the difference between the two should be correct.
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Road Master
Joined: Nov 2010
Posts: 1,156
Likes: 1
From: Nebraska
i used an infared (laser) thermometer and took my measurements right by the spark plug. I think my whole problem revolved around a map that I had emailed to me. Im also learning things about this second hand bike like it has SE high flow injectors and probably has some sort of ECU download...not sure how to determine which one it has. I guess the only way its ever gonna run right is to spend the money on dyno time.
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Road Master
Joined: Nov 2010
Posts: 1,156
Likes: 1
From: Nebraska
Got the RK on a dyno this morning. Took 3 hours to tune it up but the guy did an amazing job. First run was 65hp and 80ft lbs of torque. Last pull was 78hp and 88ft lbs of torque. Peak was around 3000rpm for both and it stretched all the way across to around 5500rpm then dropped off. Runs like a dream now. Well worth the $200 plus tax.