Getting better low end without going to 15/43
08-24-2010, 05:04 AM
#61
Destructive Tester
Superstock
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Location: N.E. oHIo
Posts: 263
Advancing the exhaust cam will cause it to open and close the exhaust valves earlier in the 4 stroke-cycle relative to the intake valves.
Primarily, this decreases the duration of valve overlap (the period when both valves are open, at the end of the exhaust stroke and the beginning of the intake stroke). Decreasing the period of overlap enables better cylinder filling and gives a measurable increase in low end torque without any sacrifice in top end power. You would also notice a higher vacuum reading at idle, typically 1 to 1.5 cm on a mercury manometer, as well as a smoother, steadier idle.
As far as doing the work, you would need a service manual, appropriate tools, a degree wheel, a dial indicator and a set of slotted exhaust cam sprockets. Slotting the bolt holes on the exhaust sprockets allow you to move the exhaust cam to the proper position after you have "degreed in" the cams.
NOTE: This is NOT a job for a "Saturday afternoon hood-lifter", nor is it "playing" with the valve timing! I am amazed at how many CCT swaps go bad due to the inability of the owner to get the cylinders on TDC compression before removing the OEM tensioner! If you have ANY doubt about your abilities in tackling this type of job....SEEK PROFESSIONAL ASSISTANCE!! It is not rocket science, but the results can be very expensive to repair if not done properly.
Rex
08-24-2010, 10:09 AM
#62
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I really knew I didn't want to get sucked back into this thread......
Here is some info on whatever you want to call it with cam timing (Oh and they refer to it as "Playing with cam timing" also, so I hope folks don't get too offended......)
http://www.sportrider.com/tech/146_0306_art/index.html
Here is some info on whatever you want to call it with cam timing (Oh and they refer to it as "Playing with cam timing" also, so I hope folks don't get too offended......)
http://www.sportrider.com/tech/146_0306_art/index.html
08-24-2010, 11:09 AM
#63
Paul
Squid
Thread Starter
Join Date: Aug 2010
Location: Orange City, Florida
Posts: 15
For now I think that a sprocket change, flywheel lightening, and jet kit will suffice. I actually found a local machine shop that will cut the flywheel and balance it. I just have to remove it and get it to them. Thanks for all of the info.
08-24-2010, 11:32 AM
#64
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I also listed the P\N for the motion pro tool to pull the flywheel a while back but can't seem to find it now. I believe it's 22X1.5mm but I could be mistaken as it has been a while.
08-24-2010, 04:27 PM
#65
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Location: Austin, Tx
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Hawk, I will pm you my contact info. I have been through a **** weekend trying to pull a 520 conversion with steel sprockets in 15/41. I went back and read some of your posts unfortunately most of those sprockets are no longer available. 43T is still avail from JT but the 41 is only available in Aircraft grade aluminum elsewhere. It would have been helpful to have your ideas. I sourced parts for the 900rr, VTR, and the Interceptor and came up with nothing in steel. Thanks for all the good info on here.
08-24-2010, 05:10 PM
#66
Destructive Tester
Superstock
Join Date: Oct 2009
Location: N.E. oHIo
Posts: 263
I really knew I didn't want to get sucked back into this thread......
Here is some info on whatever you want to call it with cam timing (Oh and they refer to it as "Playing with cam timing" also, so I hope folks don't get too offended......)
http://www.sportrider.com/tech/146_0306_art/index.html
Here is some info on whatever you want to call it with cam timing (Oh and they refer to it as "Playing with cam timing" also, so I hope folks don't get too offended......)
http://www.sportrider.com/tech/146_0306_art/index.html
Quote from linked article :
"One of the dangers of playing with cam timing is the potential for a collision between internal engine parts."
The cited sentence would seem to advise against "playing".
It is also the only time the word is used in the entire article.
Rex
08-24-2010, 09:47 PM
#67
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Quote from linked article :
"One of the dangers of playing with cam timing is the potential for a collision between internal engine parts."
The cited sentence would seem to advise against "playing".
It is also the only time the word is used in the entire article.
Rex
"One of the dangers of playing with cam timing is the potential for a collision between internal engine parts."
The cited sentence would seem to advise against "playing".
It is also the only time the word is used in the entire article.
Rex
Also the article give very good advice of only making small changes and then using a dyno to make sure that you get the results you are looking for.
Which also leads to your statement of "Advance the exhaust 4 degrees" by my experience it is very misleading to make such a blanket statement. Each engine is different and you really need a dyno to optimize any cam timing changes made.
Also, in my experience, if you change the timing to get more bottom end you do loose out on the top end of the power band. The same is true if you tune for top end power, you loose bottom end. Like the old saying, there is no such thing as a free lunch. Gains in one part of the power band will cause losses in another part.
Then the other thing which makes blanket statements about cam timing misleading is that there are at least 2 different cam profiles available in a SH. So what might work for one type may or may not work with the other.
So if you want to make cam timing changes, go in small steps and do the dyno testing.
Never take a blanket statement of advance or retard X number of degrees as the optimum setting for your bike. Each one is different and may need a different setting.
08-25-2010, 03:55 AM
#68
Destructive Tester
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Join Date: Oct 2009
Location: N.E. oHIo
Posts: 263
I have no idea how you reached that conclusion. The potential of causing damage is quite real.
Also the article give very good advice of only making small changes and then using a dyno to make sure that you get the results you are looking for.
Which also leads to your statement of "Advance the exhaust 4 degrees" by my experience it is very misleading to make such a blanket statement. Each engine is different and you really need a dyno to optimize any cam timing changes made.
Also, in my experience, if you change the timing to get more bottom end you do loose out on the top end of the power band. The same is true if you tune for top end power, you loose bottom end. Like the old saying, there is no such thing as a free lunch. Gains in one part of the power band will cause losses in another part.
Then the other thing which makes blanket statements about cam timing misleading is that there are at least 2 different cam profiles available in a SH. So what might work for one type may or may not work with the other.
So if you want to make cam timing changes, go in small steps and do the dyno testing.
Never take a blanket statement of advance or retard X number of degrees as the optimum setting for your bike. Each one is different and may need a different setting.
Also the article give very good advice of only making small changes and then using a dyno to make sure that you get the results you are looking for.
Which also leads to your statement of "Advance the exhaust 4 degrees" by my experience it is very misleading to make such a blanket statement. Each engine is different and you really need a dyno to optimize any cam timing changes made.
Also, in my experience, if you change the timing to get more bottom end you do loose out on the top end of the power band. The same is true if you tune for top end power, you loose bottom end. Like the old saying, there is no such thing as a free lunch. Gains in one part of the power band will cause losses in another part.
Then the other thing which makes blanket statements about cam timing misleading is that there are at least 2 different cam profiles available in a SH. So what might work for one type may or may not work with the other.
So if you want to make cam timing changes, go in small steps and do the dyno testing.
Never take a blanket statement of advance or retard X number of degrees as the optimum setting for your bike. Each one is different and may need a different setting.
I'm taking this opportunity to bow to your obliviously superior, at least in your own mind, knowledge on this and all other subjects of a mechanical nature.
Maybe someday, if I work real hard, I too will know everything about everything.
Rex
08-25-2010, 10:17 AM
#69
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Location: Lake View Terrace, CA
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Can I ask you which part of what I posted upset you?
Is it really wrong to check for interference when you change the cam timing? Not much to loose there if you get something wrong, well except for the motor.
Maybe it's the fact that I have never been able to change the timing to get more power out of one end of the power band without loosing some at the other end? Maybe I need to find a different dyno as the ones I have used must be lying to me.
Or was it that I disagree on saying there is a magic number for changing cam timing that will work for all bikes. I really wish it was that easy but you can't even jet two of these bikes the same and expect to get the same results. Throw in the fact that there are 2 different cam profiles on these bikes and that makes it even harder to say one set number will work for everything.
While I agree that changing the cam timing will change the power band. I can't agree that one set number will give you the best results. Sorry if that upsets you.
So it's back to you. Either you can throw personal insults some more or you can show me the errors that I have made to further my education in this matter. I've been building bikes for close to 35 years and learn something just about every time I get into one, so far from thinking I know it all, I'm just someone who tries to pass along the things I have learned. I am also always open to learn new things, if they can be proven and justified.
10-03-2010, 06:18 PM
#70
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SuperBike
Join Date: Aug 2009
Location: thorold ontario
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im gonna go another tooth up in the rear for my track setup, 44 tooth, mainly because my slick is a 190 and well im just greedy and want more for track days, plus if i go to a bigger track i can leave my 43 tooth on. 15/43 is great, revs higher gears come faster but the bike is so much fun to ride 
10-03-2010, 06:30 PM
#71
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Well my feelings on this are rather clear. Unless you find yourself on a track where 1st gear is too tall to exit the corners dropping the gearing is rather ridiculous.
Maybe it's just a west coast thing but no track around here has a corner tight enough that you can't keep the bike above 5k in 1st.
Then again I tend to use all 6 gears in the transmission.
Maybe it's just a west coast thing but no track around here has a corner tight enough that you can't keep the bike above 5k in 1st.
Then again I tend to use all 6 gears in the transmission.
10-05-2010, 09:07 PM
#72
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Location: thorold ontario
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well the track we have closest to us has some tight corners. personally i dont like using first gear on the bike as i dont have the control thats needed for first gear through a corner and the bike will stand me up at part throttle in first gear if im not easy on it, plus i still have a little fine tuning to do to the carbs and last thing i want is the bike to hesitate a little whiel i roll on first and then come to life mid corner. for the most part it doesnt do it but with our temperature changes it changes the way the bike behalves. so id rather use second over first if possible. i come out of some of the corners mid to top of second, some in third, i could use first in a few but it makes no sense as id have to shift to second mid corner so id rather come into it in third gear and hold third than shift to second and require an upshift. same goes for one corner that i come into in third gear and its a double corner, second is much tighter but you maintain a lean while transitioning the corner and i have to take second geareither jsut before i hit that corner while leaned over still or come out of the second corner in third with the motor at about 4000 rpm. that double i could do in third if the bike were geared a little higher. thats why im after a 44 tooth sprocket, ive got a 43 tooth so if i go to a track thats a little bigger i can use the 43 tooth and on one thats tighter like the one were running the 44 would do just fine
thats why im after a 44 tooth sprocket, ive got a 43 tooth so if i go to a track thats a little bigger i can use the 43 tooth and on one thats tighter like the one were running the 44 would do just fine
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