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Old 06-23-2002, 07:20 PM   #16
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yeah but my inside source says it is true and i would trust him. we will see how he does at the nats
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Old 06-23-2002, 10:54 PM   #17
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Are these Rossi engines?

If so than I have a Rossi R12 Pixy Black. And would say that it is as fast as most engines out there but gets blown away out of the corners.

It simply has no bottom end power, also hard to tune.

I dont think I will be buying another one.

But hey, you guys might have more luck with them.
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Old 06-23-2002, 11:05 PM   #18
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Quote:
Originally posted by acs
Are these Rossi engines?

If so than I have a Rossi R12 Pixy Black. And would say that it is as fast as most engines out there but gets blown away out of the corners.

It simply has no bottom end power, also hard to tune.

I dont think I will be buying another one.

But hey, you guys might have more luck with them.
yep they are rossi engines.
now you might need to have your clutck engage a bit later. to get the motor in it's power band then you will blow all the other cars away
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Old 06-23-2002, 11:11 PM   #19
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Quote:
Originally posted by nova racer
yep they are rossi engines.
now you might need to have your clutck engage a bit later. to get the motor in it's power band then you will blow all the other cars away
If I trim any more of the shoes I won't have anything left.

I also tried a heavier spring but the clutch would slip halfway down the straight.

Do you have expierience with this or the Sirio Engine? If so can I see a pic of your clutch?
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Old 06-24-2002, 07:20 AM   #20
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Quote:
Originally posted by acs


If I trim any more of the shoes I won't have anything left.

I also tried a heavier spring but the clutch would slip halfway down the straight.

Do you have expierience with this or the Sirio Engine? If so can I see a pic of your clutch?
no not yet but they should be good. have you tried running a colder plug or shorten the header to let the engine get on the pipe faster. also the AE rpm pipe has a lot of mid and lower end power
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Old 06-24-2002, 08:36 PM   #21
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Quote:
Originally posted by nova racer
no not yet but they should be good. have you tried running a colder plug or shorten the header to let the engine get on the pipe faster. also the AE rpm pipe has a lot of mid and lower end power
I'm using a Novarossi #6 plug and Yokomo's MMielke Pipe.

I look forward to hearing how your engine goes.
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Old 06-24-2002, 09:53 PM   #22
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acs,

I am currently running the pixy and have also found that out of the box the bottom end is lacking, but the mid to top end is awesome, it just pulls down the straight with little sign of hitting peak revs.

I am still working on it but i have found that by playing with the clutch, bottom end tune and gear ratios you can get very good bottom end.

If you have already lightened your clutch, try running a shorter gear ratio than you would normally ( try and get it revving hard at the end of the main straight) and get the bottom end tune right, i found that the factory setting was particularly rich.

hope this helps

DC
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Old 06-24-2002, 10:06 PM   #23
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Nova Racer- I don't know who you have been talking to but a shorter exhaust system (or a pipe with a lesser capacity) makes the power band shift in to the upper rpm ranges as the pipe get more in-sync with the exhaust port timing. Thus the RPM asc pipe is the same leangth an has a smaller capacity. Since the motor bogs on the bottom and rips on the top that is a sign of a motor with advanced exhaust port timing and more duration meaning that a longer system is needed to counter the loss in bottom end. Using the longer pipe will help in surcharging the air/fuel mix back into the motor as the packed air/fuel mix try's to excape b/c the rising pressure rate of the combustion chamber.

Quick explination, a motor that is turning 40k rpm will need a shorter pipe to quickly return exhaust gases to keep excess air/fuel mix from bleeding the sleeve. (more mix the more effecient and more powerfull the motor) A motor that is running at 20k rpm will need to use a longer pipe to work well b/c it will have a slower moving piston and it will be longer b4 the sleeve is over-packed with the air/fuel mix, and the longer pipe delays this process.

Hope you Rossi guys understand.

Last edited by JPHRacer; 06-24-2002 at 10:17 PM.
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Old 06-25-2002, 03:36 AM   #24
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Quote:
Originally posted by JPHRacer
Nova Racer- I don't know who you have been talking to but a shorter exhaust system (or a pipe with a lesser capacity) makes the power band shift in to the upper rpm ranges as the pipe get more in-sync with the exhaust port timing. Thus the RPM asc pipe is the same leangth an has a smaller capacity. Since the motor bogs on the bottom and rips on the top that is a sign of a motor with advanced exhaust port timing and more duration meaning that a longer system is needed to counter the loss in bottom end. Using the longer pipe will help in surcharging the air/fuel mix back into the motor as the packed air/fuel mix try's to excape b/c the rising pressure rate of the combustion chamber.

Quick explination, a motor that is turning 40k rpm will need a shorter pipe to quickly return exhaust gases to keep excess air/fuel mix from bleeding the sleeve. (more mix the more effecient and more powerfull the motor) A motor that is running at 20k rpm will need to use a longer pipe to work well b/c it will have a slower moving piston and it will be longer b4 the sleeve is over-packed with the air/fuel mix, and the longer pipe delays this process.

Hope you Rossi guys understand.
with my luck it seem that with the pipes that i run i almost always need to shorten the header 1/4'' to 1/2'' to get the motor on the pipe the way i like it! my self i dont like a lot of bottom end i love mid range and some high end thats why my rs12 sits and my tr12 flys. now i have read that longer pipes make lowend power and shorter pipes make high end power and to some extent that is true but you can say that to some degree but with tc's and these new super high out put motor i think that we need to have a new way of thinking and have an open mind for pipe tuning. what worked with the old cv12 might not work the same with a rs12 s3. because the radical intake timing. but i will try more pipes i have tried the paris ribbed wonder and did not like it at all. the paris al1010 good the AErc10 gt pipe is very good , all the novarossi pipes are good but they are made from pop can aluminum. the ae rpm pipe i have fell in love with, the thing is a little on the loud side but for the mid range grunt the thing makes it is worth the extra noise
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Old 06-25-2002, 12:50 PM   #25
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Sorry to say that this "old way of thinking" did not come from my experience with an os cv12. It came from the years of experience that moto guys have had to tune a 125 or a 250 dirtbike. This is not some hokey experiment that some guy performed it is a fact and will allways bee the same weather 2-stroke or 4-stroke, why do you think they have a hi-rise intake? To increase duration and shift the powerband, same with carbs nascar's used small prob. under 500 cfm for sears point b/c they never realy got on the powerband, but at daytona they would use 700+cfm b/c they are wide open.

What your saying can be true about the intake timing but again larger port, more duration, advanced timing= piowerband shifting into higher rpm ranges. There is no secrect to it, all common sence, my boss at the Hobby shop that I work at on his rc10 gt that he runs on the oval uses a OS CV.12. Why you ask? Beacuse he can, the guy that tunes the motor and does all the work used to work with Ford (???Chevy??)and worked on their motor program, he is a good when it comes to a nitro motor, b/c they are soo simple. All he does it increase the intake timing to 200-205 and the exhaust to 198-202 and now he has a motor that will wip any Rossi or Mugen that people bring out. He is also so cockey that he cut the cast head on the motor in half (yes the stock cast head) so he had to run the motor so sloboring rich to not bur it up, and he still would blow by everyone on the straights. The only other guy that can now keep up and is actually faster is an other old guy that used to work for the Honda race dirtbike team, he is famous for is 4 min main motors. He also replaces the rod allmost every race day.
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Old 06-25-2002, 09:44 PM   #26
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Quote:
Originally posted by OZDC
acs,

I am currently running the pixy and have also found that out of the box the bottom end is lacking, but the mid to top end is awesome, it just pulls down the straight with little sign of hitting peak revs.

I am still working on it but i have found that by playing with the clutch, bottom end tune and gear ratios you can get very good bottom end.

If you have already lightened your clutch, try running a shorter gear ratio than you would normally ( try and get it revving hard at the end of the main straight) and get the bottom end tune right, i found that the factory setting was particularly rich.

hope this helps

DC
Yep, this is the direction that we are heading as well.

You are right about the mid to top end performance though, once it gets going its super fast.

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Old 06-26-2002, 01:26 AM   #27
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Default not a bad price

HobbyPeople just sent me a circular with the outlaws priced at $170 not bad for a .12 outlaw motor
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Old 06-26-2002, 03:26 AM   #28
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Quote:
Originally posted by JPHRacer
Sorry to say that this "old way of thinking" did not come from my experience with an os cv12. It came from the years of experience that moto guys have had to tune a 125 or a 250 dirtbike. This is not some hokey experiment that some guy performed it is a fact and will allways bee the same weather 2-stroke or 4-stroke, why do you think they have a hi-rise intake? To increase duration and shift the powerband, same with carbs nascar's used small prob. under 500 cfm for sears point b/c they never realy got on the powerband, but at daytona they would use 700+cfm b/c they are wide open.

What your saying can be true about the intake timing but again larger port, more duration, advanced timing= piowerband shifting into higher rpm ranges. There is no secrect to it, all common sence, my boss at the Hobby shop that I work at on his rc10 gt that he runs on the oval uses a OS CV.12. Why you ask? Beacuse he can, the guy that tunes the motor and does all the work used to work with Ford (???Chevy??)and worked on their motor program, he is a good when it comes to a nitro motor, b/c they are soo simple. All he does it increase the intake timing to 200-205 and the exhaust to 198-202 and now he has a motor that will wip any Rossi or Mugen that people bring out. He is also so cockey that he cut the cast head on the motor in half (yes the stock cast head) so he had to run the motor so sloboring rich to not bur it up, and he still would blow by everyone on the straights. The only other guy that can now keep up and is actually faster is an other old guy that used to work for the Honda race dirtbike team, he is famous for is 4 min main motors. He also replaces the rod allmost every race day.
well i will try that timming with the CV 12 in my rc10 gt. thanks for the numbers
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Old 07-02-2002, 06:03 PM   #29
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Quote:
Originally posted by JPHRacer
Sorry to say that this "old way of thinking" did not come from my experience with an os cv12. It came from the years of experience that moto guys have had to tune a 125 or a 250 dirtbike. This is not some hokey experiment that some guy performed it is a fact and will allways bee the same weather 2-stroke or 4-stroke, why do you think they have a hi-rise intake? To increase duration and shift the powerband, same with carbs nascar's used small prob. under 500 cfm for sears point b/c they never realy got on the powerband, but at daytona they would use 700+cfm b/c they are wide open.

What your saying can be true about the intake timing but again larger port, more duration, advanced timing= piowerband shifting into higher rpm ranges. There is no secrect to it, all common sence, my boss at the Hobby shop that I work at on his rc10 gt that he runs on the oval uses a OS CV.12. Why you ask? Beacuse he can, the guy that tunes the motor and does all the work used to work with Ford (???Chevy??)and worked on their motor program, he is a good when it comes to a nitro motor, b/c they are soo simple. All he does it increase the intake timing to 200-205 and the exhaust to 198-202 and now he has a motor that will wip any Rossi or Mugen that people bring out. He is also so cockey that he cut the cast head on the motor in half (yes the stock cast head) so he had to run the motor so sloboring rich to not bur it up, and he still would blow by everyone on the straights. The only other guy that can now keep up and is actually faster is an other old guy that used to work for the Honda race dirtbike team, he is famous for is 4 min main motors. He also replaces the rod allmost every race day.
198-202 exhaust duration on a .12???? Isn't that alot??
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Old 07-04-2002, 01:52 AM   #30
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How fast do you want to go? ....



How long do you want it to last? ....

Last edited by JPHRacer; 07-04-2002 at 01:58 AM.
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