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Old 01-14-2008, 07:14 AM   #16
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Originally Posted by GenReaper View Post
Integra is right, there is more power to be made in advanced port timings which your average joe blow wouldnt understand, you need computers and lots of experience to achieve this properly.

Some slight porting with the sleeve with the fang job does help but if you take too much material out the air speed will drop and you will lose bottom end power if your not carefull, and polishing the inside of the crank is NOT a good idea IMO but each to there own. I just know from my vast experience it does more harm than good, its proper shaping thats important not a smooth surface for the reasons i have already stated.



eXactly...SMooth is BAD when it comes to these mills....AND u dont need a Computer to do Crank #'s....Just a Set-up station to be able to read the #'s before cutting them....Or Know by memory where and what to cut...Like my buddy max who dosent even need to put the mills on a Jig anymore to get the #'s....as he know's em by heart now and can GUARENTEE make the Snarlyist of motor's Any one has seen....but that dosent exactly help u on the track tho....Blowing off the tires in the botttom = No good.....but smooth linear power is what were after for the Ultimate Track motor....and max has been Purfecting his skills over the last 2 years or so....and i kno what he's capable of.
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Old 01-14-2008, 06:53 PM   #17
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As far as the crank is concerned, the machining imperfections won't really hurt you. They are not impeading or changing the direction of airflow enough to matter. You can clean it up if you want without fear of screwing anything up. Its relatively simple. What is a big factor is the crank intake timing. The real gains in performance lie within the duration of the crank intake port and what degree it opens and close in relation to the transfer ports. You can clean up the edges if you want and again it shouldn't affect the stock degree specs thus not altering the engines stock running characteristics. The one guy is exactly right about the polishing aspect. Alot of people firmly believe that a polished surface is smoother and more efficient but after years of racing snowmobiles and personal watercraft and designing engines for factory polaris's race program, we have found that a course surface maintains a suspended molecule structure which in turn keeps the velocity speeds up and keeps the molecules from dragging along the surface which ends up as fuel puddling on the intake side and carbon build up on the exhaust side. As far as the "tear drops" in the windows of the ports, alot of engine manufactures are putting them in on their transfer ports. The theory is to help guide the mixture into the chamber but whats more important than just getting the mixture into the chamber is at what angle and speed it enters. Two stroke engines are loop scavengers which means the fuel/air mixture should enter angled up and away from the exhaust port towards the rear booster but not to interfer with the rear booster entry. The mixture then travels up the back wall into the dome, fires, rolls over and exits the chamber through the exhaust port completing the circuit. A common misconception is that a 2 stroke engine fills the entire chamber. The idea is to keep the new mixture entering the chamber away from the exhaust port because the exhaust opens first and closes after the intake portion of the cycle. If the ports push fuel towards the exhaust port, some of the new charge gets pulled out of the chamber during blowdown causing the motor to lean out. A common remedy is to open the needles to compensate for the lost fuel resulting in reduced fuel milage and loss of engine effciency and the fuel that gets wasted also burns in the pipe increasing engine temp due to the pipe pushing the hot gases back into the exhaust port when the pulse returns and that also starts a vicious preignition cycle that causes detonation and can ruin your engine if not found soon enough. There are alot more factors that makes these engines perform the way they should and there are alot of different opinions you will hear as you go along. There are alot of good engine guys out there and its good advice to listen to them and see if you can pick up any similarities between them. If you guys are interested in some engine work, you can visit my website at www.PowerHouseRCPerformance.com I also have a more detailed explanaton of 2 stroke operation if interested. Good Luck gentlemen and i hope to hear from some of you soon.

Mark @ PowerHouse RC Performance
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Old 01-14-2008, 07:55 PM   #18
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As far as the crank is concerned, the machining imperfections won't really hurt you. They are not impeading or changing the direction of airflow enough to matter. You can clean it up if you want without fear of screwing anything up. Its relatively simple. What is a big factor is the crank intake timing. The real gains in performance lie within the duration of the crank intake port and what degree it opens and close in relation to the transfer ports. You can clean up the edges if you want and again it shouldn't affect the stock degree specs thus not altering the engines stock running characteristics. The one guy is exactly right about the polishing aspect. Alot of people firmly believe that a polished surface is smoother and more efficient but after years of racing snowmobiles and personal watercraft and designing engines for factory polaris's race program, we have found that a course surface maintains a suspended molecule structure which in turn keeps the velocity speeds up and keeps the molecules from dragging along the surface which ends up as fuel puddling on the intake side and carbon build up on the exhaust side. As far as the "tear drops" in the windows of the ports, alot of engine manufactures are putting them in on their transfer ports. The theory is to help guide the mixture into the chamber but whats more important than just getting the mixture into the chamber is at what angle and speed it enters. Two stroke engines are loop scavengers which means the fuel/air mixture should enter angled up and away from the exhaust port towards the rear booster but not to interfer with the rear booster entry. The mixture then travels up the back wall into the dome, fires, rolls over and exits the chamber through the exhaust port completing the circuit. A common misconception is that a 2 stroke engine fills the entire chamber. The idea is to keep the new mixture entering the chamber away from the exhaust port because the exhaust opens first and closes after the intake portion of the cycle. If the ports push fuel towards the exhaust port, some of the new charge gets pulled out of the chamber during blowdown causing the motor to lean out. A common remedy is to open the needles to compensate for the lost fuel resulting in reduced fuel milage and loss of engine effciency and the fuel that gets wasted also burns in the pipe increasing engine temp due to the pipe pushing the hot gases back into the exhaust port when the pulse returns and that also starts a vicious preignition cycle that causes detonation and can ruin your engine if not found soon enough. There are alot more factors that makes these engines perform the way they should and there are alot of different opinions you will hear as you go along. There are alot of good engine guys out there and its good advice to listen to them and see if you can pick up any similarities between them. If you guys are interested in some engine work, you can visit my website at www.PowerHouseRCPerformance.com I also have a more detailed explanaton of 2 stroke operation if interested. Good Luck gentlemen and i hope to hear from some of you soon.

Mark @ PowerHouse RC Performance



PARAGRAPHS.....its hard to read all that in 1 blob....and ill have Max chime in here...he will know what chu be talkin bout.
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Old 01-15-2008, 02:30 AM   #19
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Mpowerz here is a couple of photos of the crank out of my V-Spec.

The photo quality is not realy that good but it may give you an idea.

Stage 3 Mods by myself :]


Full Size Pic - http://www.users.on.net/~danzig/crank%20002.jpg


Full Size Pic - http://www.users.on.net/~danzig/crank%20007.jpg

Just to give you an idea.
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Old 01-15-2008, 02:35 AM   #20
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Thank you for the pictures....

What does that do to the mileage? Is the motor going to be more effecent?

Also the tooling marks (grinding) Is that going to help mist the fuel? Would you want to roughen up the shaft part of the intake to help mist the fuel?
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Old 01-15-2008, 02:54 AM   #21
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Yes the Motor would be more efficient.
It will flow better than stock therefore more efficient.
It will make more power which translates to using less throttle around the track and therefore you save even more fuel.

Yes, roughen up the hollow part of the crank, all the way down the inside, now i dont mean 60 grit sand paper, but if you use a dremel and a stone just leave the finish on the crank that the stone will leave.

Make sure you de bur any edges and run you finger around the edges to feel and make sure there are no burs anywhere, be carefull not to cut yourself tho

Then clean it top to bottom with solvent or something simliar and blow it off with an air compressor as well if you have one.

Do NOT roughen up anywhere outside the shaft on the outer side of the crank, just the inside.
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Old 01-15-2008, 04:10 AM   #22
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Originally Posted by GenReaper View Post
Yes the Motor would be more efficient.
It will flow better than stock therefore more efficient.
It will make more power which translates to using less throttle around the track and therefore you save even more fuel.

Yes, roughen up the hollow part of the crank, all the way down the inside, now i dont mean 60 grit sand paper, but if you use a dremel and a stone just leave the finish on the crank that the stone will leave.

Make sure you de bur any edges and run you finger around the edges to feel and make sure there are no burs anywhere, be carefull not to cut yourself tho

Then clean it top to bottom with solvent or something simliar and blow it off with an air compressor as well if you have one.

Do NOT roughen up anywhere outside the shaft on the outer side of the crank, just the inside.

Thanks again..

Im going to pull my cheap motor apart and try what I have learned here.

Also in your top picture did you open up the radius and round the corners of the intake on the crank pin side?

With polishing up the exauste port and cleaning up and smoothing up the intake. Where am I going to see the gains?

How will these mods affect motor temp? Hotter/cooler/same...
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Old 01-15-2008, 10:32 PM   #23
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Thanks again..

Im going to pull my cheap motor apart and try what I have learned here.

Also in your top picture did you open up the radius and round the corners of the intake on the crank pin side?

With polishing up the exauste port and cleaning up and smoothing up the intake. Where am I going to see the gains?

How will these mods affect motor temp? Hotter/cooler/same...


??
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Old 01-16-2008, 01:18 AM   #24
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No i didnt open up the radius, the OS crank is like that stock and i wouldnt reccomend doing it to your crank. I did machine a flute in the conterweight of the crank but the radius is stock, just cleaned up and rounded a little more to help flow and fuel atomisation.

You wont see a huge difference in power but none the less it will be better cause most power is made thru crank timings and sleeve timing modifications.

None the less, cleaning up the crank with a stone has benifits as slight as they are.

Temps should stay the same, if any thing just richen up the high speed needle a quarter turn before you run it to be on the safe side and then re tune the motor when warm.
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Old 01-16-2008, 01:28 AM   #25
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Well I gave it a shoot tonight. Just got the motor back in. Im going to see what the results are in the morning.

Here are some pictures. Also I opened up the flywheel side of the case opening to match with the intake of the crank.. Its a perfect match now.. It was hangin over about .025". (Picture 2)





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Old 01-16-2008, 12:21 PM   #26
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It pulls a bit better.. Top end comes up quicker. I need to take some time and tune it.. Its 0 deg out so that makes it a bit tougher. Im going to spend some time at the track to get it right.....

I will know better then...
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Old 01-16-2008, 03:12 PM   #27
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Hey All

Just want to commend you guys for having a go at modding your engine, its tons of fun and the feeling when you get it right or realise a difference is awesome !

modifying is a big part of racing and dont let any one tell you different .

PowerHouse's info and his site is really good ! he is on the money

Anyway all i wanted to say is enjoy the experience

Cheers MM
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Old 01-16-2008, 08:17 PM   #28
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Hey All

Just want to commend you guys for having a go at modding your engine, its tons of fun and the feeling when you get it right or realise a difference is awesome !

modifying is a big part of racing and dont let any one tell you different .

PowerHouse's info and his site is really good ! he is on the money

Anyway all i wanted to say is enjoy the experience

Cheers MM

I hear ya... I love to make things go FASTER.... with the help and knowledge of everyone on the site it makes it that muck more exciting.

Thanks again to everyone that takes the time to help and suport the NOOBS on this site....
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Old 01-17-2008, 01:41 AM   #29
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As far as the crank is concerned, the machining imperfections won't really hurt you. They are not impeading or changing the direction of airflow enough to matter. You can clean it up if you want without fear of screwing anything up. Its relatively simple. What is a big factor is the crank intake timing. The real gains in performance lie within the duration of the crank intake port and what degree it opens and close in relation to the transfer ports. You can clean up the edges if you want and again it shouldn't affect the stock degree specs thus not altering the engines stock running characteristics. The one guy is exactly right about the polishing aspect. Alot of people firmly believe that a polished surface is smoother and more efficient but after years of racing snowmobiles and personal watercraft and designing engines for factory polaris's race program, we have found that a course surface maintains a suspended molecule structure which in turn keeps the velocity speeds up and keeps the molecules from dragging along the surface which ends up as fuel puddling on the intake side and carbon build up on the exhaust side. As far as the "tear drops" in the windows of the ports, alot of engine manufactures are putting them in on their transfer ports. The theory is to help guide the mixture into the chamber but whats more important than just getting the mixture into the chamber is at what angle and speed it enters. Two stroke engines are loop scavengers which means the fuel/air mixture should enter angled up and away from the exhaust port towards the rear booster but not to interfer with the rear booster entry. The mixture then travels up the back wall into the dome, fires, rolls over and exits the chamber through the exhaust port completing the circuit. A common misconception is that a 2 stroke engine fills the entire chamber. The idea is to keep the new mixture entering the chamber away from the exhaust port because the exhaust opens first and closes after the intake portion of the cycle. If the ports push fuel towards the exhaust port, some of the new charge gets pulled out of the chamber during blowdown causing the motor to lean out. A common remedy is to open the needles to compensate for the lost fuel resulting in reduced fuel milage and loss of engine effciency and the fuel that gets wasted also burns in the pipe increasing engine temp due to the pipe pushing the hot gases back into the exhaust port when the pulse returns and that also starts a vicious preignition cycle that causes detonation and can ruin your engine if not found soon enough. There are alot more factors that makes these engines perform the way they should and there are alot of different opinions you will hear as you go along. There are alot of good engine guys out there and its good advice to listen to them and see if you can pick up any similarities between them. If you guys are interested in some engine work, you can visit my website at www.PowerHouseRCPerformance.com I also have a more detailed explanaton of 2 stroke operation if interested. Good Luck gentlemen and i hope to hear from some of you soon.

Mark @ PowerHouse RC Performance

This guy knows what he is talking about !
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Old 01-17-2008, 02:14 AM   #30
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Mpowerz, good job mate, glad everything worked out for you and your happy with the results.
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