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@jagadeesh: wat 2T oil you running for the ported set up ?
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200psi is just static compression/trapped compression. Dynamic compression will be higher than that when you put a pipe on it. None of the fuels available at pumps in India will work. And if you back off timing in order to avoid knock, you will end up losing power.Originally posted by atul_astro View PostComment
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@ arvindraju - I am using Motul synt
@ RKOLI1983 - I will have to check with Atul on that. but what you said is true i will have to find an timing which is an acceptble compromise on power.RD 400Comment
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thanks guruji200psi is just static compression/trapped compression. Dynamic compression will be higher than that when you put a pipe on it. None of the fuels available at pumps in India will work. And if you back off timing in order to avoid knock, you will end up losing power.
any suggestions to use the current head and make the most of it? Or would reverting back to the stock 5 speed head on the pipe be right?
83' RD350 HT
96' RXG
97' RXZ
91'RX100>09'RX165
2010' HH ZMR
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Actually there really isnt a way you can intuitively say which head would be better for a certain engine. Usually the engine is run through its paces for different combinations of combustion chamber geometry on a simulater. If you dont have access to high octane fuel, probably its better to run low compression head with lesser squish clearance so that you minimize the chances of running into detonation.Comment
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TIme for an update guys.
Finished 2200kms till date. The bike is doing fine. Changed the carb to a 4spd one with 230 main and 17.5 pilot. Also got an chamber from my mech [ dont know the source of the pipe but it was on his street race bike ] The bike now does about 130kmph on the speedo.
Before we all jump to conclusions on the actual speed. Honestly i dont know.
The bike gives about 22kmpl previous was 26kmpl before porting.
Need to sort out the jetting. Need 20 pilots [ If anyone has one please help me out ]
Also need to try going richer on the mains but want to sort the pilots first.RD 400Comment
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Forgot to mention the same set up on 5spd carb and stock silencer was doing 120kmph. The gain of 10kmph was after the 4spd carb and pipe.
Atul you need to send tht pipe fast man. and some jets also please [ 220, 240, 250]
Atul has been very helpful till now and i really appreciate it.
Honestly i would be lying if i say he sticks to the timelines strictly but he is much better than others :-)RD 400Comment
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Small clarification on Displacement of Cylinders
Originally posted by jagadeesh.b View Post
Just a thought on the displacement calculation (CC) here for reference. The formula to calculate the displacement of n number of Cyilnders is :
Displacement = Stroke x Pi x (Bore/2)2 x (No. of cylinders) in mm3
Case study of Yamaha RX 135 Stock
Bore = 58mm
Stroke = 50mm
Displacement in Cubic mm = 50 x (22/7) x (58/2)2 x 1
= 132157.14 mm3
Displacement in Cubic cm = 132157.14 / 1000 = 132.15 cm3
Case study of Yamaha RX 135 4th Oversize (1mm, assuming each over size is 0.25mm)
Bore = 58+1 = 59mm (And not 60mm as mentioned above)
Stroke = 50 mm
Displacement in Cubic mm = 50 x (22/7) x (59/2)2 x 1
= 136753.57 mm3
Displacement in Cubic cm = 136753.57 / 1000 = 136.753 cm3
Now I quite did not understand how 150 cm3 figure arrived for a 4th oversize piston fitted into a cylinder whose volume was originally 132 cm3 !!!
Please correct me if I am wrong here & would be very eager to know how 132 cm3 gets converted to 150 or 165 cm3 . Looking forward for a quick reply.
With Regards,
- Karthik..Comment
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in his case i think he was referring to 1.50mm oversize - 139cc..almost 140cc we can say safely
for a 165cc you need an RD piston. 64mmLast edited by atul_astro; 05-11-2010, 09:06 PM.83' RD350 HT
96' RXG
97' RXZ
91'RX100>09'RX165
2010' HH ZMR
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the bike is not on 4th OS pistons. I belive Atul had it resleeved so that it can take an 60mm piston
So according to the formula it should be
=60*(22/7)*(58/2)*(58/2)*1 = 158588.5714 = 158.6ccRD 400Comment
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The formula seems a bit wrong if the piston is a 60 mm bore. The correct formula is
Displacement in Cubic centimeter = pi*(bore in cm /2)*(bore in cm/2)*stroke in cm= (22/7)*3*3*5 = 141 ccComment
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The formula is correct
Originally posted by jagadeesh.b View Post@ RKOLI1983: Dude, the formula is correct. Our Mr. Jagadeesh has wrongly substitued the values in the formula, typical Mathematical error & wrong judgement.Originally posted by jagadeesh.b View Post
The formula again:
Displacement = Stroke x Pi x (Bore/2)2 x (No. of cylinders) mm3
He has changed the stroke length from 50mm to 60mm and retained the bore dia to 58mm, God knows why !!!
Displacement = 50 x (22/7) x (60/2) x (60/2) x 1 mm3
Displacement = 141428.5714 mm3
Displacement = 141.428 cm3
With Regards,
- Karthik..Comment
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relax kartik. there's no need to jump anyone and make personal remarks here. wont lead to anything. the setup is created by me. if you feel any doubt feel free to check out its capabilities. I have a very similar setup given to psycho_98 on the forum and sanjay mugur. they all are more than satisfied with the port setup, 150cc or not, useable power speaks for itself. And before we hear any more wisecrack comments by your truly why dont you tell us about your ride? that would atleast be something constructive rather than just taking potshots
Cheers
Atul H83' RD350 HT
96' RXG
97' RXZ
91'RX100>09'RX165
2010' HH ZMR
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Originally posted by atul_astro View Post
Hi there. Thanks for the clarification. And about my ride, will update in 10 days time.
P.S: My intention was not to get personal here, was just trying to prove (Mathematically, that is) that the formula was indeed correct.
With Best Regards,
- Karthik..Comment
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