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Post by oldgeek on Jan 3, 2015 9:20:48 GMT -5
Yes, except for the first dimension at the headpipe 28.2mm is the actual ID there. I will note that on the picture when I add the missing measurements.
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Post by oldgeek on Jan 3, 2015 19:05:55 GMT -5
I updated the photo with the additional information.
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Post by 190mech on Jan 3, 2015 20:25:51 GMT -5
Head pipe is .8* 1st diffuser is 2.3* 2nd diffuser is 6.2* 3rd diffuser is 7.6* --spacer/belly--- baffle cone is 12.2* Total length 824 Head pipe 32% Head pipe/diffusers 70%
Not a bad pipe!Headpipe and diffuser angles are a bit shallow making for a good pipe for lower to mid cylinder durations,Headpipe and headpipe/diffuser % are very close to spot on,it'll likely be good to 11,500-12,000 RPM's. Thats if there are no tree hugger baffles or screens inside!!
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Post by oldgeek on Jan 3, 2015 20:56:29 GMT -5
Thanks for the information! Current durations on this build are 130 transfers, 194 exhaust. So I guess the MHR pipe would be better off on the 70cc Zuma build which has a mild DR kit on it, should really wake it up!
I need to get the dimensions of the Technigas RS II that is currently installed on the 70cc streetrace for you to take a look at. I may pull the pipe off and get the dimensions when I install the head you step cut for me. The compression with the current head is 119psi, What compression should I shoot for when I change to the step cut head? Or should I set squish to around .8mm and just see what compression turns out to be?
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Post by 190mech on Jan 4, 2015 5:16:52 GMT -5
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Post by Lucass2T on Jan 4, 2015 14:57:30 GMT -5
Hey OG thanks for the effort! Do you know exactly which MHR pipe this is? I knew there was this 'one' MHR pipe a bit comparable with a yasuni c16. But there are TONS of different MHR pipes, normally only suited for the high-end and 77-88cc kits.
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Post by oldgeek on Jan 4, 2015 15:34:21 GMT -5
Head pipe is .8* 1st diffuser is 2.3* 2nd diffuser is 6.2* 3rd diffuser is 7.6* --spacer/belly--- baffle cone is 12.2* Total length 824 Head pipe 32% Head pipe/diffusers 70%
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Post by 190mech on Jan 4, 2015 19:53:26 GMT -5
Guess I oughta clarify,,a strong 70cc pipe will have a 1.2*(degree) head pipe,4,6&8 degree diffuser(front) cones,10 to 12 degree baffle (rear) cones..Head pipe length should be 30-32% of total length(minus tail pipe) and head pipe/diffuser length should be 64-68% total length.All the above numbers are approximate,nothing is 'set in stone' when it comes to pipe design!!
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Post by oldgeek on Jan 4, 2015 20:23:27 GMT -5
Hey OG thanks for the effort! Do you know exactly which MHR pipe this is? I knew there was this 'one' MHR pipe a bit comparable with a yasuni c16. But there are TONS of different MHR pipes, normally only suited for the high-end and 77-88cc kits. Here ya go, a picture of the label that is on the box. I believe this pipe is the MHR Race, not to be confused with the MHR replica which is 1 step below it, or the MHR Team which is 1 step above.
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Post by oldgeek on Jan 4, 2015 20:39:39 GMT -5
Head pipe is .8* 1st diffuser is 2.3* 2nd diffuser is 6.2* 3rd diffuser is 7.6* --spacer/belly--- baffle cone is 12.2* Total length 824 Head pipe 32% Head pipe/diffusers 70% Not a bad pipe!Headpipe and diffuser angles are a bit shallow making for a good pipe for lower to mid cylinder durations,Headpipe and headpipe/diffuser % are very close to spot on,it'll likely be good to 11,500-12,000 RPM's. Thats if there are no tree hugger baffles or screens inside!! Guess I oughta clarify,,a strong 70cc pipe will have a 1.2*(degree) head pipe,4,6&8 degree diffuser(front) cones,10 to 12 degree baffle (rear) cones..Head pipe length should be 30-32% of total length(minus tail pipe) and head pipe/diffuser length should be 64-68% total length.All the above numbers are approximate,nothing is 'set in stone' when it comes to pipe design!! Thank you. I really appreciate you taking the time to explain this stuff! Now all those number's from the previous post are decoded in a way even I can almost understand.
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Post by Corrosion on Jan 4, 2015 21:27:10 GMT -5
Wow I got the same pipe for my Derbi GP-1. Gonna have to watch how this works out. I got it and a Team Cylinder kit. But found it needs a longer crankshaft to operate. The crankshaft is $$ but coming down every year considerably.
So I get to See how it works for you! From what I read about it is strong in the Mid & High Revs.
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Post by oldgeek on Jan 12, 2015 19:29:39 GMT -5
I have been busy with other stuff, but I hope I can get the step cut head that John did for me installed on this scoot tomorrow (Thanks, 190mech!).
I am thinking the TurboKit pipe, or the Malossi MHR will end up on this scooter, I plan to try both of them.
I also hope the pipe that is on it now, (technigas RSII?) will work out for the 99cc build, otherwise I don,t know what to do about a pipe for that build. I gotta get the RSII pipe taken off and measured so John can tell me what it will support.
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Post by 190mech on Jan 12, 2015 20:39:14 GMT -5
COOL!Get those measurements..The TurboKit pipe will do better on a 70cc with good porting as the 103cc needs a much longer pipe,quite close to the MHR pipe.The MHR has a stinger ID that may cause some heat problems on the 103,a CHT gauge would be a nice addition...
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Post by oldgeek on Jan 12, 2015 21:30:23 GMT -5
Despite dense fog, I rode the 70cc streetrace over to the warehouse so I could pull the RSII pipe off. I will get measurements on it tomorrow sometime.
I decided to test fit the TurboKit pipe on the streetrace, and as usual this pipe will be a pain to put on this setup. It fit like a GLOVE on the shortcase 99cc the other day when I test fit it. No pipe I have tried has ever bolted right up on this 70cc streetrace cylinder. It must have something to do with this streeetrace kit.
I did get a chance to start it up to hear the turbokit pipe but thats about all. I ran out of time, and had to head home. I will take it for a ride tomorrow if the rain allows, and also test out the MHR pipe. But I need to install that stepcut head first!
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Post by 2TDave on Jan 13, 2015 6:46:10 GMT -5
I think it is the Stage6 exhaust flange angle. Both of my S6 cylinders needed work to mount pipes to. I use rollers for spacers at the engine mounting points and made brackets out of flat bar at the pipe mount brackets. I used aluminum here but the rear broke. Steel is better IMO.
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