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Post by 190mech on Jun 23, 2015 20:12:09 GMT -5
You're barkin' up the right tree Niz!If I remember right,Brent did a homebrew with a 45 crank and 47(70cc) cylinder,,durations were a problem and it snagged a ring in its short life..We are hamstrung to close cylinder thru studs,making a proper triple port exhaust hopeless,next up is the 'butterfly' bridged ex port with a bridge that swells with heat hoping to keep the rings in the grooves and not the port edges..Last is the big ol single ex port,heavy chamfers to guide the bugging out rings in the port with each stroke..The smaller bore(47mm) does have a better(not great) transfer tunnel design and will get the mixture better placed with in the cylinder than say a 52mm jug..A better crank could be had with simply retrofitting a quality MX rod kit on a 90cc ATV crank.The crank wheels are very high quality steel..I shed alligator tears daily when I look at all the MX cylinders dating back to the 80's laying on my work bench with waaay better designs than the bestest high zoot credit card racer dream cylinder that fits a Minarelli on the market now,and not a one of them old MX jugs will fit!!!  |
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Post by ryan_ott on Jun 23, 2015 21:11:02 GMT -5
It is known that the minarelli is a transportation engine but we will continue to try to squeeze every last hp out of it. Because it's what we have to work with. Some of the cylinders I'm thinking about do still have some real nice HP claims in the low to mid 20's.
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Post by 90GTVert on Jun 24, 2015 18:45:03 GMT -5
If I remember right,Brent did a homebrew with a 45 crank and 47(70cc) cylinder,,durations were a problem and it snagged a ring in its short life..( That one may have had a chance, but I went nuts on the exhaust port. It was big and wide and poorly chamfered and I was just asking for a ring to snag, and it did. It basically ran long enough to do a burnout and sputter up the road a couple of miles not hitting the pipe. I had something like 140 degrees transfer duration, otherwise the piston stuck way out of the bore. |
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Post by ryan_ott on Jun 26, 2015 21:31:04 GMT -5
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Post by spaz12 on Jun 26, 2015 22:32:52 GMT -5
Good pipe but interestingly enough, not as good a performer as the C30 or Roost 77. But At that price, the slight performance loss is quite acceptable.
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Post by ryan_ott on Jun 27, 2015 7:32:38 GMT -5
Good pipe but interestingly enough, not as good a performer as the C30 or Roost 77. But At that price, the slight performance loss is quite acceptable. Scooter parts company has it for 280 |
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Post by 190mech on Jun 27, 2015 13:31:10 GMT -5
If its a 'matched' pipe,thats gotta be as good as it gets..I was going to suggest that you build a C21,but not knowing the cylinder port layout,it'd just be a guess.. |
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Post by ryan_ott on Jul 1, 2015 10:59:42 GMT -5
Getting prepared for my 77...  An hour later....    . I love impact drivers, one of the best tools you can purchase. Saves so much time! |
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Post by spaz12 on Jul 1, 2015 14:41:02 GMT -5
You ordered the 77?
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Post by ryan_ott on Jul 1, 2015 17:01:21 GMT -5
Going with the 77, overrange, Malossi full circle crank and a few other odds and ends.
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Post by spaz12 on Jul 1, 2015 17:52:11 GMT -5
Sweet! Are you going with the Malossi pipe as well? I love silencer on the MHR's.
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Post by ryan_ott on Jul 1, 2015 18:17:10 GMT -5
Yes I'm going to try out the Malossi pipe, scooter parts company had it for a very nice price. I may also build a c21 as mentioned by 190mech to see which I like better. I think I'm going to run another Keihin 28mm PWK
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Post by 2TDave on Jul 1, 2015 18:31:29 GMT -5
What are you using for a radiator and pump?
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Post by ryan_ott on Jul 1, 2015 18:51:12 GMT -5
I have a mechanical pump and a pair of YZ85 radiators. I will be getting a inner rotor ignition so I don't think I have the capacity to run an electric pump.
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Post by niz76 on Jul 1, 2015 19:09:57 GMT -5
Very nice! Sounds like a hot setup! I wonder which you'll enjoy more in the end- the 100cc grunter, or the 77cc screamer?
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