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Post by 90GTVert on Mar 27, 2021 5:44:11 GMT -5
Oval exhaust port is interesting. There are two small accessory ports on the main exhaust. They're pretty slim. Not sure if they really do much. If you get the urge to modify the ports, you can't do much with the auxiliary exhaust ports. You'll find that they are small because the cylinder studs are right beside them. Try to cut away enough to make a decent width path and you'll probably go through into the stud passage.
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Post by Deleted on Mar 27, 2021 7:54:31 GMT -5
@90gtvert yessir I did notice that. All I've done is a little light chamfering here and there to keep from snagging a ring. Gotta say ports were pretty smooth. Not too many protrusions. 190mech Indeed I do! I got the studs. I knew the cylinder would be tall. Just didn't figure in the chunkiness.
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Post by x7rocks on Mar 27, 2021 8:48:24 GMT -5
@90gtvert yessir I did notice that. All I've done is a little light chamfering here and there to keep from snagging a ring. Gotta say ports were pretty smooth. Not too many protrusions. 190mech Indeed I do! I got the studs. I knew the cylinder would be tall. Just didn't figure in the chunkiness. It was kinda a close job getting the aux ports widened when i was working on a similar styled cylinder. Widening the transfer helped a bit as well with my setup
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Post by Deleted on Mar 27, 2021 15:15:46 GMT -5
Now I'm hunting for a pipe. I see the V8 over at PFS is available and is likely gonna do what I need this thing to do. The thought did occur to find a Stage6 Pro Rep. I've read in a few spots that it's power goes a bit beyond the 70cc range. This of course will mean higher revs on the 90.
I keep looking around for other options and there really don't appear to any. Well there are but they are beyond my range. I'm a keep looking about.
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Post by 190mech on Mar 27, 2021 16:49:29 GMT -5
It will not be a screamer,,10,500-11,000 RPM is all the transfer ducting will flow,ProRep is too short as well as a lot of other 70cc style pipes..Some can be lengthened to drop peak revs..
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Post by Deleted on Mar 27, 2021 17:06:53 GMT -5
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Post by repherence2 on Mar 27, 2021 18:05:47 GMT -5
i have run that bore. i liked it's performance over the stock 50mm bore that i had. what killed my bore was the fact that i forgot to install one of the circlips on the piston. the wrist pin drifted over the course of a few months and gouged a groove in the bore, killing it. i bought it as a partial kit from a local store, it was missing the head, but it was cheap. i ended up running it with the stock 50mm non-squish band (wavy) head. i tried running a 47mm NCY squish band head on the stock 50mm, ended up burning a hole in the piston after a few months.
i must add, i ported my exhaust outlet on the bore to match the black V8 pipe i was running.
if i could do it again, knowing what i know now, i would get me two of those kits and i would do some porting on it. that exhaust port arrangement is similar to the Motoforce mid race 70 & Polini EVO2 70. I would port one bore to the Motoforce timings (which should be on par with a Corsa) and i would port the second jug to the Polini EVO2 timings just for fun. probably even hack/shorten the piston skirts and run it single ring.
but as is, that bore kit should be some fun. if the stock exhaust timing is does not give you high enough rpm's, you can always raise the main exhaust port 1,2, or 3mm depending on how much more 1000 rpm you want. like 90GTVert mentioned about the auxiliary exhaust ports, not much room to open up the passage due to the wall thickness. i would like to try porting the auxiliary ports just and increase the ports' area.
im enjoying your Build!
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Post by repherence2 on Mar 27, 2021 19:06:36 GMT -5
the v8 sectional is good enough. not as loud as a chamber pipe. the black v8 with the plastic heat shield is quieter. i bought those black v8's when i was running the 70cc bores. the baffle plate shattered/cracked on the first v8 sectional (BWS 100) that i bought for my 94cc engine, it got Loud. bought a used one at a local shop and that one is weathered but it stood the test of time. black v8 my BWS 100 sectional new BWS 100 sectional have you seen this one, reminds me of the PG (Phongeer) short/long exhaust for the DIOs. ...or are you getting the V8 Chamber pipe?
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Post by Deleted on Mar 27, 2021 19:29:47 GMT -5
repherence2 thanks, man. I'm glad you're digging the build. Thanks for the photos too. It's really helpful to see something besides the sales photos. This is the one on PFS. www.partsforscooters.com/190-68-Minarelli-90-Exhaust-BlackLooks like the new sectional, I believe. I haven't seen that last one you posted. Where'd you find that one. It does look a good deal like the Phone we pipes that I've seen online. I've never messed with porting before, but this engine is about the learning experience, so I'm not beyond trying something new or different. Also have a spare QJ 50 that I planned to use to learn case cutting, so all good stuff. I appreciate all the info!
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Post by 190mech on Mar 28, 2021 4:31:41 GMT -5
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Post by Deleted on Mar 29, 2021 13:54:17 GMT -5
So while I'm hemming and hawing about the pipe situation. Found a coupon for the Tecnigas Next R which drops the price to $136. With shipping, that's about $146 and change. Just have to wait a while for it to arrive. So this had led to further hemming and hawing. From what I've read, I know I'm gonna have to fiddle with the fitting and set up in either case. Either way, I've given myself a deadline of tonight to make a decision.
So while I'm jumping back and forth across the fence, I got to thinking about other the gears. The RT50 and a lot of other Adly scoots are sitting with 12/48 with 36 final drive drive shaft and 13 primary shaft. From reading around I know that the Vento Zip/Keeway Hurricane/ LS49 along with the Polaris/Arctic Cat/Adly Atv gears should fit this thing. It's got me wondering about the gears I have sitting in the QJ case over in the corner. I'm thinking they probably aren't right for the Adly case since that's a QJ long.
Get2it seems to have something that would work for the primary and secondary shafts. Just a matter of sorting out the secondary gear/countershaft. 12/48 is not very easy to find. I'm a keep looking about for something from one of the other cognate engines. Could always swap the gears out of the RT when its time to start testing this thing, but I 'd rather it had its own parts.
I also keep running across the TOP Racing gear sets. Has anyone had any experience with those in a 90CC or is that not an avenue worth exploring?
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Post by aeroxbud on Mar 29, 2021 14:13:53 GMT -5
Just make sure it's for a 90cc engine, not a 50cc exhaust.
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Post by Deleted on Mar 29, 2021 15:43:57 GMT -5
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Post by aeroxbud on Mar 29, 2021 15:47:25 GMT -5
It should fit the high torque low rev engine well.👍
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Post by Deleted on Mar 29, 2021 16:00:13 GMT -5
And with the deal, I feel like I gotta jump on it. Can put the extra 20 bones toward other stuff.
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