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Post by dexameth on Nov 27, 2019 11:17:54 GMT -5
hahaha I soft seized the Polini 177 AGAIN last night. Cruising at 56-58mph (still had more - had it to 63 at one point) and it was like someone hit the brakes. Clutch in, choke out, coasting for a while then popped the clutch and fired right up. Made it home fine. This was on a 112 main jet... upjetted from a 108 a few hours earlier. This morning, headed out to work... got to 3rd gear and thought I was soft-seizing again! Pulled off to a side-road and no matter the gear, it was struggling to go and misfiring. Wait. Plug?? Pulled over, swapped plugs and all was well. Had all the power back. Made it to work. Plug was pretty black... but not covered in soot like I thought it'd be. So, rich condition AND a soft seize... what am I doing wrong? Is the Polini piston just a wimp and can't stand constant RPMs and swells up? Could be a clearance issue, but you said it had more in it when cruising so if it was not WOT then maybe the needle or needle setting needs a change. If you really go in circles with carb tuning on a 2T, then it may be time to do a leak test. Also make sure the fuel supply is good. You can lean out slowly if fuel flow is insufficient for some reason. Yeah, I thought clearance too, but both pistons fit and felt the same in the bore. And the SI carburetors have no needle, they rely on the jet stack to tune the mid range. I've played around with that a little, I might have to richen the midrange but then it'll 4 stroke when cruising. Speaking of fuel flow, I have pondered on that as well. The stock tap should flow plenty for my build since I'm only at a 112 main but I kinda think that could be an issue. Example - I shift to third, it gets on the pipe and starts pulling HARD then out of nowhere it's like someone hit a kill switch. As long as I don't hit that high of RPM I'm fine (but I'm still on the pipe at this point and it wants to keep pulling). So maybe at that high of rpm I'm draining the bowl? Hmm. Maybe.
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Post by 90GTVert on Nov 27, 2019 12:32:49 GMT -5
Speaking of fuel flow, I have pondered on that as well. The stock tap should flow plenty for my build since I'm only at a 112 main but I kinda think that could be an issue. Example - I shift to third, it gets on the pipe and starts pulling HARD then out of nowhere it's like someone hit a kill switch. As long as I don't hit that high of RPM I'm fine (but I'm still on the pipe at this point and it wants to keep pulling). So maybe at that high of rpm I'm draining the bowl? Hmm. Maybe. IF the fuel supply is an issue, what has happened to me is that if I go larger with the main jet the problem gets worse. T2 was doing what you describe a little while back and I kept thinking it was trying to soft seize. Went up in main jet size and found that the larger the jetting the quicker it tried to die, which is exactly the opposite of what should happen if it were truly soft seizing. Found a partial clog in my fuel system.
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Post by dexameth on Nov 28, 2019 8:46:57 GMT -5
Uh oh...Sonja just broke down. Coasting to a red light with the clutch pulled in and I hear a little clunk and lost all power. Spark is good, fuel is good (literally just filled up with ethanol free). Sounds like compression is different. Reeds look okay too. I can't see thru the plug hole to inspect the piston top, I don't think I popped a hole thru it but I am curious. Friend has a truck on the way...
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Post by dexameth on Nov 28, 2019 15:16:02 GMT -5
Rebuilt a stock engine for Sonja. Her soft seize yesterday left a good amount of aluminum on the cylinder and it eventually stuck between the piston and ring and stuck the ring in. No compression. Was on a group ride that just started, and Cory who was leading it got me a tow home.
I'm my attempts of removing the top end with the engine still mounted I had bent the conrod. I don't know what I was thinking but trying to hammer the pin out was a stooooopid move. I didn't brace the piston, just started knocking and then noticed it. I'm a dummy.
And I kinda lost my nerve, the hammer met the piston a few times, the case a couple and the conrod a few times... The damage was already done. Pulled the engine out and moved it to the side.
Took the other stock engine block, gearbox, clutch and added a 24/24 carb, Boysen reeds with the smaller one a carbon Minarelli reed and my stock cylinder kit that I had modified the piston and cylinder ports and made them larger. Kept the Scorpion pipe on cuz I just love that thing. Had to flush the case out from dirt and dust getting in there. Poured gas into the crankcase, spun the crank by hand a whole bunch and dumped it out. Did that a couple times. Then I did the rebuild.
Fired 3rd kick! 108 main jet, 55/160 idle 2.5 turns out. Sounds better than the Polini kit 🙄.
Test drive was great. Got to 55mph no problem just couldn't go faster as I was already 10 over hehe. The low end power is MAGNIFICENTLY better than the 20/20 with stock reed. It doesn't hit the pipe at all like the Polini kit, just pulls smooth thru like a box pipe, weird. I like this setup a lot, I'm not changing it for a while. The Polini kit is needing a hone and first over piston... Not anytime soon.
Happy Thanksgiving y'all! Time to get to the food and festivities.
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Post by pete130 on Nov 29, 2019 4:57:26 GMT -5
Well I order this piston for bbk one of the few 57mm pistons I can find that fit but what's the octagon ring for never seen befor
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Post by 190mech on Nov 29, 2019 5:17:52 GMT -5
pete130,Thats a ring expander for the second ring groove,,it puts extra tension for reasons I dont know,most folks leave it off with no problems..
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Post by milly on Nov 29, 2019 14:38:06 GMT -5
Today I finally got round to putting ACF50 on Violet after giving her a good wash a few days ago. I looked down the road as I was doing it and the salt gritter went by putting loads of salt everywhere but I dont need to worry now. Took it for a spin to shop temp dropped to 27f so back home saw it shining in the light but also saw where lots of ACF50 has run down on the tyres but it does look shiney. Will deal with it tomorrow. Will petrol be best to remove ACF50 from the tyres what do people think?
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Post by pete130 on Nov 29, 2019 17:16:18 GMT -5
pete130,Thats a ring expander for the second ring groove,,it puts extra tension for reasons I dont know,most folks leave it off with no problems.. I thought it had something to do with rings even started to think maybe to run one ring but then thought edges would hit boar lol I'll be leaving it out
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Post by Raizer on Dec 2, 2019 2:20:26 GMT -5
This wasn't just today, but I did a few things on it today if that counts? Not my scooter, but here's one I built for a customer/mate of mine recently My Mrs old Suzuki SJ50QT which is the scooter that got me back into them a few years back. The current owner had fitted a pile of parts to the old Morini engine and it still wasn't anything impressive at all, the more we all told him to give up on the Suzuki and start fresh with something like a Zip/Jog/Dio the more determined he became to make the SJ fast haha So I transplanted a 2011 Piaggio Zip 2t engine into it. Along with a Dopler crank, Polini Corsa kit, Polini PWK, Yasuni C16 and a pile of other goodies inc my old AN125 front end. Vast improvement over the old Morini haha
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Post by aeroxbud on Dec 2, 2019 9:37:41 GMT -5
This wasn't just today, but I did a few things on it today if that counts? Not my scooter, but here's one I built for a customer/mate of mine recently My Mrs old Suzuki SJ50QT which is the scooter that got me back into them a few years back. The current owner had fitted a pile of parts to the old Morini engine and it still wasn't anything impressive at all, the more we all told him to give up on the Suzuki and start fresh with something like a Zip/Jog/Dio the more determined he became to make the SJ fast haha So I transplanted a 2011 Piaggio Zip 2t engine into it. Along with a Dopler crank, Polini Corsa kit, Polini PWK, Yasuni C16 and a pile of other goodies inc my old AN125 front end. Vast improvement over the old Morini haha That's more like it 👍
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Post by pete130 on Dec 3, 2019 2:17:00 GMT -5
Well I desided to do a secondary gear kit in bee wee 100cc stock went from 13/48 to 15:40 made a bigger difference than I was expecting but 3.133 to 2.66 is a jump and stock motor but being 100cc it has the tquark to just push it it's not must slower off the line and has much better mid range and does 90-95 instead of 80-85km so it's better on pot end with out a sought. I wouldnt recamend doing on stock 50cc u really do near a bbk to push higher gearing it was more of a test for my 132cc aerox think I've got more than the power needed to really push it really think I will need primary kit as well it's one of the bigger things holding that motor back besides the pipe and plug lol came apart very easy 20 min and went pack easy as well after I pressed one of the gears handy to have a 6 ton press at home still waiting on new piston for aerox will post a few picks of rebuild see what u all think dam just remembered need new main bearings again lol
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Post by pete130 on Dec 3, 2019 2:19:15 GMT -5
I also swapped race variotor and molissi clutch and race lighten bell on bee wee it's like a diffrent bike lol may even put the turbo kit pipe on it was made for that motor not my race motor
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Post by pete130 on Dec 5, 2019 4:19:55 GMT -5
Pulled motor out of aerox to look at damage I know Theres a hole in piston hoping between the two kits same damage work out a fix I'll post pic of both barrels and pistons now I have 2 motors I can do kits on trying to work out what to do with each let you know more after I finish pulling motor down at least I've got the bee wee to ride lol
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Post by pete130 on Dec 7, 2019 0:02:24 GMT -5
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Post by aeroxbud on Dec 7, 2019 4:55:15 GMT -5
That really went big time. Blew up like a grenade! 😱
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