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Post by KSR Moto on May 28, 2018 8:41:15 GMT -5
Which scooters come with 44mm bore in stock, and what is the top speed of those scooters?
I want to install a 44mm bore in one of my scooters
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Post by GrumpyUnk on May 28, 2018 12:06:05 GMT -5
I have yet to see a 44mm bore advertised anywhere/ I have not looked overseas, outside USA, in my case. There was rumor that some machines were 63cc from the factory, but I have not seen one 'in the wild'.
You can still get 44mm kits with piston, rings, wrist pin, circlips and even valve stem seals. Aliexpress has them for twenty-odd dollars, same price as the 47mm kits. You can get them in USA if you look. Not all carry them as the demand is low, most increasing their displacement to 72cc or larger(I think).
I have one that I scrounged parts for that I plan on installing in an older Taotao that seems to have low compression. I just set the ring gap, so it is now ready for installation. I think it will give a nice increase in mid range operation, so it will accelerate more noticeably when asked. Right now, mid range response is rather lackadaisical.
If you go with a 44mm kit, you should have no problem with the starter or carburetor, I think. It should run nicely.
tom
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Post by KSR Moto on May 28, 2018 14:32:30 GMT -5
If you go with a 44mm kit, you should have no problem with the starter or carburetor, I think. It should run nicely. tom That is main reason I want to install it, I already have the kit I just need to install it, and I think that a 44mm bore shouldnt damage my crank and it should run okay on wot |
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larryhobman
Scoot Enthusiast
Posts: 117
Location: Delaware beaches
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Post by larryhobman on May 28, 2018 20:52:41 GMT -5
I have 2 scoots that had the 44mm come stock. The stock 44mm comes with a different head that is cut deeper to give it more volume. The stock 39mm heads are flat. I do not know how they run as I switched them to 47mm kits but I did use the 44mm head still that keeps the compression down some to save the crank from going bad.
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Post by diynuke on May 29, 2018 6:03:54 GMT -5
If you go with a 44mm kit, you should have no problem with the starter or carburetor, I think. It should run nicely. tom That is main reason I want to install it, I already have the kit I just need to install it, and I think that a 44mm bore shouldnt damage my crank and it should run okay on wot as long as correctly installed and properly tuned it should last you a long time no matter what you do to it. (After the break in of course xD) and i dont know where also those stories from damaged crank's come from but I've never had any problems with 2scoots that were 100% chinesium only problem i had was that the piston pen was stuck in the crank so i had to force it out. and that probably was because the previous owner ran it without any oil. and just kept riding it. at the end it would start barely because low compression but it still ran! then i put an chinesium 47mm on it and she was running happy again. Still gotta get a new 139QMB because the mount has a crack in it ;P and top speed probably won't change much but the acceleration is better and that's something we all like ;D |
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Post by jackrides on May 29, 2018 10:04:10 GMT -5
Is 44mm the largest bore without boring the cases?
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Post by KSR Moto on May 29, 2018 11:40:00 GMT -5
Is 44mm the largest bore without boring the cases? No, even 50mm fits without boring the cases |
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Post by cagiva4ever on May 29, 2018 12:05:04 GMT -5
here in Finland, we have had 44mm version imported on early 2000, right when the Scooter boom started here and when Mall's etc larger market-crocery stores also started to sell them 139QMB "10-wheel basic classic scooters.
in here these 44mm versions were supposed to be the STD 49cc 39mm bore versions, as that is what and how they were Type Approval MOT'd, but China supplyers delivered illegal models in purpose or as cutback hoax to our Importers in Fi.
1 of these engines with 44mm is Engine from "Sanili", with casted Sanili logo text on CVT cover. Scooters them selves were sold under various salesnames, like "Forte" or "Sunny". said Sanili has 64mm long valve's.
in our case at Fi, the Sanili 44mm versions were sold until year 2007, that i know of.
we have couple of these Sanili's in our Village. and i have these engines from bike breaker, and about 3 more separate 44mm cylinders and 44mm heads.
the said Sanili Forte as 44mm version as "Stock" goes TopSpeed about 75kmh. it has heavy rollers as Stock about 7,5gr. it doesnt have any CVT ristrictions or even CVK-throttle slide ristriction, or any cdi rpm limiter as Stock, purely illegal in our Finnish case Vs national type approval.....
other 44mm versions have iirc came from manufacturer named called "Fude", yet again making basic classic "10 139QMB's.
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Post by fugaziiv on May 29, 2018 12:10:53 GMT -5
44mm bikes were being imported into the states for a short period of time. Like 2009-11 maybe. EPA cracked down on them rather quickly and they haven't been imported since. Tao Tao was one of the main companies implicated if I remember correctly.
I haven't seen a secret 63 in a while though.
Matt
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Post by kagetenshi on May 30, 2018 8:59:54 GMT -5
I guess I should order some new gaskets and tear into my VIP to see just what's in there. It's pretty fast for a mostly stock 139qmb. Up to 45mph GPS with no wind. Time to get out my set of calipers!
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Post by GrumpyUnk on May 31, 2018 10:08:21 GMT -5
KAG:Up to 45mph GPS with no wind.
Downhill? With a push? To get that fast, I suspect there is more than a 39mm diameter piston/cylinder inside. If you had a 44mm, I would believe it more possible. Let us know what you find.
I think the base gasket will not matter, and using an over-size head gasket should have little effect but to allow a narrow ring open to the combustion chamber, between the head and cylinder, about 2.5mm deep...? ([44-39] / 2 = 2.5)
tom
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Post by kagetenshi on May 31, 2018 16:08:42 GMT -5
The only things I've done to it are a 19mm genuine keihin cvk carb with 88mj/35pj and a cone style air filter. At 45mph it's screaming around 9000 rpms though. And it takes a couple miles to get to that speed. But it gets to roughly 40 pretty quickly, I would say in about a block or 2. Oh, and it's a 2012 model taotao VIP cy50-a.
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Post by KSR Moto on Jun 1, 2018 13:20:31 GMT -5
I have just installed 44mm bbk in my scoot,I really liked the 47mm but 44mm requires less tuning and works great with everything stock! It will probably last longer than 47mm too!
Good acceleration, top speed is 46mph with light wind
It can be started easily on electric starter
I have a head with bigger combustion chamber but I used the stock one from the 39mm for this build
It is a long case engine with 12' wheels
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Post by GrumpyUnk on Jun 4, 2018 9:29:50 GMT -5
I think there is a rash of optimistic speedometers going around. Chuckle.
I have a 47mm with stock head that will just about peg the speedometer. 80kph indicated, level ground, or close, but I don't believe it. 80 X .62 == 49.6. As they say: "Not gonna happen". A Taotao atm50-a1, 10" wheels. I cannot believe that speed, so I won't. Not very comfortable at that speed, either.
Front wheel bearings seemingly fed some rocks or sand, with rough spots where the wheel wants to stop turning when spun by hand. Having a time removing the old, so will try some heat.
tom
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Post by scooterted on Jun 4, 2018 9:39:14 GMT -5
I think there is a rash of optimistic speedometers going around. Chuckle. I have a 47mm with stock head that will just about peg the speedometer. 80kph indicated, level ground, or close, but I don't believe it. 80 X .62 == 49.6. As they say: "Not gonna happen". A Taotao atm50-a1, 10" wheels. I cannot believe that speed, so I won't. Not very comfortable at that speed, either. Front wheel bearings seemingly fed some rocks or sand, with rough spots where the wheel wants to stop turning when spun by hand. Having a time removing the old, so will try some heat. tom On my atm 50mph indicated is 40mph gps. One day im gonna make a vid demonstrating just how bad it is. |
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