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Post by deejais on Jul 8, 2020 22:02:40 GMT -5
I have a 50cc IceBear. I see 100cc big bore kits ranging from $22 to $100 or more. Difference seems to be the higher-prices kits have a lot of additional things that have nothing to do with the actual piston/cylinder replacement.
Should I be wary of these sub-$25 bore kits? Are the components crappier than the more expensive kits? I'd very much like to hear others' experiences installing these kits. Thanks.
DJ
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Post by Zino on Jul 8, 2020 22:32:42 GMT -5
I have replaced other peoples cheap ebay kits often enough. I would spend just a little bit more so you only have to do one rebuild.
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Post by FrankenMech on Jul 9, 2020 4:42:50 GMT -5
Read here a bit before you go for a 100cc kit. Most people here seem to figure a ~70cc kit is enough, going bigger just blows up.
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Post by 90GTVert on Jul 9, 2020 6:14:03 GMT -5
Are they garbage? Maybe. Some of the cheap kits have poor tolerances and bad rings. Some seem alright.
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Post by GrumpyUnk on Jul 9, 2020 7:28:15 GMT -5
I thought I could depend on a somewhat known brand, actually in the purchase of a carburetor. I had bought carbs from them before, but this time, they sent a different version. Claimed XXmm diameter. I showed them pictures of the previously bought one, and the recent one. Obvious difference. Full refund. They (Gl*x*l) did supply a good bbk a couple years ago that was nicely done, and worked well. I do think they get supplies from the 'lowest bidder' and may not 'check their work', so the customer will not always get what they expect. They did stand behind it. If you are tight on funds, and want to play around, and are willing to check the fit of the parts, you may find a decent supplier that provides reasonable kits. I have bought from several sources from Shenzen, and other places, and one stood out, to me. DWCX, the package their parts as if they are wrapping Grandma's Christmas gift. Almost didn't want to open the package it was done so well. Not just externally, it was padded and wrapped (double) inside the box also. And. The parts were good. You do have to wait. The vendors that are represented on site get their parts from overseas sources, and have to do quality checks from shipment to shipment. They source from the manufacturer that promises(!) to supply only the best, but sometimes end up with parts from "Chin's Noodles and BBK Inc." where the secondary parts are secondary. Vendors in that market sometimes look at the bottom line TODAY, and tend to worry about tomorrow later on. They get a contract, produce good quality for a while, and then start to make things a little less good. The bits wear out, and they don't sharpen nor replace them, so the bore diameter may be off a bit, but 'It will work, ship it" (work for a while...) One time vendor will soon run out of one time customers, IMO. You pays your money, and you takes your chances. One firm shipped two kits, wrapped in plastic bags, together. They were not handled gently in transit, and there were chips and gouges. I sent pictures, and they replaced both. But. They packaged the second pair exactly the same... damaged in the box. I didn't ask for any more... They were decent quality except for the dings and chips. tom
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Post by deejais on Jul 9, 2020 9:32:33 GMT -5
Read here a bit before you go for a 100cc kit. Most people here seem to figure a ~70cc kit is enough, going bigger just blows up. Ah, interesting. Yes, I do have some reading to do. Thanks.
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Post by tortoise2 on Jul 9, 2020 9:43:38 GMT -5
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Post by fugaziiv on Jul 9, 2020 9:48:45 GMT -5
If we're talking about kits for a QMB139 50cc 4 stroke (and from the sounds of this, we are), we should keep in mind that there is no such thing as a 100cc or larger kit available for this engine. You can get close to 95cc MAX with a Naraku 52.4mm kit and a SSP-G 44mm stroker crank, but none of that is cheap Chinese product. Larger really doesn't exist for this engine. For a real break down of displacement, what you need to pay attention to is the bore of the kit since many places mis-market their kits. That breakdown with a stock crank is as follows: 47mm bore = 72cc 50mm bore = 81cc 52mm bore = 88cc On a 47mm kit you can generally use a stock head, but on a 50mm kit or larger you'll want a matched size head as stock will drive up compression too much and you'll chunk the piston. For general street use, I'd recommend a quality Taiwanese 47mm kit and a good cam. Any bigger and your reliability goes down the tubes without a decent $$$ investment in the crank. Here are some links: www.partsforscooters.com/137-13-Naraku-Cylinder-Kitwww.partsforscooters.com/Performance_cam_qmbMatt
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Post by mikehailwood on Jul 9, 2020 15:46:03 GMT -5
fugaziiv, I installed the Partsforscooters 72cc cyl./piston kit (not the Naraku) in an Agility 50. This resulted in quicker acceleration, better hillclimbing ability and an increase in topspeed on flat ground. What should I expect from installation of the "Performance cam qmb" over and above what the additional displacement has done for the performance?
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Post by fugaziiv on Jul 9, 2020 16:03:26 GMT -5
fugaziiv, I installed the Partsforscooters 72cc cyl./piston kit (not the Naraku) in an Agility 50. This resulted in quicker acceleration, better hillclimbing ability and an increase in topspeed on flat ground. What should I expect from installation of the "Performance cam qmb" over and above what the additional displacement has done for the performance? Usually a noticeable improvement of the same qualities you've already experienced. We recommend it because it's cheap and easy and does make a difference. The factory reports a 1hp gain, my seat of the pants confirms. I know that's not technical, but you'll see some added acceleration and it'll fatten up the mid range and extend the top end a bit. Matt
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Post by mikehailwood on Jul 9, 2020 18:22:29 GMT -5
fugaziiv, I installed the Partsforscooters 72cc cyl./piston kit (not the Naraku) in an Agility 50. This resulted in quicker acceleration, better hillclimbing ability and an increase in topspeed on flat ground. What should I expect from installation of the "Performance cam qmb" over and above what the additional displacement has done for the performance? Usually a noticeable improvement of the same qualities you've already experienced. We recommend it because it's cheap and easy and does make a difference. The factory reports a 1hp gain, my seat of the pants confirms. I know that's not technical, but you'll see some added acceleration and it'll fatten up the mid range and extend the top end a bit. Matt fugaziiv, Interesting. Thanks for the quick response. Pretty easy mod.
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claydoh
Scoot Enthusiast
Posts: 172
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Post by claydoh on Jul 9, 2020 18:32:25 GMT -5
Usually a noticeable improvement of the same qualities you've already experienced. We recommend it because it's cheap and easy and does make a difference. The factory reports a 1hp gain, my seat of the pants confirms. I know that's not technical, but you'll see some added acceleration and it'll fatten up the mid range and extend the top end a bit. I knew there was something I forgot to order this week, lol
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Petro
Scoot Enthusiast
Posts: 149
Location: Gothenburg, Sweden.
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Post by Petro on Jul 9, 2020 22:05:22 GMT -5
I am on my third Naraku 52.4 kit on my third scooter. I never been happier. Bought it for only €125 this time and it just works, always. Traveling Europe every summer (not this one due to corona) and this kit never let me down. I always carrying a spare cylinder/head among other parts but with this kit I never had a breakdown. Went cheap cylinders in the past (47-50mm) and they do not last, I always had to re-buy to replace my spare ones during my journeys... I am talking about doing 10.000km in about 4-5 months with a small trailer (and Nella, my Jack Russell between my feet ), in a max true 40 mph leisure pace. I am avoiding everything non branded from experience, I bet that the cheap 24mm carburetor I with vengeance through hard and high in the foot of the alpes still hasn't landed yet! If your scooter is a keeper, treat it accordingly.
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Post by fugaziiv on Jul 10, 2020 8:38:35 GMT -5
I am on my third Naraku 52.4 kit on my third scooter. I never been happier. Bought it for only €125 this time and it just works, always. Traveling Europe every summer (not this one due to corona) and this kit never let me down. I always carrying a spare cylinder/head among other parts but with this kit I never had a breakdown. Went cheap cylinders in the past (47-50mm) and they do not last, I always had to re-buy to replace my spare ones during my journeys... I am talking about doing 10.000km in about 4-5 months with a small trailer (and Nella, my Jack Russell between my feet ), in a max true 40 mph leisure pace. I am avoiding everything non branded from experience, I bet that the cheap 24mm carburetor I with vengeance through hard and high in the foot of the alpes still hasn't landed yet! If your scooter is a keeper, treat it accordingly. The Naraku 52.4 is an excellent kit, agreed. We recommend that anyone going with that kit at least upgrade the crank bearings to something more heavy duty like these: www.partsforscooters.com/169-332-Hoca-QMB139-Bearing-Seal-KitMatt
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Post by GrumpyUnk on Jul 10, 2020 9:02:44 GMT -5
If you want to go for less stress on the rotating parts, you can go to a 44mm bore, and get around 63cc displacement. I did one of those, and it actually worked pretty well. It was zippy and pulled my hill to the world a lot better than a stock 39mm. Not many go for a 63cc build any more. The parts are readily available, and I actually got the piston, piston pin, and circlips free as 'bonus' with my order. Had to get gasket, cylinder and rings to make up what I needed. tom
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