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Post by fugaziiv on Jul 10, 2020 9:26:27 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 The old "secret 63". Nice! Matt
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Petro
Scoot Enthusiast
Posts: 149
Location: Gothenburg, Sweden.
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Post by Petro on Jul 10, 2020 14:29:47 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 I personally wouldn't go so far and cleave my engine for this kit, I do how ever recommend an oil cooler kit which I think in a way compensates your suggestion.
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Post by deejais on Jul 10, 2020 21:04:23 GMT -5
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: Thanks for the good info, and interesting about the 100cc kits. The reason I'm even considering installing a kit is to be a little peppier from a dead stop, and to keep my speed when going uphill, nothing higher-performance than that. If I go with the 47mm kit, will I need to buy anything apart from that kit? Like a different carburetor? Thanks
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Post by GrumpyUnk on Jul 11, 2020 7:48:44 GMT -5
For the most part, you won't need to do anything additional for a 47mm kit. You possibly need to fiddle a bit with the carburetor. The idle mixture may need tweaking, but in general, the pilot and main jets should be adequate unless you want to peak your performance. The needle attached to the slide might need to be raised a notch to enrich the mixture as the flow rate will be a bit increased and the fuel may not be able to keep up with the demand. The spark plug will show whether the engine is being fed a lean or rich mixture. You can run a bit and compare your plug condition to pictures on the web. If the spark plug is whistling clean, no deposit at all, GENERALLY you are running too lean. repeat: generally. As I understand, there will be a 'ring' formed on the ceramic surrounding the center electrode. It will be slight, I believe, and it indicates mixture quality. The position on the ceramic indicates rioh-proper-lean mixture, I think as it goes down the ceramic. Read up. tom
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Post by Mech Warrior on Jul 15, 2020 23:26:53 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 The old "secret 63". Nice! A company called vento from early 2000's had some of their'e scooters equipped with the "Secret 63" but were sold as 49cc.
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Post by bullybike on Aug 2, 2020 20:21:56 GMT -5
Uhm I haphazardly slapped a 44mm on my 5,500mile znen, thrashed it for 2000 miles, and I just now bought a Glixal 52mm cylinder with domed piston for $14.99 on ebay! Anyone wanna place bets on my 10,000 mile warrantee? 😉🤣
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Post by bullybike on Aug 2, 2020 20:22:49 GMT -5
(shhh say not a word to FHP!) 🙊
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Post by GrumpyUnk on Aug 3, 2020 11:05:09 GMT -5
How did you like the 44mm? My short take was it added a good bit of zip over a 39mm. Good acceleration and decent top speed. Is the 52mm piston actually domed? If so, I think you may should consider getting a cylinder head to match as otherwise you will have a super high compression ratio. You can get away with the original head and a 47mm bore, but the 52mm may be past the reasonable limit. Be careful if you don't replace the head or relieve the current head a bit. From what I have seen, the larger rated heads are cut around the diameter of the cylinder so there is a relief 'out to the edge of the head gasket', which adds some volume to relieve the max built pressure. tom
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Post by bullybike on Aug 6, 2020 21:05:11 GMT -5
HIGH COMPRESSION IS GOOD! Brake out that Xylene I am running a custom head that has been ported out, I also remove valves, machine valve seals, grind cam, and throw best set of springs i have laying about. I am having a lot of fun with it! These little motors are great fun to test different air flow and cam theory
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Post by bullybike on Aug 6, 2020 21:13:17 GMT -5
but ya a 44 or 47 should be stock on American roads. I think the head i am using now was designed for upgrading because it has a dome ring as opposed to some that are more flat. My biggest challenge with this motor is preventing reversion, it likes to spit fuel😤 I am learning about Helmholtz resonators rn and testing different designs- single cylinder game changer!
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