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Post by terryosw81 on May 16, 2018 5:10:08 GMT -5
I purchased a 52mm bbk and I was wondering was it worth it is it going to break the rod ? I know I have to break it in slow if I baby it will it hold up,it's a 50cc znen
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Post by tortoise on May 16, 2018 9:33:53 GMT -5
BBK heavier piston subjects the engine to unbalanced rotational dynamics . . somewhat similar to an unbalanced load of laundry in a top loading washing machine during the spin cycle. The downside is enhanced odds of bearing failure.
For others researching . . selecting a 50cc scooter still remains the most frequent regret. Save yourself a lot of aggravation by taking the initiative to get a motorcycle endorsement, insurance, and selecting at least a 125cc scooter that is more compatible with typical metro traffic.
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Post by fugaziiv on May 16, 2018 9:56:11 GMT -5
terryosw81 If you're looking for longevity, your best bet is to go to a stock bore and be happy at 32mph. The 52mm kit will pound the crap out of your crank over time. The conrod itself will be fine, but the bearings are going to take a beating and need replacement sooner than they would in a stock application. The 52mm kit (or the 50mm kit as well) are high performance applications that give the engine much higher than stock power, but are not meant to give a stock level of reliability. tortoise is absolutely correct. If you are looking for reliability and speed, something 125 and up with proper endorsement is really the best option. Matt
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Post by terryosw81 on May 16, 2018 11:14:41 GMT -5
I would love to get a better scooter but anything over 50cc here you need a driver's license, is there anyway to beef up the bearings?
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Post by fugaziiv on May 16, 2018 11:33:34 GMT -5
I would love to get a better scooter but anything over 50cc here you need a driver's license, is there anyway to beef up the bearings? There is a (much) better than stock bearing kit that we sell for just this reason. You have to split the cases to get to the crank to install. www.partsforscooters.com/169-332-Hoca-QMB139-Bearing-Seal-KitMatt |
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Post by pistonguy on May 16, 2018 21:48:48 GMT -5
Ok ill clear up the misinformation here.
Mainly because the Scooter world especially 50cc the idea of Spin Balancing a Rotating assembly seems to be some foreign subject.
The problem of such a increase in Piston assy weight is easily and inexpensively sending your Rotating assy to one of the fine Crank companies in the states and have the Rotating assy spun balanced and the Crank pin welded for under a hundred bucks.
So it only Pounds the crank because you did Not do a proper and correct job of having the assy spun.do that and you won't have any crank or rod problems
The other thing your doing that leads so many to failures is the engine is already clapped out and from the boards get taped into a bbk, well how well do you think the cracnk is going to hold up when its almost done and you have doubled the horsepower?
The other thing is how many bbl kits of 50mm and 52mm do you think these scammers could sell if they told you you had to do crank work? darn near None! Us USA manufactures do not do business in such a unscrupulous way.
The is not such thing as in building lets a a small block chevy and throwing a crank as set of rods and a pistons and Not having the assy spun its mandatory.
On my big bore kits for bikes as a example a 883 Harley is a debar 1200, well pistons available were so much heavier you Had to rebalance the assy, well heck we design a 1200 piston for the 883 that was the same weight as OE and a reverse dish on the dome to maintain stock compression ratio for $210 and change with No Balancing or Head work Required, I columned keep them on the shelf.
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Post by pistonguy on May 16, 2018 22:00:40 GMT -5
crankworks.com/Some of my homeboys at crank work will take care of business.
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Post by pistonguy on May 16, 2018 22:02:23 GMT -5
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Post by terryosw81 on May 17, 2018 8:12:16 GMT -5
Thanks for the info, also couldn't i just buy a better Crank? And if so do you Or anyone know of a good one to get, Or would it have to be balanced anyway as well?
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Post by fugaziiv on May 17, 2018 8:56:30 GMT -5
All I'm saying is that you will sacrifice some reliability over stock with a BBK and a stock crank setup that hasn't been improved in some way. I think that's something everyone can agree on, and I think it would be irresponsible of me to represent otherwise.
Also, Falicon is good people... and our neighbors.
Matt
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Post by cyborg55 on May 17, 2018 8:58:10 GMT -5
Ok ill clear up the misinformation here. Mainly because the Scooter world especially 50cc the idea of Spin Balancing a Rotating assembly seems to be some foreign subject. The problem of such a increase in Piston assy weight is easily and inexpensively sending your Rotating assy to one of the fine Crank companies in the states and have the Rotating assy spun balanced and the Crank pin welded for under a hundred bucks. So it only Pounds the crank because you did Not do a proper and correct job of having the assy spun.do that and you won't have any crank or rod problems The other thing your doing that leads so many to failures is the engine is already clapped out and from the boards get taped into a bbk, well how well do you think the cracnk is going to hold up when its almost done and you have doubled the horsepower? The other thing is how many bbl kits of 50mm and 52mm do you think these scammers could sell if they told you you had to do crank work? darn near None! Us USA manufactures do not do business in such a unscrupulous way. exactly The is not such thing as in building lets a a small block chevy and throwing a crank as set of rods and a pistons and Not having the assy spun its mandatory. On my big bore kits for bikes as a example a 883 Harley is a debar 1200, well pistons available were so much heavier you Had to rebalance the assy, well heck we design a 1200 piston for the 883 that was the same weight as OE and a reverse dish on the dome to maintain stock compression ratio for $210 and change with No Balancing or Head work Required, I columned keep them on the shelf. |
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Post by terryosw81 on May 17, 2018 11:03:53 GMT -5
Ok thanks
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Post by terryosw81 on May 17, 2018 11:13:58 GMT -5
Ok I called the place to see what it would cost to get the crank done and they want 300 to do it witch is a little more than I want to spend but I appreciate the info,I think I will try to get a better crank I think I seen some for around 160 bucks,if anyone knows were to get a decent crank that will work for under 200 please let me know thanks
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Post by pistonguy on May 18, 2018 7:03:14 GMT -5
The Quality or Beefiness of the Crank is Irrelevant, The Rotating assy is Out of balance.
A New Crank will be far better than your old crank.
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Post by tortoise on May 18, 2018 9:06:00 GMT -5
The Rotating assy is Out of balance. Any opinions on how to achieve a do-it-yourself static balance? Most of the YouTube videos show what a static balance should look like . . but NOT how that was achieved. Seems like installing a heavier piston assembly would require adding crankshaft weight to counter-balance. How about including the flywheel in the assembly . . then drilling the flywheel as needed to balance? |
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