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Joined: Dec 6, 2016 13:17:32 GMT -5
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Post by thescooterguru on Dec 6, 2016 15:11:27 GMT -5
Not your run of the mill bore kits, we have tested over 20 factories kits and this is the best we have found, with over 3000 installed in our shop they have a great record of running with no problems. The kits will come with the rings pre-gapped, clocked, and installed on the piston. $39.99 shipped to all 50 states. We are also happy to give you help on all install questions, torque values, clearances or jetting through email, phone, or skype video. For the 139QMB, will NOT fit baja sc50
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Post by tortoise on Dec 6, 2016 16:41:33 GMT -5
Direct link. Might consider including an exhaust pipe gasket.
What is your perspective on WHY so many 47mm bore kits experience bearing failure . . example? If a heavier piston is unbalancing the crankshaft assembly rotational dynamics . . the eventual consequences seem inevitable.
As compared to so many Ebay and Amazon 139QMB carb listings . . your website is one of the very few that provide jet size options. Very commendable . . reflects significant ACTUAL experience!
As an Ebay example . . the response to a query for the pilot and main jet sizes of this carb was "The Chinese do not provide us with this info. Sorry for the inconvenience." . . just absolutely clueless! |
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New Rider
Currently Offline
Posts: 10
Likes: 0
Joined: Dec 6, 2016 13:17:32 GMT -5
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Post by thescooterguru on Dec 6, 2016 18:48:13 GMT -5
So what I've seen in my shop as the number one cause of bearing failure is the variator, the brass sleeve gets worn out and its not tight on the boss which causes an unbalanced weight spinning on the crank, I havent seen any directly caused by big bore kits, at least if they are broken in right and warmed up, but thats on my installed kits. There are kits out there from mortch and growsun that have too tall of a piston, they will run great for short trips but when the engine heats up to its max the connecting rod will expand to the point where the piston hits the head or valves which will blow the connecting rod bearing very fast. The jet size option was a must for me, not a lot of places have it, but say you were to order a kit and a carb I would look at your local weather and elevation and re-jet the carb to work where you live before I shipped it. And good idea, I will now send an exhaust gasket with every order.
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