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Old 11-10-2013, 09:55 PM
mr42ndstblvd mr42ndstblvd is offline
Motorized Bicycle Senior Member
Join Date: Nov 2013
Location: oklahoma
Posts: 52
Default is there anny real differnce in engine kits?

we all know you can get a deal on a 80cc china motor kit on ebay for 150 bucks ive had about 2 of them and have no complaints if you use quality oil "i use royal purple" and decent gas they run forever my last motor had around 5000 miles or more probablly had over 50 tanks of gas ran thru it

my question is this some sites like dax claim that there motors are built with only high quality parts and are balanced cranks high grade japan bearings ect ect ect is it really worth the extra cost to get a f80 from dax or is it just a rip off and the same qulaity as ebay specials? i have a friend who builds motorized bicycles for a living and he swears by ebay kits and that they are exactlly the same as dax or grubby stinger ect hes assymbled and sold over 89 bicycles including 4 jackshafts and a hand full of choppers so i would trust he knows a thing or to lol
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Old 11-11-2013, 12:28 AM
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maniac57 maniac57 is offline
Old, Fat, and still faster than you
Join Date: Oct 2011
Location: memphis Tn
Posts: 4,486
Default Re: is there anny real differnce in engine kits?

Dax and Arrow (and CR machine now) are the only engines I'm aware of that actually do anything more to the engines other than up the price. None of the "upgraded" kits I've seen were worth a penny more than the ebay kits.
Dax has a great reputation here with his balanced bottom end motor, Arrow builds sweet (expensive) stuff too. Don't know much about fred (cr machine) but his stuff looks pretty nice...and at the prices he charges, they should be!
Unless you buy from these three, there is no or very little difference in quality from kit to kit as far as I've seen.
I've built at least 30 or 35 kits from many different vendors. I buy strictly from rose 326 and mingsinternational now. (same vendor)
IF I ever decide to build a better quality engine, it will start with a Dax bottom end.
Just my opinion. You will hear many who disagree.
If more is better, then too much is just enough.
If you can't afford it, build it yourself.
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Old 11-11-2013, 12:40 AM
BonusParts BonusParts is offline
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Join Date: Nov 2012
Location: SE-PA
Posts: 168
Default Re: is there anny real differnce in engine kits?

Having used an "out of the box" grubee kit, boygofast kit, and now a fred race motor.... there are MAJOR quality gaps.

grubee kits on a whole are decent quality, some kits have a ****ty carb design - but they are kinda hit or miss with getting a straight crank. friend and i bought 3 kits, 2 from one batch, one from another. the 2 from the same batch were (and mine still is) great. 43.62mph with mods on mine. the 3rd vibrated like a banshee past 4500rpm (ish)

boygofast kits are decent, they seem to be a touch faster top end out of the box than grubee kits, may be from the 40mm stroke vs 38mm on the gt5 grubee. still kinda iffy with straight cranks

and finally, the FREDMOTOR. My buddy has his installed and it did 40 out of the box on a 36t. still hafta dial in the carb, but thats not a bad start. its SUPREMELY smooth running. Sounds great. LOOKS great, head is beautifully machine, EVERY single bolt is replaced with uprated hardware, the clutch is properly lubed and adjusted, everything is perfectly sealed. We did a 92.6 mile trip the day we installed his motor - not a single problem. could be more fuel efficient, but i think he needs to downjet it.

long story short.... if moneys no object, look at a fred motor. i gave my friend **** about buying one until it arrived. needless to say i've got my own fred motor in a box .

in the meantime Im having cranks balanced and straightened so i can build my own critters!
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Old 11-11-2013, 10:51 AM
crassius crassius is offline
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Join Date: Sep 2012
Location: USA
Posts: 2,785
Default Re: is there anny real differnce in engine kits?

there are diffs even between two kits ordered same day from same place - most are 'acceptable' tho
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