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Old 08-29-2010, 04:48 AM
BarelyAWake's Avatar
BarelyAWake BarelyAWake is offline
Motorized Bicycle Elite Member
Join Date: Jul 2009
Location: Maine
Posts: 7,212
Default Re: I need your guys' 2 cents on durability/ longevity issues on HT motors and.....

I jus' thought I'd share a lil experiment I've been doing & my take on "durability/longevity issues"...

Roughly following the advice found here: with only a few minor deviations (personal preference) as well as the modifications found here: (it's actually the same engine used for that tut) I built the 66cc Chinese two stroke for the Rollfast found here: and after the first week or so of initial dialing in...

I then proceeded to "neglect" it, deliberately ignoring my urge to tinker & constraining myself to just any failures that may come up...

There's been absolutely no engine related issues at all in the roughly four and a half thousand miles I've put on it so far. I have not "upgraded" the head bolts, I've had no clutch pad problems, nor have I changed out the bearings, I've not even swapped out all of the fasteners with better ones. I did however use some of SBP's grade 5 fastener kit in the more critical applications such as mounts.

...and no, I'm no "Sunday driver" heh

It's all about the initial care while building, excepting the occasional "dud" engine (which should be covered by warranty if purchased frm a reputable vendor) I can't help but think the vast majority of "reliability" issues complained of are in fact owner oversight, misuse and inexperience, compounded by (in my opinion) one small misrepresentation made by advertisers...

These are not "motorized bicycle engine kits" they're "motorized bicycle engine kits" as in the engine itself is a kit, only loosely assembled as to not loose the parts in transit and any all accessories (like throttle, tank, sprocket & chain) included as the very minimum - to be upgraded as necessary, thus their ridiculously low cost. That tiny distinction makes for a world of difference in expectations.

Not to sound harsh as I really don't mean it that way - but the fact of the matter is that due to that low cost these two stroke kits are by far the most popular kit sold - period. As a result they're somewhat misrepresented in that for many, they're the very first engine they've ever had - let alone the complexities involved in modifying something that was never meant to be motorized in the first place. Consequently you'll see what appears to be a disproportionate amount of failures associated with such kits when in fact the vast majority of such can be directly attributed to installation errors.

IF installed correctly, following the basic advice as outlined in I've found the cheap Chinese two stroke to be a wonderfully simple & reliable little motor. If you don't wish the initial prep work and really do just want to "bolt it to the bike and go" then you'll hafta spend a bit more money for a more "finished" engine built to higher standards... it's a simple matter of spending your money or your time lol

BTW - that engine of mine is no "fluke", I've another with well over six thousand miles on it & have helped locally with a number of others. None have had any engine related issues that can't be attributed to simple owner inexperience with engines in general

Last edited by BarelyAWake; 08-29-2010 at 05:10 AM.
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