Heeellooo! 1st build experience kind of...

Hi guys! Here's my first attempt at building a motorbike. I had got this kit thru bikeberry but found the engine had a good bit of defects. Of course I didn't figure this out till after the engine blew and I dismantled it to discover the flaw. Ended up just buying an Ebay 66/80cc China doll, and before even mounting it I tore it down and replaced everything that looked not so well made. Which was pretty much everything. Its running good but im still breaking it in of course.

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weefek

Active Member
Joined
May 14, 2022
Messages
371
the hole on the case where the crank goes thru seems like it got over-bored so when they put the seal on it they had to put rubber caulk around the seal.the same for the magneto side. These were two areas I failed to inspect when i got the engine. it was totally odd cause it literally looked like a child tried to quick fix something before dad saw it. Changed all the bolts, screws, and nuts for better quality ones, same with the gaskets ( Which I made myself). High speed bearings, piston rings (The Piston I left it alone its solid.) Ported and cleaned the hell out of the transfers. Shaved the head a bit down too until I can get a high compression head.
welcome to chinese quality... the best you can do is verify diameters and order better quality parts. including hardware. thankfully some of these kids have some north american oversight (I believe) and replace a lot of the crappy chinese stuff with at least half decent hardware (not industrial grade mind you which I would prefer, coming from that world). for me personally I'm in Canada and have super access the the grubee gt5b kits which are the norm here.

I'm still on my first engine. I pulled the jug off and checked at much as i could quickly, and it looked good, 320 miles or so. still good. got another spare engine which ive made a thread on and have another jug and piston outside of that.

good luck
 

Mach6

New Member
Joined
Jun 30, 2022
Messages
17
I noticed that you built yours on the Hyper Beach Cruiser 26"...Thats what I have as well...Very comfortable ride...I noticed you inverted the handlebars though...You find that more comfortable???


The coaster brakes have got to go...very weak on the Hypers...either you need caliper style brakes, drum brake hubs or disks mounted on mags like I did

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Yup. Found that out today. All good though. Got some goodies coming.
 

Mach6

New Member
Joined
Jun 30, 2022
Messages
17
welcome to chinese quality... the best you can do is verify diameters and order better quality parts. including hardware. thankfully some of these kids have some north american oversight (I believe) and replace a lot of the crappy chinese stuff with at least half decent hardware (not industrial grade mind you which I would prefer, coming from that world). for me personally I'm in Canada and have super access the the grubee gt5b kits which are the norm here.

I'm still on my first engine. I pulled the jug off and checked at much as i could quickly, and it looked good, 320 miles or so. still good. got another spare engine which ive made a thread on and have another jug and piston outside of that.

good luck
Yeah I'm jealous at some of the stuff you can get up in Canada that I can't get here in the states.
 

weefek

Active Member
Joined
May 14, 2022
Messages
371
Yeah I'm jealous at some of the stuff you can get up in Canada that I can't get here in the states.
Don't be jealous of us up here. Trust me. For a lot more reasons than just MBs.

My first GT5B is doing me ok. High end vibrations, crank isn't balanced very well at all. I have rubber hands by the time I get into town.

My 2nd engine had 2 bad bearings (Didn't check the 1st engine so who knows) out of the box and a s**tload of metal shavings in the case. The ports we're pretty decent stock to be honest. But I've put a lot of miles on it so far and no issues so I can't complain.

The Grubee clutches also have the classic problem of undersized bearings and a crap load of left/right play. I've rebuilt mine with 1/8" bearings since but the stock clutches are loud and rattly.
 

Sidewinder Jerry

Well-Known Member
Joined
Mar 14, 2011
Messages
3,260
I'm Built like an orangutan, I'm 6'3 with long ass arms and legs, so even with the handle bars down Im still straight up LOL.
Sounds like your seat isn't adjusted to the right height then. With the pedal in the 6:00 o'clock position, your knee should only have a slight bend in it. Riding with the saddle too low will eventually cause severe knee damage. It also isn't very efficient during the times you need to pedal assist.

I'm 6'2", and the 26" wheel Sidewinder is only meant for someone who's 5'10" at the most. So I raised the handlebar height to where I'm now riding in an upright position.

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The correct thing to do when coming to a stop is to dismount and straddle the top tube while stopped. Since most of us have gas tanks on the top tube we can't do that. Therefore, I use the lean method. Most roads are domed shape to enable water runoff. So generally when stopped I lean to the left on the high side of the road. If there's a dividing median and I plan to turn left on a multi-lane road, I then lean to the right.
 
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