100cc GY6

[scooterpimp]

Those kits..in my opinion are a waste of money..the bbk , properly jetted carb. Is where your best gains are found, then maybe cvt tuning ,. But thats just my experience , your results may vary.

[walleye1963]

pimps righ.first thing you need to do is find out why your scoot died? bad gas? valives to tight.dead battery.could of been a lot of things.id try to find out why it stoped first before i did anything.

[ratdog]

Does the kit say what bore the kit is. Just FYI, you are not going to get 100cc from a 49 cc engine. ( well not without a lot of machining and a few more parts then are in that kit! A lot of the stuff in that kit you do not need. The “upgrade” ingintion is worthless, and will only make your bike harder to start. The cam actually has less duration then the stock cam. They are sending you a bunch of gaskets you won’t use, expand I’ll bet the most important gasket, the head gasket, is for a standard bore engine.

I would personally recommend getting just a big bore kit with better quality parts. If you were in the US, I’d recommend you check out partsforscooters.

I would suggest you look for a BBK that showes you the top of the piston. I can tell you, based on the price, that piston top will be rough, which is not a good thing because your BBK is going to run way more hot. The rough piston top will act as a heat sink, and will cause you problems. I would look for a kit that has a smooth top piston. That will be more money, but I will bet it will be much better quality.

When you go to a BBK, you are going to have to do some carb tuning. Most of these scoots are jetted too lean to start, upping the compression will make it worse. Unless you are very high above sea level, I’m guessing you will have to jet way more rich.

Now back to your scoot...

So what’s wrong with it? Does it have spark? Is it getting gas? Will it fire if you spray starting fluid in the air cleaner? If we don’t address the problems with your scoot to start, all you will end up with is a scoot with a big bore kit that doesn’t run!

in case you don’t remember from school, your displacement is equal to pie r squared times stroke.  Your stroke is 41.4.  So if the piston in the kit is a 50 mm bore, “r” is equal to half the bore or 25mm pie is equal to 3.1416. So your displacement is 3.1416 times r squared ( 25 * 25) times 41.4. So, 3.1416 times 625 times 41.4  so 81.29 cc. Not “ 100 cc”

[diynuke]

Oct 6, 2018 12:18:01 GMT -5 aras773 said:

My GY6 died a week ago so I decided to buy a new cylinder with a bit more cc's and I found one on the Ebay (this) and the price got me concerned that cylinder, head, cdi, coil, and muffler only for a 100 euros. So is there any chances that is's like really really cheaply made or that it's like 70cc and not 100?

Also what parts do I need to buy to get the motor running again? (I only took the head, piston and the cylinder off)



Also sorry for my bad English. English isn't my primary language

I suggest you just get an 47mm kit. faster than stock while still being really tough (with a good brand cylinder)
I ran one of those really cheap bbk kits and well it did last a long time considering that there was a bit of the piston skirt broken off.
(pistonpen was seized so had to do some crazy stuff to get it loose and in there again..)


But 47mm.    well yeah I just like that size ;D 
work's great with minimum effort

[fugaziiv]

Oct 6, 2018 12:18:01 GMT -5 aras773 said:

My GY6 died a week ago so I decided to buy a new cylinder with a bit more cc's and I found one on the Ebay (this) and the price got me concerned that cylinder, head, cdi, coil, and muffler only for a 100 euros. So is there any chances that is's like really really cheaply made or that it's like 70cc and not 100?

Also what parts do I need to buy to get the motor running again? (I only took the head, piston and the cylinder off)



Also sorry for my bad English. English isn't my primary language

There's no such thing as a 100cc kit.

The largest displacement you can get out of a QMB139 is just under 95cc, and that is with a Naraku 52.4mm BBK and a SSP-G stroker crank. Also, these Ebay kits are generally junk. The companies don't properly QC their kits.

I'd bet anything that a decent Naraku 47mm kit is going to make better power than this Ebay kit.

[EDIT] I just looked at the listing. It's a 50mm kit so it displaces 81cc.

Matt

[gsx600racer]

[EDIT] I just looked at the listing. It's a 50mm kit so it displaces 81cc.

Thats 1cc better than 80cc. I wonder if they sell amplifiers that go to 11.

[GrumpyUnk]

Gotta agree that the assemblage of parts shown in the picture is 'more than is needed, but not enough of what is actually necessary.' (my words)
If you want to experiment, try a low cost 47mm piston, rings, cylinder and wrist pin bits. Make sure the piston slides in the bore freely without binding, and check the end gap of the rings while installed squarely in the cylinder bore. 7mm and 9mm are good gaps for the top and 2nd rings respectively.
Clean all old gasket material from the block(base gasket) and the bottom of the cylinder head. Check the head for flatness(warps are common in my limited experience) and correct if possible. I prefer the thicker gaskets, but the stamped metal may work if your surfaces are smooth, clean and un-warped. Check the valve seat for condition, and clean up as needed. Lube well(lots of oil helps) and assemble. Adjust valves, etc.
You can have some fun, learn some stuff, and find out if the hp/torque increase is worth it to you. You should feel a much more responsive engine for ballpark $30. Now, given that, the experience, and the result, it makes more sense to see if you want to spring for a more expensive, higher quality kit.
I do not sell anything. No goat in the ropefest. I figure the kits sold were originally destined for the local FE marketplace where the 139qmb is ubiquitous. They are 're-man' kits for clapped out scooters and carts that are prime transport in the area. They come with valve stem seals. You's need/want those in an engine with a lot of Km or miles, but not so much in the 'upgrades' market.
It seems the more quality kits may not need the ring end gap adjusted by the end user. I would check anyway.
I expect the parts that come from Taiwan are a bit better in their quality control. But I have gotten some quite usable parts from aliexpress vendors. One packaged their kit so well I did not want to open the package. Inside was layers of styrofoam, bubble pack wrap, and a plastic bag to protect from water intrusion. Very nicely done. I'd buy from them again in an instant.
Here(price is up a good chunk since April 18):

www.aliexpress.com/item/GY6-50CC-60CC-80CC-100CC-120CC-39MM-44MM-47MM-50MM-52MM-Cylinder-Piston-Ring-Gasket-Kit/32846986697.html

Their ring end gap was right on, out of the box. No adjustment necessary. Surfaces nicely finished, and the piston rode in the bore with what I think was good clearance, not too loose, not too tight. IMO.
tom

[fugaziiv]

Oct 9, 2018 11:27:24 GMT -5 GrumpyUnk said:

Gotta agree that the assemblage of parts shown in the picture is 'more than is needed, but not enough of what is actually necessary.' (my words)
If you want to experiment, try a low cost 47mm piston, rings, cylinder and wrist pin bits. Make sure the piston slides in the bore freely without binding, and check the end gap of the rings while installed squarely in the cylinder bore. 7mm and 9mm are good gaps for the top and 2nd rings respectively.
Clean all old gasket material from the block(base gasket) and the bottom of the cylinder head. Check the head for flatness(warps are common in my limited experience) and correct if possible. I prefer the thicker gaskets, but the stamped metal may work if your surfaces are smooth, clean and un-warped. Check the valve seat for condition, and clean up as needed. Lube well(lots of oil helps) and assemble. Adjust valves, etc.
You can have some fun, learn some stuff, and find out if the hp/torque increase is worth it to you. You should feel a much more responsive engine for ballpark $30. Now, given that, the experience, and the result, it makes more sense to see if you want to spring for a more expensive, higher quality kit.
I do not sell anything. No goat in the ropefest. I figure the kits sold were originally destined for the local FE marketplace where the 139qmb is ubiquitous. They are 're-man' kits for clapped out scooters and carts that are prime transport in the area. They come with valve stem seals. You's need/want those in an engine with a lot of Km or miles, but not so much in the 'upgrades' market.
It seems the more quality kits may not need the ring end gap adjusted by the end user. I would check anyway.
I expect the parts that come from Taiwan are a bit better in their quality control. But I have gotten some quite usable parts from aliexpress vendors. One packaged their kit so well I did not want to open the package. Inside was layers of styrofoam, bubble pack wrap, and a plastic bag to protect from water intrusion. Very nicely done. I'd buy from them again in an instant.
Here(price is up a good chunk since April 18):

www.aliexpress.com/item/GY6-50CC-60CC-80CC-100CC-120CC-39MM-44MM-47MM-50MM-52MM-Cylinder-Piston-Ring-Gasket-Kit/32846986697.html

Their ring end gap was right on, out of the box. No adjustment necessary. Surfaces nicely finished, and the piston rode in the bore with what I think was good clearance, not too loose, not too tight. IMO.
tom

I'd be wary of buying from anyone that lists a 52mm kit as displacing 120cc.

Here's the honest breakdown with a little 'The Running Man' flair for us 80's kids.

http://instagram.com/p/BiP1wlxF7oD

Matt

[V90Performance]

Go with a Naraku 52.4mm bbk. It won't let you down. I have 5700 miles on mines.