|
|
Post by florida on May 19, 2015 22:54:18 GMT -5
I have a 2011 4 stroke 50cc gmw that i am buying a 100cc bbk from ebay for.
The dealers on ebay want to know if i need 64 or 69mm valves.
Can i determine the size of my current engine valves by measuring the distance between the tappets?
This is what ebay wants to know correct? The size of valves on my current engine right?
Thx
Is there someplace on my engine case that would have a number i could reference to find out what size valves i have?
Would i have better luck calling up some gmw dealerships in my area?
|
|
|
|
Post by dmartin95 on May 19, 2015 23:07:05 GMT -5
This is what ebay wants to know correct? Thx No - not tappet distance, that is not what ebay wants to know. This is a picture of a GY6 50CC valve, See the length? That's what "ebay" wants to know. Do you want 64mm length or 69mm length,... They're asking this question because I would imagine there's two different size size heads...  |
|
|
|
Post by JerryScript on May 19, 2015 23:33:38 GMT -5
@dmartin is right, heads come in several different configurations, you should also confirm the distance between the center of the head bolts, there are 57mm and 54mm varieties, as well as the different valve heights mentioned.
FYI -just so you know ahead of time, the 100cc BBKs are actually about 83cc.
|
|
|
|
Post by florida on May 20, 2015 13:07:22 GMT -5
Yea, i understand a 100cc kit is 83cc.
|
|
|
|
Post by florida on May 20, 2015 13:20:03 GMT -5
This is a learning process and i am having fun while doing it.
I feel confident that i can do almost anything to my scoot with pait ence and a little help. I have a good work area with all the tools except for a few that advanced auto has.
Im keeping it real basic and only doing a few things to get my scoot running reliable and maybe a little safer ie more low end torque, fix the running lights and mounting the turn signals up higher.
I appreciate everyones help. I too take time out of my day at a few web forums and pass down knowledge to others. Gotta give to take i guess.
I also would like to network with other scooter enthusiasts in the Clearwater Tampa Bay Florida area in hopes of maybe a scooter get together or something.
|
|
|
|
Post by lain on May 20, 2015 13:46:29 GMT -5
If you want more reliability and more low end torque, I would try experimenting with variator weights first before going to the BBK. I've seen some really nice scoots that have a lot of power hidden and being wasted because of transmission errors the dealers made, liek putting a 2k clutch spring in a 50cc with only 5g variator weights, man did that thing run fast after changing to 1k clutch spring and 6g weights, it reached up to 45-50 and got to 25-30 fast.
|
|
|
|
Post by ramblinman on May 20, 2015 16:25:06 GMT -5
90GTVert vids are the best imo for anything related to a 50cc scoot. i spent numerous hours watching his vids when i had my atm50.
|
|
|
|
Post by geh3333 on May 22, 2015 2:22:49 GMT -5
I have a 2011 4 stroke 50cc gmw that i am buying a 100cc bbk from ebay for. The dealers on ebay want to know if i need 64 or 69mm valves. Can i determine the size of my current engine valves by measuring the distance between the tappets? This is what ebay wants to know correct? The size of valves on my current engine right? Thx Is there someplace on my engine case that would have a number i could reference to find out what size valves i have? Would i have better luck calling up some gmw dealerships in my area? If your going to get the 100cc bbk , why not buy a new head to match the bbk? Are the rocker arm assembly the same for both heads ? What all is different other then the valve length ? I guess I should watch the video , lol |
|
|
|
Post by geh3333 on May 22, 2015 2:35:58 GMT -5
Ok so if your buying just the bbk and not a new head , why do they need to know this ? Since either head should work with the cylinder . if you ordered a new head with the bbk , I can see asking so u don't have to order a new rocker arm assembly or actually just the rocker arms.
|
|
|
|
Post by florida on May 22, 2015 10:10:14 GMT -5
I am new to engines. I still am unsure about if I can replace the current head on my scoot with both 64 and 69mm valves. As in when replacing the head with a new one from ebay and presented with the choice of either 64 or 69mm its up to the person buying the product and not what my gmw scooter calls for, as in there would be incompatability issues and trouble if I didnt stick to whatevr size valves my scoot has stock.
So , does anyone have an answer to the question, when buying a new head along with the bbk( which i am) i need to buy the sMe size valves as what is in it right now? The stock size, do i have to stick with that ( i dont know the stock size) or can i get whatever i want, 64 or 69, my choice.
I read a verylong journal on a board from a guy with the same scooter as me and was installing the same bbk/ head. He said that "im gonna order the 64mm and hope its the right size". Ive tried to contact him but was unable. His scoot turned out to be pretty nice with the upgrades but he eventually broke his leg badly while driving the scoot in the grass.
I also saw on this website that sells scooter parts that "znen/wolf/gmw have a valve size other than 64mm and to be sure of the size of the valves in your engine before ordering the head..
|
|
|
|
Post by ramblinman on May 22, 2015 10:46:29 GMT -5
you can remove the valve cover to check but if you feel you'd still be unsure then "yes" you can change the valve size. you will need to order new rocker arms if changing valve size.
2 different size valves... also 2 different size rocker arms. either will work but both must match.
|
|
|
|
Post by JerryScript on May 22, 2015 13:56:16 GMT -5
I can confirm that Znen 50cc with engine BN139 had the larger valve size.
|
|
|
|
Post by geh3333 on May 22, 2015 20:24:23 GMT -5
I am new to engines. I still am unsure about if I can replace the current head on my scoot with both 64 and 69mm valves. As in when replacing the head with a new one from ebay and presented with the choice of either 64 or 69mm its up to the person buying the product and not what my gmw scooter calls for, as in there would be incompatability issues and trouble if I didnt stick to whatevr size valves my scoot has stock. So , does anyone have an answer to the question, when buying a new head along with the bbk( which i am) i need to buy the sMe size valves as what is in it right now? The stock size, do i have to stick with that ( i dont know the stock size) or can i get whatever i want, 64 or 69, my choice. I read a verylong journal on a board from a guy with the same scooter as me and was installing the same bbk/ head. He said that "im gonna order the 64mm and hope its the right size". Ive tried to contact him but was unable. His scoot turned out to be pretty nice with the upgrades but he eventually broke his leg badly while driving the scoot in the grass. I also saw on this website that sells scooter parts that "znen/wolf/gmw have a valve size other than 64mm and to be sure of the size of the valves in your engine before ordering the head.. According to the video , you can buy either head with either size valves . its just the rocker arms you will need to change if you switch from the 69 to the 64 . |
|
