Big Bore Belt Melt, Variator fault??

[vegaslightsss]

Hi,I have a GY6 with 50mm BBK and Big Valve Head Installed from New.Feeding it with a 23mm CVK with 88 Main at 2275 Elevation in Sunny Las Vegas. This Motor Runs like crazy. Oh Yeah I also reamed out the Pipe from the 3/8" Holes in the Exhaust restrictors on the stock "muffler" portion of the pipe,by removing the tail section and running a 15" X 3/4" Masonry Bit through it ,I also spent several hours port matching my custom built intake manifold to the Big Valve Head and Polishing all of the Intake and Exhaust Passages in the head and intake manifold I built,so she really breathes. I have never verified the top speed, but it pins the needle up hill with two adults anywhere I go.Its almost scary considering the speed & weight rating of these stock tires . OK ,enough bragging,On to my "Issue". I am running a totally stock variator and clutch setup and am ticking right at 5500 Full Throttle Miles on the Motor in 110 degree plus Las Vegas heat,often with 375 pounds of 2 passenger weight. My Son was riding home the other night from the movies and the Belt (the Original) went. I went to him with a spare,we pulled the case off and the biggest part I could find was about an inch long,the rest was rubber grindings and powder,I have no idea how it didn't break sooner. It actually punched a hole out of the bottom of the case right below the variator about 1" X 2". We were in the dark but finally managed to wrestle the new Kevlar belt on by just compressing the clutch pulleys by hand then "walking " the belt over the variator the way you would put a bicycle chain on if that makes any sense. We put the cover back on ,fired it up and pushed it off of the center stand at which point it died instantly acting like it had no clutch and a "direct drive" trans.The belt is tight as though the variator is stuck in the full throttle position. I will pull the case off again tomorrow as we were in total darkness when we "repaired it" and check it out.There was rubber packed everywhere in the case (which i replaced with a spare from the orignal GY6 50cc that came in the bike)the rear clutch assembly seems to be working OK.Any words of wisdom?. I also purchased a new variator fan as the other one had no blades left. OH YES,I probably should mention for the last week it has felt like the belt has been "grabbing" at stop lights at idle like grab/grab/grab (you get the idea) with idle speed and only stops when you accelerate ,Is this the variator not contracting because its packed with rubber possibly or any opinions or guesses through past experiences anyone.
Thanks In Advance All and Happy Scooting,Vegaslightsss

[Rebel]

Boy it is hard to read all that with no paragraphs or breaks in anything.

Sounds like the belt flew all apart and the variator is like you said full of rubber bits. I think I saw in there that you bought a new variator, that will fix the one end but you'll probably need to take the other end all apart and clean it out too, or just replace it.

On a fifty, I amazed you got the belt on without pulling the variator apart.

[vegaslightsss]

Sorry about the long winded ,poorly punctuated post. I haven't bought a variator yet,I have another one with low miles from a stock donor motor that I will clean up.It was pretty difficult to get it stretched ocer the geared plate or whatever that peice is called for sure. Once on,I should be able to pull on the belt by hand and rotate it easily correct? Thanks,Vegas

[Rebel]

well the halves of the clutch and the variator will come together and make friction but it might be move-able.

I still think you need to pull it all out and clean it up, when these go poof like that it puts a lot of rubber into the works. if you do not have a manual you can download on in the reference area. look at the bottom of my signature line for a manuals link.

[Rebel]

bedtime for me, I have to go to work in a few hours, btw you may have damaged the belt squeezing it in such a tight place, look for damage on it. And Scrappydog scooters is in your town if you need parts fast.

[vegaslightsss]

Yes, I know Shelly over @ ScrappyDog,just about a mile from my house. Is there supposed to be a spring behing the variator or just ramp plate,weights,inner pulley,outer pulley,fan,fan locater,and nut? Thats all I took off,I dont see what keeps it all toght unless its just the belt? Thanks, Vegas

[felliott]

There is NO spring.

[Rebel]

No spring, the weights move and make it slide in and out. Now the back pulley/clutch has springs and that may be where you have a lot of rubber gunk built up. Look at this youtube vid before you work on it.

[rocky88]

if im not mistaken dont the big valve head come all ready port and polished? all so do you think your getting better bottom end with that kit? cool thanks ..........rocky

[Rebel]

Makes since for a four valve head to come ported and polished but I think some may not. Probably would get most of the power improvement in the higher rpm's I think.

[Rocketdog]

Ahh well my 150 4 valve from Scrappy didn't. The price was right but it lacks a bit.




RD

[Rebel]

I know that Scrappy also has a ported and polished head he sells too, Enviromoto as well sells a ported and polished head. I'm not sure either of those are four valve or not. The one that Enviro sells I believe is actually put on a air flow bench nad checked ot for how well it does, the one Scrappy sells is coming off the bench untested but ahs a fellow that has a lot of experience with head work doing it.

As to which is best, well I do not know of any testing of the motor for power after the head is on. One has larger valves than the other but sometimes smaller valves provide beter turbulance than bigger ones do.

[mainepeace]

Even with a BBK, larger valves won't necessarily give more power. The design of these heads requires turbulence from the intake swirl to help mix the fuel and air. Also, the intake pulses have more to do with filling the chamber than absolute flow, and this is dependent upon the intake port design and the negative pressure and reflection pulses coming back through the airbox and carburetor.

Greg

[Rebel]

Feb 14, 2012 3:47:20 GMT -5 mainepeace said:

Even with a BBK, larger valves won't necessarily give more power. The design of these heads requires turbulence from the intake swirl to help mix the fuel and air. Also, the intake pulses have more to do with filling the chamber than absolute flow, and this is dependent upon the intake port design and the negative pressure and reflection pulses coming back through the airbox and carburetor.

Greg

i know that is true more often than not.