Valve adjustment look out !!

[pdaddy]

Allrightythen

Today i got my 59mm big bore kit and it's allredy in the scoot (2 hour's).

I just wanted to share some valve adjustment experiance, and this may be the same for some scoots but not all..

Ok lets start..
We all know that adjusting the Valves isnt a hard thing to do as long as everything is correct.. Top dead center etc etc..

But this isnt all, cuase if you move youre variator or flywheel to test youre gapping etc, or just turning one revolution you can screw it up... IF you turn the wrong way and have no cam one way clutch that i had on my old cam.

I will show you what i meen when my cam is powered up (tomorro).

Lets explain.. My old cam had a special bushing that only could turn the right way and stopt the cam from turning the wrong way if you turned the flywheel backwards (in this case no problems).

But my new A9 cam did not have such luxury , so by my own misstake i manage to turn it the wrong way after adjusting everything ok, but after that turn the adjustments were out of range so to speak.
With the old system this was imossible if you had put the cam and locking clutch in correctly when you seated the cam in the head.

So what should this teach a stupid swede (or American for that part)... NEVER TURN FLYWHEEL OR VARI THE WRONG WAY WHEN ADJUSTING VALVES !!

So there you go, nuff said ..

Any questions or remarks, please add or ask..

Cheers

Marcus

[pdaddy]

Ok, a small addition

I cant really recover how it all works cuase im no expert in the matter.
But there are a spring like then on the cam/valve shaft that goes down on the cam one way clutch.. It might stop it from turning the wrong way or it just makes the cam go back to TDC when turned the right way again...

Ohh this is messy

M

[swakk]

i had the same on but didn t notice problem when changing for a10?

[surfbum96818]

I read on one site that the a10 was for climbing and did not have good accel or top speed
store.awesomebuggy.com/index.asp?PageAction=VIEWPROD&ProdID=627
and that the a9 was the best for accel and top speed
store.awesomebuggy.com/index.asp?PageAction=VIEWPROD&ProdID=626
it says the a8 has good top speed
store.awesomebuggy.com/index.asp?PageAction=VIEWPROD&ProdID=628

[90GTVert]

Keep in mind that this is a buggy site you are looking at and buggies are much different as far as where they need the power and how they are geared. The A8 and A9 profiles will give you the best performance on a GY6 scooter. Don't get carried away with bigger cams or you will regret the move in longevity. Stan

surfbum96818 said:

I read on one site that the a10 was for climbing and did not have good accel or top speed
store.awesomebuggy.com/index.asp?PageAction=VIEWPROD&ProdID=627
and that the a9 was the best for accel and top speed
store.awesomebuggy.com/index.asp?PageAction=VIEWPROD&ProdID=626
it says the a8 has good top speed
store.awesomebuggy.com/index.asp?PageAction=VIEWPROD&ProdID=628

[tieso]

Engine/Geometry/Physics Basics: Smaller Rotation/Smaller Lift= Higher RPM's/Higher RPM Torque/HP & Higher Rotation/Higher Lift= Lower RPM's/Lower RPM Torque/HP. It's why off road vehicles and drag cars have high lift cams, and Sports cars have lower lift cams. Same applies to crank shafts hence the flat plane crank shafts used in high end sports cars.

Like I mentioned in another thread if a company manufactured flat plane crank shaft kits you'd have a scooter that sounds like a GSXR 1000 or Lamborghini.

There are probably a lot of neigh sayers when it comes to this because the automotive industry is a "kciD Smith" industry.

[swakk]

i live in mountainous area
no way to use top speed
the speediest i tried was 85km/h...
for me it was the right choice..
but it's a really hi lift and you can clearly hear the valvles hitting (even after a careful setting)
so, for sure it won't last a lot..

[tieso]

It could very well be with your GY6 cast you need shorter valves, but I have no idea. I can maintain 40MPH on a 25 plus degree incline with my stock setup, and I weigh two hundred pounds. ~30 degree is typical Appalachian Mountain incline I think.