Skyliner70cc
Active Member
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- Nov 17, 2007
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I hereby on penalty of perjury do hereby attest to the following fact:
The "80cc" slant head does increase compression and engine performance noticeably.
I live in Colorado at an altitude of about 6500 feet and ride up to 9900 feet on rides. One thing that really sucks is the 3% loss in horsepower for every 1000 ft in altitude. Couple this with a carb that runs super rich, power is down probably even more.
I just found the solution and IT WORKS! I bought a high compression slant head from a vendor.
Here are my observations:
1. I can no longer pedal start with my centrifugal clutch engine with SBP shifter kit. The engine compression is so much greater that I think I broke something in the auto clutch when I tried (maybe the one way bearing failed?
2. I used to be able to pull start the engine with 2 fingers. I now have to use a significantly more force to pull start the motor. The difference is incredible and I have to get off the bike now to start it using my dominant right hand. Before I could just flick start it with my left arm while sitting on the bike.
3. Power: Before I could only climb the steep hill by my home in 1st gear which is a 34 tooth mega gear. Now I can climb the hill in 3rd gear from a dead stop at much faster speeds. In fact, my centrifugal clutch started slipping real bad under the load and couldn't keep up with the engine. I did not attemnpt to determine if there was any change to top speed. I'm more concerned with hill climbing torque and am happy chugging along at 20mph.
Interesting twist: One thing I should mention is that my original head gasket was 3 times the thickness (it was stock) of the usual head gaskets I've seen on the 100+ HT engines I have installed on bikes. I do not know how much of the increase in compression is due to the thinner replacement head gasket I used with the new head or the new head itself. The new head does have a significantly smaller squish volume and I was worried that my plug top with smack the piston cylinder but it doesn't. Please check your stock head gasket especially if you have a BGF engine. This BGF engine's headgasket is crazy thick and replacing it would help performance a bunch but the slant head is definitely a better improved product.
Sorry, but the vendor I got these from is already out of stock and I wish someone else sold these.
The "80cc" slant head does increase compression and engine performance noticeably.
I live in Colorado at an altitude of about 6500 feet and ride up to 9900 feet on rides. One thing that really sucks is the 3% loss in horsepower for every 1000 ft in altitude. Couple this with a carb that runs super rich, power is down probably even more.
I just found the solution and IT WORKS! I bought a high compression slant head from a vendor.
Here are my observations:
1. I can no longer pedal start with my centrifugal clutch engine with SBP shifter kit. The engine compression is so much greater that I think I broke something in the auto clutch when I tried (maybe the one way bearing failed?
2. I used to be able to pull start the engine with 2 fingers. I now have to use a significantly more force to pull start the motor. The difference is incredible and I have to get off the bike now to start it using my dominant right hand. Before I could just flick start it with my left arm while sitting on the bike.
3. Power: Before I could only climb the steep hill by my home in 1st gear which is a 34 tooth mega gear. Now I can climb the hill in 3rd gear from a dead stop at much faster speeds. In fact, my centrifugal clutch started slipping real bad under the load and couldn't keep up with the engine. I did not attemnpt to determine if there was any change to top speed. I'm more concerned with hill climbing torque and am happy chugging along at 20mph.
Interesting twist: One thing I should mention is that my original head gasket was 3 times the thickness (it was stock) of the usual head gaskets I've seen on the 100+ HT engines I have installed on bikes. I do not know how much of the increase in compression is due to the thinner replacement head gasket I used with the new head or the new head itself. The new head does have a significantly smaller squish volume and I was worried that my plug top with smack the piston cylinder but it doesn't. Please check your stock head gasket especially if you have a BGF engine. This BGF engine's headgasket is crazy thick and replacing it would help performance a bunch but the slant head is definitely a better improved product.
Sorry, but the vendor I got these from is already out of stock and I wish someone else sold these.
)
