Ported 48cc!

[impression]

im gettign away now with not having to use a tensioner with the new frame.

it's doing ym head in wondering why my new engine has no **** torque or power at all and maxes out @ 30km/h screaming off it's head. Same model, same batch of engine as the last one that had soo muchtorque and would do 60.2km/h on a 44t sprocket :/

oh and STV mate, check this out.

http://blogs.myspace.com/index.cfm?fuseaction=blog.view&friendId=53429708&blogId=334583408

No. of Teeth/Cost (USD)
--------------- -----------------
26 to 39 / $37.50
40 to 46 / $39.50
47 to 53 / $43.50
54 to 57 / $46.75
58 to 60 / $49.75
61 to 72 / $54.50
73 to 80 / $67.50

i'm thinking of getting the 26t but the new engine wouldn't be able to pull it, i dunno.

maybe it needs wear in, maybe the clutch is slipping
maybe some porting i dunno.

we'll go for a spin on the weekend and tell me what you think

 

[arceeguy]

As far as your lack of power goes, how does the engine sound as you are accelerating? Does it sound like the mixture is too rich? A rich mixture will cause lousy acceleration and limit top speed. Could also be too lean at higher revs. I have experienced this myself on all 66cc (80cc) engines. Top end sucked, and the engine bogged at WOT. If allowed to run this way without re-jetting, the engines would have blown up even with the 16:1 gas/oil mix.

If it is revving a lot more than your other engine with the same gearing, then maybe the clutch is slipping?

On rare occasions, I have gotten engines that lacked compression because the chrome plated bore was not finished properly. They lacked the proper "cross hatch" pattern that is required to properly seat the rings in the bore. A few quick passes with the proper style flex hone fixed the problem. (once again, a rare problem - only found two engines out of 75 or so.)

 

[impression]

As far as your lack of power goes, how does the engine sound as you are accelerating? Does it sound like the mixture is too rich? A rich mixture will cause lousy acceleration and limit top speed. Could also be too lean at higher revs. I have experienced this myself on all 66cc (80cc) engines. Top end sucked, and the engine bogged at WOT. If allowed to run this way without re-jetting, the engines would have blown up even with the 16:1 gas/oil mix.

If it is revving a lot more than your other engine with the same gearing, then maybe the clutch is slipping?

On rare occasions, I have gotten engines that lacked compression because the chrome plated bore was not finished properly. They lacked the proper "cross hatch" pattern that is required to properly seat the rings in the bore. A few quick passes with the proper style flex hone fixed the problem. (once again, a rare problem - only found two engines out of 75 or so.)

I've tried 2 different 'barrels' though :/

ill check for slipping clutch when the sun comes up.

i'll also re-grease the clutch pin and bearing for the whining sound i hear when clutch is in 'drive' engaged position.