Pk 80???? And Spark Plug Question???

[jasonpadilla]

I Have A Grubee Skyhawk 66cc Motor, But I See Pirate Cycles Selling A Billet Head That Helps Cool The Motor But Its For A Pk 80 Motor, Is That The Same? Whats Pk 80 Stand For? I Use A Bh6 Spark Plug, Should I Go With A 7 Or And 8 Or Stay With The 6??

 

[Fabian]

I use an NGK BP8HS (cold plug) because i'm running a SickBikeParts shift kit on my bike and i'm able to use wide open throttle all the time, towing a heavily loaded trailer.
This has the engine running hotter and i'm in a temperate climate zone (Melbourne, Australia) with summers reaching over 40 degrees celcius( 100+ degrees in the other scale) and the BP8HS keeps the plug tip in the correct temperature zone and my jetting through analysis is perfect for my specific requirements.

If not running high loads and low bicycle speeds, a BP5HS (if you're running very rich) or BP6HS or BP7HS will have good results.

You can't determine the plug heat range untill you install a new spark plug, then run wide open throttle for approx 1 minute and immediately stop the engine, letting it cool; removing the plug and inspecting it for air/fuel mixture and clues pointing to the heat range signature on the spark plug.
This information will allow you to make a decision if you need to go up or down a heat range to suit your carburettor jetting or plug.

It's not difficult to do and if using the search function on this site and internet info to find tutorials, you'll arrive at the perfect air/fuel ratio and spark plug for the engine.

Fabian

 

[jasonpadilla]

thanks fabian i really appreciat the help, a couple more questions, 1 whats a pk 80 motor is that the skyhawk 66cc? and do you know of websites to get motors in chrome? or where to get them chromed or polished?

 

[jasonpadilla]

thanks fabian i really appreciat the help, a couple more questions, 1 whats a pk 80 motor is that the skyhawk 66cc? and do you know of websites to get motors in chrome? or where to get them chromed or polished?

 

[Fabian]

Hi Jasonpadilla

I am not knowledgeable about all the different Chinese 2-stroke bicycle engines, but essentially they're fairly similar in design and construction.

Typically the cylinders are chrome plated and the better engines use 203 bearings and a crowded needle roller connecting rod bearing.
It's important to make sure your engine uses the newer and more reliable crowded needle roller system.

In my opinion, don't bother purchasing the 48cc engine; go straight for the larger capacity 66 or 69cc variants as it has more usable mid-range power and has virtually the same external dimensions as the smaller unit.

There are other members who have much more in depth and detailed knowledge of the technical differences between engine manufacturers.
I would suggest talking to 200910000393939393 or whatever number his numeric member name is, but his christian name is Rich.
He has made extensive research into modifying these engines and is in the process of creating his own engine variant of much better quality.

Although it is of much debate and some are critical of my views on fuel/oil ratio, my preference for longevity and maximum torque output is 20:1 and (in my own engine) replacing the standard main jet with a Dellorto No 83 0r No 84 main jet.
I've found the standard NT carburettor to be reliably functional, and no real need to change to a different design unless looking for extra performance and tuning options.


Fabian