High Compression (180psi!) but Low Power on Stock Grubee Kit


New Member
Feb 10, 2019
Well, I got a new (3rd) CDI, as well as a coil in the mail, from a China / Ebay seller today. My old stock coil, and the newish CDI I got from gasbikes . net seems to be working well enough for now. I will ride the heck outta those, and replace with this newer "TZ" style electronics set that I received today, when the time comes.

I also got my dinky chrome banana pipe in the mail from China / Ebay today (different seller, I believe). Replaced my stripped exhaust port bolt, slapped on a new gasket and this new muffler with a generic-tuned expansion chamber, and HOLY CRAP, WHAT A DIFFERENCE.

I was having to use full choke to get her goin in colder weather here, and now I cannot get it started with full choke - still too rich I guess, on leanest setting, with stock carb and jet.

Got it goin no problem with zero choke, and WOW does it EVER have a LOT of power now! It is NOT a QUANTIFIED value, but it SEEMS to be TWICE as powerful now! Nearly as loud as stock exhaust with a giant hile drilled in, to bypass my clogged catalytic converter (maybe louder?) but absolutely worth it. I only ever use about 25% throttle to cruise, and MAYBE 50% going up a steep hill, so it SHOULD be okay on my short (3km) nightly (11pm) journeys home.

Feels like I got enough power now to tear my rear wheel right off if I am not careful lol :)

Still need to do a PSI test with WOT when the engine is warmed up / hot, but overall this dinky bike is running GREAT now... Now I just need to upgrade from these OLD-style C brakes o_O


Well-Known Member
May 1, 2011
Newnan,Georgia U.S.A.
Don't worry too much about the compression, if its running good I don't see a problem. As for brake pads you can try different compounds, bmx style are made of better material, I tried a couple to find the pads that work better for me. Pads will wear fast now so keep extras.