High Altitude Two Strokes?

[madbiker1]

I was curious how well the 2 stroke Chinese mid-frame engines worked at altitude? I have a couple of cruiser bikes with the 4 stroke Grubee Whopper Stopper kits here in Golden, Colorado (6000 feet). They seem to do just fine, even up the hills. I recently bought a pair of (49cc) two strokes, because they were only $130. I noticed that the kits feature 44 tooth rear sprockets. Is this an OK gear ratio? -Erik mail1@dangerouslaboratories.org

 

[stude13]

yes that is the standard sprocket. augi took his race bike to bonneville, while there, the corrected altitude was above 6,000ft. the engine was running fat. it really slowed the runs down. the emgine was a 47cc utility type

 

[spad4me]

I was curious how well the 2 stroke Chinese mid-frame engines worked at altitude? I have a couple of cruiser bikes with the 4 stroke Grubee Whopper Stopper kits here in Golden, Colorado (6000 feet). They seem to do just fine, even up the hills. I recently bought a pair of (49cc) two strokes, because they were only $130. I noticed that the kits feature 44 tooth rear sprockets. Is this an OK gear ratio? -Erik mail1@dangerouslaboratories.org

It is acutely hit or miss. Someplace in China where your kit was made someone decided what size the jet should be and where the needle belonged.
If yours runs good dont mess with it.

You can buy smaller rear sprockets You will go faster but loose hill climbing ability. Andyinchville or thatsdax sell em.

 

[madbiker1]

48 Tooth Sprocket?

Thanks everyone for your quick replies. Stude13, do you know how fast Augi's bike went at Bonneville? If I could get enough power out of one of these engines to climb some of the hills around here, I would be happy. If not, I was wondering if I should start with the 48 tooth sprocket? I saw that motorizedbikeparts.com had them for $24. The four strokes seem to have enough power here. Would the 2 strokes have more? Thanks -Erik

 

[stude13]

i think augi says he got one mph per cc-so it was either 33 or 35 mph. if you check out sickbikes, you might have your 2stroke answer. i think one of the best power options is the r/s 35 four stroke.

 

[Skyliner70cc]

no,u should use a 48 or 50 tooth sprocket