jetting questions

W

woogie_man

New Member
Ok guys will start with the basics....

66cc flying horse motor
36 tooth rear sprocket
Large intake filter, and intake
Dax jets
60 jet
Opti 1 oil


I was getting a leak from my cylinder head, so removed that to make a new gasket and polish the flange a little. Eh hen I removed the head I noticed that the piston and the head is charcoal black, and unable to scrape it off with my fingers. So I am figuring that I am running to much fuel add if right now. I was planning on making my own key, but I keep breaking bits.

Is there any where that sells smaller sizes jets? Our is someone willing to mag a few different sizes jets with the extras that I have?
 
It's unlikely you want to go much leaner than a .60 jet.
however the jet may not be accurate.
Getting a set of jet drills and a micrometer is the go.
then soldering and redrilling isn't hard.
Piston however should be black.
Colour of plug will tell more.
Is it 4 stroking?
 
At wot it is 4 stroking quite bad. Well get some sites then it feels like someone his the breaks for a little bit, then kicks the throttle back in.

Besides the jetting, what else would I be able to adjust? Posted with the needle clip and that seemed to make it worse. Though may need to let it run further to really tell?


When I removed the plug it was a dark black color, so much to rich. Need to try and learn it out a little.
 
Ok guys I have a new part of the story....

Have been playing with the needle valve in the carb today. On the lowest setting ( closest to the needle end ) and the bike is running GREAT.......Well at least for a block or so. Then the power drops to around half instantly. If I let off the throttle and slowly get back on it I get power back for a bit....then dies again.

The bike started to run the best it ever has at the 27-30 mph range, smooth as buttah!


I wondering if I need to look at a larger her size, for more fuel flow. Or do I need to look at yet another exhaust? I currently have the SD Performance Expansion Chamber from JNM motors.
 
Fuel filter looks clean, nothing to show a clog.
Pet clock was recently opened and cleaned.
Can check the cap. I do have a large o-ring around the neck of the cap to keep the fuel from spraying out.
 
Would that go right in the top of the gas cap?

I suppose before I do that I will take the o-ring out and see if that helps at all. And as long as I am not forgetful and top the tank off, everything is fine.
 
Will take a look at that 2door.

Looked inside the carb to check the jet size...it was larger than the .60 I thought was inside. If I remember it was either .65 or .70. Just started to test, when the rain came.

Was really hopeful that all I needed was the motorbicycling socket on the size of my tank.
 
I wanted to make a very intelligent suggestion to some folks experiencing the joys of the cheap 2 cycle motors bogging down and or vibrationing after certain throttle points. A lot people that are experiencing this mystery could possibly have a total of 3 problems all at once not even related to the carb or jetting. One is the magneto being junk develops a short loose ground or gets fuel soaked. It tends to want to 4 cycle. The mag eventually fails. Read about the exhaust please read on...........

The other problem I have noticed is the Throttles themselves like the ones Bike Berry sells with the real cheap Chinese kits. The cable itself is almost a 1/2" inch too long. The engine can not achieve idle and if it does usually it's by gods good luck or making the engine idle with the throttle itself. This makes junk out of a good carb. The Carb it'll soon start flooding and ejecting fuel out the airport/aircleaner. Not a pleasant surprise but when the engine doesn't seem to sing those high notes or surges vibrates nine times out of ten it's the throttle position and the magneto sensing that excess fuel load VIA the plug not firing getting fuel soaked as well then it starts to 4 cycle eventually either the mag itself stops working or the carb itself self destructs. Usually it's not jetting at all. Another thing that helps a lot of this nearly eliminates this problem from square one is to cut off the TUBE STUMP at the bottom of the exhaust tube take it apart and drill out that baffle tube completely remove that tube that sticks up from the bottom of the exhaust. Remove the nut or screw and drill out that pipe. Get rid of it. The engine will come back to life on it's own start digesting the fuel IF YOU USE A NEW MAG PLUG WITH THIS TRICK and don't forget to check that throttle cable length too... It is the reason us Stock Car people do not put mufflers on our race cars. The compression fuel and valves would LOAD THE ENGINE UP WITH FUEL OR FLOOD OUR CARBS it's too much back pressure restricting the engine. When your engine can't jettison that excess fuel it loads up bogs down effects the mag the plug and eventually STOPS YOUR FUEL FLOW... .trk
 
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Iv,built six and they all needed rejetting 60 to 62 depending on mods to exhaust and intake. The cable length doesn,t affect idle at all it,s controlled by the screw on the side of carb when its screwed in it lifts the slide .The mags are junk though and a provision to accurately set and adjust ignition timing would help.
 
To Raydog

I can take you word for word, I believe some people have solved their issues with this re-jetting. By the mechanics of all it the exhausts are too restrictive that would lead to a .45mm jet being too large at some points or too small, gas quality matters a lot to these engines and all other 2 cycle motors. But as the engines break in they do seem to require LESS fuel. Then there is gas quality which can be like a yo yo in the northern regions of the U.S.

No argument on the point of the mags or some way of setting spark timing. Should they start using an electronic CDI to control spark that is an idea. Thee most common problem here is the exhausts restricting flows. The engine with a restricted pipe can obviously take in more than it can exhaust hence going the round about way with smaller jetting may have solved issues. The potency of gasoline in different regions is also another real issue. The gas quality where I live is usually good however there are times I have gotten gas and had it bog the engines down. The engines I own and run around with. It is a really frightening scenario. Adjusting the idle screw sometimes just makes matters worse. It just seems 93 octane isn't really 93 octane at times.
 
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