Another new guy

[mapbike]

I installed a NGk bpr7hs and it made a huge difference. I rode a good 10 miles again without a problem. I just pulled the plug back out and it's black again and wet what should I do the mix ratio at? Also I'm not very fond of this carb, seems to idle sometimes and others it won't. What would you guys recommend for a aftermarket carb with more control?

Buy some Opti2 2 stroke oil mix 1.8 oz per gallon for a couple hundred miles and then mix about 1.3oz per gallon from there on out.
Thats what I do and all my engines run great.......

On the carb, go to thats dax web site and order an RT Carb and a cable from Duane and put the #70 jet in it to start with and see what you get, these are good little carbs and I have beenrunning one on one of my bikes for a year now with great results.

Map

 

[Pearl91chevy]

ahh ok newest update... chain broke and i had enough so went to farm and fleet got a 40 chain and its awsome!!! went riding, getting occasional bog and whatnot. I shut it off and it starts pouring out fuel out of the carb filter.. i pull filter off and its soaked, go and ride it and it runs awsome! get back and for ****s and giggles i pull the baffle off the muffler.. Sure enough the thing idles now which its never done and it fires right up instantly. I havent rode it cause it was so loud and its 9 at night but whats the deal here??

 

[mapbike]

ahh ok newest update... chain broke and i had enough so went to farm and fleet got a 40 chain and its awsome!!! went riding, getting occasional bog and whatnot. I shut it off and it starts pouring out fuel out of the carb filter.. i pull filter off and its soaked, go and ride it and it runs awsome! get back and for ****s and giggles i pull the baffle off the muffler.. Sure enough the thing idles now which its never done and it fires right up instantly. I havent rode it cause it was so loud and its 9 at night but whats the deal here??

Stock exhaust are the biggest power robber on these engines, the stock type exhaust are better suited for 4 strokes and not 2 smokers, order a sbp or other expansion exhaust and you will rid your engine of the performance robbing contraption. ....lol!

Map

 

[Pearl91chevy]

can i just gut my stock muffler and have same effect?

 

[mapbike]

can i just gut my stock muffler and have same effect?

Yes hat will help and drill about three extra hole in bottom muffler cap.

Map

 

[silverbear]

It's been awhile since I did a China girl build, but the last one I had the muffler was supposedly "catalytic"... it would get so hot that it was glowing red at night. Talk about restriction! In making a muffler for an antique (1934) Sachs 98cc 2 stroke, I used the China girl muffler, gutted it with the exception of a baffle and put stainless steel wool inside. Haven't run that engine much since the build is still in process, but it sounded good, not too loud and I'm sure it was able to breathe.
SB

 

[mapbike]

What SB said os a great idea and ill add that it really helps to grind the flange hole so that it is more rectangular shaped so that the exhaust does hit the flat surface of the flange when it exits the port, even with it rectangulared it still squeezes the flow down but it will flow much better and on the engines I have done this to, it was a difference that could be felt in performance, the carb needs to be well tuned for any of these mods to make there biggest difference as well.

If the engine can breathe good and the fuel to air ratio is right the performance is really improved, speed and pulling power will be very noticeable.

Best wishes.

Map

 

[Pearl91chevy]

well problem now it won start.. i checked the plug wire, gets 2.9 ohms... getting gas cause i can watch it flow down into the carb.. any help?

 

[mapbike]

well problem now it won start.. i checked the plug wire, gets 2.9 ohms... getting gas cause i can watch it flow down into the carb.. any help?

Basically if you have spark fuel and compression it will run or at least try to start.

Check all of that thoroughly, if you ride up to start up speed and release clutch and spin engine with choke in the on position you should be able to pull the spark plug and find it to be wet with fuel If you aren't getting spark, but if the plug is dry after doing this test you aren't getting fuel to the engine, if the plug is wet but still no start disconnect the wire that goes to your kill switch and try to start again.

Map

 

[Pearl91chevy]

Oki I'll give it a shot tonight. Thanks!

 

[massdrive]

Welcome... 1st lesson, things rarely fit.
Lessen 2, make it fit. That's what makes this fun, and sometimes makes you want to gouge your eyes out... lol Everyone is here for you.