Sd stinger china motor problem help

G

GoPed

New Member
Ok so I think I have been posting this in the wrong place
Ok so this is how it goes I'm running a SD stinger with some cheap craftsman 2 stroke mix at 16:1 the manufactures recommended break in mix and the thing starts and runs .shft.. but it will race then stall if I let it idle at a what seems like a normal idling speed while clutch is engaged. Also the exhaust is very dirty (ex its blue and nasty) and it is constantly like this while dripping oil. I took the plug out and it was covered with oil. My question is could I safely use a Leaner mix and would that solve the problems encountered. If not what would solve these problems.
If so what ratio would be good and/or possibly different oil to use as it is still in early break in and i don't want to mess this up. :-||
 
Most everyone here runs 24/1 for break in. I tried the 16/1 as well on my first build, it didn't work for it either.
 
check for a intake leak. spray wd40, carb cleaner ect around the area and if it stalls, rev's, or changes you got a leak. fix a air leak or it will kill your motor! FAST!! as far as mixing oil and gas i've seen 16-1 up to 100-1 that is up to you. their is lot's of post's on oil's so if you have a extra 72 hr's read up. lots of stuff on air leaks too. good luck i would just be easy on the break-in [lots of warm up and cool downs] did i say a air leak will KILL your motor! 32-1 is a good oil mix
 
Ok I was thinking of 24:1 sounds good and I will check for a air leak could even be that idindt tighten the carb enough when I put it on
 
GoPed said:
Ok I was thinking of 24:1 sounds good and I will check for a air leak could even be that idindt tighten the carb enough when I put it on
Click to expand...
I think the stinger kits use NT carbs so not matter how much you
tighten the metal to metal joint of the carb on the intake it will still
leak.
Tighten it too much and you will break the carb throat.

I use an O ring that fits in the carb and seals against the intake
but other builders like to use some kind of goop to seal.

What were you using anything to seal the connection?

16 :1 is 8 oz of oil and way too much.

Try 6 oz if you are paranoid and 5 oz
would be good to break in then move
to 4 oz which is 32 :1 ratio
 
found the problem these holes are right next to my intake gasket
IMG_0325.jpg

IMG_0324.jpg

What are these things cast out of? if its steel or aluminum ill just .weld
(weld) the hole closed with my mig welder. Would that work? Is this the problem?
oh and heres my build

IMG_0326.jpg
 
I really doubt that those casting defects are going all the way
through to your intake in your head.
Poke a wire in the holes and you will find that they don't go
anywhere.

Take the carb off and look in the intake passage and while
you are at it make a new gasket that doesn't block the flow.

Your pic is so small I can't make anything out except that you
have mounted your motor very high in the frame?????

Motor castings are aluminum.

GoPed said:
found the problem these holes are right next to my intake gasket

What are these things cast out of? if its steel or aluminum ill just .weld
the hole closed with my mig welder. Would that work? Is this the problem?
oh and heres my build
Click to expand...
 
Last edited:
MotorBicycleRacing said:
I think the stinger kits use NT carbs so not matter how much you
tighten the metal to metal joint of the carb on the intake it will still
leak.
Tighten it too much and you will break the carb throat.

I use an O ring that fits in the carb and seals against the intake
but other builders like to use some kind of goop to seal.

What were you using anything to seal the connection?

16 :1 is 8 oz of oil and way too much.

Try 6 oz if you are paranoid and 5 oz
would be good to break in then move
to 4 oz which is 32 :1 ratio
Click to expand...
oh nothing at all to seal it but If you look at my post i think this is a bigger problem however i will try some o-rings.
 
Deffinatly use the o ring to seal it and 16:1 is way too much oil I broke mine in 32:1 and am running 40:1 now that its nice and broke in. Dax did a post not too long ago that explains mix ratios. Do a search and read his post - very informative
Also castings are alloy not aluminum not sure what the engine manufaturer who produces your engine uses best to call them directly if possible. Side note new top end is relatively chap if you do need to get one ;)
 
Thanks guys got it running with a o-ring and a little leaner mix just added a little more pure gas to the two stroke mix. It isnt stalling and finally idles
dance1 also sounds better and doesn't smoke as much! Cant wait to ride it more tomorrow!

Cheers Jack (p)
 
Good for you! :D

Raise the C clip on the carb needle one notch and it will be running like a champ.
Do you have a bigger pic?
Is LA Los Angeles or Louisiana?
 
Ill upload some bigger pics the problem was my iPhone took a higher res than the site would take laff BTW LA is for Los Angeles
IMG_0326.jpg

IMG_0325.jpg

IMG_0324.jpg
 
Also I need help picking a spark plug for my SD stinger slant head. Any recommendations??
 
Last edited:
Could possibly be a little more specific? Theres a lot of Ngk plugs but which one do I need to fit my stinger?
 
Yeah sorry - I run a B7HS because its slightly colder plugh but the B6HS should work great for you \m/ - higher the # colder the plug lower the # hotter the plug from what I understand. I'm running a slant head (slightly higher compression) massive carb and open exhaust. So I use the colder plug (among other things) to combat a lean condition \m/
 
OK so now i am switching my mix to either 24:1 or 32:1
so which one should I do? I have only gone 60 miles(according to my odometer) but used a full gallon of 16:1 probably leaned to 18:1. I am switching to Lucas semi synthetic 2 stroke oil and would prefer to run @32:1. But is this too lean of a mix at this stage? If so than what mix should I run based on my current conditions?
 
Man only 60 miles on a gallon, I get 60 on each tank easy. Have you checked the main jet? Sometimes the jet will vibrate loose or even fall in the bowl. I have hear of it on the nt carb. It happened to me on the cns2, my bike started fourstroking at the end of a 40 mile ride three weeks ago so the next day I pulled the bowl and found the jet had backed out about half way. The 32/1 should be a good mix with the Lucas, I run it at 40/1 in my bikes.
 
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