Engine Bogging/ No power

[kdaddy1980]

ok i had a similar symptom that ended up being a carb problem, the clip that pulls the pin up came off, but this carb seems fine.so when it was sitting disengaged it revs fine, responds good. but as soon as you engage the clutch it wants to bogg out like it has no power. nothing that i can tell is binding up on the bike, because it pedals fine but like i said let the clutch all the way out and it doesnt matter what speed im going, what gear, or how much i rev it up it still boggs out and if i let it go it dies. i need some ideas of what it could be. any help will be appreciated.

bike specs:
26" huffy santa fe cruiser
66cc engine from mgm motors cinncinnatti( not grubee)
jackshaft kit from bikeberry
rapid/click shifter
rear disk brakes
front shock forks
double brake lever
cns/nt hybrid carb (carb screws not adjustedright?)
new 32:1 gas/oil mix (maybe i should use more oil?)

please help lol

 

[GearNut]

CNS/ NT carb? I never heard of that one!

Extremely too lean or too rich will cause this.
You did not indicate that it has hard starting or a high idle speed so that pretty much rules out an air leak.
My first guess is the main fuel jet is clogged. You did not say if the spark plug is wet like the engine was flooded to death, so I am going with a too lean condition.

If the spark plug is wet then there is a good chance that the fuel jet unscrewed itself from the carburetor body and is sitting on the bottom of the fuel bowl.

Something even as simple to repair as a bad spark plug can do this as well.
When the engine is under a load the combustion pressures are higher than when the engine is just spinning up fast with no load. A bad spark plug can be working fine with no load but miserably under the higher pressures of a full load.

 

[kdaddy1980]

CNS/ NT carb? I never heard of that one!

Extremely too lean or too rich will cause this.
You did not indicate that it has hard starting or a high idle speed so that pretty much rules out an air leak.
My first guess is the main fuel jet is clogged. You did not say if the spark plug is wet like the engine was flooded to death, so I am going with a too lean condition.

If the spark plug is wet then there is a good chance that the fuel jet unscrewed itself from the carburetor body and is sitting on the bottom of the fuel bowl.

Something even as simple to repair as a bad spark plug can do this as well.
When the engine is under a load the combustion pressures are higher than when the engine is just spinning up fast with no load. A bad spark plug can be working fine with no load but miserably under the higher pressures of a full load.

yes, its a hybrid carb, its a nt but has a choke cable like a cns. you gave me a couple ideas on what to check, this is a brand new engine with all new parts but i guess anything could happen. ill do a few more checks and ill get back with you if i figure it out. thanks for the info.

 

[2door]

I have concerns about your 'carburetor'. Where did you get it? Got photos?

The CNS doesn't actually have a choke. The cable operates a fuel enrichment system unlike an NT that uses a sliding plate to block off the air supply.
This "hybrid" carb sounds suspicious and might be the cause of your problems.

Tom

 

[kdaddy1980]

heres a pic of the bike since i havent posted one yet.

and heres a pic of the cns/nt carb. the other cable is a choke cable, i got it from gasbike, its a skyhawk carb made in china

its a yuan dong carb from china.

i got it to run a little better, i took it all apart and checked the jet and its fine, i set the pin up to the lowest notch and it seemed to help a little to get some more gas in there to keep it from bogging, but it still has a rough spot where it loses a little power and then gains it back when it goes wide open throttle.
i think i might just need to tune it a little by the screws, im not sure which one does what and ill have to look up how to adjust it properly

 

[2door]

Weird. It's a CNS with an NT air cleaner.
Just type in CNS carburetor in the search feature. You'll find lots of reading on that carb.

http://www.google.com/cse?cx=partne...j15#gsc.tab=0&gsc.q=CNS carburetor&gsc.page=1

Tom

 

[kdaddy1980]

Weird. It's a CNS with an NT air cleaner.
Just type in CNS carburetor in the search feature. You'll find lots of reading on that carb.

http://www.google.com/cse?cx=partne...j15#gsc.tab=0&gsc.q=CNS carburetor&gsc.page=1

Tom

saw something where a guy took the vent tubes off and plugged them and it fixed it. im going to try to just take it off and see what that does.

 

[kdaddy1980]

took the tube off and that really didnt do anything. i replaced the spark plug with a fresh, 3 prong spark plug. still didnt really do much for the accelleration. i wonder if i put some higher octane gas in this if it would help it burn better and smoother, has anyone ever tried that? does anyone use mid grade or premium in their bike engines?

 

[2door]

You're going to hear all kinds of theories regarding octane, high or low. Some claim to see better performance using the high priced gasoline and some, me included, say that these little engines with their low compression will not benefit from higher octane.

You'll have to be the judge on what it does for you. If it 'feels' like it runs better then it will be okay but don't expect too much in the way of performance gains.

I'll also question you about how many miles or tanks of fuel you have run. The Chinese 2 stroke is famous for slow break in. It usually takes a couple of hundred miles for one of them to start to run well and achieve top performance. If the engine is new with less than 200 miles don't expect it to run as well as it will after it has seen some road time.
They seem to be like good wine; they get better with age.

Tom

 

[kdaddy1980]

You're going to hear all kinds of theories regarding octane, high or low. Some claim to see better performance using the high priced gasoline and some, me included, say that these little engines with their low compression will not benefit from higher octane.

You'll have to be the judge on what it does for you. If it 'feels' like it runs better then it will be okay but don't expect too much in the way of performance gains.

I'll also question you about how many miles or tanks of fuel you have run. The Chinese 2 stroke is famous for slow break in. It usually takes a couple of hundred miles for one of them to start to run well and achieve top performance. If the engine is new with less than 200 miles don't expect it to run as well as it will after it has seen some road time.
They seem to be like good wine; they get better with age.
Tom

yeah its a brand new engine, so your right i bet a lot of it is being a new engine and not being broke in, speaking of breaki ng in, i started with a 32:1 ratio instead of a 16:1 like they suggest at gas bike. i found that 16:1 will clog your muffler quick. what ratio do you use for the break in period? and how long do you run it? ive tried a couple different techniques but this time just went straight to 32.maybe thats why it seems like its sticking a little bit? needs more oil? or just needs driven, i took it out and ran it a bunch earlier to try to get it lossened up a little

 

[2strokebke]

Im sorry to bumP, But im having the same problems it boggs all the time and no power, Then it somethimes have a little power.

 

[2door]

I'm one of those weird-o guys who run a 100:1 ratio and I don't recommend that to everyone. Your 32:1 is a good place to start and stay if you're using a good grade of air cooled 2 cycle oil.

Yes, I agree. Ride it and don't baby it but don't abuse it either and I think you'll see improvements as you accrue miles.
Later you might want to experiment with some carburetor jetting changes but give your engine a chance to break in before you start looking at performance enhancments.

Tom

 

[2strokebke]

I'm one of those weird-o guys who run a 100:1 ratio and I don't recommend that to everyone. Your 32:1 is a good place to start and stay if you're using a good grade of air cooled 2 cycle oil.

Yes, I agree. Ride it and don't baby it but don't abuse it either and I think you'll see improvements as you accrue miles.
Later you might want to experiment with some carburetor jetting changes but give your engine a chance to break in before you start looking at performance enhancments.

Tom

oh okay, i forgot to say it vibrate too?

 

[kdaddy1980]

no it hardley vibrates at all and runs smooth once i get it going, but starting it while its cold it runs rough until it warms up a little, i have to throttle it wide open to get it to go but once it warms up it seems to have more power. im also noticing a strange popping sound on startup, kinda sounds like a backfire with a "tinny" sound like metallic sound but only on initial startup when its cold. im still using 32:1 oil, but im using an 89 octane gas that seems to work well. also i do notice a backfire sometimes when i shut the engine off, could this be a timing issue? though i know that is rare maybe leftover gas in the cylinder? im not sure.

 

[maniac57]

That tinny sound is a leaking head gasket. I have had several engines do this.
Retorque your head bolts.

 

[2door]

That tinny sound is a leaking head gasket. I have had several engines do this.
Retorque your head bolts.

I concur. If you don't have one, buy or borrow an inch pound torque wrench. Set it to 120 to 140 inch pounds and retorque the cylinder head nuts. If the problem, 'popping' persists remove the cylinder head and check the head gasket. You also might want to 'lap' the head before reinstalling it.
That process has been covered here numerous times. http://www.google.com/cse?cx=partne....tab=0&gsc.q=lapping cylinder head&gsc.page=1
Good luck.

Tom

 

[kdaddy1980]

Thanks guys,I have a torque wrench and ill try torquing the head, I thought that could be the possibilitly of that but I didn't see any oil leaking out but maybe I missed the leak.

 

[Richluhring]

help, my new 66cc motorized bike has lost its power, i just ran my second tank of gas through and ran out. when i added more fuel and started it my power was all gone. i have replaced the plug, fuel/oil, cleaned carb, new fuel filter, replaced exahust, cleaned air cleaner and still absolutleyt no power. oh i even checked the float settings.. any ideas, could it be my reed valve malfuntioning?

 

[GearNut]

Richluhring, I will assume nothing here, so if I offend you , sorry...

By "no power" is the engine a gutless wonder or is it revving like mad but the bike is slow?
Reed valve? Exactly what engine are you running?
Running an engine out of fuel will not cause disastrous permanent damage.
How did you go about cleaning the carburetor? Did you just wash the outside of it or did you remove the fuel jet(s) and mechanically clean and inspect them?
What new spark plug did you install? ( brand/ number)

 

[maniac57]

Rich you should stay with your post rather than posting the same question in a bunch of places. You get better answers in a dedicated thread and threadjacking is considered rude.