Baja 165 wont run with new carb

[chriswh86]

Hi all,

I have a Baja 165 mini bike. It has a clone 6.5hp engine in it. The previous carb was fubar and so I picked up a honda 6.5hp carb. I put the carb on, installed new fuel line and a new tank.

Ive pulled it over 50-75 times with no real luck. I can get it to run for a second or two on carb clean but it wont keep running. I pulled the plug out again and checked to make sure I had spark which I did. The kill switch is in the right position. The engine has oil in it to the recommended level.

Fuel shut-off is in the on position and the choke is also on. The new carb has the brass screw which goes into the carb horizontally closer to the engine side of the carb. I tried it where it was when I received the carb as well as seating it all the way in gently then backing it out 3 turns. Still no luck.

The new tank is filled with 89 octane marked gas. I have also cracked the bowl drain and fuel is coming out.

I am wondering what issues I might be having, is it going to take a long time for the carb to fill? Is there some sort of different procedure I need to do to ensure a dry carb is filled with gas properly? Maybe some of the carb screws aren't adjusted properly?

Look forward to some suggestions. Thanks

 

[mckutzy]

Does it have compression? Is the sparkplug tightened down properly?
Have you tried another sparkplug just to confirm its not the fault?

 

[chriswh86]

Havent been able to test compression with a gauge. Feels good pulling it over though. Plug has been tightened down properly but I dont have another to test with at this time.

 

[leesiel]

Did you double check that all of your carb gaskets and spacers were installed in the right order and facing the right way?
I put just one upside down and couldn't get it to run properly until someone on here suggested this ; I checked and sure enuff one was on upside down.

 

[chriswh86]

Did you double check that all of your carb gaskets and spacers were installed in the right order and facing the right way?
I put just one upside down and couldn't get it to run properly until someone on here suggested this ; I checked and sure enuff one was on upside down.

That is actually a good idea. I am going to recheck the gaskets. I am also going to pickup a new plug. After doing some digging i pulled mine again and the spark I very jumpy and erratic. Ill give those two things a shot


Anyone know where the idle mixture should be set or how to set it? Mine doesnt have the plastic cap on it. Its the brass screw that goes in horizontally near the back of the carb. When I got the carb is was out about 10 turns. Maybe that is right. Not sure.

 

[cavfire]

Idle mixture screw should be around two turns out.

 

[chriswh86]

Alrighty. So today I stuck a new plug in it. Spark looks good. The old plug spark seemed to jump around a bit.

Double checked gaskets on the carb. All looks good. Adjusted idle screw to ~2 turns out. I also tried it around the same setting as it came with. No luck on anything today. Not even a hint of trying to fire..

 

[Poboy kartman]

OK.....So...just going back to your original post......CLASSIC fuel delivery problem. Why????? Ahhhh...that's the $64,000 question. Normally, it's a dirty carb. PERIOD!

Secondly, it's a carb with a bad float. Or a clogged fuel line.....or a shut-off valve closed....WHATEVER! !!!! You aren't getting fuel....pure and simple....why? IDK!

But concentrate on that first....and if possible...spray the carb cleaner, and choke the carb with your thumb as it's running....sometimes that will break everything loose...and "magically" solve the problem!

 

[KartFab]

So you cracked bowl and fuel came out? Take large bowl off and see if fuel on/off lever is working. Switched to off position no fuel should flow, switched to on position you should get a steady flow into the bowl.

There is a center beam in the carb. At the bottom underneath portion there is the jet and emulsion tube. Use a flathead screwdriver to unscrew the jet, and the emulsion tube will fall out (if not, use the flat side of the screwdriver to push it out from the carb Venturi.

Poke/spray out the jet and emulsion tube.

 

[leesiel]

If all that fails to start it....take off all of the non metal parts that you can, rinse the carb pretty good to remove as much gas residue as possible and boil it in 100% lemon juice for a good hour.
I had to do mine 3 times on one occasion to clean mine once.

 

[Poboy kartman]

If all that fails to start it....take off all of the non metal parts that you can, rinse the carb pretty good to remove as much gas residue as possible and boil it in 100% lemon juice for a good hour.
I had to do mine 3 times on one occasion to clean mine once.

This is a good point....many times...people have said: "I've cleaned my carb"... and I've said: "Well fine...BUT IT'S STILL DIRTY!!!"

Then two cleans later: "Thanks, starts first pull now, and runs fine! "

IDK about this one though...because IIRC...this is a new carb????

 

[bob58o]

Since fuel is getting to the carb, I'm assuming it is not an issue...
BUT since it's a new gas tank, did you try with the cap off? I'm sure there is a vent in it right?

 

[leesiel]

This is a good point....many times...people have said: "I've cleaned my carb"... and I've said: "Well fine...BUT IT'S STILL DIRTY!!!"

Then two cleans later: "Thanks, starts first pull now, and runs

It was probably me

 

[chriswh86]

Hey all, thanks for the tips so far. Today's updates, I took the float bowl off, cycled the float with the fuel shut off in the ON position. I determined that the bike was leaned over to far for it to fill the bowl properly. Didn't think it was leaned over that far but either way, the bowl was able to be filled completely today.

Friend came over, we could get it to run from time to time but it wouldn't idle at all. We were able to build heat in the engine but at no time could we adjust the idle mixture to get it to idle properly. There was a lot of gas smell as well as a little coming out the front of the carb when it would die it seemed.

I was going to do a bit more digging. The photos below are of the screw I am having concerns with. When I received my carb that screw (Idle Mixture?) was set at about the same spot as the photos. I have since screwed it in until it seated then backed it out 1 full turn. We are having a lot of flood type issues it seems though? Am I completely wrong about this screw, should it be out as far as the photos?

 

[chriswh86]

Alright guys, another update today. The bike is running...

The main issue that was causing the problem is low fuel in the tank & the position of the tank at the time. The petcock doesnt pickup fuel until there is about .5-1" level in the tank, and so i was barely above that and the position of the tank only aloud fuel to SLOWLY fill the bowl and so we couldnt only run for a few seconds.

Either way, thanks to everyone here and some help here as well I moved the tank to a better spot temporarily. Got the bike running and tuned the idle and the mixture screw to where it is idling and running very well!

I put new gaskets on some time ago but have found a tiny leak in them. So I will need to deal with that to get it perfect but other than that I can move on.

Thanks again guys! Appreciate the help and hopefully I dont get laughed at for my stupidity.

 

[chriswh86]

Anyone aware of what the thread is on the shaft of 6.5hp clone engines? Is it metric or standard?

 

[chancer]

Standard. 5/16x24
I think on the 24,
But really it is just simply 5/16 fine thread.

 

[chriswh86]

Ahh ok. Ive got to re-look at what I have as I thought it was metric to begin with judging by the Baja parts list/manual etc but my tap wasnt working all to great

 

[chancer]

Yeah I have a 212 Predator and 2 79cc Predators also a 6.5 Greyhound clone and a B&S 5.5 OHV intek. All use the 5/16 24 bolt.
So does my 5hp Honda Pressure washer.

 

[chriswh86]

Alrighty. I will see if I can find a 5/16 to give a shot.