Engine Trouble Engine wont start? TROUBLESHOOTING GUIDE

[weefek]

I have been running the engine for about a year now. With not that much use.

Keeping that in mind it doesn't really look like anything is wrong as far as I can tell from those pictures. How long after you installed the new carb did these issues persist? What carb did you have on it before? The more info the better.

 

[EthanRevBike]

Keeping that in mind it doesn't really look like anything is wrong as far as I can tell from those pictures. How long after you installed the new carb did these issues persist? What carb did you have on it before? The more info the better.

Ok so, I had the stock carb on there for oh about 6 months for light use. Then I changed to a "racing carb" in fall. I rode that one till the big broke around Xmas and I just got back into fixing if about 2 weeks ago. My friend brought over really lightly used carb and CDI today. I installed the carb but not the CDI yet. But no joy with the new carb. I pulled the head off and was inspecting the piston and seals this afternoon.

Is it ok to push the seals back in with a screw driver? I ride mostly mountain bikes and all are seals on there are made with rubber so it's 100% not good to do so on that.

 

[EthanRevBike]

Keeping that in mind it doesn't really look like anything is wrong as far as I can tell from those pictures. How long after you installed the new carb did these issues persist? What carb did you have on it before? The more info the better.

Yeah, it's getting great compression right now.

 

[weefek]

Ok so, I had the stock carb on there for oh about 6 months for light use. Then I changed to a "racing carb" in fall. I rode that one till the big broke around Xmas and I just got back into fixing if about 2 weeks ago. My friend brought over really lightly used carb and CDI today. I installed the carb but not the CDI yet. But no joy with the new carb. I pulled the head off and was inspecting the piston and seals this afternoon.

Is it ok to push the seals back in with a screw driver? I ride mostly mountain bikes and all are seals on there are made with rubber so it's 100% not good to do so on that.

What seals are you referring to?

To me it seems like your 'racing carb' wasn't tuned very well, hence the carbon build up.

I've been running a bofeng for 150~ ish miles and have had zero issues, i can hit way faster than i want to go (maybe 40 mph? I dont know).

Once you get it tuned and running well put a bit of seafoam in the gas and it should clean up the carbon deposits nicely

 

[weefek]

Yeah, it's getting great compression right now.

The rings look shiny , should be already broken in according to your previous description.

 

[EthanRevBike]

Ok. Do you think I should replace the CDI? Because I did check the volts (they were good) but my friend said that's kinda bulls**t the only way to really tell is to put a newer one in. Is that true?

 

[EthanRevBike]

What seals are you referring to?

To me it seems like your 'racing carb' wasn't tuned very well, hence the carbon build up.

I've been running a bofeng for 150~ ish miles and have had zero issues, i can hit way faster than i want to go (maybe 40 mph? I dont know).

Once you get it tuned and running well put a bit of seafoam in the gas and it should clean up the carbon deposits nicely

Holly f***! That's kinda insane. You gotta show me pics. I wanna see one that goes 40mph. DAM DUDE!

 

[DAMIEN1307]

Holly f***! That's kinda insane. You gotta show me pics. I wanna see one that goes 40mph. DAM DUDE!

I have a Zeda 80 triple 40 with a BoFeng on it that I took it up to 51 MPH just one time since I like to cruise between 30 to 35 MPH around town riding.

This is no real surprise to many of us here in the forums to have decently built bikes with decent motors that can achieve these things.

Here is what I do this with.

 

[weefek]

Holly f***! That's kinda insane. You gotta show me pics. I wanna see one that goes 40mph. DAM DUDE!

Honestly probably closer to 35. I have never had a speedo on it but I've kept up to some vehicles and it was way too uncomfortable of a speed for me. When I give it full throttle she really goes (44t sprocket) but I basically never go WOT. Maybe one or twice for a few seconds at a time. It just feels too sketchy to me. I'll take some pictures tomorrow. It's nothing special.

The bike also doesn't really seem to like to run that fast. About 3/4 throttle feels about perfect.

Damien's bike is fricken beautiful compared to mine. I'm more of a make it work I don't care what it looks like kind of person.

Mine happens to run well after break-in and at my altitude. Stock jet, down one position on the pin.

 

[weefek]

Ok. Do you think I should replace the CDI? Because I did check the volts (they were good) but my friend said that's kinda bulls*** the only way to really tell is to put a newer one in. Is that true?

The voltage itself will never really tell you if it's 100% good or not. Personally I would have a spare on hand regardless.

Try swapping it, see what happens.