Project Banshee...Runs but only starts and goes under throttle

[sr73087]

So I picked up a Banshee awhile back from a young guy who bought it as a project and didn't have the time or expertise to really get it running. Anyway today I finally got her running. However, it only starts with alittle throttle and must we reved constantly to keep it running. I rode it around the block today and it ran ok, but seemed to sputter alittle at lower rpms especially under load. While driving around the block, I got on it once and it seemed like it smoothed out as the rpms increased. It did look to be blowing whitish smoke especially during start up. The motor has the TORS removal setup and a toomy t5 exhaust. I am not sure if it has anything done internally since I bought it cheap not running. Jetting wise I am not sure if it has been adjusted for the known mods yet or not.

 

-I know my fuel mixture was not perfect but pretty close, could this simply be a mixture problem or is my jetting likely not correct? I have not messed with the idle adjustment screws at all.

Edited August 17, 2015 by sr73087

[sheerider11]

Wait. So you bought a bike from someone that didn't know what they were doing.

You bought it and "fixed" it.

But you don't know what jets are in it? And your mixture wasn't right?

What exactly did YOU do?

[sr73087]

Mixture was ok but could be like .001% off. But I am not sure how sensitive this motor is. If its not completely on point does performance suffer. I feel like this probably is not it since people seem to all run slightly different mixtures, but I wanted to hear what people who have alot of experience have to say.

 

It looked like the person who had it just liked to pull things apart and then not put them back together properly. So when I bought it, it ran but would not shift (fixed) and it would piss fuel out of the overflow and a bunch of other missing bolts. So I checked the carb and ended up having to majorly adjust the float height. I am concerned about as well since to get the correct height the tabs on both carbs the tabs on the float are bent at very different angles to achieve the correct height. I am a car person, so I have lots of major mechanical experience but not really with carbs. It seems easy enough to understand but I obviously don't know everything.   

[sr73087]

''I know my fuel mixture was not perfect but pretty close"..............pretty close to what? 

 

Pretty close to the exact specs listed on the amsoil bottle. I normally make it easy when mixing 2 stroke. I pump EXACTLY what I need to use a full bottle of oil and just dump it in and mix it around. Everything has always run great. This time I had 0.75 gallons of fuel and had to add 2.6 oz for everything gallon. In order to get the correct proportion (.75*2.6)=2 oz of oil. Like I said it could be like .001% off, but since I don't have experience, I wasn't sure if this could be a factor. Like I said don't think so, but I want to be sure that it is likely a jetting problem.

[Larry's Shee]

So you somehow got it running without even cleaning the carbs. I know this because a sharp fucker would have noted the jetting specs.

White smoke indicates need for leak down test.

[Larry's Shee]

I think Gravel ment AFR not oil ratio.

 

Have you done a plug chop or plug reading?

[sr73087]

So you somehow got it running without even cleaning the carbs. I know this because a sharp fucker would have noted the jetting specs.

White smoke indicates need for leak down test.

 

Like I said I normally deal with fuel injection. This is my first time learning about this.

 

Is it the same process as a 4 stroke? I have not done a 2 stroke leak down.

 

I think Gravel ment AFR not oil ratio.

 

Have you done a plug chop or plug reading?

 

No plug reading. I need to get a fresh set of plugs. Am I safer getting 1 step colder plugs or don't worry about it just yet?

 

Ok so your running a 50:1 mix (per instructions on bottle)  now we're gettin somewhere......now pull A carb off n see what jets you have and measure that float height ya bent all to shit<----this is important in a 2 stroke, you cant just go bending shit.  

 

The floats had to be adjusted to correct the overflow issue. What other way would you suggest addressing this issue? Needle and needle seat were clean, bowl was clean.

Edited August 17, 2015 by sr73087

[camp0429]

Now would be a good time to get a Clymers manual, it's the best $20 or so bucks you can spend. Get one and read through it

[sr73087]

Got it. Its not a problem to pull the carbs again and get those measurements. Just point me in the right direction and I can take care of the rest with some guidance the 1st time.

[sr73087]

Now would be a good time to get a Clymers manual, it's the best $20 or so bucks you can spend. Get one and read through it

 

I have one. Very helpful.

 

Scroll to the top of the page, Click the BHQ Tech info tab, scroll down to "what is jetting" and/or Jetting FAQ  this may help get ya up to speed.

 

Yep, I read through a bunch of this earlier. Its great info.

 

[sr73087]

Alrighty then.......

No1 .need to pull at least 1 carb and see what you have for jets..

No2, I'd highly encourage you to do a leakdown test before ya go too much further......this way your not "masking" an air leak with fuel adjustments

No3. forget about anything related to a V8 lmao 

 

I'm more into hondas but I hear you haha

 

have you just check to make sure you are not missing the choke tube?

 

I actually replaced mine, so yep it is there.

 

[Larry's Shee]

Leakdown is similar, but different, lol

 

Basically plug intake and ex, pressurize to 6/7 psi, must (should) hold for 7 min.

 

Tho you may have adjusted floats correctly, you make it sound like you reffed the shit out of float tang. With 1.5 mm range and thin brass tang, no room for gorrilas here.

[sr73087]

well, judging by your words "sputtering" and white smoke, leads to believe too rich issue, BUT it could be a bad right side seal and its suckin trans oil (leakdown test)  Since you had the carbs off and "bent" stuff, we better fix that and get back to ground zero lmao cant be bendin shit to fix stuff, you can on a Holley but not on a Mikuni lmao 

 

If the float height was off, which it was way too high (while working on it upside down), this is how the manual says to adjust it. Isn't adjusting the tang the only way to address this issue?

[sr73087]

It was measured. I used my brake pad measuring tool. The only thing I questioned was, what is considered the "top" of the float? The top closest to the needle or the highest point? There is a few mm difference. I can take a picture if that helps explain what I am asking. 

[sr73087]

Yes I see the tool. The brake measuring tool is the same idea. Do you know what they look like? I verified my reading with a veneer caliper as well. I have done a great deal of research on this including reading this section of the manual many times and its not rocket science. Many on this board and other certified instructors will tell you alot of guys don't even use a gauge. Supposedly getting the float parallel to the carb body is usually a good starting point on most carbs.