Pickin up a dirt bike

[Kenny_McCormic]

Miracle in a can, this stuff fixes anything you spray it on, seized engines are now "cheap fixes" to me.

 

[crazycart]

Yup,i either use that or Liquid Wrench,used it to free up one of my sled engines

 

[I like karts]

Man, I wish I could fid a cheap 2 stroke dirt bike. I've wanted one sice I was like 5, but my parents come up with every reason why I shouldn't get one.

 

[kibble]

Man, I wish I could fid a cheap 2 stroke dirt bike. I've wanted one sice I was like 5, but my parents come up with every reason why I shouldn't get one.

Respond with:

If I don't get one, the terrorists win!

 

[I like karts]

Genius plan kibble!

good work.

 

[crazycart]

Worked on it a bit more,got her runnin real good, its a very fun little dirtbike,BUT,it seems like after i run it for a while and get hot,it will quit running and just backfire when i kick it over,this happend the day before also,im suspecting a bad base or head gasket because after it does this it still has perfect spark..

 

[Kenny_McCormic]

Worked on it a bit more,got her runnin real good, its a very fun little dirtbike,BUT,it seems like after i run it for a while and get hot,it will quit running and just backfire when i kick it over,this happend the day before also,im suspecting a bad base or head gasket because after it does this it still has perfect spark..

Real hot eh? I would do a plug chop to be sure its not running lean.

 

[crazycart]

Its not getting REAL hot,the plug is a nice cardboard brown.And its weird because it didnt have any signs of lean running it just died instantly.

 

[Kenny_McCormic]

I would wannna run a little darker than cardboard, coco is the standard.

 

[crazycart]

I would say the "standard" changes from person to person,from my experience engines run best when there a good dry cardboard brown color,as long as there not gray/white its good lol

 

[2or3wheels]

you did mix the gas right?

 

[crazycart]

It has oil injection.(which i verified is working)

 

[crazycart]

A few days ago i found out it sheared the flywheel key (as i suspected) Made a new one out of some high carbon steel and is much stronger, runs perfect, im loving this thing

 

[kibble]

A few days ago i found out it sheared the flywheel key (as i suspected) Made a new one out of some high carbon steel and is much stronger, runs perfect, im loving this thing

I thought the flywheel key is not supposed to be "strong" so it can give out in case something goes wrong?

 

[crazycart]

Well the old one was about half sheared so i meant stronger compared to the old one.

 

[Russ2251]

flywheel key is not supposed to be "strong" so it can give out in case something goes wrong?

Once again, Mr. Kibble nailed it.
Keys are designed to give way as to prevent damage to flywheel and/or crankshaft. I would much rather replace an 80¢ key over a $150 flywheel or (worse yet) crankshaft.
Flywheel keys shear for a reason. 2nd most common reason for failure is improper torque. 1st most common reason is a sudden hard stop.
If torqued to low, flywheel will tend to 'rock' with combustion pulses and eventually works itself loose and results in shearing the key.
Over torquing can be worse. Warping or fracture can occur.
Also, taper on crankshaft and in flywheel should be clean and free of any oil. Clean these surfaces with alcohol.
Re-assemble and torque to spec.

 

[crazycart]

Well, i needed a quick fix and this works fine, its just a beater bike anyway.I raced the neighbor he had a 78 Honda express moped..smoked him.. Heres a pic, with my sweet seat and gas tank. Sometimes it slips out of 4th gear, and goes into a "false" neutral, that usually means the shifter spring is going..but it tops out around 50 mph..not to bad for a little 100.And it gets **** good mileage, i can go all day on that little tank.

 

[sayre315]

i'd give $50 for that any day

 

[Kenny_McCormic]

You smoked the express cause it was designed to make 2hp and go 30 MAX. A ported out express with a good ex chamber would keep up. Maybe outrun you.

 

[crazycart]

Lol i know..lighten up a little...and yeah i was talking to him about doing some porting, boring, and an expansion pipe..it would still take more than that to outrun me though..but hes going to sell it now i guess.

I am actually thinking about trying "Hydroforming" to make an expansion pipe for this thing..or i may just weld up a sectional..we'll see.