FA50 kit toast?

Hello,

I recently put the 60cc cast iron kit from treatland, as well as the MLM sidebleed pipe on my FA50, and upjetted my stock carb to 82.5. Everything else is stock and I’m still running the oil pump as general consensus seems to be that they are reliable.

I had it going 32 for a while with no problems but the other day, while going at full throttle for long stretches, I’d lose power and slow to about 22-25 mph... it felt the about the same as if my gas tank was running low. Slowing down for a bit would let me climb back up to 32 again so I kept riding and after it happened a few times, the engine went SKERRR (like high pitched nails on chalkboard noise) and shut down... it kicked up after a few minutes and I brought it home slowly, and there was a slight metal on metal noise coming from the engine every so often.

It’s been able to get to 32 still, and my dad suggested maybe I was running lean and getting the engine too hot so I upjetted to 87.5 main jet, and put the needle clip at the richest setting but it will still will slow down after long stretches at full throttle. Maybe worth noting is that these changes to the carburetor had very little effect on performance, ie top speed is still 32 and it takes about as long to get there.

I’m gonna take the engine apart on Monday when my new gaskets come but has anyone had this happen before and what did you do? I couldn’t find my setup in the tuning spreadsheets on the wiki so any input from someone who has done this is appreciated... (edited)

Re: FA50 kit toast?

shoulda done the oil pump delete. post pictures, I like pictures, more pictures the better.

Re: FA50 kit toast?

I’ll post plenty of pictures later, but is getting rid of the pump necessary? It was my understanding that it actually put out “too much” oil compared to the 50:1 a lot of people seem to premix. It’s just a pretty big point of convenience I didn’t wanna get rid of unless 100% necessary. (edited)

Re: FA50 kit toast?

I think you'll find that the motor had seized . The piston skirt will be scored and light aluminum deposits on the cylinder . One or both rings will be partially stuck in their landings .

Clean the aluminum out of the cylinder , gently etch the aluminum holding the rings down , remove the rings and clean the landings so the rings move freely in them again . Sand the high spots down on the piston skirt . Lube everything and put it back together .

As for the oil pump , normally , they are fine .

Re: FA50 kit toast?

Jack Rutherford /

Dang fa50s. All that work for 32!

Re: FA50 kit toast?

> Drew Cooper Wrote:

> -------------------------------------------------------

It’s just a

> pretty big point of convenience I didn’t wanna get rid of unless 100%

> necessary.

well, how convinient is it to change out your cylinder ever 15 miles.

Re: FA50 kit toast?

> Jack Rutherford Wrote:

> -------------------------------------------------------

> Dang fa50s. All that work for 32!

Something's not right there . My FA50 is very close to being completely stock and it does 30 - 32 almost anytime I run it . More on good days . ;)

Re: FA50 kit toast?

I was running around 28 on a good stretch before modifications so I suspect any lack of gains is failure on my part to install and break in the new kit properly.

In regards to oil I’m putting off plenty of nice blue smoke so I think again the problem lies with my haste to have fun with my new kit instead of more carefully breaking it in

Out of curiosity PD you say very close to stock — what have you modified on yours? (edited)

Re: FA50 kit toast?

PS: I've lost my airbox "slipper", as the service manual calls it: the little dovetail joint under the airbox that holds it shut, twice now. Is there anything I can apply to it to make it hold tighter? I've got it duct taped right now but feel the ped deserves better.

Re: FA50 kit toast?

So this is a toasted FA50 ped in reality

Re: FA50 kit toast?

I'll take PD's advice on this one and then declare how toasted anything is.

Re: FA50 kit toast?

> Drew Cooper Wrote:

> -------------------------------------------------------

> Out of curiosity PD you say very close to stock — what have you modified

> on yours?

The only thing not stock in/on my FA50 motor is :

The cleaned seized piston . It seized due to my pinching an oil line .

That piston has a single ring in the top landing . The other ring broke , being a bit too thin .

The crown of that piston has been relieved at all ports , but for the boost port at the rear of the cylinder , by about half the distance from the edge of the crown to top edge of the top landing , . I'll be catching that boost when next I take it apart .

As for the 'slipper' : if you get another , simply pinch it a little , so it fits very snug .

Short of that , use some malleable wire , like bailing or copper , and single wrap where the slipper goes . Then give it a twist . The air box should end up nice and tight . ;) (edited)

Re: FA50 kit toast?

So I’m having the same issue. What did you

do to correct your issue or is it resolved yet

Re: FA50 kit toast?

Did you buy his bike? If anything is different on your build it's not the same issue. It could be the same symptoms tho.

Have you pulled you cylinder and looked?

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