Who Rebuilds Dirt Bikes?

[Kiwioilboiler]

https://youtube.com/shorts/gf1Zeq2pKyk?feature=share

Well... she seems to run a lot better with the pwk and boyesen setup. It will idle now and not load up like it used to. It will load up if you let it idle for a while but, a few blips of the throttle clears it right up. I took it down the county road and pinned her out in 6th for a bit and no hesitation at all. She rips right through the gears with no spitting, sputtering or bogging now. Pulled the plug and it's tan. Best this thing has ever ran...

Nice. Watch out for deer.

 

[Jason628]

Nice. Watch out for deer.

Ya one more deer and this things done lol. I don't have another spare frame and set of forks and a wheel to put it back together. Ran out of amsoil so I have powerblend gold in it. Doesn't seem to mind.

 

[Bigmac]

https://youtube.com/shorts/gf1Zeq2pKyk?feature=share

Well... she seems to run a lot better with the pwk and boyesen setup. It will idle now and not load up like it used to. It will load up if you let it idle for a while but, a few blips of the throttle clears it right up. I took it down the county road and pinned her out in 6th for a bit and no hesitation at all. She rips right through the gears with no spitting, sputtering or bogging now. Pulled the plug and it's tan. Best this thing has ever ran...

Nice, did you mod that carb at all? Also didn’t realize it was a 125, that does make a big difference, disregard all of my information on intake manifold! LOL What jetting did you end up with?

 

[Jason628]

Nice, did you mod that carb at all? Also didn’t realize it was a 125, that does make a big difference, disregard all of my information on intake manifold! LOL What jetting did you end up with?

I didn't mod it at all. Had to modify the throttle cable because it was too short. I cut about half an inch off the casing which was kind of a pita but, it works well for now. I tweaked the float height to spec I think it was 16mm? it wasn't far off. I ended up with a 52 pilot and a 160 main and moved the clip down to 4 on the needle. Air screw is about 3/4 out. She starts first kick everytime now and idles without cracking the throttle. I may have to find a solution for the airbox boot. Mine has a few small cracks in it and is showing its age. I'm sure that stretching it onto the larger carb didn't help it out at all. I see 2005 cr125 ones for like $30 and look like it might work. They're supposed to be a little larger in diameter as well.

 

[Bigmac]

I didn't mod it at all. Had to modify the throttle cable because it was too short. I cut about half an inch off the casing which was kind of a pita but, it works well for now. I tweaked the float height to spec I think it was 16mm? it wasn't far off. I ended up with a 52 pilot and a 160 main and moved the clip down to 4 on the needle. Air screw is about 3/4 out. She starts first kick everytime now and idles without cracking the throttle. I may have to find a solution for the airbox boot. Mine has a few small cracks in it and is showing its age. I'm sure that stretching it onto the larger carb didn't help it out at all. I see 2005 cr125 ones for like $30 and look like it might work. They're supposed to be a little larger in diameter as well.

Right on, being a 125 probably helps with fuel demand issues for sure. So needle seat mods aren’t really needed, you could probably drop to a 50 pilot to get you closer to the 1.5 turn out air screw spec. I bet the pj would have ran better with the smaller pilot as well, glad it worked for you, be careful on long hillclumbs, until you feel it’s save, sometimes that can change things too

 

[Jason628]

Right on, being a 125 probably helps with fuel demand issues for sure. So needle seat mods aren’t really needed, you could probably drop to a 50 pilot to get you closer to the 1.5 turn out air screw spec. I bet the pj would have ran better with the smaller pilot as well, glad it worked for you, be careful on long hillclumbs, until you feel it’s save, sometimes that can change things too

Right.. will keep that in mind. I could probably raise the needle up one more or go one size up on the main. I'll do some more test runs when the temperature cools down a bit. Was almost 100 yesterday and dryer than a popcorn fart so I didn't take her up in the woods. Going to start working on the rm soon. I got this fancy new rmz four stroke but, I like riding the old two strokes lol.

 

[Jason628]

Maybe the reason it is running so well is that I put echo powerblend gold in it?

 

[Bigmac]

Maybe the reason it is running so well is that I put echo powerblend gold in it?

If you leaned out the mix, oil wise that’s going to drastically affect the tune. Your affectively jetting it up. If you went from 32 to 1 to 50 to 1 it will fatten up the fuel tune but have less oil so it will seem to run somewhat cleaner

 

[Jason628]

If you leaned out the mix, oil wise that’s going to drastically affect the tune. Your affectively jetting it up. If you went from 32 to 1 to 50 to 1 it will fatten up the fuel tune but have less oil so it will seem to run somewhat cleaner

I mixed it at 40:1 with non E premium and gave it a little extra glug. It only had marks on the bottle for 50 and 40:1. I need to get another ratio rite as I have misplaced mine or my dad acquired it lol. Normally I run amsoil saber 40:1 in all my 2 stroke stuff. a gas station that I drive by started selling non ethanol premium so now I'm going to run it all the time in my bikes and saws.

 

[Jason628]

So... found two yz250's for $2750 I may go get. One is a 2000 and needs a top end and the other is a 2005 and has a fresh top end. Both bikes have titles. I offered up my 2015 rmz450 with cash on his end and he said he would think it over.

 

[Mastermind]

Bubba's KX250 is a little laggy when just easing around. Like when barely cracking the throttle. I can't tell if it's rich or lean. Thoughts?

 

[Bigmac]

Bubba's KX250 is a little laggy when just easing around. Like when barely cracking the throttle. I can't tell if it's rich or lean. Thoughts?

If it’s blurbly it’s rich if it feels like it’s hesitating with no funny feedback like There just isn’t any power, then it’s lean, Kind of like it’s a dead spot, it’s lean

You can try turning the air screw in a half turn and seeing what it does, if it’s really bad it might need a needle clip change

 

[Mastermind]

If it’s blurbly it’s rich if it feels like it’s hesitating with no funny feedback like There just isn’t any power, then it’s lean, Kind of like it’s a dead spot, it’s lean

You can try turning the air screw in a half turn and seeing what it does, if it’s really bad it might need a needle clip change

We did a clip change to fatten it up that helped. Might need to go further. Thank you. These bikes are foreign to me.

 

[Bigmac]

We did a clip change to fatten it up that helped. Might need to go further. Thank you. These bikes are foreign to me.

Is it in all of a sudden change? Or has it always been that way? How dose it start and idle?

 

[Mastermind]

Is it in all of a sudden change? Or has it always been that way? How dose it start and idle?

Was that way from the first time we ran it. Starts really well, and idles great.

 

[Bigmac]

Was that way from the first time we ran it. Starts really well, and idles great.

Ok good, just checking! Ya keep dropping the clip, Double check the air screw, should be around one and a half turns out

 

[Mastermind]

Ok good, just checking! Ya keep dropping the clip, Double check the air screw, should be around one and a half turns out

Will do. It's got a hundred hours or so on it now. Bubba loves the damn thing.

 

[Bigmac]

Will do. It's got a hundred hours or so on it now. Bubba loves the damn thing.

That’s awesome, never hurts to check the cylinder base nuts and reed cage bolts just in case.

 

[Mastermind]

That’s awesome, never hurts to check the cylinder base nuts and reed cage bolts just in case.

We'll give it a once over when we move that clip.

 

[KcChiefs2019]

Man this thread took me back way back. 1978 or 79 Yz 125 with a copper ring head gasket. The Mono shock days. 1992 Cr250 felt like a pillow compared to tht.