How many Pistons do I have to ruin

[sledcrazyinCT]

Here is a chart that explains the ranges to help you finetune


Didn't see you mention installing new crank seals. There is a reason people keep bringing those up. Did you replace them when you did the top end work the first time? If not it is something you should really change out.

[loganm]

Yes, I did replace the crank seals. I had to remove them again when I replaced mains again while waiting for the second piston. When I sent the crank to CT racing I did not mention checking the sealing surfaces for grooves, they are grooved a little bit, but not to the point where it's consuming or leaking large amounts of oil.

First time I built the motor the ignition side seal was about flush with the case, when I was replacing mains, I managed to install the seal a little deeper. I'm not sure how deep it should be installed , I don't think I got it to the point it blocked the hole that oils the outside of the bearing.

The needle I pulled out of the carb says 35F on it, looking at needles for PE carbs that doesn't seem right at all, is it possible someone threw in a needle from a different carb at some point? It's a genuine Keihin carb, pretty sure it's the original, says PE on the side.

[Maico]

What year make and model are you dealing with?

[JesseA420]

Yes, I did replace the crank seals. they are grooved a little bit, but not to the point where it's consuming or leaking large amounts of oil.

you seem confused. there is no "case oil" going to leak out of your crank seals. the bottom of your crankcase is part of your intake tract. if you have any amount of seepage of 2 stroke oil coming from your crank seals, u clearly have a air leak there.
like i said before. pressurize like u did previously, and spray all mating surfaces including crank seals and case half mating surfaces with soapy water solution to check for bubbles.

then put a silencer on it and get it bored and honed by a reputable experienced company that specializes in 2 stroke service, or service of your model specifically. not your local hole in the wall machine shop.

we are not saying your jetting is not wrong, because chances are it probably is, but you need to cover your bases and get everything else up to par first, or you will never have a chance. re read all the comments in this thread, it is all good advice. do those things. after that you can start to try and tune it.
good luck.

[loganm]

If the drive side crank seal is leaking, it can consume transmission oil. You keep saying to take it to a reputable shop, but I guarantee if I take it back to JSR and call them out on their work I will get quite a lesson in engine building. It's not a "hole in the wall" type shop, these guys know their stuff.

Hell, I guarantee you, I can take it to whatever shop you recommend, bore it to the next size piston, new piston, fix the air leaks, put it back together with no carb changes, it'll do the same damn thing. It's rich AF at WOT, 1/3 throttle opening is lean, lean enough to overheat and sieze the top end.

[oldskool83]

I always take the cylinders to napa...they tell me what size I need and what overbore size is needed...then you pay then $50 to bore it correctly and your top end is done. Its that simple for top ends. Bottom ends you may want to redo...it's prob stock yet and well over do.

[yaegerb]

If the drive side crank seal is leaking, it can consume transmission oil. You keep saying to take it to a reputable shop, but I guarantee if I take it back to JSR and call them out on their work I will get quite a lesson in engine building. It's not a "hole in the wall" type shop, these guys know their stuff.

Hell, I guarantee you, I can take it to whatever shop you recommend, bore it to the next size piston, new piston, fix the air leaks, put it back together with no carb changes, it'll do the same damn thing. It's rich AF at WOT, 1/3 throttle opening is lean, lean enough to overheat and sieze the top end.

Seriously, can you "guarantee" us?

This thread, like most started by you, is all over the place. You NEED to start concentrating on ONE thing at a time. I still haven't seen if you have figured out where the air leak is coming from.

I could care less if your carb is tuned right now or not. Have you passed a thorough crank case pressure test yet?

[loganm]

I always take the cylinders to napa...they tell me what size I need and what overbore size is needed...then you pay then $50 to bore it correctly and your top end is done. Its that simple for top ends. Bottom ends you may want to redo...it's prob stock yet and well over do.

NAPA? That's got to be a local thing dude, I would get some weird looks if I brought it into NAPA and asked them to bore it. What do you suggest I do on the bottom end that isn't stock? Have a machin shop bore the cases for larger bearings? I replaced the main bearings and every seal.

I ordered 3 different needles ranging from rich to lean. I'm not just gonna throw them in and expect it to work. But the needle I have is not a keihin needle, I need to do some comparison between them. I'm guessing smaller diameter needle is richer, correct? I will get to working on finding the air leak this weekend.

[oldskool83]

WTF would you bore cases larger for larger bearings? You do realize most cycle shops and auto shops outsource engine boring to NAPA...You are understating nothing and I can tell. Walk to their machine shop and get schooled kid...... All bottom ends are gonna be stock but your OEM gaskets and seals are prob needing changed. You have an air leak and until you freaking address it and address a correctly bored top end your gonna just throw more hard earned money away. This is why I said take it to someone who can do it correct the 1st time.

Someone local go learn this kid.........Local thing...man your dumb.

[loganm]

WTF would you bore cases larger for larger bearings? You do realize most cycle shops and auto shops outsource engine boring to NAPA...You are understating nothing and I can tell. Walk to their machine shop and get schooled kid...... All bottom ends are gonna be stock but your OEM gaskets and seals are prob needing changed. You have an air leak and until you freaking address it and address a correctly bored top end your gonna just throw more hard earned money away. This is why I said take it to someone who can do it correct the 1st time.

Someone local go learn this kid.........Local thing...man your dumb.

I've been in the back room at NAPA. They have equipment to turn rotors and make hydraulic lines, nothing else. I've stated multiple times, they are not OEM gaskets and seals. I've inspected and replaced everything that needs it. Here's the website for JSR if you still don't believe they're legit.

http://www.bigboremotors.com

Oh and the boring cases for larger bearings thing was a joke.

This air leak is not substantial enough to throw the jetting off to the point I'm seizing Pistons. So that leaves two possibilities, bad bore/hone job, or lean condition. I have faith in the work that was done, it's far more likely this unidentified needle is the culprit.

[oldskool83]

That's not a napa machine shop. some only can turn rotors...it pays to pick up a phone or try google. so rip you motor all apart and replace everything fresh...hell it don't cost much for gaskets and seals. I bet your intake tube is dry rotted letting air in also.

This is my last post in here so after this I could care less about your problem since your a know it all it seems.

[loganm]

Intake tube is old and hard but it's not leaking yet.

I just got off the phone with John at JSR. He said it's definitely a lean spot in the needle, and that a 1 psi/HR leak won't affect the motor. Sorry guys, but I'll take a professional engine builders advice over someone on the Internet.

He said to take acid to the cylinder walls to get the aluminum out, and to go over the piston lightly where it seized.

[yaegerb]

This air leak is not substantial enough to throw the jetting off to the point I'm seizing Pistons.

wrong, yes it can.

[loganm]

wrong, yes it can.

If you have doubts, come out to Milford in a month and ride with me. I'll even pay your gas, and bring another member on here along if he wants to come.

[yaegerb]

Milford Lake? OK, I will see if I can get BKM to come too.