Soft seize again?!?!?

Just when I think I have it all figured out, I have a soft seize. This would be the third one with my 65cc metrakit. The first 2 weren't bad, just a tiny smear on the piston. This one wouldn't start up again for 5 minutes, and when I did finally get it going it made a terrible ringing, scraping noise. I had a 2 mile ride home, and I am pretty sure the thing is messed up. I am headed out now to tear it down and inspect the damage.

So my question...can you not run a metrkit at WOT for long periods of time?

I am pretty sure I am jetted right - 80 jet in a 15mm bing with 15mm intake. I have checked 37,982 times for an air leak and never found one. Please tell me what is wrong, so that if it isn't dead, I can avoid killing it in the future!

Re: Soft seize again?!?!?

I would think a higher jet would be needed

Re: Soft seize again?!?!?

What did your plug chops look like?

Re: Soft seize again?!?!?

i run an 86 jet in mine. Thats a little rich but better safe than sorry I say. If I had to guess I'd say the perfect jet would be an 84.

Re: Soft seize again?!?!?

I have the same set up with boss pipe jetted at 82. I need to check the plug again but it still seemed rich at 84 when we rode last night. I couldn't WOT with out it 4 stroking high rpms. Needle setting is at the second most rich and everything seems to be kicking ass right now. I'd say try an 82-84 for sure. I'm also running Motul 800 at 32:1.

Re: Soft seize again?!?!?

here is my piston, i need new rings for sure... can i run this piston, or do I need a new piston too? more good news, my 15mm bing has a stripped screw where it clamps on the intake. It was loose, air from there maybe? anyway, I can't get my 15mm back on there, so I am running the 12mm and the stock engine for now...30mph here I come :(

1214939819_pi9se.jpg

Re: Soft seize again?!?!?

I've run on worse with my polini. lube it up and smooth it out with scotchbrite. Piston and cyl. Worked for me and I was able to put another 700 miles on my kit before a circle clip popped out and tore it to all hell. That sucked.

Re: Soft seize again?!?!?

is it case matched? I'm starting to learn this is crucial for best performance and life of your kit. my buddy rocks a 12 bing all day long with metra 65. he goes a nice 40 and climbs hills at about 30. once you're reassembled spray carb cleaner all over when idling, make sure there is no airleak. check your intake, sometimes they warp a bit and you have to sand them down. good luck!!

Re: Soft seize again?!?!?

hmm, something isn't right.

I blast my Metra at WOT for many miles at a time without issue. SHA 16.16 with 68 jet.

How do the plug chops look? Also, check your mixture. It's usually the obvious little things thay you overlook.

Re: Soft seize again?!?!?

Did you check for casting flash when you got the kit? If you did, did you correct the casting errors, or chamfer the port edges?

Re: Soft seize again?!?!?

Woah, that piston fried. It looks like it was too lean. The rings are no good. Check out the cylinder for scratches above the ports. No good if you do. The piston shows extreme heat and bad ring blow by. This set up will never go fast with that kind of blow by.

Re: Soft seize again?!?!?

What's casting flash?

Re: Soft seize again?!?!?

I ordered a new piston from treats. I chamfered the ports when I first got it. I don't know what casting flash is either. It is not case matched. The plug chops looked good, but I guess that was wrong. I am running motul 800 at about 40:1. I think I'll do 32:1 from now on and go with an 84 jet.

There are no scratches in the cylinder. A little smearing which I cleaned up with some steel wool. The cylinder atually looks really good I think. Here are some pics of it.

1215000685_cylinder_003.jpg

Re: Soft seize again?!?!?

another pic

1215000721_cylinder_006.jpg

Re: Soft seize again?!?!?

The oil was probably it, I won't even run spensive Yamalube that thin. Upjet a 'lil.

Re: Soft seize again?!?!?

You are on the right track. Good luck for the next build.

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