Metrakit 65cc with a 15mm bing and intake. I am running a 90 jet with no air leaks anywhere. I a msure the jet is rich, it 4 strokes at WOT, and runs pretty well 1/4 to 3/4. I have soft seized twice, no major damage to the cylinder or the piston, but why does this keep happening? Neither time was at WOT, and both times were at like 3/4 and only 2 - 3 miles into the ride.
Why do I keep soft seizing?
Re: Why do I keep soft seizing?
dude you should be in the high 70's maybe 80's. Please tune that shit you are destroying your kit
Re: Why do I keep soft seizing?
also you sure you are siezing, you could just be flooding the motor
Re: Why do I keep soft seizing?
because you masturbate?
Re: Why do I keep soft seizing?
cause bing carbs are shit and you should put a dellorto on it and go way faster and not seize.
Re: Why do I keep soft seizing?
Yes, I am soft seizing. Is my jet really way too high? I was running an 80 - 82 in the stock 50cc with the same setup. My chops look nice and light brown. I have looked at the carb, intake, head and exhaust for air leaks, and there are none. What else could I check with the jetting? Could my timing be too advanced? It worked fine with the stock, so I didn't mess wit hit when I put the kit on. Would that cause overheating? I am using a 50cc high compression head and getting like 180 -190 compression with my tester.
Yes Bing carbs are shit, but I have every jet possible for it and don't want to start over with the Dellorto. I just dumped a ton of money into fixing and the kit and don't want to drop another $100 for a new carb when the 15mm bing should work.
A metrakit should run all day without soft seizing right? Please, what else could I be missing? I really want this thing to rock. There must be something wrong since with 16 x 45 gearing I can't break 40 mph.
Re: Why do I keep soft seizing?
How is fuel metered at 3/4 throttle on a bing - can you change the needle position? The answer seems obvious- if you can't adjust 3/4 throttle fuel mixture - get a better carb.
Re: Why do I keep soft seizing?
with the needle. I dropped it to richen the mix, and the thing 4 stroked all the way, so I put it back on the 2nd notch down
Re: Why do I keep soft seizing?
you are over compressed. Should be around 155 160.
Your carb is too small. And bings are garbage.
16x45 is high reving gearing and wont likely break 45 mph.
What pipe are you using.
Re: Why do I keep soft seizing?
Proma GP pipe. Over compressed? Will taht lead to soft seize? I can put the regular head back on, that got me 135- 140 compression. Maybe I'll try the head gasket and the high comp head. The carb is too small? really? Can anyone give me a success story of the 15mm bing on a 65cc metra? Dammit, I'll just buy a dellorto then. 19mm phbg seems to be the one I hear thrown around. What jets will I need, and where do I get an intake from?
Re: Why do I keep soft seizing?
ive come to the conclusion that your carb is probably too small.
because this is what happened to me on my gila. i only have a 19mm phbg.
Re: Why do I keep soft seizing?
high compresion leads to over heating leads to detonation and siezure salad
get 21 delorto for best results.
Re: Why do I keep soft seizing?
Mike has a blowed up piston to prove he knows what he's talking about. High compression makes more heat.
Re: Why do I keep soft seizing?
So drop the compression = no more soft seize? We'll give it a shot, then if it still acts weird, I'll go with the bigger carb. Thanks everyone!
Re: Why do I keep soft seizing?
Quote: Mike has a blowed up piston to prove he knows what he’s talking about.
This statement is a contradiction. He has a blown up piston so he knows what he's doing/saying doesn't make a lick of sense. I'm not saying his statement was wrong. But this one sure is.
Re: Why do I keep soft seizing?
You're wrong. You're so obviously wrong I don't even have to explain. Actually it kind of bothers me that I even had to tell you you're wrong.
Re: Why do I keep soft seizing?
Yes. Mike is right. Higher compression will cause higher cylinder temperatures. Higher cylinder temperatures will cause overheating and pre-detonation. This will result in you seizing your motor, esp if your plug looks like tannish (meaning you are running on the lean-side). 180PSI = 12.2:1 compression. 190PSI = 13:1 compression. I would stick to 10-11:1 compression. You are running too much compression. Stick the stock head back on and you should be running better. Hope this helps
Re: Why do I keep soft seizing?
"Why kit a bike if you can't tune it?" should be the better question.
Re: Why do I keep soft seizing?
well, I am new to the tuning thing, any help with exactly what to tune would be appreciated.
Re: Why do I keep soft seizing?
I learn from my mistakes. Is what I would say.
This piston is the result of timing too far advanced. Similar results could be expected from too high compression.
Re: Why do I keep soft seizing?
Oh shit Rafter, maybe that's why the Cobra isn't running right.....the compression on it is high as fuck. I'll make more base gaskets.....
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