New F80 motor is running rough

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MitchP

New Member
Oct 6, 2012
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Santa Rosa, CA
I bought an F80 from dax. I've got an NGK 7 plug and an RT carb. The fuel I'm using is 91 octane, 20:1. At low speeds the ride seems choppy. At first I had a .65 jet in there and swapped for a .7 and that made it a little better, but the bike has a lot of vibration and it's choppy at low speeds. I also noticed that every component attached to the motor seems to heat up, which I did not notice on my last kit.
 

biknut

Well-Known Member
Sep 28, 2010
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If it has a NT carb, put the needle clip in the second slot from the top.

A B7 is kind of cool. Try a B6HS, and BP6HS. Gap to 0.025"
 

MitchP

New Member
Oct 6, 2012
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Santa Rosa, CA
Ok. I've a got a 6 laying around and I've been setting them to .035/1000". So I'll add the 6 and shorten the gap. It's been in the 70-80F temp range lately.
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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Give it a few miles to smooth out. All of my recent builds have been tighter than usual. I think(hope) the quality is trending upwards. Tuning is better left until a couple hundred miles when things settle in. The heat issues can also be caused by a tight, fresh engine.
Once it has a few miles it will smooth out quite a bit. Mine usually take three or four tanks minimum to fully break in.
 

MitchP

New Member
Oct 6, 2012
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Santa Rosa, CA
Yeah I just don't remember the first being as choppy. I tried the Ngk 6 and the 7 set to .030 and the 7 was the winner. Would you guys recommend buying 87 octane? I think it could be 4 stroking a little.
 

MitchP

New Member
Oct 6, 2012
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Santa Rosa, CA
It's smoothed out actually. I forget that my first build was a complete P.I.T.A.
To do list: buy 87 octane, mix it. Get a torque wrench, set heads to 12 (ft pounds?).
 

biknut

Well-Known Member
Sep 28, 2010
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It's smoothed out actually. I forget that my first build was a complete P.I.T.A.
To do list: buy 87 octane, mix it. Get a torque wrench, set heads to 12 (ft pounds?).
That's the wrong torque wrench. Get a torque wrench that reads in inch pounds. I torque my M8 head bolts to 125 in lb.
 

MitchP

New Member
Oct 6, 2012
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Santa Rosa, CA
I packed red grease into the clutch actuator and between the bucking bar and bearing. It's a lot quieter now that it;s got some miles on it too. Should I pack grease into the clutch too? Like unscrew that bolt and pack it in?

 

crassius

Well-Known Member
Sep 30, 2012
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it's sealed at both ends, so shouldn't need it - I doubt it would hurt anything tho
 

fatdaddy

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May 4, 2011
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San Jose, Ca.
Yeah, A little grease on the big clutch gear and the small bevel gear. Just a few dabs, It will spread itself around. And don't get any on the pads for obvious reasons. It's a metal to metal gear, OF COURSE it needs a little grease. And I always pull out the bucking bar, shove grease in the hole and push the bar back in. Then I pull out the clutch lever and grease it up too. Anything thats metal to metal needs grease.
fatdaddy.
And OH YEAH, If ya get ambitious, pull the clutch plate and you'll see the tiny bearings in the clutch itself. TRY to get a little grease in there too. Sometimes I just drop a little heavy oil,(50-60wt.) into it. Again, it's metal to metal, Needs lube. Just a drop or three, too much will spin it back on the pads. oil+pads=BAD.
 
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maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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memphis Tn
I packed red grease into the clutch actuator and between the bucking bar and bearing. It's a lot quieter now that it;s got some miles on it too. Should I pack grease into the clutch too? Like unscrew that bolt and pack it in?

If you pack this area, grease can work it's way past the bearings enough to contaminate the clutch pads. I saw this problem here in a clutch thread somewhere...
 

biknut

Well-Known Member
Sep 28, 2010
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I always fill the transmission shaft area with grease. Even if it does get past the bearing it won't get on the clutch pads.
 

MitchP

New Member
Oct 6, 2012
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Santa Rosa, CA
Yeah I'm pretty sure the noise is coming from the "transmission" shaft. I meant to get a big plastic syringe and pump it in but I figured I'd ask first. It's really thick so I don't think it would become runny. Also I cracked my head in half today (the motor's, not my own) so I put on the old one and it runs the the same.
 

biknut

Well-Known Member
Sep 28, 2010
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Dallas
You don't really need to pump 14 gallons of grease into the hole. 13 gallons is plenty, or just do like I do, and stop when you get up to your arm pits.
 

crassius

Well-Known Member
Sep 30, 2012
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Ok. I could SWEAR I saw a pic in a tear-down thread where whoever was pumping red grease into that spot. But yeah she runs.
what you probably saw was a reinstall of one that had been out - these usually don't need grease unless you take them out, then put them back in
 

Huffydavidson

STREETRACER/MANUFACTURER
Jan 29, 2012
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st.louis,mo.
It was next to the blinker fluid .how the **** do you crack a head in half ?????? terminology it is a clutch shaft not a transmission shaft . it only requires a little bit of Greece just to keep it wet .it doesn't need to swim in the ocean just because you live next to it !!!!!
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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memphis Tn
Granted, the post mentioned he had been filling it for a long time before it got messy.
I think a little would be good but don't fill it full.
 

MitchP

New Member
Oct 6, 2012
276
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Santa Rosa, CA
Maniac57,

correct me if I am wrong, "If more is better, then too much is just enough." Obviously I need to buy the Costco size red grease.

Huffydavidson,

I actually bought a torque wrench and set it to 12ft pounds and tightened the bolts in an X pattern. Then while I was riding I just heard 'snap' and then my bike started sounding like a compressed-air tool.