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Locked up cub motor. Don't know why.


J-Madd

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The other part of the equation way have to to with you gas cap. The stock caps and some of the cheaper aftermarket caps do not relieve the negative pressure fast enough and thus limit the vlow of gas out of the tank. :thumbsup:

 

Well I had a gutted out stock cap before I built this 4 mil, but now I have a billett aftermarket cap from modquad (which doesn't flow as much as the gutted stocker) but I can blow air through it easily, but the way this thing sucks gas, I could see that being the problem. I used almost a half a tank in 5 miles and most of that was going slow through trails, only a couple couple miles of wide open gravels.

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I would get some billet bowls and drill the vent line bigger on the gas cap. may not need the bowls but for 150.00 seems a whole lot cheaper than rebuilding the top end and or replacing a crank.

 

 

That's exactly what I'm going to do. Anyone know the quickest place to get new nikasil on these cylinders, assuming they're scarred beyond honing (I'll know tonight; too disgusted yesterday to work on it.)

 

How many people have ran these things out of gas? I read a thread last week where a guy ran his brand new

Cub out of gas also, but he just lost compression. I guess it's easy to underestimate how fast these monsters pull gas out of the carbs, versus how fast gravity can feed it in.

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That's exactly what I'm going to do. Anyone know the quickest place to get new nikasil on these cylinders, assuming they're scarred beyond honing (I'll know tonight; too disgusted yesterday to work on it.)

 

How many people have ran these things out of gas? I read a thread last week where a guy ran his brand new

Cub out of gas also, but he just lost compression. I guess it's easy to underestimate how fast these monsters pull gas out of the carbs, versus how fast gravity can feed it in.

 

If you need to get the cylinders re nik'd, your challenge is going to be how fast you can get them done. Your best bet is to send them to where you bought them from or to a big name engine builder. Sometimes local cycle shops can get it done as well, but in all cases, they are sending out to a thrid party. If you were in WA or CA, I could probably hook you up with a place to get it done.

 

As for the billet bowls, since you're on gas, you may not need them. Making sure your tank vent and fuel lines are properly sized may be enough. If you were on alcohol then the bowls are a must in addition to possibly needing a fuel pump. It's a fairly common occurence to have a fuel supply problem like this in a heavily modified atv or motorcycle. :thumbsup:

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Might want to check out your water pump impellar. Next time your bike is running, make sure that water is circulating while it's running.

 

Did it run smooth in 6th, able to rev out?

 

How much ignition timing are you running?

 

I was running +5 degrees timing advance, and it ran very smooth in 6th gear, revved out well with heavy red label wheels and 22'' realtors. I installed a new billet impeller when I built this motor. I opened the radiator to see if it was circulating, but I couldn't tell because of the motor vibrating the water. I rode a good while before this happened, and it never seemed to overheat. No puking of anti-freeze or noise when I shut it off.

 

As far as the cylinders, I guess I'll send them back to Jeff, then he can forward them to whomever. I was just hoping I could send them straight to the 3rd party myself to cut back on turn around time.

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As far as the cylinders, I guess I'll send them back to Jeff, then he can forward them to whomever. I was just hoping I could send them straight to the 3rd party myself to cut back on turn around time.

 

The turn around time is the trick with nickasil. Most of the coating and plating houses out there operate with a pretty large bag log of work. If you can't get anyone to do better than a month for you on lead time, give me a shout. I might be able to work something out to help ya. :thumbsup:

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The turn around time is the trick with nickasil. Most of the coating and plating houses out there operate with a pretty large bag log of work. If you can't get anyone to do better than a month for you on lead time, give me a shout. I might be able to work something out to help ya. :thumbsup:

 

 

Thanks, I'll let you know.

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I called the platers that jeff uses the other day and they said they have about a two week turn around time. Also if ya want to pay alittle extra you can get an express service where they bump ya up the list and get your stuff done faster. I have done this before in order it get my stuff back and running for a race.

 

just a heads up.

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PINGELS DONT FLOW THAT MUCH I RUN DUEL PEC IN MY TANK ON METH WITH NO PUMP STOCK BOWLS NO PROBLEM I WOULD THINK THAT YOUR OIL SEPARATED FOR YOUR GAS KLOTZS WILL DO THAT IN COLD WHEATHER AND YOU CAN TRY AND HONE THOSE CYLINDERS BUT IT NOT GOING TO PUT A DENT IN THE NIKASAL

 

I thought you were the one who had your stock bowls opened up by welding a secondary bowl or some kind on there. Or was that someone else I saw at walden?

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