New China girl carb problem..help!

[Dead66]

diameter matters, but also how long the passage is thru the solder and brass - both effect flow rate

Are you referring to the length of the jet itself, or the length of the tube between the jet and the carb where the needle sits?

How is this length adjusted?

 

[MotorBicycleRacing]

So you drilled a 63.5 jet
It is not possible to drill a 68 jet using stock drill bits.
#70 bit is stock jet size at 71.

Are you doing the plug chop with a new plug?

#72 0.025 0.635 63.5
#71 0.026 0.6604 66.04

#70 0.028 0.7112 71.12

Whoopsie I was wrong. I used a #72, sorry. It was dark and I could not see the markings so I just counted the spaces, but I counted in the wrong direction. I went smaller than the #70 and used a #72.

I only drove for 10 minutes. Once she warmed up there was no 4 cycling at top end. But it took 5 minutes for that to happen. At the end of ride I cut motor off at full throttle and pulled the plug. It was brown. Not wet. Not white. Really looked no different than before. I am now wondering if I should give it another try with a # 74?

Once she warmed up she was zinging pretty good. I don't want to run her too hot. But I do wonder if she should not have been running better before 5 minutes of warm up riding to get rid of four stroking?

 

[crassius]

Are you referring to the length of the jet itself, or the length of the tube between the jet and the carb where the needle sits?

How is this length adjusted?

the length of the hole you drill - if you fill the dimple on the jet with solder, then drill that, you have both the length of the original passage plus the length of the hole in the solder - worst case, you also have solder inside the body of the jet making it longer on that side too

in some cases, if you drill exactly the size it originally was, just the extra length leans it out a bit

 

[Dead66]

So you drilled a 63.5 jet
It is not possible to drill a 68 jet using stock drill bits.
#70 bit is stock jet size at 71.

Are you doing the plug chop with a new plug?

#72 0.025 0.635 63.5
#71 0.026 0.6604 66.04

#70 0.028 0.7112 71.12

Yes, according to my drill bit set, the stock was a #70 = .028
I soldered and drilled to a #72 = .025

I did not put a new plug in to do the chop set. I can do that. Never thought that would make a difference.

What should I set the gap at?

 

[Dead66]

the length of the hole you drill - if you fill the dimple on the jet with solder, then drill that, you have both the length of the original passage plus the length of the hole in the solder - worst case, you also have solder inside the body of the jet making it longer on that side too

in some cases, if you drill exactly the size it originally was, just the extra length leans it out a bit

Ah!!! I see now

 

[Dead66]

This is off topic, I know. But I did a search for "hub" and found nothing. You fellas here seem to know what your doing so....

I rode my bike about an hour yesterday. Most of the time at half throttle. Got home and smelled something burning. Not bad, but I smelled it. It was coming from rear wheel hub. I stuck my fingers through the spokes and touched the hub. It was VERY hot.

Do I need to disassemble and pack the bearings? Do I need a new wheel?

This is on an Onyx 29ner from Wal-Mart. It has maybe 5 hours run time.... Maybe 10 hours

 

[crassius]

if that has coaster brakes, re-greasing is important, but the wheel will probably fail at some point anyway if you use those brakes

put some real brakes on it

 

[Dead66]

Thanks for the reply. It has coaster brakes. It also has caliper brakes on front. I use them together. Was going to put caliper brakes on bale but there was some reason that made it difficult and I nixed it. I can lol at that again.
So it's the brakes causing the heat?

 

[Dead66]

Let me rephrase that question. Is it the use of the breaks that causes the heat, or is it something about having coaster brakes on a wheel like this that produces heat even when the brakes are not in use?

 

[crassius]

on a coaster brake bike, there is only one gear which limits speed to 15mph or less

brakes and wheel bearings were only built for that speed - if brake is never used and bearings are well greased often (assuming one doesn't throw the bearing cap away when fitting sprocket) the wheel should last fairly well

even on geared bikes, things like freewheel pawls wear out rather quickly due to speeds in excess of designer's expectations

 

[Dead66]

Now I am learning given the bike have, would you suggest that I buy a new wheel? If so which one?

Or should is there something I can change on this hub to improve its longevity? Remove coaster brake?

Thanks again

 

[crassius]

my GF has a coaster brake bike, but it has the bearing cap installed and has two hand brakes also so the coaster never gets used