Noob Needs some Advice

[Slogger]

Hi guys. I have some noob questions so I came here since there are so many experienced members that hang out. Bike is a wally world Onyx, the engine is from DAX, a 50cc Gen 4, it says. The carb says "NTTC" and it's throat is actually about 13mm (the actual port, down in the flange.) It has the black air filter with 4 or 5 small inlets.

1) I have a 29", 48 spoke rear wheel. I know the standard sprockets are for 36 spoke rims, so there will be trouble mounting this thing. Is it possible to go with 6 bolts, 2 on each back plate some way or other?
Also, I notice some installs have the dished sprocket facing out, some in.
A video I watched said to face the sprocket to maximize chain clearance from the tire, is this right?

2) The Dax 49cc Gen 4 engine came without any oversize mounting parts. I am filling a cart at SBP and already put in the right front mount, but what about the rear? My bike has a 1 1/4" seat post, will it work with the basic clip and hardware in the kit? I didn't see any rear mount parts available at SBP, so I figure it might work without any special parts.

3) This town is at 837 feet above sea level. I don't know what jet is in the carb, but any idea what the right main jet might be? Carb is an NTTC.

Any info would be greatly appreciated. I like to get things close to right in one try, with some info I figure I can spare the bike a lot of take it apart/put it together/ take it apart...

Here's what's in the cart (so far) over there at SBP- it's all subject to change at this point. This thing is running into money, but it should be a lot of fun when running. All the plugs are for tuning/experimenting.

1 x NGK B7HS Spark Plug
1 x Exhaust Gasket (keeping a spare)
1 x Engine Sound Dampeners (might work, who knows)
1 x Carburetor O-ring (carb didn't have any)
1 x Plug Wire - High Performance (speedo should work)
1 x NGK B5HS Spark Plug
1 x NGK B6HS Spark Plug
1 x Front Engine Mount - Large Universal (sized for engine boss/ frame tube size)
I'll be adding a V brake on the front wheel.
Thanks for checking the thread and especially for any info you can provide.
Slogger the N00B

 

[crassius]

o-ring on your list is usually only used with the CNS carb - I've never used one with the standard carbs

I would recommend a 36 spoke wheel for someone not well experienced with mounting the rag joint and getting it true, but a 48 can be best done by loosening a few spokes and putting a slight bend in them to clear the bolts, then truing up the wheel when you tighten them around the bolts.

good luck

 

[Slogger]

Thanks Crassius. That's pretty much what I expected. If I have trouble getting the wheel trued up I know a guy I can take it to. I like the smooth rolling 29s.
The O rings are only a couple dollars and if I have an intake leak I'lll have something to try before going to the glue.

 

[Slogger]

I dropped the big one and ordered a manic adapter for the sprocket.
One way to fix these pesky problems is to stand back and throw credit cards at them.

 

[Slogger]

I have a package of leftover fiberglass muffler packing material from my motorcycling daze.
If I extend the intake manifold a few inches with tubing, and pull the guts out of the muffler, removing a baffle or two and adding a little glass pack to soften the tone, I may be able to get enough low end grunt to pull the new 40 tooth sprocket that comes with the kit.
At least that is the current thinking. I ordered a couple jets, a .66 and a .72 to give me a little flexibility there.
If the rear motor mount works out, I'll be in business.

 

[crassius]

depending on your weight, that 40 may work OK - I build them with 44s since the hills are steep here & customers are often north of 220lbs, but I can run a 41 with no problems for my bikes

 

[maniac57]

Be careful not to crush the frame tubing with your mounts. The aluminum frame on the Onex won't last unless you use a sleeve to spread the loads from a u-bolt style mount.
I used a chunk of pipe cut in half and welded to the mount. Make SURE it's ROCK SOLID and will not move when you yank on the head.
You will also have a hard time securing a chain tensioner properly, so try to install your kit without using one if possible. Crassius already covered the rag joint.
Keep a very colse eye on the rear hub as they are weak and will self-destruct very quickly if out of adjustment. Be religious about greasing and maintenance!
You will also need new handlebars as the Onex bars are 1" and none of the kit controls will fit.
Any regular 7/8 bar bolts right on the stock gooseneck.

 

[maniac57]

This guy makes some sweet mounts PERFECT for the Onex frames.
http://www.bikebobber.com/home.html

 

[Slogger]

depending on your weight, that 40 may work OK - I build them with 44s since the hills are steep here & customers are often north of 220lbs, but I can run a 41 with no problems for my bikes

I built one for my boss at work, it had a 40 (I think) with 26" rims and pulled me around fine. I think with the 29s I'll have to do some pedaling to get her moving, but then it should be ok. I like the relaxed, slower RPM at slower speeds, too.

 

[Slogger]

Be careful not to crush the frame tubing with your mounts. The aluminum frame on the Onex won't last unless you use a sleeve to spread the loads from a u-bolt style mount.
I used a chunk of pipe cut in half and welded to the mount. Make SURE it's ROCK SOLID and will not move when you yank on the head.
You will also have a hard time securing a chain tensioner properly, so try to install your kit without using one if possible. Crassius already covered the rag joint.
Keep a very colse eye on the rear hub as they are weak and will self-destruct very quickly if out of adjustment. Be religious about greasing and maintenance!
You will also need new handlebars as the Onex bars are 1" and none of the kit controls will fit.
Any regular 7/8 bar bolts right on the stock gooseneck.

Sounds like solid advice, thank you!
I deliberately went for a lower output engine, to avoid stress on the aluminum and less vibration overall. the kit's rear engine mount is just a strip of cheap sheet metal, I don't even know if it will fit a 1 1/4" seat post yet. The new engine looks so tiny.. Hard to believe it could run thousands of miles without a meltdown. I know some break-in tricks, gleaned from flying big R/C planes to help it smooth out quickly and jetting carbs is my specialty, at least on m/c engines. It's too bad the little carbs don't have a hose barb at the float bowl drain, then you could set up the float height without any guesswork.
I'm onto the onyx's cheap hubs, I had to reset the combs before I rode it, they were too tight. I will pack it with High temp grease I used on the motorcycles.
It's the good stuff, whatever it is.

I'm a slow rider, I just want to use it to purr around and enjoy the sunshine. I got all my 'need for speed' out a long time ago.
If the frame does crack my buddy is the best man on a tig you ever saw.
He likes to show off and does a great job on everything I bring him.

I will try to spread the load at the mounts, but the front is already ordered from SBP. I have a bar that is real comfortable, black and 7/8".
I'll be taking my time building, and I don't have much time to spend on it so it may be a few weeks before I get to fire it up.
That manic hub driver deal will save a lot of cursing and swearing, but it wasn't cheap. Oh well, it's only federal reserve notes.

Buy silver, it's stupid cheap fellows.

 

[Slogger]

This guy makes some sweet mounts PERFECT for the Onex frames.
http://www.bikebobber.com/home.html

His rear mount will be here in a few days. Thanks a million, that saved me a lot of searching, Maniac-
This place is great!

 

[Slogger]

I used the ratio/speed calculator program to get the figures for this gearing.
The 29" wheels give it some long legs. The slower RPM will be nice, but I doubt we'll be doing any hill climbing at the Widowmaker.
Here's what I found:
29" Wheel, 40 Tooth rear sprocket
Drive ratio = 16.4 / 1
1500 = 7.9 mph
2000 = 10.5
2500 = 13.2
3000 = 15.8
3500 = 18.4 ahhh, the sweet spot
4000 = 21.0
4500 = 23.7
5000 = 26.3
5500 = 28.9
6000 = 31.6
6500 = 34.2
7000 = 36.8 These are just for a reference, I don't think the 50 will crank this high hauling my 250 pounds on it's poor little back.

 

[maniac57]

Once it's broken in it should pull 6.5-7k fairly easily.
The 49cc's seem to run out a bit better than the 66cc's do so there ends up being very little difference.
Especially with a tuned pipe I see no problems pulling 7k.
But I would not make a habit of trying for max rpms until three or four tanks....

 

[Slogger]

That's what Duane the builder told me, too. The 66s had more grunt but topped out about the same.
That would be wild if the thing would hit 35. I'm beginning to prefer the 40 tooth, I've always gotten ticked if an engine was too busy at cruise.
As far as max RPM, it will have to be done at some point to seat the rings, but then I'll be slowing back down. I'm just going to bicycle it around. Putter down the street so quiet nobody even looks up. Ahhh, Sweeeet.

 

[a.graham52]

iv got a 66 on my genisis twenty-nine (mtb verson) from walmart. iv delt with the rear hub, make sure your axle is strait, mine was bent from the store. i find that my bike will do 26-28 farily well and enjoyable with stock gearing. runs the best there too IMO. i dont what yorus has for brakes but i know my rear pads were junk. very soft and way out of adjustment from the store as well.

today i was delt broken rear wheel spokes too. so somethign else to consider.

 

[Slogger]

A.G.- Mine needed the bearings loosened up, but after adjustment they're very free and smooth. The runout is tolerable, I don't think the axle is bent.
The coaster brake is progressive and controllable, but you have to stand on it to stop from any speed higher than a dog trot. I have a front brake, cable and lever due in next week.
I bought it to pedal and the engine idea came to me later.
If I was buying one for motorizing I would have gone to a free-wheeling 26". I liked the lines of the frame, liked the death-dealing fenders, and it's big enough to keep me from looking too big for it. It was bought to ride by pedal power, which it handles pretty well. Very easy to pedal.
As a motorbike it will only be used at most a couple hours a month, so my wheels might hold up for a while. When they begin to fail, I'll deal with them. If money were no object I'd get a drum brake front and a freewheeling hub for the rear. Maybe next year..

 

[a.graham52]

yeah just wanted to let you know. a bent axle wont make the wheel wobble, it will just put too much pressure on one side of the cups and less on the other. wont notice it until you wear them. mine were loosening up every 2-3 days (30-70 miles).

 

[Slogger]

Oh- 30 to 70 miles every 3 days. I haven't even put 10 miles on my bike yet, so that must be why I haven't had that trouble. That's a lot of motor-bike riding. I just fool around with my bike, not planning to do high mileage on it.
I wonder how many guys commute daily with their bikes. That might be an interesting thread.

 

[a.graham52]

Yeah. Iv got two choices on how to get to work. One way is 10 miles (20 miles round trip), the other is 6 miles (12 miles round trip). So depending on how I feel, the miles really add up fast!

 

[Slogger]

That's hardcore.