NU50 First Start with Kit

Well, I finally put the bike together and did the first start. I bought this bike in barely running condition, so it was pretty cool to see it up and running. I tuned the carb and is starts very easy and idles nicely. It has great power now and quick throttle response.

The bike specs are:

1982 Honda NU50 Urban Express

DR70CC Kit

Weak-Ends Intake

PHBG 21mm Race Carb

Weak-Ends Exhaust

I few problems I noticed are:

1) an air leak, which I initially thought was the exhaust, but now think it is the gasket between the cylinder and the head. The exhaust is very tight and feel air coming between the head. I reused the stock metal gasket. I would to like to put a gasket similar to the cardboard one from the block to cylinder. I'm guessing the head might be a little warped and need to be milled or a thicker gasket installed. Anyone know where can I get a new gasket?

2) The throttle cable is now too short and since I deleted the oil pump, it has an extra cable which is not used anymore. The weak-ends intake stretches the carb a few inches out. I had the line hooked up to the bike, but whenever I tuned all the way to the left, the throttle would go fully open. Where is the best place to get a single throttle cable the right length?

3) I took it for a ride and it has some awesome low end power now up to about 20 mph. I wasn't nailing it (still on break in), but couldn't get any more speed. It was like it scooted to 20 mph then hit a wall. I haven't changed the belt (Ax31), clutch, or the variator weights yet. I'm guessing the problem is with either of those. The belt looked fine upon inspection, but I haven't looked at the weights yet. Any ideas?

I can't wait to drive this thing when it is all working properly, but it needs some further tweaking. I don't know what people were thinking when they say the weak-ends exhaust is quiet. It's about twice as loud as the stock exhaust on throttle. I still think the power is going to be worth it! I am so used to driving a stock NU50 and getting honked at and driven off the road constantly. Now it should be a little easier! Thanks for any help.

Re: NU50 First Start with Kit

It is possible that the CDI is is restricted

Re: NU50 First Start with Kit

It feels like I need more gears. I have to check vin number again and see if it is the Iowa model. There was no decals on the bike so I just assumes it wasn't. These were the only models with a restricted cdi, right? If it is, think this will work: http://www.ebay.com/itm/RACING-CDI-BOX-HONDA-HOBBIT-CAMINO-NC50-NU50-EXPRESS-PA50II-MOPED-/300704973185?hash=item460369c181&item=300704973185&pt=Motorcycles_Parts_Accessories&vxp=mtr

Re: NU50 First Start with Kit

I checked the vin and it is not the Iowa model, so the CDI shouldn't be the issue. My guess is the weights or the belt holding me back now.

Re: NU50 First Start with Kit

Downhill Harvey (OFMC) /

AX31? Yes you need a new belt. Stock or BX31.

Re: NU50 First Start with Kit

@Harv not quibbling here just to do it here- but I'm going like 55mph with an AX31. This fine fellow needs to spend some more time working out his throttle cable issues, I think.

Re: NU50 First Start with Kit

I ordered a new cable online with a 90 degree bend at the end and a longer length. Once I dig further into the case I should have a clearer idea what the problem is. I also want to mill the head and solve the air leak. I will post updates. The problem is finding the time to work on it.

Re: NU50 First Start with Kit

I heard the ax31 is a stock equivalent.

Re: NU50 First Start with Kit

Downhill Harvey (OFMC) /

@huckersteve,

D'oh, I was guessing. I know the AX-40 sucks on a Hobbit, so I just thought it would suck on an Urban too.

Re: NU50 First Start with Kit

OK I am having trouble getting 55mph right now actually. The bike is realistically delivering 45 right now (iPhone app numbers) but at TIMES has gone faster. I think it's a matter of being carried along in a pack, not sure. That and again, belt choice. Either way, your bike is improving now but you should be getting into the 40's with your setup properly tuned in, I think.

Re: NU50 First Start with Kit

Big Favor: Do you have any pics of the starter asembly??? I can't get this damn thing figured out.

Re: NU50 First Start with Kit

Gruff "(OFMC)" - /

By gruffie at 2012-07-26

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