nu50 bogging/gutless

Just got my nu50 running, its an 82. Cleaned tank, replaced all main fuel lines and filter, cleaned petcock and filter in that, and cleaned out the carb twice. Starts good now and idles well, will take throttle but has absolutely no power when I'm on it(I'm 115 lbs and it basically won't go). Also replaced the belt. After throttle the idle drops down to barely running, or dies completely. I haven't went through the auto choke yet, but I suspect that it may be stuck on. Anybody have any other ideas? I'm going to go through the auto choke tomorrow just to be sure its not that. My compression seems good(haven't tested yet, but don't have blowby) could low compression cause the complete lack of power? If so I'll get some rings and do those as well.

Re: nu50 bogging/gutless

sounds probably lean still. i mean always worth checking the usuals, timing and stuff, but sounds like you've probably got an airleak, possibly still clogged jet, maybe there was an oil injector thats now gone and leaving an air leak. you still got all the original filter and stuff?

Re: nu50 bogging/gutless

No, at the moment I just have some filter material ziptied on. And the oil inlet is plugged, I pulled the barb fitting out and threaded the hole and put a bolt in it. I'm premixing at 40:1. Lots of hokey stuff going on to be honest, I'm just trying to get it running ok then I'll go through the steps.

Re: nu50 bogging/gutless

Well, dug into the auto choke, the gasket is fubar. Going to make a new one. Also ordered a cone style air filter so that should help too. Pretty sure it was the air leak from the bad gasket. Be a few days before I can be sure unfortunately.

Re: nu50 bogging/gutless

Captain Janeway /

You mentioned plugging the oil inlet on carb, but what did you to to the pump? Pull it and put in a plug or what?

These bikes are prone to air leaks on the crank seals if you can't find one elsewhere.

Stock carb? They're a pain to get clean especially first time.

If you leave it on kickstand and turn throttle do you get that back wheel moving or does it not even move on kickstand? If it's not moving you might make sure you're throttle slide's moving right. Maybe it's stuck. Turn the bike off and just look into the carb outlet with the filter off. Do you see the slide moving up and down? OK, not that.

How's your exhaust look? if it's clogged and can't breathe it could be that as well.

Here's your new best friend:

NU50 manual

Re: nu50 bogging/gutless

Honestly I forgot all about the oil pump, its still there, with the hose wide open I'm sure. Throttle slide is moving good and the rear wheel is turning when it's up on the kickstand. Also exhaust is good, flowing plenty. Once I have the air filter I will deal with the oil pump as well. I may just wind up scrapping the stock carb and getting one of the revolution carbs. I replaced the gasket on the auto choke and the issue is no better. Also noticed last night that my needle is probably not sealing, had some gas coming out the back of the carb. Lots of stuff I'm dealing with, really just need to dig into it for a few hours and fix the obvious stuff so I can pinpoint the issue.

Re: nu50 bogging/gutless

Captain Janeway /

> Justin Orr Wrote:

> -------------------------------------------------------

> Honestly I forgot all about the oil pump, its still there, with the hose

> wide open I'm sure. Throttle slide is moving good and the rear wheel is

> turning when it's up on the kickstand. Also exhaust is good, flowing

> plenty. Once I have the air filter I will deal with the oil pump as

> well. I may just wind up scrapping the stock carb and getting one of the

> revolution carbs. I replaced the gasket on the auto choke and the issue

> is no better. Also noticed last night that my needle is probably not

> sealing, had some gas coming out the back of the carb. Lots of stuff I'm

> dealing with, really just need to dig into it for a few hours and fix

> the obvious stuff so I can pinpoint the issue.

Fix the oil pump. If all of that is open you have a big air leak. Don't ride it until you fix it.

Get the bike running well stock before you start swapping everything out. It will make it easier to troubleshoot things, especially without a lot of experience on them.

Read the manual linked above. It's really well written and will make your life easier

Re: nu50 bogging/gutless

I read through most of the manual and it is veryhelpful, and my bike is tore down to the case at this point. Found that the oil pump was also not fully seated on the oring. Pulled that out and measured it and made a blockoff plate with an oring seal so that is now fixed. The gasket on the magneto/stator cover was also bad so I will get a replacement gasket made for that. Those were my two big leak factors. Crank seals look good so at this point I'm going to reassemble. I also plan on replacing all the hoses on the auto choke so I'm sure that will help as well. So far everything else looks good. Intake/reeds were very clean and fully functional. Hopefully all of these fixes do the trick.

Re: nu50 bogging/gutless

Jack Rutherford /

basic causes of your problem

too lean or too rich jetting;

low compression;

air leak at cylinder head or cylinder/case or at exhaust;

poor spark;

crank seals would have to be really bad;

lack of fuel;

dirty carb/clogged jet(s);

very excessively worn belt;

brake(s) sticking;

clogged exhaust. (edited)

Re: nu50 bogging/gutless

Went back through everything. Replaced all the lines on the auto choke, got the new air filter on, installed oil pump blockoff, and replaced the gasket on the stator/magneto side. Reset carb back to specs according to the manual. Got everything bolted back up and she fired right up, had to adjust the carb a little to get the idle right. Hopped on and it seems to have good power now. I had to make a new kickstart stop(the old one was basically nonexistent).I also made new weights for the variator out of delving. Plan on taking it for a good spin tomorrow to see what it will do now. Now on to the lights wiring. Thanks for the input everyone.

Re: nu50 bogging/gutless

What did you make the kickstart stopper from? Pics? This is a part that is absolutely unobtainium. Per someone's advice here on the forum, I remade mine by glueing up old inner tube.

Joe

Re: nu50 bogging/gutless

I madeit out of some plastic, hdpe to be exact. When I open it back up I will take a picture for you. I will get it sketched up so I can make more as well, I had to drill and tap a hole in the stopper plate to mount it. Meant to sketch it up before I bolted it all back together but I was too excited, just wanted to see if all my fixes worked haha.

Re: nu50 bogging/gutless

Awesome. I'll be looking forward to see it.

Joe

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