NX250 Thread -- official ADV owners manual

[Orkodelamuerte]

Originally Posted by crobox

I am considering hybridizing this bike with a CanAm 250 2-stroke. I found one that can be had for cheap.

•Either pull out the NX250 engine and stuff it into the CanAm rolling frame (with appropriate mods to the frame so I can use the radiator and probably the NX's fuel tank too)
•Or try to fit the swingarm/shock/rear wheel and also the triple clamps/forks/front wheel of the CanAm to the NX frame.

I'm an excellent fabricator and machinist, so I'm not worried about the work involved.

I'd end up with a water-cooled four stroke 250 with electric start in a dirt bike chassis with good suspension and common tire sizes.

Any thoughts?

Thanks,
Christian

Man, I took the time to look at the work you´ve done on that van and on your XL... You are a hell of a fabricator! I won´t be surprised if u pull out a chopper out of that nx 250!!!

The problem with it is that you put so much effort on your proyects, that by the time you finish, u have to put it behind a glass for exhibit instead of using it, for it would be a shame to tear it.

[crobox]

Originally Posted by Orkodelamuerte

Man, I took the time to look at the work you´ve done on that van and on your XL... You are a hell of a fabricator! I won´t be surprised if u pull out a chopper out of that nx 250!!!

The problem with it is that you put so much effort on your proyects, that by the time you finish, u have to put it behind a glass for exhibit instead of using it, for it would be a shame to tear it.

Ha ha! Thanks!

Well to begin with, I hate choppers, so no need to worry about that!

And as for putting it behind glass... Well I use the hell out of my Scout. Drive it all the time, all over the place. But the XL is a bit of a different story. You are sort of right, I AM worried about wrecking that bike while I get better at off-road riding. That's why I want a little 250 to rip around on. The truth is that I would build this bike "quick and dirty" instead of making it pretty.

So, I'm still not sure about whether to get this CanAm and start cutting up bikes, or on the other hand just try to find a good shock and set of forks that I can bolt onto the NX. Any input appreciated from you guys who have worked on these bikes more than I have.

Thanks!

[scrambler66]

Originally Posted by crobox

I am considering hybridizing this bike with a CanAm 250 2-stroke. I found one that can be had for cheap.

Any thoughts?

Yes, why not stick to Honda ? 20 Years ago a french guy put a NX250 engine into a CR125 chassis - looks quite neat. He even managed to use a 310cc piston but never told how - thats what he wrote

je viens de retrouver une moto que j‘avais fabriqué en 91/92, le premier 4 temps liquide a démarreur dans un châssis de cross!!! moteur NX 250 bore-up, partie cycle CR 125 1990, réservoir CR 84....

The story with the shock is that it is way too short for serious offroad use. Only 321mm, the maximum length you will get into the NX250 swingarm is 327mm or you will have to start grinding at the linkages. And there are simply no other dirt bike shocks that are this short – a couple of guys tried SV650 shocks, but I found it still way too soft and street oriented. Something that may work is a shock from a BMW F650 Dakar (not the normal, shorter version) – the length fits but this shock is probably rare in the US and thus expensive? In front you may use any fork from a XL600, Xr600 or XR250 (later versions, the early XR forks are barely longer) but you will have to swap stems.

But if I had your abilities, I would put the NX250 engine into a Cr or XR250 (ev from this forum had done this) frame.

[valvecrusher]

Originally Posted by scrambler66

The story with the shock is that it is way too short for decent offroad use. Only 321mm, the maximum length you will get into the NX250 swingarm is 327mm or you will have to start grinding at the linkages.

And there are simply no other dirt bike shocks that are this short – SV650 shocks, too soft and street oriented.

In front you may use any fork from a XL600, Xr600 or XR250 (later versions, the early XR forks are barely longer) but you will have to swap steems.

Still there is no shock that will bolt to stock links? hmm maybe a CRF150R, or maybe the Ninja250/? KX80, CR80?

What about bolting a different Honda swingarm, shock and all....to the shock tower upper on the regu.ar NX frame?
like say, a XR250L swingarm, CRF150R swingarm, etc..


There have been some AWESOME conversions in this thread, one using a RM80(125?)...and others..

[scrambler66]

Just for fun I tried a little sumo conversion – in front I used a wheel from a Chinese made Kreidler DD 125 (2.50 17 rim, fits plugandplay), in the rear the stock 16’’ wheel. Tires in 100/80-17 and 120/80 16 with supermoto look are made by Heidenau (K66). And first road tests are promising; it’s quite fun to drive and it sure changes the look of my Nixie

And in case someone wonders: the NX is my winter bike, so I couldn’t throw some color on the frame ;-)

[RollingJ]

It looks like my NX has sold...

I just took a deposit and it will be gone by the end of the month.

It's been a great bike for me. It got me back into riding after 15 years off, and took me places I should not have tried to take it.





I'll be picking up a CRF250L pretty soon as my in-town toss-around bike, and so my youngest boy has something to drop. Momma just might let him drive it to school in a couple years.

I'm eying an 06cr250 with a scotts damper and a reculse clutch though...

[crobox]

Originally Posted by scrambler66

But if I had your abilities, I would put the NX250 engine into a Cr or XR250 (ev from this forum had done this) frame.

Thanks for the thoughts, guys.

I have spent the last several hours reading reading reading, searching searching and searching this thread using the search function, and learning all about the SV650 shocks, the GSXR shocks, and the XR250 forks (although there seems to be less info about the front suspension options than the rear). I've already ditched the stock airbox in favor of a UNI pod filter, so the GSXR option looks interesting.

Meanwhile I've been hopping back and forth to ebay and craigslist looking at prices for these parts.

I love the idea of swapping the engine into a CR or XR frame... I really do. The trick would be to find one, and find it for cheap. I'm really trying to keep costs minimal on this little project. I could get the CanAm for a trade for some stuff I don't really need, so the total hit to my bank account on that option would be $0.00.

As you can see I am still bouncing ideas around, and haven't really settled on what direction I'll go.

I did get the new valve shims in the mail today so I might get a chance to reassemble the engine tomorrow and try to fire it up.

Now back to ebay and craigslist....

[crobox]

Ok, so while I am bouncing around all these fancy ideas of how to turn this little bike into a toss-around-trail-bike, I am also working on the engine.

A few days ago I checked valve clearances and they were all a bit tight. Right side intake was tighter than the exhausts, but I COULD get a feeler gauge in there. Left side exhaust was too tight to even get a .002" gauge in there, so I made a guess about what shim would work. Then I ordered shims.

I'll cut to the chase here... no matter what shim I put in there... EVEN WITH NO SHIM, the left intake valve is too tight for even the thinnest feeler gauge.

What does this mean?? Sunken valve seat? I'm sure I'm gonna have to pull the head to inspect, right?

Thanks for any insight you might be able to offer,
Christian

[RollingJ]

It's either worn seats or a badly cupped valve face.

It's time for a head job.

[Ratchdaddy]

Originally Posted by crobox

Ok, so while I am bouncing around all these fancy ideas of how to turn this little bike into a toss-around-trail-bike, I am also working on the engine.

A few days ago I checked valve clearances and they were all a bit tight. Right side intake was tighter than the exhausts, but I COULD get a feeler gauge in there. Left side exhaust was too tight to even get a .002" gauge in there, so I made a guess about what shim would work. Then I ordered shims.

I'll cut to the chase here... no matter what shim I put in there... EVEN WITH NO SHIM, the left intake valve is too tight for even the thinnest feeler gauge.

What does this mean?? Sunken valve seat? I'm sure I'm gonna have to pull the head to inspect, right?

Thanks for any insight you might be able to offer,
Christian

I had the same problem on my first engine. At the time I was running a business and short on time so I took the bike in to a local shop when it became too hard to start it. The mechanic told me that it had "sucked a valve" and would need a valve job wich was in the 600-800 bucks. Kinda steep for a bike I bought for $800. I got lucky and found another entire engine on fleabay for $200. The new engine runs good. Now I need to eventually sort out the rusty gas tank/dirty carb issues. Anyone have a clean spare tank for sale?

[thirstybuck]

Originally Posted by crobox

Ok, so while I am bouncing around all these fancy ideas of how to turn this little bike into a toss-around-trail-bike, I am also working on the engine.

Christian

Have you tried to run this motor/bike at all? I know when I put a used head on my NX that the clearances were a little tight initially but I checked them after a couple runs and there were back in spec. Just a thought.

[Psychoboy]

A few days ago I posted about overheating issues with my NX250. Well I'm here to give everyone an update for those carious.

I refilled the radiator with new Coolanol, replaced the spark plug, adjusted the idle. It runs nice now. In fact I took it out on trails in the desert and did roughly 150 miles total (highway doing 65-75MPH and dirt/trails/sand). No issues. No dieing at all. No heating issues. Ran perfect.

[jsonder]

Originally Posted by Psychoboy

A few days ago I posted about overheating issues with my NX250. Well I'm here to give everyone an update for those carious.

I refilled the radiator with new Coolanol, replaced the spark plug, adjusted the idle. It runs nice now. In fact I took it out on trails in the desert and did roughly 150 miles total (highway doing 65-75MPH and dirt/trails/sand). No issues. No dieing at all. No heating issues. Ran perfect.

Good deal.

[Dirtstar1]

Sometimes I do something worthy of a photo. Thought you guys would like to see the NX in action

[fikse]

Originally Posted by Dirtstar1

Sometimes I do something worthy of a photo. Thought you guys would like to see the NX in action

Nice