A while back, I bought one of my kids an SSR SR70C dirt bike. I was so impressed with the little bike that later, when I was looking for a used 250 to ride with my kids, I decided to take a chance on SSR's larger machine, the SR250S.
Information about these bikes is somewhat hard to come by; despite their low price, and although the pit bikes seem to sell pretty well, I've only spoken to a couple of other SR250S owners.
I expect to get a lot details wrong on this page and I count on readers who know more than I do to set me straight. Please, if you have corrections or additional information for the page, email it to me at .
The NC250 is manufactured by Shandong Asiawing Motors Co.,Ltd. (their website appears to be down at the moment I am writing this). It is distributed to other countries around the world by other importers. In the United States, the bike is imported by SSR Motorsports and is known as the SR250S.
In Europe, Borossi distributes the bikes, now under the Asiawing brand.
In Australia, the bike is distributed by Crossfire as the XZ250RR.
The SR250S is patterned on the 2007 model year CRF250X. In most cases, parts for that bike will fit the SR250S.
Crossfire, who for some time imported the NC250 into Australia as the XZ250R and XZ250RR, published this PDF, which lists parts compatibility between their bike and the CRF 250/450. I have reformatted the table for the browser and removed the untranslated chinese.
A parts diagram is also available.
I have not verified any of this information, so use at your own risk.
| No | English Name | Material Spec | Commonality |
|---|---|---|---|
| 1 | plastic body | PP | All the plastic bodys are saame except front side fairing and number plate,but the fixing hole is common use with Honda. |
| 2 | front forks | 53x58.5-910 | The structure is same as CRF450 53x58.5-930, but different in length. |
| 3 | rear shock | 500 | same as CRF 250 |
| 4 | linkage, suspension | alloy,forged | same as CRF 250 |
| 5 | linkage, swing arm | alloy,forged,cast steel | same as CRF 250 |
| 6 | guide, chain | PPU | same as CRF 250 |
| 7 | chain guide insert, rubber | PPU | same as CRF 450 |
| 8 | plate, chain guide | aluminium sheet mould | same as CRF 450 |
| 9 | brake assy,front and rear | same as CRF 450 | |
| 10 | seat | same as CRF 250 | |
| 11 | guard，disc brake, front (protector) | PP | same as CRF 250 |
| 12 | guard，disc brake, rear (protector) | PP | same as CRF 250 |
| 13 | guard, caliper, brake, rear (protector) | PP | same as CRF 250 |
| 14 | exhaust pipe and muffler | aluminium | same as CRF 250 |
| 15 | element, air filter | Foam | same as CRF 250 |
| 16 | filter net,air filter | stainless steel net | same as CRF 250 |
| 17 | tapered roller bearing,steering stem | 320/28 | same as CRF 250 |
| 18 | oil seal, steering stem | same as CRF 250 | |
| 19 | holder,fuel tank bandage | Rubber and stainless steel | same as CRF 250 |
| 20 | oil seal,middle bolt | 37-22-4 | same as CRF 250 |
| 21 | plane bearing,middle bolt | 36-22-6 | same as CRF 250 |
| 22 | outer bearing,middle bolt | 17x30x6 | same as CRF 250 |
| 23 | guard ,air filter,rubber | rubber | same as CRF 250 |
| 24 | plate, duct fitting,air filter | iron sheet mould | same as CRF 250 |
| 25 | holder, filter element,outer and inner | PA nylon | same as CRF 250 |
| 26 | sub-frame | steel | same as CRF 250 |
| 27 | hub protector, front | PE | same as CRF 250 |
| 28 | guard, fork,(protector) | PP | same as CRF 250 |
| 29 | clutch lever with carburetor ventilate switch | same as CRF 250 | |
| 30 | anti-hot rubber,rear side fairing | thermostability silica gel | same as CRF 250 |
| 31 | fixed nut,rear fender | PE fairing and purposemade nut | same as CRF 250 |
| 32 | tensioner | PPU | same as CRF 450 |
| 33 | bracket, brake hose, | 6063 alloy | same as CRF 250 |
| 34 | spacer，front fender | steel step space | same as CRF 250 |
| 35 | spcacer,fuel tank fairing | steel step space | same as CRF 250 |
| 36 | bolt,seat | steel step space | same as CRF 250 |
The NC250/SR250S engine is a Zongshen ZS177MM, manufactured by Chongqing Zongshen Power Machinery Company (宗申).
This engine is also used in a number of other Chinese motorcycles and scooters, perhaps most notably the Zongshen RX-3 adventure-touring bike, which is distributed in the United States by the California Scooter Company
The ZS177M is definitely not a clone of the CRF250 engine, at least not when it comes to service parts like filters.
When searching online for SR250S parts, it is helpful to use "NC250" rather than "SR250S", since the bike is called NC250 everywhere except the US.
Crossfire published this parts diagram for the ZS177MM.
Parts for this motor are plentiful and relatively cheap if you don't mind having them shipped from abroad.
http://www.aliexpress.com/store/group/NC250-Parts/207293_251843072.html
Another option is to purchase parts from CSC for the RX-3: http://www.cscmotorcycles.com/OEM-ENGINE-COMPONENTS-s/239.htm
The ZS177MM does not use the same oil filter type as the CRF250.
The oil filter included with the bike is a serviceable screen-type filter, not a pleated paper filter. When changing the engine oil, you can remove the filter, slide the core out of the screen, and use a solvent and bristle brush to clean the screen. I used compressed air to blow out any bits from the screen.
Although I neglected to get a photo of it, I gave the bike an initial oil change after about 6-8 hours of riding, since many forum trolls had claimed the filter would be full of shavings as the engine inevitably destroyed itself after a few hours of use. I found virtually nothing, a few very fine bits (which I think might've been from the filter screen itself), and a little bit of ferrous gunk on the oil drain plug magnet, about what I've seen on any brand new motorcycle.
I'm going to stick with the serviceable filter for now, although I think that CSC RX-3 pleated paper filters will fit this motor. I will be interested to hear if anyone tries it.
By the way, my oil drain plug was sealed with gray hi-temp RTV rather than a crush washer, although I used a crush washer instead of more RTV when I made the first oil change.
The NC250 carburetor is manufactured by Sunworld Moto. Mine has the marking SWR H34AS4-1514 PHB E34.
The carb is pretty similar to a Keihin PWK, which has a flat slide and a venting arrangement similar to the Keihin QuadVent carbs.
The pilot circuit on this carb uses an airscrew rather than a fuel screw. From the dealer, the factory setting for the air screw was 2.5 turns.
The effect of adjusting the air screw is not instantaneous, in my experience I need to work in quarter-turn increments and give the system about ten to twelve seconds to catch up with the change in air.
The needle is marked N68E and appears to be a standard PWK type. The clip is in position 2 from the factory.
The easiest way to remove the needle is to unbolt the petcock, remove the carb fuel line, remove the tank, and then unscrew the plate where the throttle cable enters the carb body. I think a patient person could probably do it without removing the tank, but the tank is so simple to remove that I don't think it's worth it.
The needle can be removed from the slide once the cable is unhooked. The SWR has a clever window in the slide that makes hooking the ball-end easier.
The main jet is marked "140", and looks to me like Honda Part no 99101-357-1400, which a Keihin main jet.
The pilot jet is marked "45", and appears to be a standard Keihin PWK/CVK/PE style.
The main jet can be removed with a 6mm driver through the portal on the bottom of the float bowl after unscrewing the plug.
To get the at the main and pilot jets:
The main jet is the smaller 6mm brass hex bit, which is screwed into the emulsion tube. On my carb, the emulsion tube was torqued slightly less than the jet, so the tube and jet came out together, no big whoop.
The pilot jet is situated alongside the main jet, but I couldn't get to it through the portal, and had to remove the bowl.
A word of warning, there's a small breather tube pressed into the bowl at an angle, which will catch the left float if you pull the bowl straight down when removing it, which can bend the float. I suggest removing the small vinyl hose from the bowl first, then jiggle it to make the tube clear the float.
The main jet on my bike seems fine, but I did have some trouble with idle when hot and between closed and 1/4 throttle, so I replaced the 45 pilot jet with a 48 and moved the needle clip from the second to third position. With the 45 pilot, the fastest idle I got was with the airscrew almost all the way out, with the 48 it's about eactly 2.5 turns. Moving the clip to position three the motor feels like it pulls better at zero to quarter throttle, but I haven't ridden it much yet with this setting. I think the stock jetting is probably close enough to right that a minor pilot increase and the clip change from 2-3 may be all I need.
Needles and jets (both main and pilot) are readily available on ebay very inexpensively. I got a pack of 10 pilot jets for 8 or 10 bucks, and there are packs of 10 needles for 15-20$. Because of this, I would avoid buying a CRF250X jet kit. Although I suspect that the the needles and main jets will fit, I don't know (and most of the kits I looked at don't tell you) specifically what size jets and needles are included. The engine and carb in the SR250S are not similar to the CRF other than both using Keihin carbs.
The Zongshen and Asiawing manuals recommend 91 or higher octane fuel. I've been using 93 so far.
The stock exhaust on the NC250 has the appearance of an aftermarket pipe, is fairly light (4.8lb/2.2kg), but lacks an internal spark arrestor.
I ordered a Lexx Slip-on Exhaust, but I can confirm that it is not compatible with the SR250S. In addition to being the wrong diameter pipe, the mid-pipe is the wrong length, has the wrong bend, and the mounting bolt carrier is in the wrong location.
According to Borossi, rear suspension is "rear pergressive FastAce Performance mono shock absorber with spring preload and rebound and compression damping" (sic). The shock didn't have a manufacturer's mark that I could find, and I'm not sure whether the FastAce shock is a Borossi-specific upgrade. On the SSR bike at least, the shock appears to be patterned on a KYB.
I took my rear shock to my local RaceTech dealer, MRP Motorsports, and had the factory spring rated. The stock spring is 270mm in length, with 58mm and 60mm ID on the top and bottom ends, respectively. The rate is 6.1kg/mm, which differs considerably from 2007 CRF250X rate of 4.8kg/mm according to Racetech.
At 250lb, I've resprung mine with a 66 N/mm Öhlins spring (06310-17), which Öhlins lists as a KYB replacement spring. More Spring Rates.
Also according to Borossi, the front suspension is an 47mm Upside-Down FastAce Performance fork; rebound and compression adjustable.
The rear shock fairly easily using this method, which involves removing the pipe and unbolting the subframe, without having to remove the airbox. I recommend loosening the pipe clamp by the carb outlet, and have some (I used zip ties) to support the subframe while the shock is out.
The stock handle bar tapers from 1.125" to 0.875" (1 1/8 to 7/8)
I'm tall with a long torso so I like bar risers if I'm standing on the pegs a lot. I think I'll add some to this bike, but haven't yet.
I tried adding a set of 2" Rox Risers, but using them would require lengthening the throttle cable. Also it is virtually impossible to tighten both handlebar bolts while the Rox Risers are installed. A ball-end hex wrench may be able to do the job, but since the throttle cable is too short anyway, I'm not going to bother.
The shifter is of the folding design, similar to the CRF250X pattern, but I haven't compared them.
Length is about 5" from the front edge to the center line of the shifter shaft, which I measured as 0.425" (10.8mm?). I crudely measured this without detaching the shifter. If you are looking for this measurement let me know, I'll take it off and get a more accurate measure.
I haven't determined whether the SR250S plastics are a match with the CRF, but I've got a couple of photos that might prove useful:
Available here
TBolt USA carries levers and misc parts. They're helpful on the forums so I plan to buy from them when I can.