Shineray piston and crankshaft for AX-1 / NX 250

[kuroguro]

Vor 17 Jahren hat Shineray für die XY250GY den NX250 Motor kopiert - zumindest optisch. Die ganzen Motorenteile aus China stammen vermutlich von diesem Motor, wobei nichts wirklich passt.

I found a Russian blogger that has explored some of the differences between the clone and nx, I have not seen it discussed here before. Google translate web page doesn't seem to work on it for me - try the browser built in translator.

https://bikepost.ru/blog/94749/Poleznaj ... -AX-1.html

If I understood the translation correctly he replaced the cylinder, crankshaft and stator/rotor with the Shineray versions - still good after 25k km. All the bearings and timing chain from them were bad. Also there were multiple differences.

At the end of the post he lists bikes that were available for the Russian market (all Shineray and Yingang rebrands) however due to emissions regulations none are for sale anymore . There are some parts left but not much. The only place that still actively sells clones near by seems to be Ukraine (Shineray Z1).

https://mot-o.com/zapchasti/shineray_25 ... 1_250.html
https://mot-o.com/zapchasti/shineray_25 ... enval.html

There are multiple Shineray resellers in UA with various amounts of parts in stock (including the whole engine). None of them ship to EU directly - so between the war delaying things, reshipping and import costs I'm not sure if this is a viable route but it might be worth a try if there are no other options.

About the important part - I think the various Chinese sellers on aliexpress and amazon (AHL pistons and exploding conrods etc etc) are not from Shineray or the rebranded clones. Apart from the 300cc kits I've rarely seen Shineray parts on these sites. They definitely don't have KW3 markings and I've only seen the whole crankshaft assembly sold as a single unit. Also they have oiling holes on the top of the conrod.

shineray.png

I understand they are not Honda quality but from what I've heard most of their engines are at least decent and have some quality control. The crankshaft assembly is ~90 EUR at current exchange rate. With reshipping and customs tax it may be possible to get one for ~130-150? Maybe? And another problem - we don't know how good is the bearing inside. The blogger mentions possibly replacing it with a NTN/SNR K30X38X18 bearing but I'm not sure if he did that on his crankshaft or not. Also the tolerances would still likely be loose without changeable roller sizes?

In other news the Shineray X2 got an EFI upgrade in China to pass emissions. Also they did an SWM branded scrambler with our clone engine also with EFI. Sadly I haven't seen either outside of China. Their current emissions standard isn't too far from EU but with 5 years since the release I'm guessing we won't see the bikes (or engine parts) here again :<

http://www.chmotor.cn/guide_detail.php?id=43140
https://www.bilibili.com/video/BV1Hz411i7tx/

[scrambler]

Thanks for the research; there's some valuable information there.

Honda AX crankshaft shineray.pdf

It's good to know that Shineray conrods are supposed to hold; it might be worth buying a crankshaft. I'd just use the conrod, though. The current status of the Chinese conrods is: the lower needle bearing is available from Prox viewtopic.php?p=25083#p25083 or Honda viewtopic.php?p=33697#p33697 , so one could try a Chinese conrod again. Perhaps the Chinese needle bearing was the problem, and the broken conrod was just the resultant damage. I'll probably try again next winter, somehow things have to go on. The Honda bearings make sense because they are available with rollers of different strengths to minimize tolerances.

So there are original Shineray pistons in Ukraine https://mot-o.com/zapchasti/shineray_25 ... 50-3a.html - 18€ plus shipping? I'd noticed before that at least two different types of Chinese pistons are offered: some look like the original ones, and some from AHL with differences in the piston skirt. viewtopic.php?p=24900#p24900. They're also easily recognizable by the fact that they have a second row of oil holes. The Shineray piston looks like AHL?

Shineray piston.jpg

The SWM Six Days doesn't look bad, maybe it will come to Germany after all. Then hopefully we could buy connecting rods and pistons

SWM six days 250.jpg

ps - good discussion here - I'll separate the posts later and create a separate thread for them so that the information is easier to find later.

[kuroguro]

Thanks for the research; there's some valuable information there.

As my nixxie is approaching 90k km on the odometer I'm starting to get worried about parts There are not many standing on the leader board with the first engine intact.

The Shineray piston looks like AHL?

I had not noticed that! And it does carry the KW3 markings. On some of the Russian sites the piston looks the same for Irbis Z1 which is also a rebranded Shineray. So AHL does have some clone parts.

11729.jpg

Picture from a parts reseller website but the watermark on the picture is from the official distributor (I don't think they list the parts anymore). https://oilshop55.ru/shop/11729/desc/po ... 0-irbis-z1

[scrambler]

I don't think you have to worry about the piston/cylinder, as long as you don't do anything stupid (like me). The Nicasil cylinder was still like new at 105,000 km (see pic below), and the piston rings were still within tolerance. And piston rings are still available for the '88 US Nixe, which for some reason has different ones https://www.webike.de/products/24970308.html

So they can be replaced if necessary. The only problem when overhauling an NX250 engine is, as mentioned, the upper conrod eye. I don't know of a permanent solution for that yet. Perhaps we should start a crowdfunding project to have the conrods remanufactured.


after 105000km mileage

[kuroguro]

Heh, true! I suppose reading all the repair threads has made me a slightly paranoid.

Still nice to know there are some options for parts, even if they are Chinese. I wonder if Shineray's oiling hole makes any difference for the wear/seizing in the top eye of the conrod. It would be hard to test without driving it for years.

A proper conrod would be nice. Unfortunately getting people to crowdfund can be like herding cats I'm afraid not many would be willing to put money down unless their conrod is already broken. Of course the only way to find out is to try!

[lbel67]

Hi guys, new here but long-time follower. Owner of a Dominator originally 239cc then fitted with 249cc cylinder, and hoping to be able to rebuild in the next couple of months. Just a quick note on the alternate piston rings sold lately by Honda (mentioned by Scrambler), these are from VFR 750, they look alike but have different end gaps (smaller for the compression ring, larger for the second (scraper ring). Difference noticeable when you put the VFR ones over the NX ones). Other than that, no other apparent differences, noting however that I'm not sure if the material is different as the VFR rings are designated for cast iron sleeve and not nikasil. I will probably try these in my rebuilt, if I ever get the time to do it, although conventional wisdom would steer towards using the original KW03 set (the only one I have left).

[scrambler]

Just a quick note on the alternate piston rings sold lately by Honda (mentioned by Scrambler), these are from VFR 750, they look alike but have different end gaps (smaller for the compression ring, larger for the second (scraper ring). Difference noticeable when you put the VFR ones over the NX ones).

Hello Lambros. Thanks for the info. Interesting that there are differences. They seem to be working flawlessly; I'm not aware of any problems. But my US Marlboro NX250 has a slightly higher oil consumption, which I attributed to the dusty rally. Could it be due to the piston rings? In any case, the VFR piston rings are for sure a better alternative to Chinese parts. Presumably, you're using a Honda piston?

It's still a mystery why the '88 US NX250 got piston rings from the VFR. Stricter emissions regulations in California? The fact that the US NX250 also used standard piston rings from '89 onwards speaks against this.

[lbel67]

Hello Scrambler and thank you for letting me know as I have not yet tested the VFR rings. I measured the gaps in a spare cylinder I have with a .001mm taper/out of round (i.e well within spec) and I got approximately 0.25 for the top ring (which is in my view ideal per the NX manual spec) and (if my recollection is correct) approx. 0.60 for the second ring (thus a 0.15 out per the manual service limit ), which may perhaps explain your slightly higher oil consumption.

To note that my brand new KW3 rings in this same cylinder give approx. 0.30 top and second (within the manual spec but to the upper side). Always on a Honda piston and I have a couple of used ones in very good condition, but still used. Sadly, I have been unable to find a new OEM piston for my upcoming rebuilt and the VFR piston is shorter at skirt side.

In my view, the above VFR ring gaps were made to follow the universal ring end gap rule: tighter top, looser second to let some blowby out and not disrupt the function of these rings by "trapping" gases between them, which to me makes perfect sense. Fully agree that VFR rings are way better than any aftermarket ring set. A learned Honda dealer I asked about this, said that initially Honda used the VFR rings in the first NX-AX models and then changed but I am not sure this is the case.

[lbel67]

The only problem when overhauling an NX250 engine is, as mentioned, the upper conrod eye. I don't know of a permanent solution for that yet. Perhaps we should start a crowdfunding project to have the conrods remanufactured

I only solved this problem permanently with a Samarin conrod. Unfortunately the factory closed a few years ago and these are no longer available in the market (to the best of my knowledge). Machine-shops sometimes opt for pressing a phosphor bronze ring in the upper eye, which I have also tested with good results (no notable wear) for 50k klms or so.

[scrambler]

Machine-shops sometimes opt for pressing a phosphor bronze ring in the upper eye, which I have also tested with good results (no notable wear) for 50k klms or so.

Interesting – do you know a workshop that would do this on the NX250 con rod? The specialist companies I spoke to all unanimously rejected it, saying the conrod eye would be too thin. Samarin really doesn't seem to exist anymore; even the German distributor isn't getting any responses from them.