Counter shaft replacement

[Schorschi88]

Hi folks!

I finally disassembled the Hawk engine, mainly because of the worn out counter shaft.
Now im encountering the problem that the Hawk counter shaft 23220MN8000 is not produced anymore and out of stock.

So, my question is: Can i fit a XRV650 counter shaft with part number 23220MZ8H00 instead?
On pictures i can't make out a difference.

Many thanks in advance.

Cheers and best regards from Austria
George

[rpcraft]

It's really going to be a gamble. If you can buy it from some place that it can be returned I would go that route, Buy it and measure the surfaces and compare, then check the spline and gear counts to make sure they are correct and physically in the right space. Also make sure the oiler holes match up and that interally it appears to be the same (as far as where holes are drilled and tapped the same threads and lengths. It's likely no one has tried it but I know for a fact Honda is famous for setting a part # for each bike that is a different part # for another, yet still the same part. The XRV motor is so similar it most likely is but unless someone has done that very same swap its a gamble either way. Most folks never strip things down to fix the shaft, but rather weld the sprocket on, so unfortunately its not a common repair to begin with.

Wish I could offer more and better feedback.

Not sure how practical it is to buy off ebay but there are a couple on there listed right now, used obviously. This one looks to be in much better shape than others. if you put a new gear on it and put a new retainer and screws on it and keep it maintained well you'll probably get a very long life out of it. usually what ruins it is people never changing the front sprocket, and doing zero maintenance.

https://www.ebay.com/itm/185352901602?hash=item2b27e4d3e2:g:YH8AAOSwp~5iOjmb

[Captain 80s]

Honda is famous for setting a part # for each bike that is a different part # for another, yet still the same part

I think your advice is spot on. But I worked at a Honda dealer for 12+ years, and they will use the same part number if it is indeed the EXACT same part. Usually it's a case that there is a difference so small it may be inperceivable, but it is there, and the part received a new part #. Or the actual part is the same, but the finish treatment is different. When you look at part listings for bikes, the center code (which refers to the original model, or model family) will vary quite a bit.

[rpcraft]

That is good info to know! Thanks. I knew it would be pointless to have multiple part #'s for the same part but just have never been able to perceive some differences. Mostly when I see things it is looking at carb parts so sometimes you just really wonder what the heck the difference is.

[DrPMC]

The XRV motor is so similar it most likely is but unless someone has done that very same swap
https://www.ebay.com/itm/18535290160...8AAOSwp~5iOjmb

The XRV countershaft isn’t compatible.

The method for attaching the front sprocket is poor on an otherwise sturdy and intelligent design. It’s a part that is going to have a hard life and its no better than marginal.

[Schorschi88]

The XRV countershaft isn’t compatible.

Can you tell the difference between these two shafts?

[Luis]

We had some time ago a discussion about counterschaft compatibility with other Hondas

[rpcraft]

We had some time ago a discussion about counterschaft compatibility with other Hondas

I'm guessing it has a direct nut on the shaft as a retainer vs the retaining plate?

[DrPMC]

I'm guessing it has a direct nut on the shaft as a retainer vs the retaining plate?

The XRV has the same arrangement inside as the NT650 for attaching the sprocket. I can’t remember with certainty, but I think that that the problem is with the compatibility with the gearbox internals. Perhaps reference to the part diagrams for both models might help?

XRV owners have the same problem with the countershaft and there is quite a lot of discussion out there on the topic. The relevant part for the XRV is https://ruggedroads.co.uk/epages/00c...jectID=9528208

[Schorschi88]

I think that that the problem is with the compatibility with the gearbox internals. Perhaps reference to the part diagrams for both models might help?

Referring to this site https://www.gearingcommander.com, the gear ratio is exactly the same to the XRV.

And here is the only hint i found, that the shafts should be the same: https://www.xrv.org.uk/threads/xrv65...-guide.169136/

replacing the worn RD03 countershaft 23220KW9000 with a good 23220MN8000 from a NT400 Bros, think the whole gearbox cost £85, being from the little 400 this shaft has no wear on the sprocket splines.

I will order the shaft from the XRV and will post the result here.

[DrPMC]

I hope that works out OK. Looking at the parts diagrams the counter shafts look different to me:

https://images.cmsnl.com/img/partslists/honda-xrv750-africa-twin-1997-v-austria-transmission_bigecy1p41e__1500_eb66.gif

https://images.cmsnl.com/img/partslists/honda-nt650-hawk-gt-1991-m-california-transmission_bighu0289e1500a_f36d.gif

Regarding that quote from the XRV forum, I wonder if he’d dismantled the XRV’s gearbox at that point or was assuming that they’d fit? I remember thinking the same at one point, when I was looking for a replacement for my XRV engine. Incidentally, the comment about wear on the splines is erroneous - the wear isn’t caused by the power of the engine but by running the chain with insufficient slack.

[squirrelman]

has no one suggested welding the sprocket in place ? cheap and dirty but it works.

i don't understand why anyone would disassemble the engine before confirming the parts to fixit were available.

[Schorschi88]

https://images.cmsnl.com/img/partslists/honda-xrv750-africa-twin-1997-v-austria-transmission_bigecy1p41e__1500_eb66.gif

This is the counter shaft of the 750cc engine for RD04 and RD07. It's different for sure.

RD03 https://images.cmsnl.com/img/partsli..._1500_1cd8.gif
NT650 https://images.cmsnl.com/img/partsli...1500a_f36d.gif

Beside the picture quality, there should be no big difference.

i don't understand why anyone would disassemble the engine before confirming the parts to fixit were available.

I can understand your point of view. But i removed the engine mainly, because of upgrading the engine power. (high compression piston, cylinder head, flatslide carb and cams from RD07)
Then i realised the worn out shaft and i wanted it done properly. The engine has 57.000 miles on the clock now.

[DrPMC]

This is the counter shaft of the 750cc engine for RD04 and RD07. It's different for sure.

RD03 https://images.cmsnl.com/img/partsli..._1500_1cd8.gif
NT650 https://images.cmsnl.com/img/partsli...1500a_f36d.gif

Beside the picture quality, there should be no big difference.

I can understand your point of view. But i removed the engine mainly, because of upgrading the engine power. (high compression piston, cylinder head, flatslide carb and cams from RD07)
Then i realised the worn out shaft and i wanted it done properly. The engine has 57.000 miles on the clock now.

Yes, I can see what you mean - I missed the reference to the 650. When I think XRV, I assume the 750 engine, which certainly doesn't have a compatible shaft. It will be useful knowledge that these XRV650 shafts can go into the NT400/650 motor - its such a common problem.

Seems perfectly reasonable to strip an engine down before you have the parts on hand. You need to know what you need and, in any case, there is always a solution if one looks hard enough.

It would be interesting to read more about your engine build - are you going for the JE Piston 82mm units and what carbs are you fitting?

I'd like to have the FCR units but can't afford it. Instead I've converted some CVKs from a bank of 4 from a Kawasaki (https://www.hawkgtforum.com/forum/ho...nversion/page3). I've not got around to installing them yet - perhaps next winter, if I'm still around...

[6]

perhaps next winter, if I'm still around...

Planning on going somewhere?