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CRM250AR the Honda oddball

6504 Views 24 Replies 6 Participants Last post by  mekros
I'm a sucker for punishment.... The RGV is on hold since I had to move interstate, it's now being babysat by a friend who has too many RGVs.

I've settled into life in NSW reasonably well and thought I would have a change in riding style and go the dirt bike/motard path (Yamaha WR250R).A few other friends in Melbourne decide the same thing and a bike is spotted up here that he wants, no problems, I can store it temporarily. The deal is done, a price is worked out and the bike lands at my place. A month later said mate says he will long term run into financial problems. I decided to take on the bike and fix it up, decide what to do later. Besides, who can resist a two stroke, especially one that has a reputation for being different.

So the bike is a 1997 Honda CRM250AR. It's a two stroke single, with "activated radical" technology. So at low throttle openings it closes the exhaust port to next to nothing, raising the compression to use the waste heat and unburnt fuel to cause compression ignition (diesel along). Once you get on the gas, it behaves like a normal spark ignition engine and powers along, so in theory you get the best of both worlds.

(space reserved for a picture of the bike when I find it from the archives somewhere)

The fun starts with the bike itself. It has an ADR compliance plate, but was imported as a bike from the UK. I don't know how it works, but it has the plate and engine number so when I register it later I'm not complaining.

Over the long weekend period I decided to break from the family routine and get some shed time. In next to no time it is stripped down.

This is what I achieved:

corroded exhaust and suspension link

A lot of help from liquid spanner

Remembering to be methodical


...and tagged

end of day 1


Slow progress time because it is spent cleaning

first round of cleaning the expansion chamber from this...

...to this

Honda dirt bikes from the same era have a dreaded reputation of seizing their swingarm pivot bolts. I seemed to have lucked out and with a bit of cleaning the bolt is at this stage
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Time to work on the front end. More bagging and labelling of bits

A well greased head stem, it's a shame the bearings weren't shown any love, the grease in both bearings had changed colour so they looked like rusty grease as lubrication.

The state the project is currently sitting in. I now need to buy parts and start taking the hard bits out. My supervisor is also telling me that I should stop work and spend time with the family.

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Is this a road register able motard?
Will be awesome when it's finished
Never mind, I just read the last paragraph lol
would be a fun bike and probably one of a kind
I know of someone that tried to stick a cr250 cylinder on one, he got unstuck with going to far oversized in the bore and can't get a piston that is reliable. That would be silly fun

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Long live the thumper! I had to look up what the hell "Active radial technology" was.

Also, some kid has nicked your pen!
Said kid got bored this weekend so minimal work achieved.

This week there is minimal physical progress. The linkage bearings are good so I am not going to replace them.

I've been tabulating bearings, looking for generic part numbers, and comparing quotes.
Oh boy, can you do me a massive favour? I bought a 99' CRM which apparently had a swing arm replaced. Now, the previous owner also mentioned the linkage bearings need replacing and rightfully so because they were utterly destroyed. So I get home and I'm trying to just put it back together so I can keep it as one piece til I have enough time to work on it and no matter which way I try and installed the linkage and shock, it won't line up with the swing arm. I noticed that there was a "Pro-Link" sticker on the swing arm which I had also seen on my mate's '84 CR500. A little research showed me that the first model of the CRM had that and the swing arm/suspension was different. think the previous owner bought the wrong swing arm but I need someone to take some measurements for me. Would you be able to get these two measurements for me? http://i.imgur.com/5FAiPHY.jpg I would be greatly appreciative if you can. No need for dead accuracy, just to prove or disprove my theory. If it wasn't for this my AR would be registered and riding by now!
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I can measure components for you, I won't be able to do fitted out measurements until later.
Awesome. Just has to be a rough measurement (to the nearest millimeter). Basically just need the distance from the centre of the swing arm bolt to the centre of the linkage bolt in the X direction of the swing arm, and the vertical distance between the bottom of the swing arm and the centre of the linkage bolt in the Y direction of the swing arm. Cheers for helping though.
Bit of slow progress

Compiled the parts list and now I have to ring around and get quotes for the generic parts and Honda specific parts.

Got a mid 90s CR250 tank

Did a 30 second dry fitting to see what it would look like:

Also taught myself an important lesson I to relearnt the hard way....don't work on the bike after only four hours sleep and 12+ hours at an office. I tried to Ezyout a bolt and managed to snap the Ezyout, only to realise I was working on a sprocket bolt rather than the brake rotor bolt.

I had a better look at the rear wheel while I was there and think it definitely needs a rebuild.

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Why are you trying to fit the CR250 tank? Less weight?
The main reasons were for weight saving, larger capacity and a plastic tank doesn't rust. There's a bit of work to do and I need to jump on the scales to see what the actual difference is.
A couple of weeks of family duties and finally a get a few hours piece and quiet to duck out and do some work.

Headstem bearings removed:

I ended up using heat and ice, the dremel, and a drift (screw driver) to get them out. Due to operator incompetence the dremel did more harm then good though:

All that is left to do now is to try and get the lower tripleclamp bearing off the stem.

swingarm bearings removed:

suspension linkage ones are being annoying though.

I've done my pricing around of bearings and bits and pieces, would you believe I called 3 Honda shops in Sydney, the closer to the city you are, the more expensive it is, and one very well known dealer won't even call back after repeated messages left on the parts department message bank.
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Ha they never call back, gotta harass em. Have you tried bearing shops, Lane might be able to point you to one to check out.
The bearing shop in Melbourne I use us far cheaper than any Honda dealer, there are specific bits like spacers , axle bolts and swingarm bolts that you can't really go generic on.

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Get the part number and google it.

Plenty of mobs OS that will ship you parts, if you buy enough, it's much cheaper than buying local and have all the import parts Honda Australia aren't interested in.

Good to see you haven't lost your 2 stroke spirit!

I'm not far off selling my SP NSR and it hurts.
Have you had a chance to measure up the swing arm yet? I have my NSR almost ready to move off the bench, almost CRM time!
Sorry mate, been forgetting or my hands are dirty and can't get to the phone to check what you needed. Keep on my case though!
Life has been busy outside of the bike world, over the weekend I managed to break out the heat gun and blind bearing puller:

Bagged and tagged as usual

Aluminium spacers will have to be made for this now that I have dimensions.

Parts have been ordered from Honda and are awaiting arrival from Japan. I found it was cheapest to buy from a local dealer, the overseas prices were pretty much on par with the locals before you factor in postage!

The common bearings are the only ones I need to order now.

I forgot my linkage bearings so I'll give them another shot when I get out there again.
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