Shaun's (AR's) CRM250AR/CR250 Conversion

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 19 Jun 2012, 08:01

I really, really wanted a CRF headlight, too keep the subtle Honda theme, and many aftermarket ones look out of place. It took me ages to source them, and the price was shocking, plus hardly anything available on ebay. Eventually though I did manage to get the plastic and the glass headlight separately on ebay for very good prices, however of course the CR had no mountings for this (later discussed).

In the mean time, between me and Gary at fusion-mx, we designed the custom graphics which I’m still to this day thrilled with and wouldn’t change. I gave him rough designs via email, photos and sketches in paint etc. After many, many tweeks, eventually they were perfect and on order, along with new plastics. I was chuffed when they arrived:

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Obviously the first thing I did was try them on the bike, and oh did this get me excited and put a smile on my face:

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Anyway, as mentioned earlier, now came the mounting of the headlight. This was a fairly tricky one as the original should be rubber mounted, however not too challenging in comparison to other bits of the bike. I had the special top-hat washers made once I’d worked the sizes out, and made the brackets myself:

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The larger bracket was later powder coated, and I polished the stainless triangle brackets.

The next thing on the cards was sorting the wiring loom!! I had already labelled it and worked out where everything went pretty much, but I had to wire in the aftermarket headlight and tail light, kill switch and ignition key, along with all the new switch gear, brake light switches and Trail Tech speedo. I spent a lot on the electrical items as I was searching for quality and reliability. I also chose to used waterproof 2 and 3 pin plugs where necessary, for ease of assemble and obviously so they’re waterproof and therefore reliable and durable.

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A few cups of tea, masking tape and a multimeter had the wiring pretty much sorted.

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Once this was all in place, I managed to test it on my old running AR, and everything seemed to work fine!! However when finally crimped I couldn’t get a spark… which made me extremely annoyed!! I traced it and found that I has mixed the kill switch and ignition wire on the loom up (I remembered the labels had fallen off and I assumed the thicker wire was for the ignition).

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 19 Jun 2012, 08:07

I tried the loom on the bike and routed it many times to avoid entrapment and melting!!

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I then decided to make a fancy sprocket cover with holes for ease of cleaning. This started with cardboard template as usual, then a thin piece of aluminium sheet carefully shaped and drilled, and a couple of black nylon spacers made.

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This was later powder coated when finished and I’m extremely pleased with it!!

Next was to mount the rectifier/regulator and the ECU. Obviosuly these had to be carefully placed to avoid damage, water and to keep the regulator cool. The regulator was placed in a similar position to the standard CRM, however later found to foul the shock, so I had to file minor amounts off the cooling fins. The ECU was located in the airbox which seemed obvious, but the exact position was difficult to determine, as the wiring was tight, and I wanted it soft mounted and easy to remove. My initial thought was to make a mock ECU and vacuum form a holder to fit under the seat, but decided this wasn’t the best option. I experimented for a while with cardboard, and finally came up with a design using some thick foam and ali sheet.

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 19 Jun 2012, 08:18

I was fairly happy with this although it wasn’t quite finished. I then decided to sort the exhaust completely. I started by a cardboard bracket for the additional subframe bracket:

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And then making it out of ali:

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I then carefully chopped off the original DEP silencer bracket:

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And cleaned up the silencer as best I could:

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The new bracket I made was then welded on:

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I cut down and shaped the original DEP bracket to suit:

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And then this was welded on and the exhaust was sorted!! Getting the angles correct was quite critical.

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It was also time to properly pipe up the rads… which I was slightly worried about due to lack of space. This took ages and lots of trial and error techniques, including purchasing lots of connectors and various size and shaped silicone hosing. I also had some special T-Pieces and reducers made at work as the exact sizes weren’t available.

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My next massive dilemma was the autolube tank. I did not what so ever want to have to pre-mix, this was one of the major things for me keeping a 2 stroke and therefore doing this entire project. I was now so close to the end, and was worried about how I’d overcome this task, and didn’t want to bodge or avoid having autolube. To cut a long story, I tried all sorts of little bottles. For weeks I was emailing companies on fleabay asking them to kindly measure small tanks they had advertised for scooters (ie rad headers and small 2t bottles). I also tried nitro car and plane fuel bottles. In the end I decided to just make one out of ali.

I experimented with shapes and sizes… bearing in mind there was very little space left, the angle had to be correct, capacity sufficient and ease of filling. In the end I managed to fit a section of pipe insulation in… and began calculating how much 2t a tube of this size could hold.

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I then ordered a piece of ali tube to the maximum allowable diameter and cut to length off ebay, and made two end caps using aluminium sheet.

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In the mean time also I was playing with mounting the two fuel solenoids and had to move the chain runner to accommodate for the sprocket offset.

[img]http://i26.photobucket.com/albums/c122/ ... 57.jpg[img]

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 20 Jun 2012, 09:08

I decided to lower the bike, as I’m not the tallest bloke in the world!! In fact far from, and it makes handling and dabbing the floor a dam sight easier.
Koubalink, lowers the ride height by about 1 ¾”:

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I also ordered a CR bashplate off ebay (actually a gift from me ex girlfriend):

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This had to be modified slightly to suit the CRM engine casings – Just a little heat and bending was required. Some bits in the mean time, including my engine casing and previously made pieces turned up from the powder coaters also:

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Also I polished the two headlight mounting brackets:

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The previously made bottom bracket was now powder coated and I popped in the rubber grommets:

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I made some drawings for the inlet and outlets of the mini 2 stroke tank, based upon measuring the original CRM ones so I could use the original cap, filter and piping. I then chopped the tube/tank and angled the outlet:

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This was then tack welded in place. The following photos show the progress of the 2 stroke tank. It was very difficult to ensure it cleared and vibrating or hot parts, and I made two special rubber mounting brackets. To get it welded correctly, I had to use masking tape and markings, have it tack welded, then check it fit, seam welded and then tack weld the next piece and so on until it was complete….

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 20 Jun 2012, 09:19

Finally it was finished, the side bracket was used to mount one of the solenoids:

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And finally it was powder coated… the lads at the powder coaters wondered what on earth it was. I must admit, It does look amazing!! ;)

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The total capacity is 350ml…. which should do 150 miles…. More than a normal days trail riding, however I now carry spare as I did get caught short once!! I also tidied up the loom once I knew it was all working, and taped it a bit like a tree:

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Everything was pretty much done, and to be honest I was buzzing…. Next came the best bit… the strip down, clean, engine rebuild and final build… knowing everything should go back in place. I was still extremely apprehensive though. I began cleaning the filthy engine:

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And polished the modified DEP silencer, from:

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to:

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As mentioned earlier, the standard AR carb diameter was too small for the CR airbox rubber, so I made the necessary measurements, made a drawing and had a special sleeve made at work. I filed down the original lip, and bonded the new sleeve on using araldite.

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The carb also had a thorough clean using a sonic bath, carb cleaner, Cillit Bang and an airline!!

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And jetted it using the Mugen jet kit (thanks for your help Glenn), with a best guess at the jetting, using the advice on this Forum under ‘Modifications’:

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Somebody at work very kindly polished the head steadies I made on a machine, talk about SHINY:

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 20 Jun 2012, 09:28

All the bits I had been collecting were ready for the engine rebuild:

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Barrel cleaned:

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In the mean time I took the suspension off to be re-valved and softened to suit my weight and riding style:

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Now, unfortunately the crank had spots of rust, and I immediately feared the worst!! Hence I had saved a lot of money to prepare for the worst case scenario, which was confirmed when the crank was split. Although no play in con-rod, rust marks are a no-no, therefore I decided to have it rebuilt.

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New conrod kit supplied by Leisure Trail (I think off a Maico 490 or something):

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Here I attempted to clean up casting defects and improve the gas flow in the cases and barrel (please don’t copy this or slate it as I don’t profess to be Stan Stevens):

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I later read that this ‘mirror’ finish is incorrect, and it should be not so smooth, so roughed it a little using a coarse scotchbrite:

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I also trimmed the base gasket over-hang, again to improve gas flow:

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 20 Jun 2012, 14:55

I also gave the power valve a dam good clean. Before:

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After:

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I finally sourced some similar new engine casing bolts, took me ages to find, and had any odd sizes and bits zinc plated:

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Crank cleaned and rebuilt by SEP:

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I think the final, and very most exciting parcel arrived in the post:

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My sexy new wheels, wow was I pleased with them, but gutted they went up £100 just before I was ready to order:

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Also some carbon fibre bits I ordered:

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I cleaned the frame as best I could, but decided not to polish it as it’s an offroader:

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And so here begins the final build (whilst awaiting the engine from Leisure Trail) – Boy was I getting excited, and impatient waiting for the engine to return.

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Ready for engine ;)

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 20 Jun 2012, 15:01

Renthal flexi-lever (I ended up buying both clutch and brake levers):

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Hydraulic brake switches and brakes bled:

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Finally had the rear sprocket spacer finished on the machine (it had to be tweeked to suit the Talon hubs, and lightened by removing excess material):

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Wheels with tyres and mousses, sprockets and discs fitted:

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Yessss….. engine back, and looking fantastic!!

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Freshly plated bore:

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And in she goes…..

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Custom exhaust flange with brand new gasket:

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Swing arm in:

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Coil on and starting to pipe up rads:

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Further progress:

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 20 Jun 2012, 15:08

Boyesen Reeds (I did try the RAD valve for the CRM, ordered from America, but it wouldn’t fit upon final build- LONG STORY!!):

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Cables, wiring and hosing under tank:

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Vaccuum hoses into airbox:

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Getting there slowly:

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Shiny head steadies bolted in place:

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Oil tank ready with solenoid mounted:

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Further progress:

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Fuel in, and now she’s ready to start, I was so nervous, I was literally shaking:

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OK, to be honest took ages to start and I couldn’t figure out why, good spark etc and fuel getting through. Finally started but wouldn’t tick over. Later I found out I had the tickover screw the wrong way, as it works the opposite way on the AR to what I’m used to. So I had her running, now had to get the plastics chucked on and ready for the MOT, which was booked in about an hours time. The final build from the bare chassis only took one or maybe two full days.

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 20 Jun 2012, 15:16

And off she goes for the MOT, which she flew through bar the advisory for no rear chain guard I think:

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Once MOT’d I had to register her at the local DVLA. I had checked all this out beforehand, and got all the necessary forms and paperwork. All seemed to go well, until I got a letter through saying that my ‘Year of Manufacture’ certificate from Honda was wrong (they had put an extra digit in the chassis number). I ordered this well in advance as I know they take a while to come, so I had to pester Honda for a new one, and to hurry up with it. Eventually the new one came, and I went back to the DVLA and registered it. It was now a waiting game for the log book through the post and so I could insure it on the road. Finally this came, and I took her for her first blast on the road!!

Here’s just some of my favourite finished pictures, I hope you like them, apologies for so many:

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Thanks to my sister for the above coloursplash photoshop edit which I begged her for, she had this printed on a canvas for my birthday.
Unfortunately the bike doesn’t look this good now, which is why I took so many scenic photos when I first built her. She has the obvious usual signs of off-road use, but this is why I built her after all. I must say she’s a pleasure to ride, and really puts a big grin on my face every time.

I have experienced several teething problems as expected, all of which I have now sorted. I did re-jet the carb once after a plug chop and a play around, and since have had the bike dyno’d. Max power was 30BHP with 22lbf torque. To be honest I expected a little more, however after reading on the forum, it seems that is about right!! I still haven’t weighed her, but not too fussed. I’d like a comparison to modern Enduro bikes, however I’d not be too competitive, as I haven’t aimed for maximum lightness, mainly practicality and looks.

The project took around a year from start to finish, during which I was at work full time, at Uni part time and bought my first house, so not too bad considering!! It cost in the region of £6,500 to complete, but the cost was nicely spread by buying bits as and when I could afford them. It meant many sacrifices had to be made, but was worth it! It could have been done an awful lot cheaper, but could have also cost a lot more. I don’t regret any of the money I’ve spent on it, as it’s now exactly as I want it!! Just one wheel is worth more than my entire car!! Haha.

Here’s a few pics out and about (apologies for the ones taken on my phone):

Here she is, line up against my mate’s AR, a nice comparison:

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And lastly a few action shots of me pratting around on her, not long after a steady running in:

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Finally, I must say a massive thanks to the following people, who have helped me in one way or another towards this project, without you all, I’d probably be sticking a box of bits on eBay.
Therefore, a big thanks to:

• Firstly, everyone who has helped me financially, by either lending or giving me money towards it, or buying Christmas/Birthday presents which are now all over the bike.
• Everyone at work that has helped (far too many to mention) for all your time and efforts.
• All the lads on this Forum for continued support and advice (even though I managed to keep the actual project a surprise).
• Shock-Tech suspension for the suspension re-valve and set up.
• Pro-Racing for all the excellent quality aftermarket electrical items.
• Gary at Fusion graphics for the fantastic custom graphics kit, thanks for your patience!!
• Both my neighbours for receiving parcels all the time when I’m at work!!
• Leisure Trail for sourcing CRM parts, and the full engine rebuild.
• The lads at CJ Ward for all the Powder Coating.
• MX-Bits.com for all the pro-carbon accessories and those lovely wheels!!
• A special thanks to Scott Clarke and Glenn Williams (Glenn who owns a CRM mk2, and is on here as ‘250greenlane’), two very good friends of mine who have helped in many with their knowledge and experience, and kept the banter rolling. Massive thanks lads, I owe you both a beer or three!!

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by njhardy » 22 Jun 2012, 08:08

A stunning project Shaun- I bet you are well proud. Well done. What's next?

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by Active Rascal » 25 Jun 2012, 11:25

Thanks very much Steve for posting that up, and thanks nj for the comment. No plans next, I was going to do my old AR up as a super, super-moto, but I can't justify spending the money!! :(

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by back off road » 26 Jun 2012, 00:10

cant justify spending the money ???? how do you justify £6.5k on a trail bike project ?
Im thinking about a bike with more valves than a powervalve

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by knackeredMk1 » 27 Jun 2012, 09:56

BOR - Won't even bother answering that :roll: .

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Re: Shaun's (AR's) CRM250AR/CR250 Conversion

Post by Active Rascal » 27 Jun 2012, 17:06

Yes I can justify it, to be honest this is probably my one and only bike project (at least for a very long time) so I might as well do it right, have it exactly as I want it and have no regrets. Hopefully it will last me a long time. Trail riding and Enduro is my hobby and passion, and I try to use the bike at least once a week. A super-moto to me is a 'nice to have' and would hardly ever get used - Hence I couldn't justify spending a small fortune on it, when as I said, one wheel off the CR/M is worth more than my car!! :)


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