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‘79 Honda CX500 – JMR Customs

Posted on June 30, 2014 by Andrew in Tracker. 28 comments


‘Plastic Maggots’ they called them. And all for an unassuming little fairing that some ‘genius’ decided didn’t suit their tastes. Talk about throwing the baby out with the bath water. Thirty five years later and the Honda CX series’ full potential is only just being realised. With a bullet-proof v-twin, shaft drive, liquid cooling and failsafe electrical system, this is a bike that oozes potential. Just ask the boys who used the bike to take the 500cc pushrod record at Bonneville. Them, and the very talented Josh Mott of JMR Customs.


“This is my latest creation, a 1979 Honda CX 500 custom,” says Josh. “I’ve always wanted the chance to put my own twist on a CX, so I put the word out around the Boise area and a couple of months later Boise Vintage Cycle unearthed one that they kindly donated to us. The bike was in very rough condition, but like always I do my normal checks. If it has spark and compression then nine times out of ten I can clean the carbs up and get it running. The bike had both and it fired right up.”


As soon as Josh knew he had something to work with, he began coming up with ideas. But not before stripping everything off the bike that he wouldn’t be using. Then he and his dad started brainstorming. “I had been noticing that most everyone building up the CX model had done a low-mount exhaust. The idea was to do 2-into-1 pipes and have it exit out the center of the rear fender right above the wheel. I was able to have them come straight back and connect right in the center of the rear wheel. The rear fender I made around the exhaust in 3 sections of 16 gauge steel.” He also made the seat out of fibreglass – remarkably, it was his first time working with the material and he managed to impress himself with the end product.


By building the exhaust up through the centre of the bike, Josh had the added task of relocating the wiring, battery, CDI, and the regulator/rectifier. Unsurprisingly, the only place he had room to place them was underneath the motor. Accordingly, he built a battery box that he could mount all of it components inside cleanly; the wiring now runs down the frame in between the carbs and neatly into the battery box.


The headlight assembly was all hand-made with the headlight itself coming off of a XS650 Yamaha. Josh wanted to make a cool-looking dash and headlight bucket all in one piece, so the speedo, tacho, temperature gauge, choke, and ignition switch are all mounted onto the dash itself. And the hat tip to the original ‘plastic maggot’ fairing has not gone un-noticed… at least here in the Pipeburn offices.


“After most of the chassis was mocked up, I noticed the stock suspension and triple clamps made the bike look slightly like a chopper with its uphill stance. The stock triple clamps raised the stance 1 inch. So I found a set of CL360 clamps that (surprisingly) fit the frame with no modifications and it dropped the bike by 1 inch. It helped, but it still was not where I wanted it. I then shortened the forks 1 inch from the inside and installed 1 inch longer eye to eye shocks on the rear. By doing this, it gave the bike a great ‘bulldog’ look and made it look nice and level.”


The wheels were something that Josh took a chance on. He pre-drill holes 2 inches apart all the way around the wheel, powder coated them black, and then drilled them again for a highlighted look. With the white wall Shinko 777s, we think they came out pretty damn nice.


“Everything on the bike was done in-house, except the powder coat and upholstery. The paint credit goes to my dad, Randy Mott, and the photo credit goes to my girlfriend, Kate Robbins. If you have any questions, feel free to get in touch.”


  • Fantome_NR

    These guys are among the very few who actually get the stance right on the cx500, which is very awkward and ungainly. They nailed it here.

    • JBB2

      I agree that the stance worked out well, from the lowered front, shortened forks, and raised rear. I think it also helps that the black part of the two-tone paint on the tank makes the bulk of the tank sort of disappear in the side view. I probably wouldn’t make the same choices Josh did throughout, but I find it hard to quit looking at this bike. Nice work.

      • Fantome_NR

        Yup. Lots of stylistic things I would have done differently, but the core of the build is solid, because they solved the inherent stance problem of the cx500. It’s a nice rendition of a street tracker.

        • JBB2

          I just picked up an ’82 GL500 from a neighbor fo’ free; I hope I can do something half as clean as JMR did here. It’ll have to sit something like this one does.

      • enorm

        I’m not sure raising the rear is a good idea, the power train suffers a performance loss from having a “crack” in it – as seen in the pictures; the shaft is pointing downwards a little too much for my taste. Nice build however

        • JBB2

          Is there a performance loss? The power is torque times rotational speed; the speed won’t change with the angle and I don’t think the torque would. A sharp angle would wear the joint out faster, though.

  • The bike looks special. I like how the exhaust was sorted, but to be honest, not sure about front end looks, it seems a bit high to me.

  • Fix

    I didn’t realize how weedy the stock forks are on that bike.

  • ccc40821

    It wasn’t just the fairing that screwed up the original CX’s styling, as the gas tank was an absolute disaster too, and likely earned it the nickname. The Custom version of the CX that eventually followed was as nice as the first attempt was ‘orrible. Wonder why they didn’t just start out with a regular tank and fairing to start with.

  • Ripvan

    Stock front and ohlins rear what’s that all about

  • Lewn

    Some lovely touches on this bike, they got it 80% right IMHO.
    Love the real world tires, Renthal parts on the front end, new dash, seat tank, paint, mini cowling and mini front fender. With the new shocks modified forks the bike does sit well.

    However on the minus side the old brakes, and old forks do detract somewhat from the overall build. Also I’m not sure about living with those pipes in the real world. Aesthetically…yes good idea, nice modern muffler with no pipe wrap or other silly hipster-esque nonsense which is good, but it seems like you’d be roasting your legs for the sake of style?

    • Moshjott

      Actually you don’t even notice the heat. The pipes make the bike run exceptionally well. They make a 500 feel like it’s got more hp then what you it really has. As far as the suspension and brakes? They work pretty dam good for a bike that was made in 1979! It’s not like you’ll be racing this bike at Daytona?

  • bsa

    Another sweet bike Josh! I loved your CB450, but I think you’ve definitely topped it with this one.

  • Andy

    Why do people keep those awful stock carbs?

    • Moshjott

      Because CV carbs are very good carbs if they’re tuned right!

      • Andy

        “if they’re tuned right” is the catch with those CV carbs. Everything was figured for using the factory airbox and stock double-walled exhaust. Rebuild kits for those keihins along with air cut-off valve sets put you at about 50-60 a pop. Mikuni VM30s or 32s are 80 on up and easier to tune.

        • Moshjott

          Both carbs are good carbs but cvs are more touchy when it comes to changing the air box and pipes as you said. But when tuned right these carbs work amazing. There’s a lot of work that goes into getting those to work with a 2 inch exhaust.

  • Genji

    CV carbs with pods and some hot pipes right next to them. I bet this thing runs great! I like the form but the execution doesn’t look well thought out. Plus, just looking at the burnt pipe, you can see it isn’t running right.

    • Moshjott

      Obviously you don’t know what your talking about! No technician in the world that is a performance tech would tune a motorcycle off the coloring of the exhaust pipes. They’re made out of mild steel and mild steel blues when it gets really hot.

  • CQ

    Josh…ignore the naysayers….no need to dip to their level. CQ

  • duh

    Is your sister enjoying the bike you built for her??

  • TheRumRunner

    Everyone here that’s hating… where’s your bike?

    • duh

      not hating…sometimes humor is used for a point. Lots of nice touches here…not fond of the whitewalls and color scheme

    • Bob D.

      EXACTLY. Not to mention that this is straight-up *awesome* work. On my best day I could think up some of these ideas, but never could I execute them at this level–and I’ve been tinkering with bikes for damn near 40 years. Hats off to you, Josh.

  • Mr. J.

    Hi from Germany,

    in the 80s I got two of these bikes – ugly (?) but absolutely reliable. Rode them for more than 10 years.
    When I saw this bike i didn’t believe what I saw – one of the beautiest custom bikes I’ve ever seen, especially in the cx500 custom “scene”.

    Chapeau to JMR Customs, good work. Or in german: fantastisch (fantastic).

    Mr. J.

  • bigal

    I’ve always thought the CX twin motor was special and a thing of beauty alone. These guys managed to build a bike around the motor worthy of its unique engine.

  • arnold

    I wouldn’t be not as crabby if I was able to hear what that exhaust system sounded like at full boil.