CCM 644 DS

Needed a project to keep me sane. Just didn’t realise that it was going to be a complete rebuild.

So what is a CCM 644 DS, well basically its a bitza. CCM built the frame and swinging arm then used parts from several different manufacturers, Brembo brakes, WP suspension, Suzuki XF650 engine, plastics from Yamaha and Honda. You could think of it as an uprated DR650. The DS part stands for dual sport, so many came with offroad and supermoto wheels.

Note: My bike is in supermoto trim, so some parts may vary.

Info on CCMs is a bit hit and miss, so I’m documenting everything I use for future reference. You don’t have to use these parts, but it will give you a starting point. When searching for chassis parts I generally start looking at early 2000 ktm 250 exc stuff.

Part Item Identified
forks seal kitAll-Balls Racing – 56 – 126
fork bushes kitAll-Balls Racing – 38 – 6053
taper roller headstock bearingsAll-Balls Racing – 22 – 1026
rear master cylinder seal kitAll-Balls Racing – 18 – 1079
rear caliper seal kitAll-Balls Racing – 18 – 3050
front caliper seal kitAll-Balls Racing – 18 – 3047
brembo front padscarbon ceramic 07BB04.CC
brembo rear padscarbon ceramic 07BB02.CC
braided hose kithel performance HBF0881
rear wheel spoke nipples8 gauge / 7.6mm barrel
Side Panelsufo YZ 125 / 250 (96-01) – remove air scoops
Fork Protectorsufo all CR / CRF
rear mudguard/fenderufo YZ 125 / 250 (98-02) – cut required
led rear lightpolisport RSP LED 3.0
front forksWP 4357 MXMA – google for service manual
front wheel bearings2 – 60042RS
rear wheel bearings2 – 60042RS + 1 62042RS
swinging armmy choice –
2 – HK2016.2RS-MB bearings each side plus 1 SD20X26X4A-INA seal, time will tell if this works, but its better than stock
caliper bleed nipplesM10 x 1mm
Fork cap o-ring*46810016 – 48 x 2mm
Fork slider snap ring*43570099 – 53 x 2mm
ktm fork guard bolts59001092050
ktm foot rest springs54603041000
ktm foot rest pins54603044000
front master cylinderyamaha yzf r125 brembo – requires m10 x 1 to m10 x 1.25 adapter – hel performance H8153132C
Bearingsrefer to pictures in engine bearing section – all koyo – except 3
3suzuki 09262-22028
* additonal parts to complete fork rebuild on top of All-Balls Racing kits

Issues so far –

Completely stripped the bike as it was a mess.

  • Plastics old and in need of replacement
  • All bearings shot
  • gearbox jumping out of gear
  • shock leaking
  • rear master cylinder leaking
  • rear wheel nipples seized and rusty
  • side stand loose
  • wiring – wires shorted, poor soldering, loom unwrapping
    • loom also butchered to fit Acewell speedo
  • engine oil leaks
  • chain and sprockets shot
  • rear wheel sprocket bolt holes filled with filler and oval
  • seized engine bolts
  • headstock bearings shot

I’m currently getting the rolling chassis completed, as I have a small man-shed and there are currently parts everywhere.

So far –

  • frame and subframe have been cleaned, blasted and resprayed satin black
  • welded up the side stand hole and redrilled it, blasted then painted satin black
  • swinging arm cleaned, blasted and new bearings fitted
    • stock is single bearing and o-rings which is crap, I fitted 2 sealed bearings each side plus an extra seal on the exposed side
  • rear wheel – rebuilt with new hub, spoke nipples, seals and bearings
    • gallery below shows using a blow torch, gentle heat, and internal bearing puller, makes removing bearings a pice of cake
  • airbox stripped and cleaned – issues with captive nuts
  • rear caliper rebuilt plus new piston – I use an airline on low pressure to pop pistons out
    • ktm 28mm piston was very expensive at £40, and my local dealer was out of stock, did some measurements and bought a brembo car caliper piston for £9, same part,  wtf?
  • new brembo ceramic rear pads
  • rear master cylinder rebuilt
  • new rear brake line fitted
  • new rear mudguard fitted
  • new rear light fitted
  • new side panels fitted
  • front forks rebuilt – new bushes and seals – picture shows using long socket and ratchet to hold the fork leg when doing the bottom bolt up
  • fork yokes cleaned
  • headstock bearings replaced
  • new lockstop plate
  • new renthal fat bars
  • new throttle
  • new renthal grips
  • front wheel cleaned – new bearings and seals
  • front brake caliper rebuilt
  • stainless bleed nipples fitted to front and rear calipers
  • new stock dash bought and fitted
    • bargain deal, but kmh speedo, sourcing 60mm alternative
  • Polisport MMX headlight and spacing brackets fitted
  • ufo supermoto front mudguard fitted
    • junked the CCM cable guide and fitted a plastic ktm one. required spacers – plastic 10mm OD x 5mm h x 6mm ID
  • started cleaning carbs – wtf

  • Fitted fork guards – factory ones were CR, so I bought ufo CR and the foul on the wheel as the CCM front wheel is offset to the right.
    • Dremel’d side off guard and fits fine
    • will buy some ktm ones to try
    • used ktm fork guard bolts
  • front master cylinder was very damaged, couldn’t find a replacement ccm one, turns out same MC is fitted to a yamaha yzf r125, just make sure you get the brembo one plus a m10 x 1 to m10 x 1.25 adapter
    • blasted MC lid and lever to match cleaned up clutch lever
  • factory foot pegs bolt on, bought some ktm pins and springs to try
    • pins too long, will trim and redrill split pin holes
    • drill foot rest mounts and foot rests with 10mm drill – very carefully!
  • ordered parts to start on custom wiring loom
  • photoshop’d ccm loom diagram to give full length view, working on colour wiring diagram that I’ll check during loom build

  • finished front caliper and fitted, bolts will be tightened – this is dry build!

Engine Rebuild

Started work on the engine rebuild and hit a, temporary, brickwall as I’d forgotten about the snapped off bolt in the crankcase.

Tried penetrating oil, eze outs, left-hand drill, heat, nothing would shift it. Had to drill through the side of the case to get to it. Its now off with a friend to be tig welded, so that I can redrill and tap the hole.

Looking closely at the case the bolt hole has a small hole at the back which would let moisture in, so I’d recommended ensuring that the bolt in that hole has copper slip or similar on it.

Decided to do the crank bearing, as I’d borrowed the Suzuki tool to remove the bearing. Pretty straight forward job using tool and air gun, you could potentially make a tool out of a large socket and dremel out the shape required. I used the old bearing as a drift to fit the new one.

I also removed all the old bearings from the crankcases, using a bearing puller and a blow torch. In a few cases its easier to use the puller as a pusher.

There’s one unique bearing that has a rolled pin fitted, everything else you can get from a bearing supplier but that one is dealer only and ridiculously expensive.

Some of the bearings also have a seal only on one side, so you have to buy sealed bearings and remove one seal, I’ll detail all the bearings when I get to fitting them.

I’ve used Koyo bearings throughout.

removing the crank bearing

Hold up!

The above picture was me practicing on the wrecked original engine, just realised on the actual engine, that I’m using, when I split the crankcases the bearing came out with the crank without me having to remove the nut. Stupidly I’ve assembled the bearing and nut onto the crank already, when the bearing should be pressed into the case and the crank pulled into it.

Will disassembled and do it right.

Moral of this story – RTFM! ( read the f….. manual ) – sigh!

Crank case Repair

Crank case has now been welded and after an hour or so with a Dremel and some files is nearly finished.

I used a sharpie to emulate engineer’s blue, makes it much easier to see what you’re removing. I levelled the weld to the crank case by filing and sanding across the case to spread the load and keep things level.

Engine Bearings

The bearings are a little strange engine as some are dual sealed bearings with one seal removed. Caught me out as I measured the bearing in the cases and then ordered them, only to find on removal there was a seal on the back face of three of them.

You can spot them in the photos as the bearings have an extra shoulder visable where the seal would normally sit. The 3rd bearing with seal on the back is the gearbox output shaft bearing.

and what happens if you don’t maintain your engine/oil levels…..

5th gear had let go on the original engine, so I’m replacing both 5th and 3rd (usual gearbox issue) gearsets. They were also under tolerance when measured.

All bearings are being replaced because –

  • A – you should
  • B – check video below

source of gearbox issues, to start with I could barely turn the shaft.

Gearbox Rebuild

Started rebuilding the gearbox with new 3rd and 5th gearsets. I’m doing those because 3rd is the normal weak point and my gears were outside tolerance and on the original engine 5th let go destroying it, prior to my ownership I should say, 5th was also outside tolerance.

Driveshaft rebuild is pretty straight forward, I’m also replacing all bushes, washers and circlips. The only thing to be aware of is there are two washers that fit together with offset splines, so they act as a basically circlip but thicker to take up slack.

To fit these you must push the circlip on the other side of 3rd gear further down the shaft so that you can locate the two interlocking washers first then slide the gear back and fit the circlip into its groove.

You also need to be aware of this for disassembly, otherwise there’s no way you’ll get it apart. Shown in the first gallery picture, 1 and 2 interlock and 3 needs moving in the direction of the arrow, past its locating groove then brought back.

Countershaft has caused a stopping point at the mo due to 2nd gear being pressed on. My gear puller wasn’t up to the job. So will call in another favour and borrow one.


Moved onto cleaning the carbs. They were in a state and required extensive cleaning plus standard o-ring, gasket replacements plus stainless bolts. Vacuum system had previously been removed so I bought the proper Suzuki blanks to cover the outlets.

I don’t have a ultrasonic cleaner, so I just use degreasant and elbow grease plus a pure brass wire brush. I also managed to get a new choke linkage on eBay at a bargain price.

Have a few stainless screws on order to finish the rebuild.


No Major Updates

I’ve worked through Covid, so am having problems finding time for the bike of woe.

Gearbox problem expanded as I tried at a friend’s bike shop to remove 2nd gear and with heat and a massive puller it didn’t shift at all. So did some googling and managed to get a NoS shaft at a very good price, but that mean’t I required more parts to build the shaft, currently awaiting 4th gear arriving.

Have managed to blast and paint the engine casings and bought a small press, so will be fitting all the bearings soon.

Once the engine is sorted I can make the wiring loom and then there might, finally, be light at the end of the tunnel.