Slow Progress

Moving house soon so updates have slowed as I’m clearing stuff to make the move easier. Gas Gas has been sold to make space.

Swapped out some bolts to flanged button head allen bolts, these can be tricky as the head is shallow but as long as the threads are clean and you use some anti-seize then there usually aren’t any issues, but they look so much better.

Also sorted the plastic bung that covers one of the breather outlets on the airbox, I used XF650 parts.

Engine Paint – Take 2

Re-blasted the front pipe, then coated it with flameproof primer and top coat curing each coat with a hot air gun.

Still not convienced about the VHT paint. When the bike was running it started to produce tiny bubbles and smoked like crazy, but did stay on the pipe. I checked the temp of the pipe with a thermometer and when running it only hit 320c way below the 1000c the paint can cope with.

Still have to repaint the mid pipe, as that discoloured and will look for an alternative paint in the future.

Tidying Earth Cables

After doing some rerouting of cables found that battery earth cable was way too long. So cut and recrimped it to sort it out.

Also forgot to tighten the top shock bolt and once the subframe is attached you can’t get a socket or spanner on it. So purchased some ‘s’ spanners and cut the end down to fit, had to shorten an allen key as well using my dremel cut off wheel.

Engine Paint

So the VHT engine paint I used requires some, fairly, specific heat cycles to cure it. I started the bike to do this and within seconds the header paint bubbled and in plaves started to turn a gold colour. I stopped the engine and once cooled the header paint cracked and lifted off of the pipe, sigh.

The exhaust is painted in flameproof flat aluminium rated to over 1000c and the engine is painted in engine enamel rated to 288c and fuel/oil resistant.

Also when starting one carb slightly leaked and as I wiped the fuel off the starter motor, the engine enamel clear coat came with it, WTF. You can see highlighted in the photos below where the clear coat has smeared as the fuel dissolved it.

I’ve contacted VHT to try and understand what’s happened, as the entire engine is painted with their paints which are supposed to be heat and fuel proof.

I’m hoping you need to complete the heat cycles to cure the engine enamel and before that happens it can be affected by fuel, so you have to be really careful and I was unlucky with carbs leaking on to the starter motor, which is easily removed and repainted.

Throttle Postion Sensor (TPS) Adjustment

Started the bike to cure the engine enamel, more on that later, and noticed the throttle response was poor so decided to check the TPS was correctly adjusted as I just ball parked it on reassemble.

The process its very straight forward, remove the fuel tank, remove the TPS connector and take a resistance reading across the outer pins of the TPS. Once you have this reading multiply it by 0.76 and this gives you the value you should get when checking the top and middle pins at full throttle. In my case it was 5.0 k Ohms, so multiplied by 0.76 gives 3.8, the actual reading was 3.98.

I used a cable tie to hold the throttle wide open and found my value was off, so loosened the two bolts holding the TPS and adjusted it to get the correct reading of 3.8 K Ohms.

Throttle response was much better once adjusted.

More Tweaks

So more tweaks towards the finish line. The front wheel wasn’t right and close inspection was way off line, I checked the parts diagram and realised I’d fitted the spacers incorrectly once that was sorted I fitted the seal and speedo replacement spacer and all was good.

Next was the speedo pickup, soI cut a small slot in the bottom of the fork protector and attached it with a cable tie. Seemed the most pragmatic solution without spending hours making a bracket.

Also removed the sidestand cutout switch, as the sidestand didn’t operate it properly and there was no way it was every going to be 100% reliable due to how poorly it was made in the first place. I made a small loop connector to join the ends together.

Drilled the footrest and mount for the new pins, I did one side ages ago and never got round to the left so finished that and repainted the mount and footrest after drilling the holes out to 10mm.

Then I spotted the lockstop plate barely hit the lockstops so lifted it with a couple of washers and fitted the new front spocket cover.

Chain Guides and Shock Guard

Started sorting the chain guides and ran into a few issues. The guides supplied by CCM are for 520 chains and as 644 models use a 525 you need to open up the front guide to make it fit properly, or just let the chain cut its own path, I went for the former using a dremel and sanding drum.

I replaced the lower chain tensioner’s plastic guide with a nylon one from Haines and the lower rear guide still thinking about its purpose, as not sure it adds any value. I fitted the new nylon part by heating it in a cup of boiling water then attached a nut and bolt to one end and gently bent it to shape, will change the nuts for nylock ones.

Once the guides were in place I rivetted the chain together and discovered another issue, the chain hits the tyre. After speaking with Anthony at Haines I adjusted the rim by offsetting it slightly to the right by attaching my dial indicator to the swingarm and loosening and tighting opposite spokes until I had clearance.

Fitted a new rubber shock guard, requires 4mm x 10mm rivets, I added some 4mm washers to the back to ensure the rivet clamped on to the holders. typically ran out of rivets, sigh!

Footpeg Pins

Finally sorted the footpeg pins, found some hollow stainless ones on eBay, they were listed as being for a KXF250.

They are a bit longer than required so I cut 5mm off the end and redrilled the split pin hole using a cobalt drill. The mounts of the frame were drilled out using a 10mm drill and then deburred and repainted then the pegs fitted with KTM springs and stainless R clips. At the same time I sandblasted the rear brake pedal and fitted a new pivot bearing.

Finally result is much better than the rubbish CCM nut and bolt arrangement.

Fuel Tank

Started by cleaning the tank using brake cleaner to remove the old graphic’s marks then polished it using a soft polishing mop and compound mounted on a drill. Then I stripped and rebuilt the fuel tap.