JHoe's Duke 390 revival!

Mirius said:

Stock rear shock bolt is grade 10.9 so it might be worth trying to find a better bolt. I’d rather replace a standard bolt when it needs it than have a prettier but weaker one snap in such a critical place.

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Agreed. I'll get a new bolt from KTM themselves today.

I visited them yesterday for a new exhaust manifold gasket and couple of brackets. While they didn't have the brackets in stock, they were willing to order them for me. Right now I've made a sizeable list lol. Apparently the belly pan is cheap, around $8 or so. Might as well replace it.

Smalls cuffs on the rear wheel were polished out





Finished coating them all



The cleaned and coated sprocket carrier looks fabulous hehe



If I manage to get new handlebar grips, I'll tackle stripping the handle bar, sand and paint it as well as the left side footrest and gear levers, which already have a ton of surface rust on them.

Today's progress :

Replaced all the fairing philips screws with SS allen units



Grab handles painted matte black



Bought more parts from the KTM service center.
Managed to get the fork protector only for the right side, have placed an order for the left one as well.
My bike never came with a toolkit so bought one.
New side stand bolt to remove all sloppiness from the existing side stand
New ABS rings and rotor bolts when I do up the wheels. @Mirius you mentioned in one of your videos that rotor bolts have red threadlocker on them, turns out it is pre applied and all the new units have them.
New handle grips. Come to think of it, I should get a new throttle cable and change it as well.



Exhaust is all put together with new dampers everywhere. Heatshield is held with new SS bolts with anti seize on them. The nut inside one of the bolts holding the heat shield broke inside, I had to take the exhaust again to the welder who cut a small portion, retrieved the broken bit and welded on a new M6 nut in it.

Dirty_Duke said:

You are doing some fine work here. Anymore updates?

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Yes - there is plenty. It was very slow progress, you'll find out why and I did not update the thread.

This chapter starts off on a whim. The last maintenance checklist I hadn't ticked off is changing the coolant. One fine day I woke up and decided oh heck with it, lets just strip down everything cooling related anyway

and so I did. I had to leave the hose from thermostat to the head in place as I could not get any of my pliers in to take off the clamp. I ran some water through the pipe to make sure I flushed the old coolant from the block.



Since the radiator was off, i could clean around the head and even better with just the exhaust off. It was prompty treated with some ceramic coat as well. I noticed the hose connecting T-pipe to the thermostat has been rubbing on the engine. not good.



There were some "brown chunks" stuck on the radiator cap that got me nervous



Inside of the radiator didn't look too bad for being almost 9 years old. I blocked off the holes with some self fusing tape, filled it with a mild acid and let it sit for couple of hours anyway and it helped...somewhat.



Worst among corrosion was actually the nipple that goes to the expansion tank. Inside of the pipe had some off cream pastey substance inside

JingalalaHoe said:

New handle grips. Come to think of it, I should get a new throttle cable and change it as well.

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And I did. Throttle cable was very old stock, manufactured on July 2016. The 2014 came with a newer throttle cable and I made sure to get the right part for my 2013 bike. I also got a new water pump seal, O-ring for the T-pipe, new trim around the speedo which KTM calls it "the dashboard" and a new windscreen because it was cheap and my old one was scratched badly. I also got a new clutch release fork from newer dukes because it seemed it was longer and that would make the clutch easier to operate. New spring for it because the old one is rusted.

Next came off the water pump cover and I encountered more issues, which I have documented here : Need help with marks in the water pump cover / impeller

Come with a prospect of having to buy a new thermostat hose, off I went to the service center again and got a new pipe. I did not get an exact part match and instead got an "updated part"



It seemed a tad smaller than the old one, which I saw it as a win since it wouldn't rub on the engine case anymore.

So with the whole water pump cover saga behind me, it was time to install the new one. Oh no it wouldn't be that easy, sigh. The aligning dowels on the old cover were stuck on with some kind of glue and they just REFUSED to budge, not matter how many times I tried with pliers.

Off I go to the service center who told me that don't have the part. none of the bajaj service centers had the part either. Stuck with a prospect of a non running bike, I thought of going to my welder guy, have him apply heat and remove the old dowels for me.

On the way to the welder, I gave my mechanic a visit. I showed him the old cover, he used locking pliers was able to extract those ****ing dowel pins. PHEW now I can finally go back to putting together everything.

While I was at the KTM service center asking for the dowel pins, I noticed a 2nd gen radiator fan in their junk pile. I asked them if I could have it as I wanted to transplant the shroud to my old 1st gen fan. They gave me the part since its trash for them anyway.



It looked straight forward to me, take off the 3 screws and swap over the shroud - the mounting holes all match up so it must be a direct fit, however it wasn't that simple. I had tot ake off the fan blades to swap over the shrouds - this meant destroying the blades. I could have carefully cut the old shroud around the motor, used it as sort of a "cap" on the working fan. This was again a bit complicated, I would have to make cuts to the frame of the working fan to make it work. I did not want to cut and paste something as critical as a radiator fan, however I may be sure that it would hold. So I let it go and use the old fan as is.

Enough OnlyFans rant, lets continue with the rest. The overflow tank was cleaned inside with a bottle brush thoroughly, there was some orange debris inside.



When it came to put everything together, the radiator fan is held to the radiator with some weird screws with tabs. I unfortunately lost one in my garage, spent over 1.5 hours searching for it and couldn't find it. I found a screw with a low profile and wiiide head, similar to the screws used to secure the plastic parts on our bikes but in M6 thread. Thankfully this hack worked and the nut holding the radiator fan torqued up just fine.



With these, all my cooling related problems would be solved, for not at least.

I may have failed to convey how FRUSTRATING it was to get the cooling parts sorted -

Day 1 - I take apart the cooling loop, go to the service center and get myself a new water pump seal and T pipe Oring
Day 2 - I discover the broken water pump cover. Hop over to Service center again and get new cover
Day 3 - Notice the damaged hose. Go to service center AGAIN and get it
Day 4 - Stuck dowels. Go to service center and it isnt available.

All these delays are because of my inexperience dealing with motorcycle cooling loops including inspecting all the parts at once and stop assuming other will not be other things wrong after finding one faulty part.

However these delays gave me time to work on other parts just to keep myself busy and not drown in despair. One of these was refurbing everything on the handle.

So I had purchased these handle grips from a TVS Apache RTR - an Indian commuter bike. It has the most supple grip out of ANY bike Ive tried, even better than the really expensive touring bikes out there. All my bikes are running grips from this bike.

It comes with an accelerator pipe, however I did not check in advance if the orientation is the same and if it would work on the KTM.

The moment of truth when I opened up the KTM right side switch, it will work!



However I celebrated too early. Thedre is an extra plastic section after the cable lock that would interfere with the throttle operation



It only took me a minute to snip off the excess using my trusty side cutter



Handlebar and its holder got a fresh lick of paint



Handle bar switches had tons of muck and years of tired plastic on them



They were deep cleaned, I doused the electrical connectors inside with a considerable amount of iso propyl alcohol to make sure every little bit of water inside gets absorbed. The eventually got their ceramic coat as well.



As expected, the hand guards were touching the throttle grip when I tightened the bar end weights to the handle. Last time around, I trimmed the rubber on the grips but I did not want to this time. Instead I stacked on some washers till the two did not touch each other.



As for finishing touches, I replaced all the bolts and screws with SS allen bolts, inspired by @Syer Shulver . They look nice!



With this done, I realised I put on the top portion upside down. I need to take it off, flip and put it back again. Ugh.

Right, I had some more time with even more cooling delays so I decided to tackle the front end, which I had planned to do later on which involved taking off the wheels. But oh well.

Filthy corners



Cleaned up. Every nook and cranny of the alloy, especially the rectangular pockets right behind the rotor were also cleaned. It was difficult witht he rotor in place but managed it.



Insides of the front fender, before



and after



Front fender got a really good polish. It was ceramic coated along with remainder of the front end, including front alloy, caliper and fork legs.



I took off the rear foot rest, painted them and assembled them back with new Orings, SS washer and cotter pins. Took apart the gear lever and gave the same paint treatment.





At this point, I lost the screws to fix the fan to the radiator. I spent over an hour searching for it and just gave up. I luckily found an alternative I have posted about in my previous posts. But my headaches were not over yet.

I had put in the end can of the exhaust into the bike and left it as is with the fresh rubbers. These new "rubbers" were much much stiffer than the perished remains that were before. This also meant the tab that was welded back did not fit at all. No matter how much shoving I could do, that hole would just not line up.

I finally gave up, took the exhaust out. Went back to the welder, told him to cut the ear and extend it out by another 5mm. This also meant the paint and ceramic coat I had done on the exhaust would also go into the trash. I just wanted to put together the bike for now and worry about cosmetics later. Once I was back, I sanded the area that was welded and did a patch up job with the matte black paint.

Once I got the old dowels out, I put in the new water pump gear and then rest of the pipes. I thought of putting the exhaust on before the radiator as it seemed easier.

So went in the exhaust. Again things did not want to go in and it took me a lot of shaking and cursing before the bend pipe went into the end can. I let go a huge sigh of relief, buttoned up all the nuts and bolts then called it a day. I remembered @1jzsupra 's advice not to let fingers touch the polished exhaust surface. I switched to a new pair of nitrile gloves then proceeded with assembly.



Come next morning, I was excited to finally put everything together and get the bike running. I slapped on the radiator and fan and prepared it for fillup. I went with distilled water + redline water wetter instead of regular coolant, prime reason being I like a pinkish/purple coolant. My PC is running on redline water wetter and car with Glysantin G30 for reference.



The radiator took around 1030ml before the bleed screw started to overflow. I topped up the overflow tank to the max.

I was now very happy - The manual said 1100ml of coolant capacity and I got close to it! I was excited and put the tank cover on. I bolted on everything down to the last screw, then I found one of the rubbers which was mounted from inside of the wings, on the floor. ** the * **.

Took off the tank cover and this time I decided to put it on last. By this time I was pretty frustrated again. I cooled down then the hanging headlight irked me off. The insides were all dirty and dusty, the plastics around it were badly faded as well.

So took them all off



Cleaned them all, I realised I missed coating few spots on the forks which were obstructed by the headlight. Promptly finished them all off. Fitted them back on once the coatings cured somewhat.

With the bike prepped for start, I connected the OBD2 adaptor, fired up torque. Started the bike and it seemed to run just fine. I read somewhere about the 15 minute adaptation for idle and thought of letting it idle for 15 minutes. I was facing bad lumpy idle where idle RPM would see saw from 1500 and 2000 RPM. and I had nothing to lose while I use the time to monitor temperatures.

I started with an ambient temperature of 26*C. The temperature touched 95*C and the fans kicked in, they shut down when temp went down to 90. I did some homework on this forum about temperatured whent he fan comes on and off, this seemed to be in line. Fans kicked in again and turned off then the 15 minutes were up. The idle seemed to have somewhat stabilised and I wasn't convinced this worked.

With the 15 minutes of running, the clear pipes started turning golden yellow. I'm glad the yellowing was even and no fingerprints could be found.



Come next morning, the tank cover got a round of polish and fitted on the bike



Finishing touches, the new tool kit goes under the seat. Belly pan was fitted back.



With this, the bike was fully put together

With the bike fully assembled, I went out on a shakedown trip, 60KMs to nearby paddy fields. I carried my toolkit and a liter of distilled water in case of any leaks etc.

Started the bike, went well. let it warm up for couple of minutes. Gave it a bit of throttle and the bike died. So there is still something to be fixed.

Nonetheless, I started again, gave a bit more throttle to prevent the engine dying and set off. The bike felt surprisingly smooth, smoother than before and less vibey. Was this the new comfy handle grips at play or was it placebo?

I reached my destination without any issue whatsoever. Stopped to take some pictures









When I reached back home, the idle was more or less stable now, with 100rpm fluctuations instead of the earlier 500RPM. The power band had become smooth and linear, no longer peaky. Riding the bike in the city is now so so so much better and almost all knocking down below has disappeared.

At this point, I'm not sure what made the bike better. Was it the new Motul 300V oil? Slipper Clutch? New O2 sensor? switch from 91 octane to 95 octane gas? But I'm loving the end result!

There will be a small hiatus from me at this point as I want to spend more time riding the bike than wrenching. Soon I'll be taking off the footrests to paint them and changing the steering bearing set. Any other problems/issues will be addressed and documented here too.

JingalalaHoe said:

There will be a small hiatus from me at this point as I want to spend more time riding the bike than wrenching. Soon I'll be taking off the footrests to paint them and changing the steering bearing set.

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Okay so I lied. My good friend who sold me this bike said he will be in town this Saturday. He wanted to see the bike "finished" and he kept asking about the footrests if they were painted or not. SO I took a decision to finish them off now itself.

Taking off the left side foot rest was fairly easy. Taking the right footrest however was honestly, a bit scary. This involves removing the swing arm bolt and it will for sure separate out the swing arm from the chassis. I first took out the thinner M10 long bolt, then used it to drive out the swingarm, replacing it and stop the swingarm from falling out. This worked and I was able to take ouit the swingarm bolt and the right footrest while the whole thing was still intact.

The left footrest was HORRIBLE on the inside, as expected because of all the chain lube gunk.. It took me a while but I managed to get it reasonably clean



Soon I cleaned all the parts to prep them for paint



I've had a sloppy side stand for a while, after inspecting the parts it looked like the bracket on which the side stand pivots had worn down. While replacing the bracket, I might as well replace the pivot bolt as well as the lock nut holding it. The spring was cheap enough so why not change that too for better looks? I got new sing arm nut and one for the long M10 bolt just because new shiny nuts.



One of my rubber foot rest had the grinding nut? missing on them. Getting new one of these would be next to impossible. I rummaged around the nuts and bolts with me and found couple of things t hat might work.

I first put in an M6 grub screw into the foot rest



I then screwed in a M6 SS acorn nut. This looked so good, I took off the nut from the other foot rest and replace with the same



The side stand was painted. I added a thick M6 washer under the magnet for the side stand - I read about the side stand sensor being a factor with the bike dying when I press the clutch with the bike moving. This issue was driving me crazy and I was willing to try anything to fix it. With the washer added, my problem has gone off completely! My assumption is with the magnet closer to the sensor thanks to the washer, there would be less error. It still might be placebo but I am confident with the results on my bike that this indeed solved my problem.



While I was at the KTM service center, I picked out the rear hugger and chain cover from the RC390 too. I had a look at the RC and was pretty confident this will fit in perfectly onto our dukes.



Frames were also painted



RC390 parts got a lick of ceramic coat inside out. New unused plastic parts need very little prep so I was super thankful. I've put in M6 captive nuts that I had with me since a while instead of buying new units from KTM themselves. Same goes with the bolts needed to secure the new covers. I had to reuse one self tapping screw from the old chain cover, rest of the hardware was new.

Mirius said:

Stock rear shock bolt is grade 10.9 so it might be worth trying to find a better bolt. I’d rather replace a standard bolt when it needs it than have a prettier but weaker one snap in such a critical place.

Click to expand...

While the chain cover was out, I replaced the SS bolt with a new OEM KTM rear suspension bolt with the right grade.

With this, I can confidently say the cosmetic restoration is now complete. Barring few things such as rotor bolts and ABS wheels which will be swapped when I get to the wheels, eventually.

JingalalaHoe said:

Few days later, the low beam wouldn't work. It did again intermittently and I suspected something else was bad. There was a 4 pin connector connecting the headlight plug to the harness, two pins in it looked corroded/full of something weird. I did not have a can of electric contact cleaner, I then depinned each of the 4+4 pins, cleaned them with IPA and a brush then put them back. This seems to have fixed the issue for now.

Click to expand...

So this issue did not get fixed. In fact, the low beam stopped working altogether. I intended to check and fix it soon, that's why you may have noticed I did not put in the 4 snap rivets on the sides of the headlight in all my earlier photos.

I am confident in sorting out wiring issues but I don't like spending time diagnosing electrical problems. But now its come to an impasse. Oh well.

I hooked up my test light and started probing. The fact the headlights work only when the engine was on was irritating. Oh well I soon found the culprit, there was no power coming from the low beam wire from the LH handlebar switch.

I then disassembled the switch and took apart the low-hi beam switch. Nothing felt out of place, everything looked normal. I cleaned the contacts and checked it worked and it was working!

The resistance across the switch was negligible but this wasn't the case from the switch to the 6 pin connector. My DMM usually reads an error of 0.6ohm and this was the reading across when testing the switch and resistance for the high beam wire. However, the low beam wire read a resistance of 17ohms which was a bit too much. I depinned the low beam plug from the 6 pin connector and the crimp looked fine. I'll leave it to be investigated for another day.

Plugged it back on the bike and the low beams worked. I then realised a small mod I could do to make the switch more reliable, however I'll leave it for another day. The low beam seemed dimmer than the high beam, it could either be the extra resistance or the low beam being 5W lesser than high beam (60W vs 55W) but this will do for today.

I also managed to mangle one of the pivot clips. Thankfully I bought 2 new ones from the service center last week and it came in handy. The snap rivets went in finally and the headlight will be buttoned up for good this.

...or maybe not. I saw this bike at the service center with the numberplate relocated below the headlight



I want to replicate it but do a better job. He has got clamps made that hook on to the 2 bolts that hold the headlamp pivot frame. I'll do something similar but bring the numberplate in front so the middle part does not get obscured like it is right now.

So I'm in another town and visited the local KTM service center. Got these parts

New tank decals, so I can apply these properly without wrinkles
New handle bar riser rubbers
Couple of missing collars
New brake/gear lever rubber. I wanted two to replace both but there was only one in stock
New speedo connector rubber strap

Today starts off with wiring for my new twin horns. Ive added a wire from the battery through a fuse box with a 10A fuse to the location of the old horn and put in a relay at that spot.



Relay was zip tied to secure it in place. Reused the stock horn connectors on to the relay



I took couple of angled metal brackets that are used to put up shelves on the walls - enlargened the holes, cut them to use and painted them black to hold the new horns in place



They're mounted and working! I'm proud of the wiring and routing, they pretty much disappear into the chassis with no trace, no matter what angle you look at them





Even after the recent meter refurbishment, I still got some fog inside



So this time, I changed over the gasket from a 2mm oring to 2.5mm oring. the 2.5mm oring is a very tight fit but rest assured, there is no way any moisture can get past it. Old 2mm on left v/s new 2.5mm on the right. I've ordered a new meter shell so will be taking apart this meter again next week.



New rubber strap to secure the speedometer connector



Missing collars where the headlight bolts onto the triple tree. Took out the lower handle support and painted them. Swapped out the old rubbers for a new set as the handle was actually moving forward on heavy braking. Turns out one of the bolts was loose and a simple tighten could fix it. I anyways had new rubbers so swapped them out anyway.



Disassembled the fuel cap and painted it too. I did not do a good job and it turned out lumpy. I'll redo it again in the near future. The dummy plastic allen bolt thingies are 10mm long, I'll replace them with M5x12 units with a nut underneath.