News

My 2013 KTM Duke 390: Overhauling the cooling system & other updates

26th December 2023, 11:03 by Dev Shah

I had to take off the fan blades to swap over the shrouds - this meant destroying the blades.

BHPian SunnyBoi recently shared this with other enthusiasts.

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

The radiator fan terminals also had the same gunk as the headlight plugs. I soon found out this is either grease or some dielectric compound. I left the residue as is.

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 promptly 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

While I got new handle grips, I should change the throttle cable as well , right? The clutch cable was also cahnged not too a while ago, the last remaining old cable would be good to be replaced as well. 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.

I then saw a crack on the water pump housing. I went through old pictures and the crack was present before. I could still thread a bolt but it wouldnt tighten anymore.

Time for a new water pump housing. New on top, old on bottom, the countersunk edges on the side

The coolant hose going from T piece to the thermostat had a deep gash, plus wear marks from rubbing against the engine all this time. You can see the part of the engine where paint has come off in the second picture on this thread.

While fiddling around the water pump side, I looked up, saw a sticker ont he fuel pump. I was made in dec-2020, which means it was changed recently! Yay, saved on a large-sh expense!

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 to take 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 side shield of Yamaha RX. 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 now 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. 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.