I'm Done With RC390's

[TVann]

I really wanted to like the RC390. I've always been a fan of thumpers and lightweight small displacement race oriented sport bikes.

Bought a used 2017 RC390 with 5k miles and good service history. Rode it about 1000 miles when it overheated and blew the head gasket. Spent $3500 having the head milled, new KTM hi-comp head gasket installed, plus a larger radiator fan, radiator shield, silicone hoses etc to lower the engine temp.

Took it out for my first ride after having been rebuilt - blew head gasket in 50 miles. Guy who rebuilt engine is some old guy who used to build engines for Gary Nixon (google for specifics) and knows more about doing so than everyone on this forum combined. He's rebuilding it again, at his expense, but says he can't warrant it further and frankly, based on what he's researched about the engine, suggests I stay as far away from KTM's Indian built 387cc engine as I can.

Meanwhile, my little ninja 250, built to the hilt and thrashed past redline to 14k rpm for 11k miles, runs like a champ; never a problem.

Live and learn.

 

[projek7r]

On your recent post you were talking about rebuilding with the fire ring barrel. Did you blow it again after it was rebuilt "at his expense" (3rd time?) So you are on rebuild #4 or is he still working on rebuild #3? Thanks.

 

[TVann]

Rebuild 2. Blew head, fixed, blew head again. Currently: I bought the fire ring cylinder head from Gray Area KTM. I've got the Spears head bolts. I've got new hi-comp gaskets. If that doesn't do it I'm going to light the entire bike on fire and post it on this site. KTM should be ashamed of the shit they're supplying the public. I'll never buy another KTM ever. EVER.

 

[projek7r]

Sorry man, hoping the fire ring resolves things for you. Im buying a new motor myself at this point and will follow suit with the Fire Ring and head bolts.

 

[TVann]

"I'm told" that the fire-ring and spears bolts basically makes it bulletproof. I was hesitant to use another hi-comp gasket this time around but Paxton at Gray Area assured me with the fire-ring and the studs I'm good; ain't gonna blow. Fingers crossed. I'm hoping you'll be successful as well, as it's a seriously fun bike in principle. As long as its reliable I'm happy with it. I give KTM credit for developing and marketing such a cool small-displacement bike; it's just the quality issues are really frustrating.

Good luck to you, and keep us informed as your build progresses.

 

[projek7r]

Thanks! Same to you, I think you are a little further along so cant wait to hear about it. I will def keep everyone posted about mine as well. Was hoping not to see any coolant come out from the oil pan but at this point dont want to risk trying to fix the top end issue only to end up with a main bearing problem down the line.

 

[TVann]

So... finally got the bike back after new fire-ring cylinder and Spears head bolts with hi-comp gasket. Ran it in 98f North Carolina weather and the engine temp remained at two bars under the Hot line for the 100 miles I rode it.

However, it being a KTM, the bike is now stalling whenever I stop. Once cooled down, it starts, runs for a second and cuts off. Yay.

And, my guy hooked up an autotune to my PCV. Which doesn't show a trim table even though the software says its running...and the engine light is on all the time, because, I'm told, that's what happens when you hook up the Autotune sensor (which sounds to me like complete horseshit).

To summarize: my bike didn't blow another head gasket, so that's something. It just won't run, the engine light remains on, and my $400 Autotune won't work. Other than that, the bike runs perfectly.

I Really want to like this bike. Really. I just wish it would co-operate.

Back to the shop she goes......

 

[projek7r]

Sorry you are going through all this...100 miles then no longer stays on? Any error codes? Have you tried isolating the PCV from the picture? Such a bummer. I just replaced our 2015 RC390 with a 2019 Husky 401 motor and it started right up, hopefully it holds up.

 

[oroone]

Sorry you are going through all this...100 miles then no longer stays on? Any error codes? Have you tried isolating the PCV from the picture? Such a bummer. I just replaced our 2015 RC390 with a 2019 Husky 401 motor and it started right up, hopefully it holds up.

Have you opened the clutch cover on your 401? is there an internal spring that creates tension for your clutch lever? I just replaced my cable and lost all tension in the actuator. I really dont want to open up the clutch if I dont have to.

 

[1JZSupra]

Hey, shoot me a PM in you need some help with that auto tuner. I have one on mine and I have had great success with it.

 

[projek7r]

Have you opened the clutch cover on your 401? is there an internal spring that creates tension for your clutch lever? I just replaced my cable and lost all tension in the actuator. I really dont want to open up the clutch if I dont have to.

No but make sure that the clutch release spring is on correctly - I ran into the same issue. https://www.motosport.com/oem-parts/husqvarna/2018/401-vitpilen/clutch-cover?fam=engine