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DUKE 390 TICKING NOISE

Hi everyone,

I recently rebuilt my bike's because it was burning oil. During the process, I did a valve clearance adjustment. I replaced the shims to bring both the intake and exhaust clearances strictly within factory specs.

However, during reassembly, some of the threads for the camshaft caps stripped. I had to get them retapped (helicoiled/threaded inserts) and used new bolts—some of which are non-OEM.

I double- and triple-checked my work: I rotated the engine manually 6 to 7 times and re-verified the valve clearances, and everything was perfectly within factory spec before closing it up.

But now, the engine is running quite loud (classic ticking/tapping noise). I've been riding it for about 2 days, and here is my theory:

I suspect that after running the bike for a bit, the new cam cap bolts might have backed out slightly or stretched, causing the cam caps to lift by a fraction of a millimeter. This would increase the valve clearance and cause the noise.

Has anyone experienced something similar? Do you think my theory holds weight, or could it be something else?

Any insights would be highly appreciated! Thanks in advance!

u/Secure_Ad_7760 — 9 days ago

DUKE 390 won't start: No spark (very weak)

Hi everyone,

I'm rebuilding my bike and I’m trying to figure out an electrical issue on my bike and I'm losing my mind here.

Even though all the wiring and connections seem perfectly fine, I am barely getting any spark at the spark plug pipe —it feels extremely weak. For context, a while back a friend pranked me by telling me to hold the pipe while cranking, and I got a massive shock from it. So I know what the normal, strong spark should feel like, and right now it's basically non-existent.

Here is what I’ve checked and done so far:

  • All ground (earth) wires are clean and tightly connected (including the ones behind the ignition coil shown in the first).
  • The starter motor cables are secure.
  • I just got the battery charged thinking that was the culprit, but nothing changed.
  • Bonus issue (shown in the 2nd video): You can't hear the usual priming sound from the fuel pump when I turn the key on. It seems like it's completely dead/not priming.
  • 2nd video https://streamable.com/7g62um
u/Secure_Ad_7760 — 11 days ago

DUKE 390 HELP!

I'm trying to figure out where to connect this hose. Does anyone know?

u/Secure_Ad_7760 — 12 days ago

DUKE 390 CLUTCH COVER PROBLEM! HELP

Clutch cover is not fitting properly. What am I doing wrong? This shaft seems to be blocking it.

u/Secure_Ad_7760 — 13 days ago

DUKE 2017 TECHNICAL HELP!

https://preview.redd.it/tu0d7gyg5g6h1.png?width=1200&format=png&auto=webp&s=4a633c86059b7c47fc870a021cac964aa6c5bdf2

https://preview.redd.it/f0hd64pi5g6h1.png?width=1200&format=png&auto=webp&s=c126b501eafd115d85fb9823898fe7133d87770a

Hi everyone! I was wondering how bad the condition of my piston skirt and cylinder is. I know the straight lines on the cylinder are bad, but just how bad? Do I need to replace them asap? And I was wondering one more thing. Are Duke's piston rings the same as dominar 400?

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u/Secure_Ad_7760 — 27 days ago