Low End Engine Noise

J.B.

J.B.

Active Member
Hey Y'all Im new here!
Ive already found your posts extremely helpful. Thank you.

I own a stock 2021 BS6 Himilayan 411. Evap removed.

It has 3k miles
I recently did a valve adjustment, checked my timing chain tensioner (sits at half, chain stretch ok), changed my oil and greased the swing arm and linkage assembly. I have typical tappet noise and some minor timing chain noise. (My valves were WAY too tight. Less then .08 on BOTH. I set them to spec .08 intake .23 exhaust and the tappet noise got louder but chain noise reduced.) Lastly, my spark plug showed signs of hot and lean (ash deposits, some dicoloration). My piston has some black carbon, not a lot. For low miles, this bike seems to be.... problematic. Rough idle, backfire, louder than I expect mechanically.

I have low engine noise! (I put a towl over the exhaust and listened closely. Noise around oil pump and clutch basket area.)
When I put my head under the bike I can hear it clear. Are these engine generally loud in the top and bottom end, or is it possible I have a bearing issue? Do oil pump chains on these bike have a lot of noise generally?

I have a "chirp" when my clutch is cold. Ive read a lot about this on other bikes, mine has it. My clutch feels nice however.

I have only rode this bike about 100miles since I bought it. I dont trust it for distance or off in the mountains where I want to be yet.

Thank you so much for your feedback.
J.B. Oregon USA
 

Attachments

  • PXL_20251117_030653555.jpg
    PXL_20251117_030653555.jpg
    568.7 KB · Views: 23
Last edited:
Only 3k miles? has it been sitting a long time without movement in old oil (acid in oil can damage bearings). Any service history available?
In general these engines are tractors. I have seen multiple post 100k km that have been mistreated to the max by short term renters without engine issues. Our own 500cc upgrades run on the same basis but with almost double the power. Still some have hit 60k km and none had any engine troubles.
Of course it could be a lemon - and I regret to inform that I never put myself flat on the ground to listen to the engine sound from that perspective LOL.
with all those specific questions regarding noises and whether they are OK or not I suggest you take your phone, run it slowly around the running engine, possibly with comments from you when a certain suspicious noise is coming up. Then upload to YT and post a link here.
Otherwise we are the kids who hear about chocolate pudding and are expected to love it from the description alone.
 
sam2019 said:
Only 3k miles? has it been sitting a long time without movement in old oil (acid in oil can damage bearings). Any service history available?
In general these engines are tractors. I have seen multiple post 100k km that have been mistreated to the max by short term renters without engine issues. Our own 500cc upgrades run on the same basis but with almost double the power. Still some have hit 60k km and none had any engine troubles.
Of course it could be a lemon - and I regret to inform that I never put myself flat on the ground to listen to the engine sound from that perspective LOL.
with all those specific questions regarding noises and whether they are OK or not I suggest you take your phone, run it slowly around the running engine, possibly with comments from you when a certain suspicious noise is coming up. Then upload to YT and post a link here.
Otherwise we are the kids who hear about chocolate pudding and are expected to love it from the description alone.
Click to expand...
Only 3k! Im the 3rd owner already.... may be a lemon. I was so excited to buy it I didnt do a great pre inspection before purchase... I love this bike style.

Your reply made me smile. I will make a video.

Also a tip for engine listening in the low end. . . I put a folded towel over the exhaust tip to quiet my exhaust thump and the resonating sound from the pipe, trick I learned from my auto shop teacher many years ago.

Your posts I have read a lot of, I appreciate your work.
Thank you.
 
Main bearings are huge on this engine.
Oil pump chain is running in oil and doesn't cause problems.
Backfire? Has the exhaust been modified?
Tappets setting has been revised? I would set at 8 and 3 thou tight.
 
The exhaust is stock as far as I know.

Today, I adjusted the TPS. At closed throttle, the signal was at 0.74v. I backed it down to 0.60v. The idle cleaned up, and the sputter nearly disappeared (not completely). I reset the ECU (battery disconnect) and gave it a 15-minute idle reset period when I reconnected the battery.

It's pouring rain today, so no ride test. No video of the noise.

The bike is different when it's at riding temperature. Noise and function levels change.

I've heard online that the IAC valve can cause backfire. I don't know for sure. On deceleration, it will pop/backfire a little.

I set the valves to 0.08mm intake and 0.23mm exhaust, as this is what I've seen online everywhere. It's a bit tickier now. The timing chain sound was loud with a closer valve gap before I dialed the valves back—the chain is quieter now, valves louder. I think I'll have to find a sweet spot. In the PNW, we get icy cold weather and California-like heat. It's cold now. Might do better closer.

I'll keep hunting and learning. I'm hoping it's dialed perfectly by spring. I have plans for the WA/OR USA BDR (BackCountry Discovery Route).
 
Dealers with the diagnostic tool can reset IAC.
15mins may not be enough to get to operating temperature, I do 25 to 30mins and use an infra red thermometer.
 
my Himmi had exhaust pops and stalling after i bought it at 2200 miles
a prowler must have broke into my garage and stole my EVAP and EGR parts
and since then she has not had many pops or stalls

still waiting for the tooth fairy to put a RedBox under my pillow (wishful thinking)
then i will feel good about having the prowler come back and steal my cats!

ohh yeah, it sounds awful
I have learned to ignore most of it
 
Last edited:
ham said:
still waiting for the tooth fairy to put a RedBox under my pillow
Click to expand...
If the tooth fairy manages to give you a camera or a mobile you could add a pic of your ride as profile pic and we could know if you have a BS4 or BS 6 - just an idea ...
 
ham said:
its a US spec 2021 so Euro4
Click to expand...
I'll bet its a BS6. That color scheme was never used on a BS4. Just check visually: is the ECU glued to the Throttle body? if so = BS6 (Euro5)
 

Attachments

  • tb-bs6.jpg
    tb-bs6.jpg
    16.9 KB · Views: 7
You must log in or register to reply here.
Back
Top