Engine knock on cold start / rough idling after Valve Adjustment and Spark Plug replacement

~TABASCO~

RIDE ON ADV is what I do !
Founding Member
2011 Site Supporter
2012 Site Supporter
2013 Site Supporter
2014 Site Supporter
Vendor
Joined
Apr 4, 2011
Messages
7,328
Location
TEXAS
That idle behavior does not look to be a problem. The momentary RPM dip seen at the end seems to be due to the additional load applied to the electrical system when the fan kicked on.

Im always down to learn and find new ways on how to fix things.... In this situation, I've worked on a zillion Tenere bikes and have NEVER seen this RPM drop before. If this is actually an electrical issue I would really like to learn how this happens and how to fix it for the future. Ive had guys that have had WAY to much electric "stuff" on there bikes and its been way overboard, and I still have NEVER seen anything like that. I admit, just because Ive not seen it doesn't mean it cant happen..... LOL
 

WJBertrand

Ventura Highway
Joined
Jun 20, 2015
Messages
4,516
Location
Ventura, CA
My ST1100 and 1300 would show a slight momentary dip on the tachometer needle (recovering immediately) when the fan initially kicked on, so I thought this was normal, but maybe not for the Tenere? On my 2nd Gen Super Tenere, I don't think the digital bar tach is sensitive enough to show it and I've never ridden a first gen with the analog tach. I think I can sometimes hear a little idle RPM variation while the tach remains steadfastly at 3 bars. As the OP's bike is a 1st Gen, I wonder if the wiring recall has been done?
 
Last edited:

Jlq1969

Well-Known Member
Joined
May 5, 2018
Messages
1,749
Location
Argentina
why don't you try something simple and cheap before going expensive ... rev the engine "out of failure rpm" ... say 2000 rpm, and keep it there ... in that range you are out of idle control ... .if the fault persists (the rpm drops or oscillates)… .then it is spark or injection… .if the fault disappears everything is ok… and you have to go check the idle. and in the idle section, the first thing to check is the throttle position sensor… if there is wear or contact failure… .the ecu cannot know in which position it is… .if the sensor is ok… .then remove the coils to check that they do not have rust, which generates resistance and causes the spark to shoot towards the engine instead of the spark plug ... and check that they have not removed the metallic coating from the coil pencil
 

Jlq1969

Well-Known Member
Joined
May 5, 2018
Messages
1,749
Location
Argentina
You shouldn't pay attention to the engine's acceleration. If you watch the video, you will see that what really matters is the rpm drop. the acceleration (above the idle rpm), is a consequence of the ecu trying to maintain the 1100 / + - 50 for which it is programmed. You could check that the oxygen sensors are well connected. that is to say "sensor 1 in cylinder 1", if they are inverted ... you also have a problem
 

Revz

Member
Joined
Aug 13, 2020
Messages
80
Location
Central Minnesota
Thanks for precisions. Could you tell me what TBS abd TB means? On my side bike is not hard to start and runs well when not on idle, and no visible performance decrease to me. It is just "unstable" or variable RPM with occcasionnal knock but very few compared to before.

What this video, it doe it even when hot (100C) on idle (watch until the end):
You may ask the dealer to run your VIN for the idle recall.
 

Don in Lodi

Well-Known Member
Founding Member
2012 Site Supporter
2013 Site Supporter
2014 Site Supporter
Joined
Feb 1, 2011
Messages
5,780
Location
Lodi Kalifornia
Just a reminder, all this chit started After the stealership Fixed the bike. They eff'd something up, they damn well better make it right.
 

Jsbedard1977

Member
Joined
Jun 29, 2021
Messages
34
Location
China
I finally got my bike back, everything is fine now, no more knocks, it seems they gave the job to a more experienced tech guy. They readjusted the valves and problem is resolved, they did not charge me back for this additional work. Thanks for support guys!
 

Jsbedard1977

Member
Joined
Jun 29, 2021
Messages
34
Location
China
My only remaining problem if I would say so on the bike is apparent oil consumption, and oil reading on the little gauge, from what I saw on this forum, some people seems to experience same issue because of the erratic "dry dump" oil reading...Thanks
 

BaldKnob

Well-Known Member
Joined
Aug 11, 2012
Messages
776
Location
SENC
My only remaining problem if I would say so on the bike is apparent oil consumption, and oil reading on the little gauge, from what I saw on this forum, some people seems to experience same issue because of the erratic "dry dump" oil reading...Thanks
If your low oil light isn’t on, then I would trust there is plenty of oil in the crankcase. Don’t just look at the sight glass and add/remove oil. Check level per Yamaha procedure... ride bike, park bike 10min, check oil level.
 
Top