RPM suddenly drop when start moving, cold engine

[kenvieri]

Hello everyone, my bike is 2015 MT 09 Tracer.

My bike had a problem since February, When I start the engine and shift into the 1st gear, I release the clutch level (about half) and give gas to move forward, the rpm will go to around 2500 rpm and move forward and I HOLD the clutch level and the grip without moving my hands, however, when I move forward about 3-5 meters, the rpm will suddenly drop to about 1000 rpm and lost power. Does anyone know what problem and how to fix it?

Stock spark plug, K&N filter, Motul 10w-40 300V engine oil, Black Widow full system exhaust, Air temperature about 23°C.

[peteinpa]

Make sure your clutch switch is working. Only thing that could come into play on take off.

Might also be a big lean spot with the exhaust and no ECU tune.

Edited March 31, 2021 by peteinpa

[skipperT]

Check engine light on? Did you check for codes? Is the fuel fresh? Does the engine actually stall or just lose power momentarily before you can then sort of “accelerate through it?” Does it change once warmed up or happen all the time? Did this start happening one day and then go away, or is reproducible every time?

does the TCS light flash? Does the ABS light stay on? Are your wheels spinning freely or are the brakes dragging?

sorry for all the questions but need more info.   

-Skip

[kenvieri]

1 hour ago, skipperT said:

Check engine light on? Did you check for codes? Is the fuel fresh? Does the engine actually stall or just lose power momentarily before you can then sort of “accelerate through it?” Does it change once warmed up or happen all the time? Did this start happening one day and then go away, or is reproducible every time?

does the TCS light flash? Does the ABS light stay on? Are your wheels spinning freely or are the brakes dragging?

sorry for all the questions but need more info.   

-Skip

Thanks for the questions.

the engine light was not ON, the fuel is fresh, TCS light off, ABS light off and the clutch switch work properly. I have NO power commander or ECU flash.

It happens only the engine is cold, when the C.Temp raise to about 60°C, all normal.

Even I ride slowly or over 100km/h, the bike work normally when the engine is hot.

I asked 2 motorcycle mechanical technician and they also said it is the problem of ignition coil.

and they said the ignition coil malfunction and cause the problem.

How annoying.😖

[1moreroad]

Could it just be the auto high idle disengaging? Happens in my Tracer and my truck. No power loss, though. Just trying to rule out the easy stuff. 

[Jfundo]

I think that with the aftermarket exhaust and K&N filter you are running too lean when cold.  Computer mapping can't properly adjust for that situation.  

[kenvieri]

8 minutes ago, Jfundo said:

I think that with the aftermarket exhaust and K&N filter you are running too lean when cold.  Computer mapping can't properly adjust for that situation.  

I used K&N and full system blackwidow for over 4 years, nothing happened before. 

This situation happen for 2 months……

[kenvieri]

1 hour ago, 1moreroad said:

Could it just be the auto high idle disengaging? Happens in my Tracer and my truck. No power loss, though. Just trying to rule out the easy stuff. 

This happen when the high idle is still working

[Jfundo]

Hmmm...used to be problems that only show up when cold were due to carburator issues (because you can't do anything about your engine needing a richer mix when cold).  Specifically the choke.  Of course you are all computer controlled, so there must be some reason that the injectors are providing too much, or too little fuel.  Since you haven't changed anything, it just started doing this, we need to look at things that could wear out or deteriorate.  I can't put my finger on what it could be.  Outside chance that it is the fuel pump is slightly tired. 

The ignition coil doesn't care if it is cold, so that probably isn't the problem, unless your bike is stored outdoors and it gets moisture buildup inside of it.  Same deal with spark plugs, they don't care if it is cold.  

I could be way off based on your hint about you having the clutch halfway engaged might point us to a clutch issue.  How many miles are on it?

[kenvieri]

4 hours ago, Jfundo said:

Hmmm...used to be problems that only show up when cold were due to carburator issues (because you can't do anything about your engine needing a richer mix when cold).  Specifically the choke.  Of course you are all computer controlled, so there must be some reason that the injectors are providing too much, or too little fuel.  Since you haven't changed anything, it just started doing this, we need to look at things that could wear out or deteriorate.  I can't put my finger on what it could be.  Outside chance that it is the fuel pump is slightly tired. 

The ignition coil doesn't care if it is cold, so that probably isn't the problem, unless your bike is stored outdoors and it gets moisture buildup inside of it.  Same deal with spark plugs, they don't care if it is cold.  

I could be way off based on your hint about you having the clutch halfway engaged might point us to a clutch issue.  How many miles are on it?

it is only 30000KM only.

[kenvieri]

That shit happened this morning when I was going to work.

Everytime I take off with cold (under 65°C) engine, perfect clutch and right hand handling, the rpm raise to 2500 and I thought it should be a good take off, that shit happened just with 5 meters after taking off and rpm drop to 1000......Roarrrrrr

[betoney]

If it happens every time the engine is cold and never happens when the engine is properly warmed up... have you considered letting the engine warm up before taking off? 🤷‍♀️

[kenvieri]

3 minutes ago, betoney said:

If it happens every time the engine is cold and never happens when the engine is properly warmed up... have you considered letting the engine warm up before taking off? 🤷‍♀️

I know, however the problem never solve

[skipperT]

Definitely not ignition coil packs, those usually would fail under higher loads and taking off from a stop at lower RPM I don’t think qualifies. Plus, the bike runs ok after warming up.

I’m with Betoney on this one: what happens if you let the bike idle for several minutes while putting on your gear?

Another thing that’s comes to mind is a faulty fuel pressure regulator. Starts and runs but takes a bit for the system to build fuel pressure because it’s bleeding off once the engine is off for awhile. It’s easy to check fuel pressure while running and after sitting for 5-10 minutes(or longer) or so.

a wonky TPS sensor could cause this and not throw codes. So could wear in the clutch or clutch cable. Something in the emissions system (pinched line or breather). Tight valve clearances and TB sync being out. You’ve got lots of possibilities. Best bet may be to demonstrate the symptom to a tech/dealership so they know what they are trying to troubleshoot. 

-Skip

Edited April 1, 2021 by skipperT

[BBB]

I suspect your clutch cable just needs adjusting. Check first that you don’t have the original cable that came with the 2015 Tracer, it was upgraded to version 2, with a smoother bend near the lever. The original was prone to snapping.

It reads as if you have viscous drag in the cold gearbox oil, which goes away when the oil warms up. Adjust the cable at the lever end and see if you can alter the symptom.