21 GT Idle Issue + Surging when held at constant speed

[Bernard]

Sadly my attempts to eliminate this odd idle speed issue have failed thus far. Last week (prior to fresh spark plugs), the bike was surging pretty drastically and felt rather unsafe at times.

The engine seems to surge, buck, or sputter at times. In idle you can see the RPM's drop momentarily and then resume. In motion it occasionally happened but my last ride felt a bit more 'violent' with surging feeling unsafe-- felt like a cowboy at a rodeo. After today's TBS and fresh spark plugs it felt a bit smoother till I went for a ride and the idle issue was readily apparent. Things I've tried: throttle body sync, clean throttle bodies without removal, fresh spark plugs, oil change, fuel has been changed a number of times from different petrol stations. I think next is to look for any vacuum or exhaust leaks. Then fuel filter, O2 sensor, or clutch might be after that unless anyone has any further tips. Taking it to a dealership for a warranty repair may be needed with a list of what has been checked. I wonder if the Yamaha diagnostic tool would more readily show the issue despite no messages on-screen. Or they could at least further check the TPS.

 

[2and3cylinders]

You sure the ECU plugs are fully seated and clicked in place. Same goes for all other connections?

Going into the dealer is recommended especially it your under warranty.   

[ZigMerid]

6 hours ago, Bernard said:

Sadly my attempts to eliminate this odd idle speed issue have failed

I guess my first question is, why are *you* trying to solve these problems rather than getting the dealer to look after it? You're implying a 2021 9GT so I presume it's still under warranty. Yes?

If you have a crappy dealer, can you not find another? You don't need to go back to the dealer you bought it from.

Failing that, I would go to a trusted local mechanic to at least diagnose what's going on and take their report back to the dealer. That will cost you some money as your local mechanic obviously needs to be paid, but it's valuable ammunition against dealers wanting to avoid helping you.

 

Edited July 11, 2022 by ZigMerid

[psyshack]

Isn't there a ECU recall/updated flash to take care of dying, idle and surge issues on 2021 bikes?

[Bernard]

Thanks all. All connections appear secure and properly connected.

I chose to work on this a bit upfront as the dealership near me is backlogged for a few weeks. Other 'reputable' dealers in the area are close to an hour away and this is my primary mode of transportation at the moment. It is still under warranty and will likely be brought in... I just have a hard time letting others work on things at times as I thoroughly enjoy learning as much as I can about how to repair these issues on my own accord. I had two phenomenal mechanics who were my go-to over the years but they sadly closed up shop which is when I found the need to start doing a ton more of my own work on motos. Inspired me over time to do everything from tire changes to fork oil replacement. I won't do a complete rebuild (yet) or valve clearances since I have no proper work area but still think I can get this sorted out somehow. Totally understand the notion behind bringing it to the pros while it's under warranty, just very difficult with timing and my needs at this moment.

The recalls were announced just before I put my deposit down in March. They held the bike ~2-3 weeks till they could get the part in to replace on the throttle. All recall work was supposedly complete and this problem cropped up after 8k miles.

 

Edited July 11, 2022 by Bernard

[Bernard]

Rather quick update since I think I MAY have found the source of my issue. I read a thread on the forum when researching the throttle body sync and as a result I chose to leave the hoses connected afterwards for future checkups without a ton of disassembly. Was starting to inspect for any obvious leaks and spraying some WD-40 when I saw the hose was disconnected off the far left nipple. Reconnected and idled in my driveway without any stuttering so far. Added a ziptie to see if it'll hold but may be in for another disassembly to put on clamps (not sure why I neglected this in the first place).

I also removed a bit of oil despite knowing I put in the appropriate amount. Same ordeal, I've read some folks leave their oil to drip overnight whereas I tend to wait till it slows down to a slow drip. Sight glass I recall always seeing completely over the top and reading here points to it being normal.

Going to cool off for a bit then test ride again. Fingers are crossed!

[2and3cylinders]

Don't ask me how I know to check if the ECU is plugged in properly

Me, you and

[ZigMerid]

On 7/12/2022 at 6:35 AM, Bernard said:

I chose to work on this a bit upfront as the dealership near me is backlogged for a few weeks. Other 'reputable' dealers in the area are close to an hour away and this is my primary mode of transportation

Ahh. I see. Quite a crappy situation.

Hardly unique to Yamaha, but I think across the globe we're all experiencing a decline in dealer capability and availability over the last few years. I guess we never knew how lucky we were...

I will say that, at least in my area, good independent mechanics have survived and are now picking up a lot of work that previously went to dealerships.

I know this doesn't helped Bernard because he is already into indi mechs, but regardless of how mechanical you are (or not), finding a good independent mech and getting them to do some work on your moto will pay dividends down the road.

 

[2and3cylinders]

I found one, he has not only a very well equipped shop but it also has HVAC.

And his rates are reasonable, when he feels like working. 

Biggest issue is the trip to get there is a bit of a hike.

From my house to his shop is almost 45 feet!

 

[Bernard]

11 hours ago, 2and3cylinders said:

I found one, he has not only a very well equipped shop but it also has HVAC.

And his rates are reasonable, when he feels like working. 

Biggest issue is the trip to get there is a bit of a hike.

From my house to his shop is almost 45 feet!

 

Thanks! I'll be there in 12 hours and will bring some refreshments of sorts. I can't stand to be out working in the heat anymore. Pretty sure I'm making careless mistakes and causing myself more issues as a result. Going to see if I can get a dealer to look at it soon and hold me while I cry, haha.

[Bernard]

Hi all, just sending a quick update since a bit has changed since my original post. I got a check engine light some time ago and checked the code thrown by the ECU was related to the TPS. I checked the TPS with a voltmeter to see the resistance readings were jumping around quite a bit when throttle bodies were being opened...

Ordered a replacement TPS but the estimated ship date continually is being pushed back (should have been shipped earlier this week). Contacted a number of places to learn there is a nationwide (USA) backorder on the part (B3L-85885-00-00). The one place who did provide a time estimate was August 21st... oof. It seems silly for me to trade the bike in without giving this a shot first but here come's that anticipated wait time a shop would have needed to provide all the same. Super bummed not having my two wheeled therapy for a while yet.

Hope everyone else has been well and enjoying some (hopefully) flaw-free rides! I will return eventually and keep you all posted with any updates.

[2and3cylinders]

 

A TPS isn't difficult to replace, if it doesn't need to be calibrated or installed under warranty, can't you do-it-yourself?

 I finally after 7 months did get some therapy this last Monday

 The longest I'd ever gone in almost 50 years

 And everything I did over the Winter to prep for Spring which passed to summer seemed to function as desired, a veritable magic carpet ride!

 

 

[Bernard]

15 minutes ago, 2and3cylinders said:

 

A TPS isn't difficult to replace, if it doesn't need to be calibrated or installed under warranty, can't you do-it-yourself?

 I finally after 7 months did get some therapy this last Monday

 The longest I'd ever gone in almost 50 years

 And everything I did over the Winter to prep for Spring which passed to summer seemed to function as desired, a veritable magic carpet ride!

 

 

Yep, just need to wait on the part to ship from the backorder in a month. The big pain for me is going to be finding a suitable way to access the screws to replace. I'm hoping a small ratchet will be able to wiggle itself in the crevice but it will be a right fit. Looks like the frame is blocking the exterior access sadly.

[2and3cylinders]

Find tooth ratcheting boxing wrenches

 You can put a bit a quarter inch boxend and ratchet it and you're golden

 If you can break it loose a flex screwdriver will work as well

 There's gotta be a way

 All I can say is on my fastest red 15 it's a breeze 😎

 

[Goralkin]

On 7/22/2022 at 8:34 AM, Bernard said:

Yep, just need to wait on the part to ship from the backorder in a month. The big pain for me is going to be finding a suitable way to access the screws to replace. I'm hoping a small ratchet will be able to wiggle itself in the crevice but it will be a right fit. Looks like the frame is blocking the exterior access sadly.

Hello Bernard,

I can see that quite a time has passed since your initial post. However, I'm so curious about how that issue was resolved eventually.

I have the same symptoms as you mentioned on my 2020 GT, and I swapped and adjusted every possible sensor. It's only 6k on my Tracer. I already have the parts to rebuild the gearbox, but before doing so, I would like to hear from you what solved it in you case?