Missed most of this year riding

I have a 2014 VFR800 Deluxe. Currently has 34,000 miles. I have been chasing an expensive gremlin/tommyknocker. I am not getting a M.I.L. so it's difficult. My symptom is no top end power in 3rd gear and beyond. It started with not being able to redline in 5th gear and has progressed to 3rd gear and beyond. My top speed currently is 110 and the bike is struggling to get there. Now let me list the expensive parts:
Regulator
Stator- light wear
Clutch- wasn't burnt
Fuel system-pump, regulator, and injectors
Ignition coils and plugs
Valve inspection- everything in spec
Throttle Body Sync- perfect on all 4
New tires
Clutch slave cylinder completely inspected and bled 3 times
After all of this labor and new parts I am still having issues. Reading around here I am seeing a M.A.P. sensor failure- what are those symptoms? ANY help would be great!!

 

I am not much of a tech by any means so my advice is limited. I am sure our more knowledgeable people will jump in to help you our. BUT! If you are going to start spending a high amount of money on exploratory repairs, often a lot of which are not needed, I would find a very reputable Honda dealership and take the bike in.

I made a mistake a few years ago trying to find the problem which was causing sudden high revs. There was a lot of suggestions offered by a few people here who I had a lot of confidence in. But to no avail. Fortunately for me, to follow their advice, cost me very little money. So, I went for professional assistance. This included a lot of expense at a shop where the tech really did not know his business. I took it to a well established dealership in the city about 1 1/2 hours away. They knew right at the start, what the issue was, and to proceed to rebuild my clutch. My money was well spent going there.

BTW. I just love your bike. Actually when I went into the established dealership, my intent was to test drive one just like yours, fully equipped, exactly like I wanted. Even the colour was white. But the ergonomics of the VFR has changed from the 6th gen to the 8th gen. I was pretty damned sore after a 1 hour test ride and there was no way I could enjoy that bike the way I enjoy my present bike. Several previous injuries to my back was the primary issue. That is when I decided I was going to have to keep mine which is where I made the decision to walk into the service department.

 

Is the air filter (and its housing) clean ? If it is, do you significantly consume more than usual ?

 

Air filter and housing thoroughly inspected and cleaned. I had a certified mechanic perform valve job.

 

I understand that the fuel pump was already replaced. If correct, why had it been replaced ? Maybe the fuel pressure check had failed ? Was the fuel pressure REchecked AFTER the fuel pump replacement (and was it OK at that time) ? (a clogged fuel line won't help even a new fuel pump)... What about the fuel consumption compared to before the gremlins entered into the game ?

 

Hi "Sir"
Sad to hear of your bike woes. Sounds like you've outlaid a fortune on parts and labor.
The 8gen VFR would have to be the most reliable VFR built! I would be absolutely surprised that both R/R and the Stator would have needed replacement, the charging system of the 8gen is excellent.
If you are NOT seeing the Fi (M.I.L) light ON then that excludes a lot of stuff. So what's left are things like poor fuel delivery, contaminated fuel, injector blockage/poor spray pattern, spark plugs, valve clearances, dirty airfilter, vaccum leakages and not much else!

I sure hope that with all these parts replaced that they actually gave you back the supposed faulty items!

Interesting your mention of, and the amount of work on the clutch! Are you experiencing clutch slippage?

The MAP sensor main issues are that the vaccum hose can come off, do know of one faulty unit, but they are generally extremely reliable. However any issue with the MAP sensor will flag a flashing Fault Code of either 1 or 2.
NOTE - If the ECM detects a fault code whilst riding the M.I.L light will illuminate ON and not flash. The fault code Will Not Display unless the bike is stationary with the SideStand DOWN and Kill Switch to RUN.

After all that's been done on the bike I would check for any vaccum hose leaks, charge and remove the battery take it to any good auto store and have the battery Load Tested, make sure your battery terminals are clean and tight.
Is your bike completely standard ? No modifications, additions etc.? What fuel are you using? You say the Airfilter is clean, how old is it?

VERY IMPORTANT WITH AN 8GEN - The fact your bike has been worked on a lot. MAKE SURE the fuel breather hose is not kinked. The hose slack that is created from raising the tank to the maintenance position MUST be taken up by pulling on the hose on the right side of the bike at the small hose to large hose joiner AS the tank is lowered back to normal position. If this is not done there is a high probability of kinking and blocking the hose. ANY strong vaccume as you try to release the fuel filler cap is an indication of a blocked breather hose and requires immediate attention as damage to the tank can happen!
I guess that if high vaccum is appearing in the tank due to a blocked breather then the Fuel Pump might struggle to provide proper Fuel Rail pressure and delivery when high RPM'S and acceleration loads are demanded.

Good luck hope this helps. PLEASE keep us posted with any fix to the issue.

 

The valve job and throttle body sync was done by a mechanic. Everything else by me. I have a pile of good parts for future repairs. I will double check the hose you are referring to, pretty sure I have it with the proper slack. I am leaning on bad throttle position sensor. The M.A.P. sensor will default to an operating measurement and allow normal acceleration. The only thing I see in the shop manual that prevents normal acceleration is a faulty T.P.S. Battery has been changed to OEM. Injectors were replaced at 110 each, all 4 replaced by me.

 

I checked all hoses and everything seems "normal". I decided to start Sir Snarl and I am hearing rattling near the catalytic converter. I thoroughly cleaned the T.P.S. connection since it's right there. I dunno, so incredibly lost here. The Throttle Position Sensor has to be purchased with: injectors, fuel rail, and throttle bodies- OEM is 1,300 USD- ouch. Especially considering I have new OEM injectors.

 

Holy shit, I hope you get this fixed. I'm dead curious as to the cause. Good luck to you.

 

There is one other 8th gen rider in my area who is starting to experience the loss of redline power in 5th gear, he wants to know the fix as well.

 

I don't think you'll solve it by replacing (even OEM) parts at random. You need a systematic approach, and just replacing things won't solve it, I am afraid.

 

Probably a long shot BUT, have you tried turning the Traction Contol to OFF, see if this has any effect?

 

I rarely ride with traction control on. So it's not the issue, unfortunately.

 

So has the bike had a compression test?

 

I am having a diagnosis done in 3 weeks. 34k miles is "low" for compression issues?

 

Yep - but you are saying you have loss of power.
You have to start at basics.

What works, what doesn't.

You have posted your bike won't pull out in 3rd or above and has a lack of power. Plugs, compression, spark. Thats what I'd be looking at.

 

Have you also thought about putting it on a dyno for a check pull

 

I replaced plugs and coils. I have been repairing motorcycle since February of this year. With shipping delays and scarce shop availability it's been a slow go. The plugs were replaced at the same time valve inspection was performed by my mechanic. I will continue to update as soon as I go fast again.

 

I had a fellow VFR rider take it for a spin just in case I was getting accustomed to the power. He confirmed, it's not riding properly.

 

I'm certain its not riding correctly & the reason for a dyno pull is that the A/F ratio can be checked at the same time. Also if its making the right amount of power. They all make circa 95-105hp. It will also tell you if its leaning out at the top end etc, etc.. However compression test first...