VFR1200F top gear acceleration problem

Was wondering if any VFR1200F owners out there have experienced the issue that I am experiencing. This first came up in passing situations while traveling at 80 mph in 6th gear and accelerating to pass traffic to just above 100mph, I felt what I originally thought was a slip in the driveline. As this has gotten worse, I've considered it could be something causing a momentary lapse in power. It does not occur when accelerating through all the gears. It does not occur if I downshift to 5th gear and then accelerate. The drivehaft was replaced under the recall and I've taken it out and as far as I can tell, it's okay. Don't believe it is the final drive as I replaced it with a second hand final drive I got off of E-bay that had 12k mi on it. Figure odds of two final drives showing the same isse are slim. Not the clutch, I replaced the clutch plates and still have the problem. This didn't start until 71k mi. Bike was in to dealer at 70,400 mi for valve clearance inspection. I'm stumped and tired of throwing parts at this issue. Any help would be appreciated.

 

You may have answered the question or at least narrowed possibilities, seems to be a chance that 6th gear is experiencing a mechanical “jump/slipping” engagement inside trans. Not good news as a big procedure to split cases & examine gears is next straw to grasp!

 

PS, try applying pressure on shift lever constantly after selecting 6th, might be able to “hold” gears engaged. Still requires lotsa work to fix but at least you could possibly make it a work around cheat solution...

 

Yeah, the thought of having to split those cases has crossed my mind. So has taking a long hard look at how attached I am to this bike. I'll try holding the shift lever with my foot while accelerating as I've described. Thanks for taking the time to reply. I appreciate any input on this.

 

how many miles on the bitch ? first owner ?

 

I'm the second owner. It had 26,000 miles on it when I bought it, but this problem did not start until 71,000 miles. It currently has 76,000 miles on it.

 

I am not sure as I do not own a 1200 and only had a brief test ride before concluding it was too heavy for me to handle safely. However based on your inputs I would be surprised that it is mechanical - a momentary loss of power sounds electrical. If it was a mechanical defect with the shaft drive then a damaged spline would probably affect all gears. This sounds like Traction Control is getting upset and intervening. Why - don't ask me as I have not read the relevant owners manual for your bike.

I certainly found that occasionally Traction Control was very unhelpful on my 8th Gen basically stalling the bike when trying to pull away uphill on loose gravel trails. Hence I now routinely turn the damn thing off in poor grip environments (which is probably exactly what it was marketed as being able to help with) as I for one like to be in full control when riding on dodgy surfaces.

If you can identify a driving situation where the problem always occurs - see if it stops with the traction Control disabled?

 

This bike does not have traction control. The only rider-aid I guess you would call it is ABS. Though I have not ruled out the possibility of this being electrical because, as you pointed out, seems if it was mechanical, it would be occurring more than just a 6th gear roll-on, unless it is that gear in the transmission. Seems to me I accelerate harder in 2nd and 3rd gear than any other and never experience an issue there. Thanks for you input, I appreciate it.

 

OK it is an early 1200 model without Traction Control, so can we assume there are no MIL codes showing as the ECU could possibly record intermittent faults on the ignition side and allow you to home in on potential faults with sensors, and coil packs?

The checking should be similar to that on an 800 but check your user manual for the location of the connector.

 

The video is helpful. When I turn the key on, the MIL light comes on and goes off and does not blink. I do not have a HDS pocket tester to check it, though I did find the four-pin plug under the seat next to the battery.

 

I'm experiencing the same issue. How did you solve it?

 

Never did, been riding it as a 5 speed with no problems as long as I don't go for that 6th gear. To fix it will require pulling the engine and splitting the cases. To have this done at a dealership would run $4,000 to $5,ooo. Planned on doing this myself , but got sidetracked, maybe one of these days I'll tackle it.

 

If your Fi light does not flash a code (Sidestand down, kill switch to run) then there are No active faults. Does the Fi light ever illuminate in 6th gear with the problem happening? If not then its not storing a fault code.
Suggest it might be worth visiting a Honda dealership that has the Honda HDS tool so that a full diagnostic check can be carried out. This can also check the full calibration of the fly by wire throttle system etc. Perhaps this might pick up an issue.
Just thinking out loud, don't own a 1200.

 

Just a thought, as I re-read your original post it reminded me of my experence with my '98 - 800. I had a similar issue in that a felt loss of power only happened in top gear under hard acceleration. I also suspected the clutch discs, because not only did I feel a loss of power but I also noticed the engine RPMs were increasing faster than my ground speed. I pulled the cover off and measured the individual clutch plates only to find them easly within spec according to the factory service manual. The clutch basket had some slight wear in the effect that I could see and feel ridges between where the plates made contact, so I carefully filed the ridges smooth. The result was not different!

I also measured the free length of the clutch springs while I had the clutch apart. They also were within spec. So I ordered a set of new slighty stiffer springs to replace the 20+ year old origanals, and after installing them have yet to notice any slippage. Problem solved, the old springs had lost enough "strength" that the clutch was slipping under the load.

My conclusion to my issue was this: It would first show up in 6th gear because the ratio is the highest, thus the pressure on the clutch is the most. You may feel the you are accelerating harder in the lower gears, but the pressure on the clutch to "slip" is the highest in the top gear.

I'm sure there is a way to measure the spring "tention" as to how much pressure the spring applies at a certain compressed length, but I don't have the ability/tools to take that measurement. That may be your next staring point. I hope your get it sorted.