Bog & Swamp at c.4500 RPM [SOLVED!]

So, am in Hollidaysburg, Pa., en route to Erie.  The latter is no doubt on the bucket lists of all reading this.  

On the way here, I encountered a problem that is new to my GRiSO, which has been running wonderfully for quite some time.

A few miles from touchdown, I found that it would bog when the tach went over over 4500 -- probably more accurately, 4.7K -- or so.

Almost felt as if running on one cylinder, a phenomenon I am familiar with as my EV is doing that now as only the right side fires.  I do love character.

Doesn't feel as if it will die, just says, "no more than this."

When I got here, I found that it will -- when not under load -- roll effortlessly through to redline.  Hmmmm.

No idiot lights; no other detected differences.

Saw nothing here about this before (apologies if I missed something), but did see mention elsewhere of possible overheated and failed cat causing similar bogging.

I am going to pull the plugs to see if those reveal anything, but would be grateful for your thoughts.

I can ride with this so long as I am not going to cause damage, but it will be less fun.  Also concerned that 4.7K today might become 3.2K or the like tomorrow.

Best,

Bill

I would think if it was the cat, then the symptom would show under no load. Nevertheless, check for discolouration of the pipe.

I'd suspect spark. Under your no load test, did you blip the throttle, or roll it as you would at speed?

Thanks, Mark.

See no color change in can -- stock fatso.

Did not blip. Two rolling to-the-top checks.

Plugs out now.  Both tips look like one of Kathi's lattes, but if I may say without revealing my negligence, they are old and even rusted at base.

We'll see if I can find some NGK CR8EK's or compatible alternatives tomorrow.

Very grateful for the prompt feedback.

I don't suppose you travel with laptop or tablet and GuzziDiag cables, like some nerds?  [You must be registered and logged in to see this image.]

^^^^^^^^

No, but staying with John Wells. He has such and I think that he -- unlike my worthless self -- knows how to use!  He's in a meeting and I cannot confirm.

He has numerous new and vintage Guzzis (including an 8v Stelvio), but no GRiSO.  Naturally, I don't have map with me unless my loaded one is "readable" with laptop and cables.

Bill

No map work required. You can use GuzziDiag to test the injectors, spark, fuel pump, et al.

Great!

Found local source for plugs.

Will see if we can get into it's electronic innards in the a.m.

In the meantime, beer calls.

Seriously, very -- as in VERY -- grateful for your assistance.

Bill

CR8EKB's are just as good Bill.

Sounds more like aspark drop out. Are you still using the original plug caps?

Pete

Thanks, Pete.

Odd re caps.

I "KNOW" I swapped the OEM as you recommended.

Then, today, when checking plugs, one was "new," other not.  

I did use cable tie to pull up both.

Will post guzzidiag results tomorrow.

Local "all brands" UJM dealer was so helpful on the phone while ago that I feel obligated to buy the EK ones.

Bill

Did you have a glimpse to the diagnosis menu? Perhaps you will find a hint there?

Bill, can you swap the plug caps over? That would mean the other cylinder would fail or not and illiminate that possibility?

So, we broke the code.  Solved the mystery of the bog.

First, thanks to all who had suggestions.  

Interestingly, it was not the plugs (tho I did buy some new ones and will swap them out when I get home this weekend.

And, it wasn’t the caps.  In fact, contrary to what I said, I had installed the new NGK’s.

And, no, while I had not been smart enough to check error codes, we figured running Guzzidiag would reveal any errors.

So, the envelope, please …

John fired up Guzzidiag -


[You must be registered and logged in to see this image.]


Then, I popped the saddle to connect its cable to the GRiSO and discovered that what I had packed like this in the space formerly occupied by the snorkel


[You must be registered and logged in to see this image.]


… had become this along the way …


[You must be registered and logged in to see this image.]


Doh.


The beast needed air under load, but not when rev'ed in the shop.

Ran like the proverbial shaved ape all the way up to Erie today.  Grand, grand, grand.

Bedtime here … ciao, and thanks again.

Bill

Bill, velcro is your friend here. Glad it's solved.

Tee hee!

Good job!

Note that it's called "Stop & Go". Never was there a more appropriate name for a product. Glad you got it fixed, Bill. Wouldn't it be nice if everything were that easy?

I have just reinstalled the snorkel for the same reason. The puncture repair kit I had in the snorkel space was moving about and partially blocking the inlet. With my own map I could not tell any change in the performance of the bike and now all I am hearing is the Termi pipe and not the inlet noise, which is a pleasant change.
I don't know if anyone has any evidence that removing the snorkel does improve performance or just 'seems' to, if not mine's staying in place for now.

Funny, I had the exact same thing happen during my current trip in Italy/France! In my case also the bag with the tire repair kit had been sucked/shoved in.

A prevention measure would be to drill the airbox lid with holes so that you are not relying on the snorkel aperature at the rear.

Or in my case, I've removed the lid entirely. No ill effects.

Bill, if you had plugged it in you would have had a turbo :-)