Heartbreak happens

[thepittsburghguzzi]

After over 18,000 flawless miles, my baby left me in need of a tow. 2012 V7C, she's been my loyal sidekick since February 2016. I made a trip from Pittsburgh to New York City this weekend, and about 200 miles into it, she started exhibiting some strange behavior. I would be cruising at constant speed, between 70 and 85 pretty much the whole way, and from out of nowhere she would start to surge, drop down and pick up a few mph, and generally felt like she was misfiring. If I pulled hard on the throttle I could accelerate out of it. It would come and go the rest of the way to the city. I checked all my electrical connections. My right hand spark plug wire seemed a bit loose, but trimming it and refitting it didn't solve this. Plugs are only 2,000 miles old. Riding through the city itself (an amazing experience on its own) was perfectly fine, but that's probably because there wasn't much opportunity to hold a constant speed. Finally, on the way home around 10:30 last night, two hours from home, she starts surging so bad that I could barely accelerate enough to get myself to the on ramp that I was luckily close to. I pulled into a gas station and once again and pulled the tank. Refitted every electrical connection I could find, hooked it all back up again, and my test ride concluded that I wasn't able to fix it that night. Thank goodness my insurance includes roadside assistance, they came and took me and my bike home. My initial theory is a failing coil, because it seems to get worse as the bike gets more hot. I feel like a failing fuel pump or clogged fuel filter are ruled out because I was usually (except for the last time it happened) able to accelerate out of the surging. I'm off Thursday and will be pulling the coils, wires, and caps and testing all of them. Anyone have any thoughts on this? Recommendations on new wire / caps or coils to replace them with? Any enlightenment would be helpful. As I wipe the tears from my eyes. Poor beautiful Scarlet.





multiple images upload

[twowings]

lack of fuel pressure caused by leaking fuel filter, fuel line, fuel pump.   

[rocker59]

Replace the caps on the spark plug wires.

[guzzisteve]

Bout time for a tune up. Clean the TB's also and airscrews. Maybe your valves tightened up. Spark caps on those are known to go bad, but never seen bad coils since around 93. Plug it up to see if a code shows.

[Lannis]

I'm not an expert on these, but I do keep a stable of old bikes on the road one way or another, and I don't think the old rules have changed.   

1) Compression first
2) Ignition second
3) Fuel third.

If you don't do it in this order, there's sad times ahead.   Valve clearance and compression check first.

Spark, from the spark plugs first through the caps back to the trigger and source voltages next.

Fuel last once these are all verified.

Lannis

[thepittsburghguzzi]

Thanks guys! I plan on pulling and testing the coils, wires, and caps (which I plan on replacing regardless because they have a bad rep around here). I'm completely unfamiliar with the fuel filter situation. Should I end up replacing it with something better that you guys have had luck with? 18,000 miles, I am surely due to replace some of the original stuff with something better.

[tonUPRacer]

Thanks guys! I plan on pulling and testing the coils, wires, and caps (which I plan on replacing regardless because they have a bad rep around here). I'm completely unfamiliar with the fuel filter situation. Should I end up replacing it with something better that you guys have had luck with? 18,000 miles, I am surely due to replace some of the original stuff with something better.

Here's a link to the fuel filter issue. Basically switch out the plastic filter to all metal. Lot's of folks have done this as preventative maintenance, other's have not. http://wildguzzi.com/forum/index.php?topic=88841.0

[Cam3512]

Make sure your plug wire is not resting against the inside of the cylinder.  The later models had that issue, and would eventually melt the insulation.  The factory's fix was to wrap a thick cylindrical RUBBER block around the wire at that point, just making it take longer to melt through.  The real fix is to wire tie it up to the frame and out of the way.

[kingoffleece]

That's what I did.

[Vagrant]

are you sure it's not a gas tank venting issue.

[Huzo]

Is it dropping one cylinder or a bit on both? If it's one, swap the coils over and see if the opposite one fails. The fuel venting one is a good theory, put the spare key in the cap and next time it dies, whip the cap open and see what happens.

[rocker59]

The plug caps are a known weakness.

The fact that the bike runs fine at high RPM, but runs rough at low RPM, and the fault is repeatable with use of the throttle, points to a bad connection on the plug wires.

[thepittsburghguzzi]

are you sure it's not a gas tank venting issue.

I thought that may be it, but I blew through the vent hose that comes up from the top-forward part of the tank and it was clear.

[thepittsburghguzzi]

The plug caps are a known weakness.

The fact that the bike runs fine at high RPM, but runs rough at low RPM, and the fault is repeatable with use of the throttle, points to a bad connection on the plug wires.

I'm replacing the caps first thing. By the time the issue was at its worst, it happened at all RPMs. Trying to pull away from the gas station, it woikent accelerate beyond 30 or 35, it just sounded like it was running on one cylinder. But if I let it cool down for a while, it'll start and idle just fine.

[twowings]

Check the fuel filter...

[thepittsburghguzzi]

Finally have some time after work I can tinker around wirh the bike.

Anyone tried this set? No reason it shouldn't work well on my V7C, right?
http://www.harpermoto.com/spark-plug-wire-set.html

[Tom H]

The set would include the coil wire that you would not use.

Also, the ends of the spark plug wires have the metal fitting to fit in a dist. cap. I don't think that the coils use the metal fitting. I think, but not sure, that they just screw on to a pin like the plug caps???

Also double check the plug caps. They may be a certain style for the new V7 versions. I hope someone comes in and confirms the plug cap needed.

Tom

[SmithSwede]

Your symptoms are similar to what I've experienced.   It was bad spark plug caps.   Definitely do that first---cheap, and even if it doesn't fix the current problem, well----the OEM plug caps are a problem waiting to happen. 

And please post back once your have fixed the problem!   Helps to build up the data base of Guzzi problems + fixes. 

[lorazepam]

Check your evap canister, and the line that runs from the canister to the intake. My canister cracked and did the same thing. Vacuum leaks suck.

[guzzisteve]

Your symptoms are similar to what I've experienced.   It was bad spark plug caps.   Definitely do that first---cheap, and even if it doesn't fix the current problem, well----the OEM plug caps are a problem waiting to happen. 

And please post back once your have fixed the problem!   Helps to build up the data base of Guzzi problems + fixes. 

Tell the OP what wires & caps you used on your mod, so he knows what works.

[Kev m]

So I had no idea the spark plug wires/caps were the same between the 2TB and 1TB models. I don't remember hearing of problems until after the 1TB models (like mine) were out for some time.

[Muzz]

Haven't touched the 13 year old caps on my 2TB. Of course, they don't have that cover thing on that the later ones have.

[malik]

The first few times the missing & surging at around 4,000rpm happened to the V7C I isolated it to the air filter/air box - cleaning the box & replacing the filter solved it. Another time it was corrosion on the RHS HT wire - found by testing the caps/wires/coil with the ohm meter - trimming the corrosion at wire end & replacing the caps (NGK LB05F) & plugs solved that. Around 120,000 km it started again, but by then the gearshift return spring had broken & oil was passing by the clutch rod seal & contaminating the clutch plate, so the motor came out anyway. Whilst apart, I found the throttle bodies had a thick coating of carbon (over-filled oiled filter?) & cleaning that (& whatever else it was that I did) seemed to fix that problem for a while. Now at 170,000km it is running worse - high idle (1,500-1,800rpm) followed by low idle (700-800rpm), running like a dog in traffic & and at 3,000 - 4,200rpm, plugs fouled with black carbon - new plugs fouled in 70km.

Taking the opportunity to take care of a few other things as well - new clutch cable, new tyre, fresh oils & filters, re-set tappets (all OK but for the RHS inlet out to 0.15mm, instead of 0.10), polished the rocker covers, replaced the spark plug caps with new (will test the resistance once more), the fuel filter was replaced at 164,000km (along with the tank, fuel pump & fuel lines) so that's unlikely to be a factor. Next is to check the compression, balance the throttle bodies, & re-set the TPS to see if I still have problems. Guzzidiag says there's an error with the lambda sensor, so I shall try turning that off. The fast idle cable wasn't working well (haven't used it for years anyway), but I've fixed that while there. I don't know if I will have found the problem(s) by the time this is finished, but we'll see. I can feel a Guzzidiag learning curve attack coming on -  perhaps some logging may reveal something. I have not yet check the state of the inside of the throttle bodies - putting that off as long as possible - they are a bugger to get off & put back on. I am committed to getting it running well again, when it's running sweetly, it's still a better ride than the V7S.

Good luck with yours & let us know if anything works.

[Yukonica]

So I had no idea the spark plug wires/caps were the same between the 2TB and 1TB models. I don't remember hearing of problems until after the 1TB models (like mine) were out for some time.

Kev, I don't think they are the same. Look at Malik's post; he used LB95F for his V7C caps.
NGK_VD05EM replaced my caps  after the originals failed in the same way OP describes. (2013 V7S)

url to NGK decoding:
http://www.ngksparkplugs.ca/documents/Resistor%20Covers%20Decoding%20English.pdf

[redhawk47]

You said that you checked all the electrical connections but there is one (actually two of them) that you might have missed.
I had a similar problem with my V7II Stone, caused by one of the fuel injector plugs not being full plugged into the injector. Sometimes it was fine, other times it wasn't making the connection so the engine was running on one cylinder - barely. I my case the check engine light usually came on when running poorly and it went out when running fine.

[malik]

Sorry, a typo - the 2TB caps are LB05F (my prev post modified). Definitely different plugs & caps with the 1TB models - for that bike I'm using XD05F caps with CR9EK plugs (not standard - plug has a different post).

[Kev m]

Ok, so if the caps are different and we've not seen reports of problems on the caps of 2TB models, why are people suggesting the caps?

[thepittsburghguzzi]

Ok, so if the caps are different and we've not seen reports of problems on the caps of 2TB models, why are people suggesting the caps?

I feel like I've read a lot of complaints about the caps on all the V7s since I've been a member? As for a small update, I tested the coils, caps, and wires after about a ten minute city ride to the shop. Nothing read *too far* off what it should be. The caps are rated at 5K ohm, one cap read 4.75 and the second read 5.23... what I'm wondering is if I were to test them immediately upon showing the dreaded symptoms, would the resistance be a lot higher? Maybe they weren't hot enough yet? The coils and wires tested fine, but again, the bike was fresh off a city run, not a highway run.

I ordered some nice NGK caps that'll arrive tomorrow, and I plan on replacing the wires soon because a small section  of the insulation melted against the engine fins. I also treated every electrical connection I could find with dielectric grease.

I took off on a twenty minute highway ride, holding 65mph and she performed flawlessly. Not a hint of the issue. Stopped for a bite to eat, headed back home, and then it happened again... after the bike had sit for about 20 minutes. When it happened, I pulled over and quickly removed the gas cap in case it was a vacuum issue, but there was only a tiny little whoosh of air and the problem persisted all the way home. My theory is that while the bike was moving, there was enough cool air to keep whatever part is failing from getting too hot. And then while it sat, heat radiated from the engine and cooked things a bit. I could be way off here, but it's a guess.

 I'll start with new caps for now and take some laps around the outskirts of the city and see what happens.

Thanks so much for all the input!

[Kev m]

I feel like I've read a lot of complaints about the caps on all the V7s since I've been a member?

Considering the 1TB models debuted in 2013 and you joined in 2016 that wouldn't surprise me. But my point is the decade before maybe 2014 or so I don't remember hearing about any problems with smallblock spark plug caps.

< shrugs >

Keep us posted what you find.

[Muzz]

I ordered some nice NGK caps that'll arrive tomorrow, and I plan on replacing the wires soon because a small section  of the insulation melted against the engine fins. I also treated every electrical connection I could find with dielectric grease.

Insulation melt is not a good thing.

About your treatment with dielectric grease. Brighter cookies than me (Chuck in Indiana) warns about using dielectric grease, and insists on Vaseline. Suggest you pm him to find out why.