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rich888

missfire at 3k. (new guzzi owner)

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I have a 2001 V11 Sport. It's my first Guzzi and my first 'proper' bike!

Took it out today for my first run, having passed my test yesterday (hoorah!)

I have noticed quite a severe missfire at around 3k rpm. The bike is very hesitant and the rev counter is swinging about like crazy.

At higher rpm (4k-6k) it seems fine and lower (2k) seems ok too.

 

I bought the bike before I had passed my test, so it has been sat in the garage for a few months with an occasional run up.

It has new plugs, which I will pop out later and check.

I have the bits for connecting up to the computer so can try some diagnostics.

It has no mods other than some afermarket rear cans.

31000 on the clock.

 

Any common reasons for this?  What should I check first?

 

Any help muchly appreciated.

Cheers!

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29 minutes ago, rich888 said:

I have a 2001 V11 Sport. It's my first Guzzi and my first 'proper' bike!

Took it out today for my first run, having passed my test yesterday (hoorah!)

I have noticed quite a severe missfire at around 3k rpm. The bike is very hesitant and the rev counter is swinging about like crazy.

At higher rpm (4k-6k) it seems fine and lower (2k) seems ok too.

 

I bought the bike before I had passed my test, so it has been sat in the garage for a few months with an occasional run up.

It has new plugs, which I will pop out later and check.

I have the bits for connecting up to the computer so can try some diagnostics.

It has no mods other than some afermarket rear cans.

31000 on the clock.

 

Any common reasons for this?  What should I check first?

 

Any help muchly appreciated.

Cheers!

To reply to my own post, will check valves first, then TPS tune.

Already confused by valve clearances! Manual says intake 0.1mm and  exhaust 0.15mm, but posts here say 0.15mm and 0.2mm... will check mine first anyway....

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The miss and the rev counter jumping around could be an electrical issue. Perhaps a loose ground, weak battery, or charging issue.

It is always good to check valves and TPS, but neither of those should be able to affect the rev counter like that.

The question is, does the issue with the mis-fire cause the rev counter to dance like that or does the issue with the rev counter dancing like that cause the mis-fire. Or are both simply symptoms of a larger problem.

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2 hours ago, GuzziMoto said:

The miss and the rev counter jumping around could be an electrical issue. Perhaps a loose ground, weak battery, or charging issue.

It is always good to check valves and TPS, but neither of those should be able to affect the rev counter like that.

The question is, does the issue with the mis-fire cause the rev counter to dance like that or does the issue with the rev counter dancing like that cause the mis-fire. Or are both simply symptoms of a larger problem.

Hi GuzziMoto,

I think the missfire makes the tacho drop off. 

After checking valves which were a little tight, it seemed better but is still lumpy at 3k rpm, I think it is also worse when easing off the throttle.

Checked for cracked inlet rubbers. The one that connects the throttle body to the engine is perfect. There are a few cracks in the other one that goes off to the airbox. I would assume this one is less critical as it's upstream of the throttle body.

TB shafts have a little play in them, but it is only a tiny bit.... You can only just feel it.

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Start here with basic tune up:

 

 

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5 hours ago, JBBenson said:

Start here with basic tune up:

 

 

Thanks JBBenson, Already on it! 

I found that the previous owner or the previous tuner has shaved off the insulation on the TPS wires to expose the conductors.... oh dear.... I think a tee connector would have been a better solution!

All of the fixings for the TPS ect have had paint or nail varnish put on to lock the screws, or maybe to show if they've been tampered with or moved...

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Where can I get GuzziDiag? Links posted earlier seem to be 404....

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Thanks for the heads up on the broken link. I'll try and get those restored.

Running issues combined with tachometer misbehavior point to Relay #2. A complete upgrade to the Best Relays is likely in order.

Best Relay

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25 minutes ago, docc said:

Thanks for the heads up on the broken link. I'll try and get those restored.

Running issues combined with tachometer misbehavior point to Relay #2. A complete upgrade to the Best Relays is likely in order.

Best Relay

Cheers docc. Will check relays again. I think they had been replaced...

What is the best choice for new relays these days?

 

(edit)

 

Did find these:

https://cpc.farnell.com/imo-precision-controls/srz-1ct-dl-12vdc/relay-spco-12v-dc/dp/SW02641?st=relay

30A only though...

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Relay selection developed into a long investigation with a promising outcome.

The "Best Relay" thread specifies the OMRON G8HE-1C7T-R-DC12 High Current relay.  I've seen all kinds of attempts to use something lesser, but why?

No question tachometer issues along with running issues  commonly = Relay#2. Relay#5 (the back one) is the other high current position, but replacing the entire set is a good idea.

There can also be issues with the connections in the relay bases. I like to use an electronics cleaner and Caig DeOxit®.

Kiwi_Roy gave us a whole tutorial on servicing loose relay bases:

Relay Base Repair

 

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What about the ignition pickup/pickup gap?

Ciao

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8 hours ago, rich888 said:

Those relays look OK. 30 amps is plenty of capacity. It would be worth getting a set if you have trouble geting Omrons. Try them and report back. That is what this forum is great for. 

One of the relays needs to be a 5 pin SPDT (also called SPCO) in a V11, and the rest can be 4 pin SPST. The relay sockets can take 5 pin relays in all positions, so you should forget the 4 pin relays. When you have a set of 5 pin relays you can swap then around on the side of the road when things on the bike go quiet or dark.

Some people call this swapping relays trick "troubleshooting" but when it is getting dark and rain is threatening, the troubleshooting can look more like "wild flailing" to an observer. Just say to yourself "at least it isn't a Harley". :D

Seriously though, as Docc said, the Omrons work well, and the relay base repair suggested by Kiwi_Roy solved a problem on my bike. After tightning all the spade connectors in the relay bases (a really fiddly job) some intermittent problems disappeared. I put dielectric grease on all the sockets before I put the relays back. Then I put some foam tape between the relays, thinking that it would reduce the movement of the relays in their sockets.

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8 hours ago, docc said:

Relay selection developed into a long investigation with a promising outcome.

The "Best Relay" thread specifies the OMRON G8HE-1C7T-R-DC12 High Current relay.  I've seen all kinds of attempts to use something lesser, but why?

No question tachometer issues along with running issues  commonly = Relay#2. Relay#5 (the back one) is the other high current position, but replacing the entire set is a good idea.

There can also be issues with the connections in the relay bases. I like to use an electronics cleaner and Caig DeOxit®.

Kiwi_Roy gave us a whole tutorial on servicing loose relay bases:

Relay Base Repair

 

The ORMON's are obsolete now aren't they?

(edit) Just found digi-key has a few of the SPST left but none of the SPDT, so bought 12! (to have some spares and avoid £12 shipping)

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Quick update.

Learned that there are two wiring arrangments for TPS!

Anyway long story short, my TPS baseline is 375mV which is rather high!

 

Checked the relays. All but 1 are OMRON's. One is a Tyco. Terminals all look clean, no sign of green crust etc.  I did notice that the printing on the relay cases is pretty poor, makes me wonder if they are fake Omron's LOL! Normally stuff like that is perfectly printed and not smuged!

 

Next hurdle is getting the GuzziDiag working. Doesn't seem to connect with either of my OBD/USB cables, which I use on my cars.... Plugged OBD into 3 pin 'fiat' adaptor, connected croc clips to battery. Hit Connect. Switch on ignition, but Guzzidiag says Igntion is not on. No sign of any comms between PC and OBD cable (it has data leds).

 

OBD/USB was on Com17, which GuzziDiag seemed to detect.

 

Is GuzziDiag fussy about OBD cables?

 

 

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Hi,

setting the TPS baseline is the first step. Remember, all connections to the throttle must be removed before adjusting the voltage.

The valve play should be at least 0.2mm for Intake/Exhaust. 0,3mm is my recommendation, the V11 camshaft has very! long ramp-up slope, >100°. The standard setting will result in sligthly opened valves in that area, resulting in mean pressure loss and decreased valve cooling.

Once this is done sync the throttles in idle, try to keep the bypass screws completetely closed and do the sync with the throttle stop screws. CO trim should be set to 0 initially and only be changed if you have no means of actually measuring AFR.

GuzziDiag always works, but a KKL adapter with an original FTDI chip is needed. There a lot of counterfeit chips in the market, they will mostly not work.

Cheers
Meinolf

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