Decel popping on my 2v Sport 1200

I'm slowly getting my new-to-me 2008 Sport 1200 sorted out. The Mistral exhaust sounded awful, and leaked around the carbon ends, so I drilled the rivets to find the packing all pushed down to the end of the pipe. I repacked it nice and neat, but it's still too loud, but it also pops quite badly on decel. I've tracked down a factory can which will land in a few weeks. It seems to go through fuel pretty hard, and maybe it could be a bit smoother. In the meantime I want to get through a tuneup.

First, I think I should check the map. I used GuzziDiag and a Beetle map on my '17 V7, so I'm hoping I can figure out this bike. Do I read the 5am instructions? Find out what map it has, and go from there? Any advice on checking O2 sensors, etc? Will bad ones show up in GD?

Then it's?:

- valves
- plugs
- plug caps? (I hear they are prone to problems)
- TB balance
- oil change

Thoughts?

Hope we like photos here.

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Ah, CanBike, it's a 2V dunger, just like mine.

Popping on the overrun could be considered as one of the following:
- a burble that some like; or
- backfiring that pisses everyone off

A few things will affect this:
- Exhaust leaks - exhaust flange gaskets are missing or totally compressed, the gaskets where the header pipes join the pretzel, the gasket (if there is one) where the pretzel joins the muffler. Any of these points will leak and cause some backfiring, though this is totally map dependent.
- ECU Map - on mine I cut the fuel on the overrun for all TPS readings below a certain point (can't remember where exactly, I'd have to look in the map). This gets rid of totally, the backfiring and provides most excellent engine braking. Plug caps are a little bit precious on the 8V engines, not on yours.

Plug caps shouldn't cause this but you never know - the 1200 Sport 2V engine has inner and outer plugs and generally the plug caps are pretty hardy, though one of mine failed as I was servicing it at 150,000 km. PITA to get replacements as NGK are no longer making them. Original Part no in VD05EMH. You might need to do some work to source replacements. The only downside to this failing is a slight miss when accelerating. The outer plug caps will also work if stuck - the inners are 120 degrees and the outers 90 degrees. A loose plug lead on a spark plug or at the coils could also cause issues. Time to check it all out.

An oil change while good will not cause this problem

Valves should be set at 0.1 mm for inlet and 0.15 mm for exhaust. It could be a crook plug but you would notice other things like a miss when accelerating.

Do a service, balance the throttle bodies, reset TPS, replace any exhaust gaskets that need it. When all this is done, if the problem still exists, then look at the ECU map. Mark (Beetle) has an awesome map for the 2V Sport that will also work quite well with a less restrictive muffler - I should know, it's his work on my Sport and she goes very, very well. So well, that he likes to follow me when we go away.

I have a (shock horror) GT Reverse Cone muffler and there is not much inside it - sounds fantastic on the overrun, too.

Report back here on your solution/finding and ask questions. Many here willing to assist.

BTW, I don't think that is an original muffler for the Sport. You may find the original quite suppressive of the performance within. The original design is a Z-fold arrangements that you cannot modify. It includes a cat too.

The Mistral Conical isn't a bad exhaust. There doesn't appear to be a dB killer? Or is it just not in the pic?
Properly packed, sealed, plus the dB killer it should run reasonably well, and the pipe should not sound awful.

It's a 5AM, so proceed as per 5AM instructions. It may have been remapped by the PO? A properly mapped 2V should get 4.5 - 5.0 Litres per 100km if you don't go silly with the hurry handle.

And pull like a train from 2000 rpm, even in 6th gear! Blurp, blurp, blurp sounds good in the lower gears!

Oz1200Guzzi wrote:

Ah, CanBike, it's a 2V dunger, just like mine.

Popping on the overrun could be considered as one of the following:
- a burble that some like; or
- backfiring that pisses everyone off

A few things will affect this:
- Exhaust leaks - exhaust flange gaskets are missing or totally compressed, the gaskets where the header pipes join the pretzel, the gasket (if there is one) where the pretzel joins the muffler. Any of these points will leak and cause some backfiring, though this is totally map dependent.
- ECU Map - on mine I cut the fuel on the overrun for all TPS readings below a certain point (can't remember where exactly, I'd have to look in the map). This gets rid of totally, the backfiring and provides most excellent engine braking. Plug caps are a little bit precious on the 8V engines, not on yours.

Plug caps shouldn't cause this but you never know - the 1200 Sport 2V engine has inner and outer plugs and generally the plug caps are pretty hardy, though one of mine failed as I was servicing it at 150,000 km. PITA to get replacements as NGK are no longer making them. Original Part no in VD05EMH. You might need to do some work to source replacements. The only downside to this failing is a slight miss when accelerating. The outer plug caps will also work if stuck - the inners are 120 degrees and the outers 90 degrees. A loose plug lead on a spark plug or at the coils could also cause issues. Time to check it all out.

An oil change while good will not cause this problem

Valves should be set at 0.1 mm for inlet and 0.15 mm for exhaust. It could be a crook plug but you would notice other things like a miss when accelerating.

Do a service, balance the throttle bodies, reset TPS, replace any exhaust gaskets that need it. When all this is done, if the problem still exists, then look at the ECU map. Mark (Beetle) has an awesome map for the 2V Sport that will also work quite well with a less restrictive muffler - I should know, it's his work on my Sport and she goes very, very well. So well, that he likes to follow me when we go away.

I have a (shock horror) GT Reverse Cone muffler and there is not much inside it - sounds fantastic on the overrun, too.

Report back here on your solution/finding and ask questions. Many here willing to assist.

BTW, I don't think that is an original muffler for the Sport. You may find the original quite suppressive of the performance within. The original design is a Z-fold arrangements that you cannot modify. It includes a cat too.

Thanks for all the info!

The popping is a sharp crack, and too frequent. I don't mind a nice beefy note, but this sounds sickly. Ha. I checked for leaks and didn't find anything, but I'll have a closer look. The can itself was leaking prior to re-pack, but I've got it buttoned up now. I may take another crack at the repack, as I'm thinking I didn't get it wrapped tight enough. (I welded backing nuts on each end for future tinkering)

I didn't know it was double plugged. Interesting. I'll have a look at the caps when I get into the valves. I see GP Bikes has the 120 degree caps, other vendors are all out of stock.

I'll report back as I work through it. I quite like the bike, the engine is so... weird and it pulls hard, and it handles lugging well, which I like to do occasionally. Get a smidgen too low in the rpm, and then roll it up without a downshift and it just lurches forward, then catches that sweet spot! My gut tells me, that it can run better than it does.

Thanks!

beetle wrote:

The Mistral Conical isn't a bad exhaust. There doesn't appear to be a dB killer? Or is it just not in the pic?
Properly packed, sealed, plus the dB killer it should run reasonably well, and the pipe should not sound awful.

It's a 5AM, so proceed as per 5AM instructions. It may have been remapped by the PO? A properly mapped 2V should get 4.5 - 5.0 Litres per 100km if you don't go silly with the hurry handle.

Thanks for the input!

It has the DB killer, just out the pic. I used some generic 5/8" fibre exhaust sheet from Amazon. It was a bit of fiddling. Each end of the can has a harsh profile and I'm not sure I got the fibre butted tight at the ends.

The bike had a few owners, so maybe a PO remapped it. I'll try to read it tomorrow. I have GD V46 running stable on my MacBook Air, so fingers crossed.

The hurry handle on this bike produces great joy! It's hard to be sensible at all times.

Another pic of my "weird" looking bike. (you don't see them up here)

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Get the caps while they are still available. I ordered some from GreenSpark in the UK and have been promised them Julyish.

The inner plugs are a 16mm hex, so you will need a 16 mm, thin wall, deep plug socket with a 3/8" drive. A 1/2" drive will foul on the frame rails. PITA to get to.

As you drop down to 2600 rpm on the overrun, the idle part of the map comes into play. If this is where your popping starts, a main fuel map adjustment can cure it.

The exhaust flange gaskets compress quite thin and may not appear to be even in there. Replacements are not expensive.

Before you start fiddling with the throttle bodies read up on how to tune a W5AM Guzzi. Do NOT try and alter the idle Bt moving the throttle stop screws which should be sealed with yellow paint and left that way. If they have been moved you may well be in a world of pain....

I read and downloaded the existing Bin file on my Sport using the IAW5 V28 reader. But I can't seem to get anything on my Mac to read it. I seem to recall being able to read some text stuff on my V7 Bin file last summer...but maybe I'm misremembering it.

(Also, I at first mistakenly tried using the MIUG Reader, but it would just go to the "turn off ignition"prompt after a few seconds. Hope I didn't hurt anything)

I'll reach out to Beetle via email as well, to see if he can tell me if my current 08 Sport 1200 map is factory.

Also, in prep for figuring out the TB sync, I took pics of the adjustment screws. Which one of the two, is the screw of doom, never to be touched? And is the yellow paint a good sign they've not been adjusted?

Or is it a different screw?

Thanks!!

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Nice pictures!
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guzziownr wrote:

Nice pictures!

Thanks! I'll be sure to not go near the dreaded screw.

Beetle kindly helped me determine that my map is factory.  So, I've purchased his 2V 1200 map! (His V7iii map worked great on my '17 Stone.)

The Sport has 25k kms, and it's possible it's never had a TB sync, so that's next, along with valves, plugs, and oil change.

Any thoughts out there on the best value for a manometer?

Thanks!

Morgan Carbtune.

^^^^^^^
This

Unless you have olds kool gauges that are damped - if not damped you will never read them with the vacuum pulses.

I use these and had to solder the vacuum port and put in a very small hole (0.25mm). Even that was too much and ended up crapping in a pile of paper towel at the back of each gauge - now it's "acceptable". They cost me Zero so it's what I've got!

Received my Morgan. Nice bit of kit.

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How about  a mercury carb stick would  that work as well.  I have one that I use on my mk4 lemans for balancing the  carbs

Yes, it's just not healthy, especially when there are cheap, accurate, alternatives available.

After about 15 years some of the rods in my Morgan became sluggish and the readings were different and variable. Stripped, cleaned and dried it but it appears that the tubes get scratched over time.

Thats why i have moved to dial gauges, i had to calibrate them against each other (one runs 4% lower)

They are easier to use on the move, so i can strap them to the handle bar mount and check the throttle opening synch for 15 minutes when warm.