Parking it up for the winter.

[FrankenDesmo]

Drained the tank this evening and put in 5L of Esso Supreme 97 - but as I am in Scotland, they put the 5% ethanol in there. I'll just have to make sure I don't let it sit again!

Unfortunately not much changed - as it warms up the idle moves up to 3k and stays there, and it hesitates significantly around 3.5-4.5k (possibly from 'normal' idle all the way to 5k, if the idle were where it should be), and then pulls more or less strong all the way to ~8k (maybe one or two hesitations as it's pulling up from 5k). Cruising at speed at 4.5k+ is smooth, but low speed stuff where I find myself holding ~3.5-4k it is all over the place.

Pulled the plugs - top cylinder is dry and white around the tip, black around the thread. Front cylinder is dry & black all over. White = lean right?

I need to wait until I've got a new air filter as the one in it really is quite filthy (or has yellowed with age). I'm not sure how old the fuel filter is, either, so I'll get a replacement. I was thinking of attempting running it without the air filter to see if that improved anything, but I think I risk leaning it out further, so I don't think it's a good idea.

Otherwise I think it might be time to invest in a set of carbtune gauges and get to balancing them, adjusting the pilot mixtures, and going from there.

And I guess I should probably strip them off and give them a clean, first.

Time to learn a whole lot more about carbs!

No doubt about it: strip and clean those carbs first and then adjust them! It certainly sounds as though a jet is blocked on the vertical cylinder but some carbs have concealed filters in them which need cleaning too. Of course you could try running some carb/injector cleaner in your 5l of Esso and hope for the best...

Someone with experience of Monster carbs may chime in...

N

[FrankenDesmo]

Righto, carbtune ordered, and later today (after I get the more boring chores done...) I'll take the carbs off and give them a strip down & clean. I've got a new set of std plugs, air filter, and fuel filter on the way, so sometime later this week all of those bits and the carbtune should show up and I can get on with syncing and setting them.

I'm searching around for more info on the carbs, but it seems like there isn't a definitive source of information for things like float height (I've seen references to 14/16mm but can't find the sources due to pages not existing anymore). If I've got my info right, they're BDST 38mm CV carbs?

[mickj]

If you can only get ethanol fuel just make sure the tank is as full as possible before parking it up, I am now in the habit of always filling up before parking the bike as I have two with plastic tanks and both are deformed with ethanol contamination, keeping them full seems to be preventing it getting worse.

[Luddite]

With the high tickover and white plug, it certainly sounds as if the vertical cylinder is running weak. I wonder if you've got an air leak on the intake side for that cylinder.

I read back through your posts and, at the beginning, you said you removed a Scottoiler. They're operated from the intake vacuum, aren't they? If so, was the vacuum feed properly blanked off? If not, it could be drawing air through there causing it to run weak.

If it's not the Scottoiler, I'd still check all the intake plumbing for splits or leaks. With the engine running, you could try spraying small amounts of Easystart or carb cleaner on to the plumbing. If the engine speed changes, (as the fluid is drawn in through the hole), then that's where the leak is. (Be sparing with the spray as the fluid is, of course, highly combustible.)

[FrankenDesmo]

Good call Luddite - I haven't removed the scottoiler yet, but it doesn't work, so could certainly be related. I'm about to pop out the shed now to start having a look and I'll take the opportunity the remove the scottoiler anyway (and appropriately blank off where it was connected to).

At this point it's probably a good idea to strip the carbs anyway since I don't know what state they're in (and the weather's ****e!).

[FrankenDesmo]

OK cup of tea time, I've done about all I can today (gotta see the girlfriend at some point to keep up appearances ).

The scottoiler is very likely involved - when I went to trace to vacuum hose, it fell right out! Unfortunately that made tracing where it came from a bit difficult, but it looks like there is an L-piece sticking out of the front cylinder's inlet pipe (not the top cylinder, which has the white plug). I didn't quite get to the point of removing the carbs so haven't had a good look at both pipes yet.

I've got the carbs with the heaters, so I'm guessing that when I unbolt the oil inlet & outlet I should expect a bit of leakage, however I'm also not sure if the heater is currently on or off - the tap is currently in line with the main oil line between the engine and cooler, so at a I guess I'd say it's off? Although I guess it is a moot point as there wont be a whole lot of oil in that part of system while its not running.

With the faff involved to get the air & battery box off (which has an elephant on it, btw), I'm thinking I might take the opportunity to get the starter circuit upgrade done (+ replace the starter brushes/terminal). I'll see how I go with funds.

BTW - any tips or things to do while I've got the carbs off?

[Luddite]

Glad you're (hopefully!) getting to the source of the problem.

It's many years now since I've had to deal with any carbs, so perhaps some of our resident carb gurus will be on to offer some sage advice.

In the meantime, this recent thread contains some information you might find useful:

http://www.ukmonster.co.uk/monster/s...ad.php?t=58033

[Mr Gazza]

The carb heater tap is a diverter valve, that is to say it always supplies the oil cooler in which ever orientation. As a general rule ball valves always have the handle pointing to the direction of flow. So yours is currently to the oil cooler only, when the handle points up the carb heater line, then the flow will go to the carbs and also the cooler.
The sort of weather we're having at the moment might initiate carb icing; cool but humid, so it wouldn't be a bad idea to have the warmers turned on. It also helps no end to blank off the air to the cooler with a wrap round affair of some sort. It will not overheat until the air temps get well on their way to the 20's.

I think it is definitely worth your while trying it again with the vacuum hole blanked and new spark plugs, before you wrench the carbs off. Also check the throttle and choke cables for free play, either could be holding the butterflies open if they are out of adjustment and upsetting the tickover.
It would be rather frustrating to find nothing wrong with the carbs after going to the trouble of removing and stripping them, not to mention the expense and wait for diaphragms ect… That's not to say that you don't have a carb problem, but I personally would try all the cheap and easy things first.

[Darren69]

I'd go with Gary's suggestion as its a real pain getting them off.I'd put a good dose of fuel injector cleaner in the fuel and running it through and maybe spray carb cleaner in if the injector cleaner isn't helping. I suspect that the vacuum pipe was probably leaking too which won't help.

[FrankenDesmo]

Originally Posted by Mr Gazza

The carb heater tap is a diverter valve, that is to say it always supplies the oil cooler in which ever orientation. As a general rule ball valves always have the handle pointing to the direction of flow. So yours is currently to the oil cooler only, when the handle points up the carb heater line, then the flow will go to the carbs and also the cooler.

That's what I thought was happening, cheers for the confirmation.

The sort of weather we're having at the moment might initiate carb icing; cool but humid, so it wouldn't be a bad idea to have the warmers turned on. It also helps no end to blank off the air to the cooler with a wrap round affair of some sort. It will not overheat until the air temps get well on their way to the 20's.

I'll keep that in mind particularly as I'm right up north.

I think it is definitely worth your while trying it again with the vacuum hole blanked and new spark plugs, before you wrench the carbs off. Also check the throttle and choke cables for free play, either could be holding the butterflies open if they are out of adjustment and upsetting the tickover.
It would be rather frustrating to find nothing wrong with the carbs after going to the trouble of removing and stripping them, not to mention the expense and wait for diaphragms ect… That's not to say that you don't have a carb problem, but I personally would try all the cheap and easy things first.

I suppose I was slightly worried that further trial runs could lead to permanent damage on the top cylinder, as well as not being sure that the carbs have been in a great state the whole time I've owned it - I really only got a few days riding before it was SORN'd due to the RR issue, and it did have the odd hesitation down low (though that could all be due to the scottoiler vacuum line coming loose).

I've actually got them off bar the throttle cables - tomorrow I'll check the cable adjustment, have a look for any potential vacuum leaks, and throw in the new plugs & air filter. It's involved but not particularly onerous to get the carbs off if I find I need to after that. One task that is much less daunting now that I've actually done it.

Originally Posted by Darren69

I'd go with Gary's suggestion as its a real pain getting them off.I'd put a good dose of fuel injector cleaner in the fuel and running it through and maybe spray carb cleaner in if the injector cleaner isn't helping. I suspect that the vacuum pipe was probably leaking too which won't help.

I suppose it can't hurt to try! I'll pick up some easy start & injector cleaner while I'm out and about.

[manwithredbike]

The throttle cables removal is the hardest part. I found them very fiddly getting them disconnected and even more fiddly reconecting them.
Before removing and stripping them, I'd try adjusting the idle jets first, just a quarter turn at a time before testing/riding again, clockwise to lean your front cylinder a bit and quarter turn anti-clockwise to richen your top one slightly.
See the diagram at the bottom of this linked page http://ducatisuite.net/carbsynch.html

[the lodger]

I would check for air leaks at the inlet manifolds. Spray the area with WD40 with the engine running to see if the revs change.

BTW I wouldn't use Easystart unless your bike is actually hard to start and even then use it sparingly.

[FrankenDesmo]

I did wonder if I could use WD40 for that, cheers.

[FrankenDesmo]

I got it back together on Sunday night, then realised my new socket sets didn't come with plug sockets, nor the correct size deep socket for the NGK plugs (18mm - the Denso ones already in it were 16mm, which I also didn't have, though a 17mm did the job to remove them ).

So got hold of an 18mm plug wrench yesterday (couldn't find a socket locally, just a whole one-piece wrench ), and put the new NGKs in. Noticed that the Densos were the equivalent of an '8' on the heat scale and the new ones are '9' (stock), so I've gone a grade colder by the looks. No idea what the implication will be, but perhaps a hotter plug is needed up here in the cold, dark north .

I plugged up the vacuum port where the scottoiler was connected as best I could (snipped a bit of the scottoiler line, jammed a bit of ~1mm wire up it, jammed it into the L-piece and put some heatshrink over the whole thing.

Bike started up a lot nicer (new plugs & air filter - go figure). All seemed well until it warmed up, then the revs went back to 2.5-3k
I tried spraying some WD40 around the inlet runners to see if there was any change, there wasn't anything perceptable. Removing the makeshift plug off the vacuum nipple caused no change, and even holding my finger over the nipple hole only dropped the revs by maybe 500, down closer to 2k.

I also noticed that the exhaust pulses from the front cylinder were not as 'smooth' as those from the top, and this seemed to be the only cylinder that was missing/hesitating. Revving the bike with my hand close to each exhaust the top cylinder was smooth & strong, but the front was very 'lumpy'. The bike stinks of unburnt petrol while running, too, so I don't know if the front cylinder is running rich, and the top lean (as the old sparkplugs seemed to indicate), which is making the front rough but the top seem OK.

I wasn't able to ride it out as I needed to hang around home waiting for a plumber, and it was bucketing down outside. This afternoon I'm going to take it for a quick, hard ride just in case that helps at all (I've got some injector cleaner in the fuel).

Otherwise I'm picking up a long screwdriver and waiting for the carbtune to turn up (and vacuum nipples with new seals and proper caps), then I'll check/adjust the sync. With the mixture screws, the advice seems to be to screw one in all the way, noting how many turns, and setting the other to the same - in my case I'm not sure which cylinder to use as a baseline as top "seems" to be running OK, but that could be because it's running lean?

What about the idle speed screw, should I be messing with that at all? The bike does seem to have had a slightly higher idle the whole time I've had it, which points to the problem that I've never actually had a solid baseline on this bike - I'm effectively sorting out niggles from it being stored for several years (the previous owner purchased it and had it running, changed the belts & oil, but it's always had at least a small hesitation and the idle not quite right, based on the brief amount of time I was riding it after buying it).

Arg, more questions than answers!