M600 poor idle and low speed - Shim kit group buy or loaner?

[slob]

I've been advised by numerous Ducati mechanics that rubbing them down is fine, as I was worried about exposing an unhardened surface. Like blunt I use fine emery on a flat surface and a figure 8 motion with regular rotation of the shim.

sram: I use a very large flat blade screwdriver for pushing down the closing rockers when measuring.

[sram]

Thanks for all of the suggestions and thoughts.

I've just come back in from the garage. About five hours in total today! I must be the world's slowest worker, although a good hour or two must have been spent lapping shims.
I believe I have a good overall 'feel' when it comes to mechanics and engineering (not claiming to be an expert in either, though!) and I know how important it is to lap these shimmy shims so that they remain square. As I was lapping I was taking multiple measurements around the shim to ensure that there were no high points.

I managed to get the closers that needed replacing to a nice and tight clearance, barely perceptible. I was sure to give the shims a spin and take repeated measurements to ensure there were no tight spots and that the cam turned over with no interference. One of them I just about managed to get a 0.03 blade in whereas the other one wouldn't even accept a 0.02, so I'm happy with that. The other two closers are not as close, but they are well within the 'checking' tolerance. All of the openers are now perfect, although they're the easy ones to do, so that's no surprise.

When I was trying to source collets and shims, I found an ebay seller that I sent a message off to. He didn't have the sizes I needed but we had a few messages back and forth and I mentioned to him that it was such a pain to hold down the arm, push down the closing shim and then remove the collets. He suggested pushing down the arm and then inserting a large screwdriver or similar from the opposite side. I tried this and found that putting an 8mm Allen key in held the arm down and allowed me to work on removing the collets and shim with both hands. I've never seen this mentioned in any of the guides but it has transformed the entire experience so it is well worth mentioning and I recommend trying this the next time you happen to be removing closer shims.
He also reminded me to use foam ear plugs to block the oil return holes so that collets didn't find their way down them, which would be disastrous. I owe this guy a beer for sure!

The light started to fade and I was really starting to suffer from the cold wind, so I called it a day after getting all of the valve covers back on. I'll pop the belts back on tomorrow, finish the reassembly and then hopefully go for a ride to see if it's helped with the low speed running and idle. I've got to nip over to my dad's to use the grinder and bench, as I bought new tensioner bolts to replace the current ones due to the Allen sockets being fairly rounded. I couldn't find the exact same length in the low profile head and so I went a few mm longer. Let's just hope the rain holds off tomorrow so I can sort these bolts and then get the whole damned thing back together again.

I'll be sending all of the larger closer shims back to EMS in order to benefit from their shim exchange service. I'll never need these larger sizes, but the next time I do this (or let someone else do it!) it will be very beneficial to have a few shims in the 5.9-6.2 size (the one 6.2 that I had was lapped down to 5.85, boy did that take some time).

Thanks again, will hopefully update with good news tomorrow :-)

[Marcus14h]

Scram: did this manage to sort your low down running problem?

I am having a similar issue with my M600, it is due a valve clearance check but I have also just serviced a lot of parts and wondering if it’s something I’ve changed. I swapped the stock air filter for a simota racing one from wemoto so wondering if that is causing a lean mixture, I also put new brake pads in and have a feeling they’re rubbing, so wondering if they could be the problem. I also changed my fuel filter and chain and sprockets but not sure if they could be the cause. It also needs new rear wheel bearings soon, so basically could be anything haha, should be just glad it runs!

[sram]

Sorry for the delay in replying. I'm afraid to say that the valves all now being well within the 'checking' tolerances have not improved anything

I have ordered the Litetek carb seal kit and I'm going to rip the carbs apart yet again next weekend if I have the time and inclination.

Another symptom I don't think I've described so far:
When starting for the first time, I apply choke and the bike starts very quickly (so long as it hasn't been sitting for a week or two in which case it needs a few attempts of the starter, presumably while the fuel is pumped)
I ease off the choke a bit until it's still on and the engine is running at a fast idle
During this time, I can blip the throttle and the bike responds instantaneously and settles back down again to fast idle in an instant.
Once the bike is warm and will idle without any choke, a quick blip of the throttle results in it bogging right down/missing and sometimes cutting out completely. This is what it's like even after a half hour ride.

I really need to get the throttle response to behave like when it's running on slight choke. Although obviously riding it with choke on is very lumpy as presumably it's way too rich.

If I can't see anything wrong after going into the carbs yet again (going to check the diaphragms properly this time and also check the air cut off valve which is the other diaphragm behind the white plastic cover on the side of the carb) then I will be seeking advice on where I can take it. Would you recommend a Ducati independent who has a lot of experience with the Mikunis and older bikes, or would a general tuner with a rolling road be more suitable, as presumably they will have a lot of experience with carb tuning in general rather than Ducati specific stuff?

Thanks

[jonzi]

Can't help with most of what you asked.

But with regards to who can help, then I can recommend Dave Woods, in Aylesbury.

He has set up a number of bikes for me. All have been spot on.

[sram]

OK, carbs are off and my arsenal is slowly being delivered and building up:

Litetek seal kit arrived (cheap as chips even with postage and very high quality - much cheaper than even any of the kits on ebay)
Stainless torx head bolts for the float chambers (the hex bolts that someone has installed in the past are just too much of a faff to get a 1/4" drive socket on squarely)
Two cans of holts carb cleaner
One can of Electolube Air Duster (£18, but the best and most powerful air duster I've ever come across - use it at work fairly regularly when repairing computers)
New fuel resistant 5/16" tubing for the diaphragm breathers, although this is a tad tight and so have reordered some 3/8" stuff, but it won't arrive in time for Saturday
JIS screwdriver bits to remove the diaphragm covers and air cutoff valve covers without damaging the screws

I really wish I'd bought the M600 jetted new old stock BDST 38s that were on ebay six months ago. I think they were just under or just over £200 and I could have whacked them on, saved all this hassle and rebuilt the original carbs in my leisure without taking the bike off the road Oh well, lesson learned!

Stay tuned for pics, updates and hopefully shrieks of joy...

I used to try lapping shims to the correct size. I agree that it is bad practice as they will be hardened and you don't want to be messing about with the hardened surface. I don't think that they are hardened all the way through.

Originally Posted by Perryl

I used to try lapping shims to the correct size. I agree that it is bad practice as they will be hardened and you don't want to be messing about with the hardened surface. I don't think that they are hardened all the way through.

Originally Posted by BLUNT

Oh, that's interesting. I always though that I was bodging, but I wasn't!

Good information. Thanks.

[sram]

Bordering on stupidity, I spent all of the available daylight outside yesterday working in 4.5 degrees with five layers on
I got the carbs rebuilt with the new Litetek seal kit and noticed the following:

* The slide holder seal, which Litetek describe as one of the most critical seals in the Mikuni, wasn't damaged, but was fairly flattened and hard.
* One of the main diaphragm caps has a small split in the section which the spring sits over. I don't think this is actually causing any problems, as the cap is still airtight, but while I have them off the bike I may as well try and source a replacement as I'll regret it later.
* The last time I had to remove the carbs it was because fuel suddenly starting pissing out of one of the overflows. When I dismantled it, the float valve assembly had become detached from the plastic fuel inlet piece (the bit which has the o-ring on). This is just a snap-fit and so it snapped right back on, but I was worried as to how it could have become separated without the bike suffering any real knocks. I added some araldite between the pieces to hopefully ensure that it would never happen again, but the araldite appears to have reacted slightly with being constantly immersed in petrol. I was able to scrape off the glue without too much effort and so I think it's time to buy a new float assembly. I can't wait to set the float heights, that is such a fun job.

I was determined to check the air cut off valve diaphragms this time, as I've never inspected them on either occasion that the carbs have been off. One carb's cover is easy to remove, but the other one is blocked because the carbs are joined together. I didn't want to get into splitting the carbs and so luckily a 1/4" drive JIS '2' screwdriver bit can be placed on the screws and then turned with a small 1/4" ring/combo spanner. Time consuming, but worked fine and I was able to inspect both valves and diaphragms (both turned out to be perfect).

Was too cold to take any pics and I'm just going to have to be patient and wait for yet more parts to arrive for next weekend before I have any hope whatsoever of getting the bike back together.

Right, time to get outside and investigate the fitment of my newly arrived heated grips...

[sram]

Good news. After installing the new float assembly and diaphragm cap and putting everything back together with new choke, opener and closer cables, the throttle action is now very smooth and it snaps back when the throttle is released.
It's running better than it ever has and I think now it's probably time for me to take it to a tuner in order to have the idle screws set properly using a gas analyser.
The new carb closer cable, although identical when held up against the old one, just would not go into place with a locknut on each side of the carb bracket and so I had to put both locknuts on the other side of the adjuster. This got the carb snapping shut perfectly and I can't really see much of an issue with doing this? If and when the cable stretches slightly I may be able to relocate one locknut to where it should be, although I can't really see it stretching as it's the cable that I believe is under the least stress. Must've taken two hours to fit all three cables. One of the worst jobs on the Monster, for sure!



The Oxford sport heated grips are working nicely, although I'm a bit worried about the Monster's electrics and so I haven't yet tried them at 100% with the headlight on
This article made me slightly paranoid
http://www.ducati-upnorth.com/tech/chargingfailure.php
and I've already had one regulator fail on me. I bought a tiny little weatherproof LED voltage meter that I must hook up to an ignition live supply. I had it running for a few weeks permanently wired into the battery and everything seemed to be fine regarding the charging voltage. Better safe than sorry though!
Is anyone else using heated grips and have you had any issues regarding overloading the rectifier or generator?

So, some good progress over the Christmas period! The only thing I need now is weather above 5 degrees and I might be able to go on a bit more of a ride.

Thanks for all of the help and suggestions to get to this point and all the best to everyone on here for 2018.

[sram]

On wow. Today was revelatory. I am over the moon right now and it feels like I’ve reached Monster running nirvana after almost three years and two monsters. I thought I’d have one last tinker before booking into a tuner. I warmed the bike up this morning and then dug our the colourtune that I bought a couple of years ago. Ive used it before, but I’ve never been able to get the spark colour to change much, with it remaining blue even after turning the mixture screws counter clockwise 3-4 turns. Well, this time I wondered what would happen if kept turning. I must have turned about 6 full revolutions and I saw the colour of the combustion turn a lovely yellow. I slowly turned it back in until the yellow disappeared and I was left with “Bunsen blue” (as the instructions advise). I then repeated this for the other cylinder and all I can say is: oh my god. I now have a bike that responds instantly when I snap the throttle from idle. There is no hesitation and the exhaust note is crisp and consistent, unlike it was when the mixture screws were 2-3 turns out.
In all of my reading and research on rebuilding and tuning the Mikunis, everything I’ve come across suggests that anything more than 3 turns out from fully seated won’t have any or much of an effect on the mixture. Today’s tinkering seems to contradict that. I must be at about 5-5 1/2 turns out and the bike is running like it never has before. There is now an urgency that has never been present with this monster.
I’m still tempted to have it checked by a pro with a gas analyser, but for now I am going to bloody enjoy riding it and the responsivness off idle.

[Jez900ie]

Result! Welldone & enjoy.

[Darren69]

Did you get one of these in the end?

https://www.ebay.co.uk/itm/152866191887?ul_noapp=true