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Very nice and lean. That pipe looks like it means business!!

did some work on the MM500 today. it is difficult to start but I have to recommission the bike. so carburettors will be cleaned and ignition timed. When running at 2000 rpm the battery is charged so the regulator does work (apperently). the choke must be used to keep it running. when I turn the chokes of ithe engine will run but dies then suddenly. When warm it starts more easily.

new tires are ordered as the ones fitted are from 1992, and dry.

has onyone of you experiences with the oil-filter-modification? https://www.heimracing.eu/motorradzubeh ... to-morini/
(scroll down a bit)

bought a container aspen 4-stroke fuel, bike starts much easyer and idles at 1100 rpm without chokes. short testride proved positive. so carburation etc is quite good for normal fuel. have to decide if I'm going to run it on this fuel or re-yet the engine for modern fuels.

checked the timing belt, seems to be first issue from factory so could be 30 years old. no more running till replacement.


so it seems to be a genuine low-milage bike stored for most of its life

nice find!
but why tune it for aspen?
these things should run on E10 pump petrol.

well, at the moment it is difficult to start on E5/E10 and won't idle. When warm it will idle at 1200 rpm, requiring choke and then suddenly die. cleaning carbs didn't improve anything at all. Out of curiosity bought a canister of Aspen-fuel and presto, 1100 rpm tick-over and no stalling. test-ride also proved positive.

so now I have to decide on future use:
as a daily driver -> rejetting is necessary
as a weekend runabout -> could do with an occasional can of aspen, albeit expensive

sounds like your carbs are a good candidate for another ultrasonic clean.
the worst carbs i ever had were from a Aprilia pegaso, those drove me mad, impossible to set them up.
I eventually got them clean by soaking them in acetone for a week.

ultrsonic clean -> will do, eventually
first objective is to get it on the road.
new tires and RDW are for next week

I've always stuck to Shell V-Power, or other high octane pump fuels as much as possible, but had no running or starting issues with 95 octane.

Poor starting, if the carbs are in good health and properly set up, can be down to a degraded ignition winding on the alternator, weak magnets in the rotor, or the usual suspects of leads, caps and plugs (non resistor, or 1k caps).

status as of today:
- belt replaced for new
- tires renewed

the tires were indeed from wk 25 1982. took some effort the remove the hardened rubber. fitted bridgestone battleaxe (BT46)
90/90 front, 110/90 rear. my experience with bridgestone is good, use them on the BSA and LM as well to great satisfaction.

next, check on exhaust decibels and requirements before going to the RDW

received a left-side engine case today. will be used for fitting an external oil-filter. time-frame: unknown but probably before next season

some advice needed with regard to removing the castle-nuts.

bought a C-spanner (like this one https://www.kramp.com/shop-nl/nl/vp/40- ... b6-4149690 )
but can't move either nut, not even with a fair amount of force.

so how to undo these nuts for removing the exhaustsystem
regards A

I would try and get a spanner as per viewtopic.php?t=6411
This type engages with more of the nut. A 350 version will not fit the 500 by the way.
I would then try applying penetrating oil for a few days, warming the engine then try again with a smack from a lump hammer. If you do get them out, clean the threads of carbon as best you can and apply some moly paste.I use Optimol grease, left over from the much easier BMW exhaust nut maintenance. Best of luck.
John

sound advice, started with penetrating oil today and see if I can get hold off one of the topic-spanners. as for today, no movement at all.

I still have a few spanner’s left if you need one