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Discussion Starter #1 (Edited)
so it's a long weekend and i have the opportunity for some extended play time in the factory. bob is starting to give me the shits, predominantly driven by indecision, and i'd like to get the 400ss back into one piece as its eligible for a club permit now, but that requires getting the engine out of minnie who is now unregistered again because i'm not keen on paying the outrageous rego for a bike i rarely ride, as much as i love it. i kind of can't be bothered doing an engine swap.

the easiest thing to do to ensure i have a bike to ride as required, even though i don't think i really want to ride it and i know i don't need the temptation that it comes with - even though it's not that fast, it's way faster than i need given our draconian policing of speed, 400's are much better for my licence health - is get the 851 back on the road. it is complete after all.

it only needs a big service, tyres, fuel hoses, rear shock reco and possibly exhaust change. the exhaust has to come off to get the shock out, and then i can put the st4 headers back on. i think i have some std st4 mufflers to go on it for the rwc, which you need for a club permit application these days. i don't really want to have to do the shock thing twice, but then i don't want to wait for it being rebuilt either. guess i'll have too. i think the fork seals have "leaked" due to it being moved a few times in 13 years, but i think a strip, clean, grease and refill will work there. i did increase the preload on the gold valve emulators back in the day trying to stop it bottoming out so hard, but really i think i needed to go up in oil height. i know a bit more about that now than i did 15 years ago.

i'm a bit stuck over tyre choice. it has the sp michelin stickers on the swingarm, so i'd look like a goose with anything but them on it. the power rs my cost are $20 more than the road 5 (before i actually checked my buying prices just now i was expecting it to be much more), and while my heart says sports tyres my head says road 5 would be better in every way than the pilot sport i was riding on 15 years ago. which are now all cracked and in need of banishing.

i'm curious to get back inside it. i did the valve clearances when i had it all in bits after i bought it in early 2001. i replaced the stainless steel collets with mild steel, as working with the stainless ones is just infuriating. and the next 6,000km over 3 or so years had them bed in enough that it was back to the typical rump rump rump idle you get with the early soft closing springs and loose closing clearances. i'm interested to know just how much they've opened up.

i don't recall where i got to with the eprom development years ago, and i've learnt a bit since. i'll move one of the spark map rpm break points to where i want the idle speed - 1150 or so - like i've done with an sp3 eprom, which allows a heap of advance around 1000 rpm to make them idle nice cold without losing control of the idle speed as it warms up. and i'll sort out the wacky environmental trims the eprom seemed to have. i moved the air temp sensor out of the airbox and up behind the lhf indicator years ago, but the trim table still gave a noticeable variation between cold and really hot days. probably somewhat exaggerated by the excessive closing clearances - seems to be worst at 3500 rpm or so.

so plenty to do, but less than anything else i own requires. quite possibly this is an enabler to leading to sell it - getting it all up to the level it needs to be at. although hunny bunny didn't seem to think that was a good idea, i really don't think i want to ride it. just because i don't sort of thing.
 

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i'm a bit stuck over tyre choice. it has the sp michelin stickers on the swingarm, so i'd look like a goose with anything but them on it. the power rs my cost are $20 more than the road 5 (before i actually checked my buying prices just now i was expecting it to be much more), and while my heart says sports tyres my head says road 5 would be better in every way than the pilot sport i was riding on 15 years ago. which are now all cracked and in need of banishing.

I went with sport tires on my 851 (Diablo Rosso II Corsa? I think?) precisely because I knew the tires would dry rot before I wore them out, so why not have the stickier stuff on it? I wore out the tires on my Monster in about 2200 miles, so I went with Angel GTs on that, but the 851 got the good stuff.

And if you're thiking of selling it, wht difference does it really make anyway? May as well go with the ones that live the fantasy rather than the practical ones. The next guy ins't gogin to buy it with tire longevity in mind (most likely).

My 851 was a low mileage, not used much bike and it took more time and money to make it roadworthy than I expected, but that's the game. Truth be told... I'm sorta kinda considering selling mine too now... but it is a fun bike to take out every so often. I like the "This bike is older than YOU are, punk!" aspect to it.
 

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Discussion Starter #4
luckily my 851 is an 89, so it was one of the first bikes to be fitted with what is now almost the universal 120/70 and 180/55 17's. michelin blurb says the rs has better wet grip than the power 3, which is hard to see looking at the greatly reduced tread. but they know more about it than me.

i needed some tyres for a 900ssie last week and found michelin, pirelli and metzeler don't make their current sports tyres in 170/60-17.

mine had 57k km on it when i bought it, now has 63k. it's lived like you'd expect, and it's not pristine. so i don't know if it's worth selling at this point.
 

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Discussion Starter #5 (Edited)
so i had to move the ss to move the ss to move the monster to move the ss to move the monster to move the 749 to get the 851 out.

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my dusty friend. i'll take the bodywork outside tomorrow maybe and give it a hose off.

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last time it rolled under it's own power. nearly 13 years. is that a bad omen?

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all the fuel lines were cracking, so i had to get them all off and pull the injectors which is a kind of a pita job on one of these. but getting it all off while they were still solidly mounted made it then easier to get the throttle bodies out. Wondering now if i should fit some of the other later sets i have, which have air bleeds and they'd be handy if i put a p8 ecu in it. i did have an s4 set, but i played with the pressure reg and it now has 5 bar pressure and the regs are different. not sure how well they'd fit with the 851 trumpets and airbox.

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how it ended the day. well, a few hours after i started at most. i was hoping to get the valve clearances and cam timing done, maybe tomorrow.

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i had to pull the marzocchi shock out as i want to get it redone. i pulled it apart to have a look what was inside it years ago when i had the ohlins in it, but i stupidly sold that to some bloke and had to put the marzocchi back in. i'll get my usual bloke to go over it. i have a reco kit somewhere for it to use too. pulling the shock is a real pita. you have to pull the exhuast headers first, as the lower shock bolt comes out into the hole through the swingarm the exhaust goes through. then remove the suspension rocker/hoop screw to allow the front of the rocker to pivot right up so you can get the shock out, then pull the oil breather box and coolant overflow bottle and pull the rear subframe bolts so you can pivot the subframe down at the back to get the bloody remote res out - the hose goes through a very small slot. not as bad as a diavel allegedly - you have to pull the swingarm out of one of them to get the shock out i'm told due to the remote res hose.

i measured the spring and it calcs as a 7.67 kg/mm. that sounds a bit soft for the 851, not sure what the ohlins had now. it's a fairly small od spring for a single shock, only 48mm id. i'll have a look at the aftermarkets and see what i can get for it. the spring should be black too, as my original 89 brochure shows.

well, just spent a while searching the 851/888 forum and it seems the ohlins came with an 11 spring, and most run a 9.5 or 10. i found this that i wrote years ago, which describes the rebound adjuster internal system i found when i had it apart. i found it quite interesting:

the rebound damping system is a lot of opposing faced cones that load the shim stack. the book shows 4 sets of cones, like <><><><>, i remembered it as more than that. anyway, as you wind the adjuster in it compresses these cones which then loads the shim stack more. my shock has 67 possible clicks of rebound damping, it's only the last 10 or so that actually give any noticeable change. just keep winding the adjuster clockwise (from memory) until it stops - you should have a shitload of rebound. if not, go full anti clockwise. still no rebound, rebuild.
 

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Discussion Starter #6
well, today didn't quite go according to plan. with the shock, coolant overflow and breather box out, getting to the vertical exhaust valves were easy as. closing clearances were up to 0.12 and 0.14mm, from the 0.05 they were set to when i first got the bike. swapped shims and done. went to the horizontal exhaust - broken collets on the lh. did the rh, went to the inlet - broken collets on the lh. did the rh, went to the vertical inlet - broken collets on the lh. pitfa. i'm assuming i can still get the collets - i found a couple of shops listing as having them. otherwise ill have to go to another plan, most likely involving the set of 748 heads i've had for years.

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Discussion Starter #7
got the new collets and valves shimmed. checked the cam timing, horizontal was the 108/108 i set it to 17 years ago. vertical was both advanced a couple, so i rolled them back as required.

ran out of time to get any further. still waiting on a fork seal. the tyres turned up - i went with power rs in the end, probably should have gone road 5. anyway, decision made.
 

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Discussion Starter #8 (Edited)
so, i kind of dropped the ball on this. i'll try to catch up.

forks had leaked at times - typically after being moved around a bit. lh leg was the worst.

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the lh leg in the m1r has no damping mechanism as such, except for this tapered lower piece that, as the leg moves down over it, decreases the clearance the further down it goes and that allegedly gives some increased compression resistance the closer it gets to bottoming. i put some of the repsol 15w30 oil in this leg, but maybe i should have just gone normal 10 weight. don't know now. not sure that it'll make that much difference. the photo is upside down.

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the rh leg in the m1r has a rebound adjustment valve, but in mine that was disabled when the gold valve emulator (compression damping only) went in and other rebound holes were drilled in the damper rod. both legs have 0.90 springs fitted. i found the originals when doing this job, and thought i'd calculated their rate, but didn't enter it in the spreadsheet it seems.

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i did find a dent/chip in the chrome in one of the legs, hopefully it won't cause an issue. i do have a couple of new lh legs for it, don't recall if this was the left or right now.

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the original marzocchi duoshock went out to peter at promecha to get a rebuild and revalve. back in the day i had an ohlins in it, but stupidly pulled it out and sold it to someone. i do have a showa from an 888 that will probably go into a monster at some point, so i figured id just go with the original for the sake of. i had a genuine kit for it i bought years ago - when i got it out to use the bump stop fell apart in my hands. otherwise was usable. the shock in the 89 is sort of a central piece - it has to go in before the exhaust headers as the lower bolt goes out into the header cavity, and it sits under the breather box and is obstructed by the hose and valve and won't come out with the rocker and hoop connected and the subframe has to be lifted at the front at least. it's a bit of a pita. so you hope it's good to go as is. peter found an ohlins spring to suit the small diameter (110n/mm or 11kg/mm) and in it went.

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13 year old rear brake fluid was pretty clean, whereas the clutch reservoir had the typical mud.

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... put some of the repsol 15w30 oil in this leg, but maybe i should have just gone normal 10 weight.
Yep, rule of thumb is 5 or 10 weight hydraulic oil is superior to multigrade engine oil for forks, thinner oil will impart a more 'lively' suspension, thicker oil will make the suspension less responsive but not better, retarded is a good way to describe it :/ & nobody wants their suspension to perform retarded imho.
 

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Discussion Starter #10 (Edited)
i had to replace all the fuel hoses, and found that one of the injectors wasn't opening at all, so they were removed and sent out for cleaning. both came up ok, so went back in with new hose and metallic quick release fittings to replace the plastic ones that had that perished plastic look about them. i have a heap of genuine fuel hose i bought years ago in one of my tubs, but only remembered about that once i'd finished cutting up the new hose. oh well.

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then the throttle bodies went back in, which again on the 851 is a bit of a pita. there's lots of things that really don't go together too easily on these - certainly the 888 is a lot nicer to work on in simple ways.

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next was refit all the mundane bits - radiator, etc.

i run the fuel hoses outside the frame so i can get to the quick release connectors. it makes getting the tank off so much easier. this bike is a bit non original in every day practical ways - like the 916 throttle with fast idle button. it used to be an every day bike, so needed to be useful.

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and then it was time to fire it up. luckily, it did.


which was all pretty cool. ran it until it was hot to discover that thermo fans only work when you remember to plug them. idle mixture was a bit dirty, and maybe idling a bit high. but successful for the time.

until i pulled it off the bench and parked it on the side stand and saw it pooling coolant under the reservoir. a little split in the reservoir body just above the side bolt insert, which realistically i had had warning of due to coolant on the frame when it was all apart. i did look, but couldn't see anything so blissfully hoped for the best. no bliss was found, making it a good time to walk away and piss and moan and go home.

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but the next time i got to play with it i had to find the new reservoir i had, not in the box my spreadsheet said it was in it turns out after a search, and then i had to fit it - another pita. i unplugged a few things so i could lift the subframe straight up to make it much easier, but that caught me out later as it turned out.

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i did some eprom mods, which i thought would make it start easier. just to ensure it'd go pear shaped, i video'd it.

https://www.facebook.com/bradthebikeboy/videos/1376404305796341/?t=18
 

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Discussion Starter #11
Yep, rule of thumb is 5 or 10 weight hydraulic oil is superior to multigrade engine oil for forks, thinner oil will impart a more 'lively' suspension, thicker oil will make the suspension less responsive but not better, retarded is a good way to describe it :/ & nobody wants their suspension to perform retarded imho.
the repsol 15w30 is a fork oil, and it works well in the old shitters as a general rule. i did have normal 15 weight fork oil in that side previously, but thought i'd try this stuff. i got a heap of it cheap and the forks have drain plugs so i can drop it and put something else in "easy enough".
 

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Discussion Starter #12 (Edited)
back when i was riding it i made a lot of mods to the fuel mapping compared to the um011 eprom i was originally using. the advanced inlet cams require a fair bit more midrange fuel and a bit less at the top end, and i had leaned it out at the bottom. but i was surprised how much i had changed it when i did a comparison as below. it's bizarre to think that you can take 35% out of a fuel map and have it still work. blue numbers across the bottom are rpm, red up the side throttle opening in degrees. they way the p7 ecu works, every time you turn the key on it looks at the voltage coming out of the tps and calls it 0 degrees throttle opening. the later ecu all use an angle from throttle fully closed as the idle reading, and they also have air bleeds in the throttle bodies so you don't change the angle, you open or close the air bleeds to adjust the idle speed. so if you find a way to make the bike idle better and you wind the throttle shut, it effectively changes the relationship between throttle opening and fuelling as it now has less opening for the same fuelling (fuelling is set) and so it's a bit richer. likewise, if you wind the idle stop in and open the throttle a little more it will idle fine until you turn the key off then on again, and now it will be leaner because you have more air flowing with the same fuel. i think i have the throttle much more shut at idle than i would have expected, and that skews the very low throttle fuelling quite a bit, allowing the 35% leaner setting.

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another issue with the original um011 eprom was the air temperature correction table, which leaned it out quite a bit with higher ambient air temps. technically chemically correct, but in this application there was a couple of issues. first is that the ambient air temp sensor is mounted in the bottom of the air box. sounds like a good idea, but the problem is that the airbox is above the engine under the fuel tank. when the bike sits idling, it has a huge heat source below it and a big insulator on top. if you're riding on a 17 degree day (celcius) and pull up at the lights for a few minutes and it gets a heap of heat into the airbox and the air temp gets up to 41 degrees, when you go to take off again the 3.1% enrichment it had at 17 degrees has turned into 6.3% lean, a change of 9.4 degrees. so you go to take off from the lights and it's 9.5% leaner than it was and it hiccups and you pull the clutch and grab a bit hand full of throttle and roar off and instantly the 851 has a reputation of a grumpy thoroughbred that doesn't like traffic. whereas in reality it's just a bad application.

years ago i moved the air temp sensor up behind the lhf indicator, in a nice dead air space.

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that helped a lot, but on hot days it'd still get a bit funky down low. so this time i went after the trim tables. the tables are as below. um011 was the ultimap 851 eprom. 009b is the original ducati 1989 851 eprom (the b bit is the revised software that i believe had changes aimed at saving the starter clutches). i'm not sure why the um011 was so different, i think i had seen environmental trim tables like these in the 851 sp files maybe? i forget now. anyway, as below. looking at it now, i can see that i've also leaned it off overall by about 4% - at every temp point my trim reading is that much leaner. i'll have to do something about that.

as an aside, when they did the 008b eprom, which was for your 851 with the top of the airbox cut out and the muffler welded in end baffles removed (in the race kit notes), that eprom was identical to the 009b except for every point on the ambient air temp correction being 6% richer. meaning the mapping was 6% richer overall.

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to help the cold starting i richened the engine temp trims, like i have done to my 996sps eproms. i think one of the reasons these things were poor starters back in the day was that they didn't have enough enrichment. so they wouldn't fire, then they'd fuel up the plugs and people would go the old "flooded it" line. if you put more cold enrichment in, they tend to start a lot quicker. on the later bikes, they use two tables for this - an engine temp table that has much less variation from engine cold to hot (which is realistic) and a "enrichment from first rotation" table, where for x number of revolutions from the first start it will add y amount of fuel. so for example for the first 10 rotations when the engine temp is 5 degrees it'll maybe add 50%, then scale it back as they saw fit over the next (up to) 4000 revolutions. when the engine is hot it'll add much less and end the enrichment much quicker. this may have been a way to make it work better on the air cooled engines, which take a lot longer to warm up in a measurable engine temp way (coolant makes it so much easier to control and measure).

the 750ssie and 900ssie and m900ie with the 1.5m ecu all run rich for the first 3,000 revolutions after every start, even when hot, which is a real pita when you're setting the idle mixture and part of the process is beginning the electronic procedure with the engine not running and stopping the engine to save the setting. we got real sick of the 3 minute waits with them.

some tables on many models lean off over 80 degrees or so engine temp too. i tend to zero that out, but again it's probably chemically correct.

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Discussion Starter #13
so i lost a whole long post? bummer. it was here last night when i went to bed. can't see me typing all that out again.

well, now it's back. this site is getting weird.
 

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Discussion Starter #14
well, i lowered the idle speed a bit and now it won't start and just idle happily without throttle input. and it has a really weird shut off when you almost close the throttle around 3,500 rpm. i thought it was the fact i'd taken all the fuel out at 0 degrees throttle, but returning it to std there didn't help. and the idle's a bit crappy like it has loose closing clearances again so maybe some of the new collets have settled very quickly. i can see i'm going to have to recheck them, or it'll drive me spare.

and it overheated to the shithouse because the block plate in the radiator's lh tank seems to have failed, and the thermostat had fallen apart internally and, because they're nla now, i had to buy a new later model one (aprilia version is the cheapest) and pull the bits out and fit them all into the original housing (the different bit) and refold the metal retaining ring. i had a new radiator, so fitted that too.

so now it's got its club permit, but also needs more tuning work to make it rideable without pissing me off. and i'm already hating it.
 

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Discussion Starter #15
i decided to fit a p8 ecu so that i would have some diagnostics to see what the inputs were doing, and used a modified version of an 888 eprom. pulling the single seat base off every time i want to swap an eprom really shits me - flashing ecu is so much easier than this last century manual shit. i fitted the ecu in a rush to make it nicer to ride before actually going for a ride to met someone, so i didn't get to play with anything else. i did check the fuel pressure too, as i hadn't done that initially as it had started ok once the injectors had been pulled and cleaned. it was fine.

it still idles crap, with lots of o2 and hc on the 4 gas analyser - like it has large closing clearances. allegedly i fixed that. i didn't give it a leak down test, maybe i need to see if it just has leaky valves instead.

when i get some free time at the end of the year maybe i'll strip it and do the valve clearances again and refit the original radiator so i can keep the "new" one new-ish. if the valves are leaky sensibly i'd fit the 748 heads i have, but i'm so over working on this thing and wish i'd never touched it now that anything like that will be way past my tolerance threshold i think.
 

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Discussion Starter #16
so i tried fitting some later throttle bodies with air bleeds along with the p8 and it didn't help at all really so i kind of got the shits with it, but then riding it gave me the shits totally with how it idled while sitting at lights. eventually i could see the only way for me to want to ride it was to fit the heavier closing springs. did that over the last couple of days.

i did a report for it on my blog and it's much easier to link to that than put it here and bring all the images in.

https://bradthebikeboy.blogspot.com/2018/12/closing-rocker-spring-change-on-851.html

it idles a lot lower and smoother, although it did stall a couple of times which is a new thing. i'm still not really enjoying it, it's not being used in the best environment for it (riding around town). i have to take some photos of minnie in the hope that someone will put it in their magazine, then i can pull that apart and swap the engines so the 400ss engine is out and i can start building it back up. it'd be a much more appropriate town bike, and it too is old enough for club permit rego.
 
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