My 'new' 1982 ducati 900ss. Video + questions

Right: firstly, the bike looks beautiful and original, a really nice example. The reason for the stalling, is that you have to free the clutch plates before every ride, by pulling in the clutch and kicking over the engine with the ignition off, until the clutch fully disengages; it is a pain if you are used to modern bikes, but there it is. The choke opens a pair of large jets which allow the engine to flood with petrol for starting; the bike will not run properly when the choke is lifted, so it must be flipped off within a few seconds of starting and the engine held on the twistgrip at around 2000 rpm until it has warmed up. The engine will not have a great tick-over due to the size of the carbs, and will not tick- over properly until hot, so your present tick- over revs are probably ok; it is not a good idea to set the tick -over speed too high, as anything over 1000 rpm will give you a notchy gear-change.

You are correct with the gear-change - 1st is down.

You will either grow to love this bike, or hate it!

Congratulations Avoca. You are going to get a number of subjective responses; lots of good guys on this forum.

My 2c:

Choke! Luxury! I have ticklers on my 40mm Dellortos. Agreed as above; kill the choke as soon as the bike starts and take over with the throttle.

My 81 MHR will idle on it's own after about 30 seconds but I set it at 1100rpm. I do not suffer from notchy gear changes. The owners manual states 900rpm but it's much more common to see the 40mm Dellorto bikes run at 1100rpm. Mine will run at 900rpm but it's a little lumpy; how you got yours to idle at 600-750rpm is amazing. To set the carbs up properly, you really need to ride the bike and get the engine properly warmed up.

It's funny that I've only ever seen two YouTube videos of 900 bevels being kicked over cold with the pre-clutch break. My first Ducati was an 860GT with kick-start only and the start sequence I was taught back in 81 was to pull the clutch lever in and kick the bike over a couple of times to "break the clutch". Despite using this technique, it's possible that your clutch is not set-up properly; this is what it sounds like from your description. There should be a couple of mm play at the clutch lever cable. This can also be measured at the engine-side clutch lever. I would check the whole clutch movement over; it's very simple from a mechanical perspective. I've read others complain about problems with clutch actuation. One easy thing to do is remove the little "Ducati" cover on the left side clutch casing; it's purpose is to get access to the end of the clutch pushrod adjuster screw. Stick a screwdriver in to touch the end of the the screw and pull on the clutch lever. The screwdriver should move at least 2.5mm for the clutch plates to free-up properly. Also gauge how smoothly the clutch rod returns; it should be instantaneous with letting go of the lever. If not, the clutch pushrod is gummed up and needs a good clean. There are 7 parts not including the adjusting screw and they are not all the same diameter. One part is a ball bearing and it can develop flat spots.

Yes, down into first and up into the remaining gears. If your clutch is too tight or sticking then gear changes will not be happy.

The front shocks have two bolt positions for the mudguard; yours is probably attached using the lower ones so just undo them, raise the guard and see what it looks like. Yours does look tight from the pictures.

Do you have manual(s)?

I just looked at some pictures of my front mudguard and it does look a little higher than yours but I think I used the lower bolt holes on the fork legs. I'm traveling until Friday and will take a look when I get home:

Can you tell I'm stuck in a hotel room far from home?

What a great looking bike.

The front mudguard is bent a little; I'd remove it completely and see what it looks like unstressed. There may be a little play in the holes cut in the mudguard that will allow you to straighten it as you tighten the mounting bolts. Same goes for the rear seat; take the squishy bit off and take a good look at how the seat pan mounts to the frame; there is zero play on mine but our bikes are different so it may be possible to shift the seat pan so that it is straight and then tighten it up.

I like your fuel cross over between the taps; not standard but not a bad idea. One little tip if you have an unreliable memory; I put a tiny black Sharpie pen dot on the top of each fork leg to identify which position is off for the petcocks as one is forward and one is backwards, at least on my bike. It's no fun running out of gas on a bendy road and not knowing which way reserve is/are. Your cross over will only delay things!

I think you have a non standard, labelled, ignition pick-up cable or cable shroud exiting the left casing at the front left. This is suggests that your pups or at least their wiring, may have been replaced. The video shows the original coil block but I could not see if there were Bosch exciters or not. Does the bike has an upgraded electronic ignition?

The bike sounded lumpy in the video but it may just need a good ride to blow away cobwebs. Try set the tickover at 900 and see how happy it is. I use vac gauges to get it spot on. The front carb rubber cable cap is not in position and pulled up out of the way. On my bike pushing this little cap into position is enough to slightly change the vacuum as it straightens the cable end.

Your fairing frame has the wrong end screws. I'm guessing you should have the same as mine: Back to Classics

Good luck and post more pics.

-Thanks for the responses, everyone! I've been out on a trip so I'm sorry for not responding.
-Thanks for the info on the choke. Generally speaking, how long, roughly, would you consider the bike "warmed up"? It's winter here and I don't want to mess around with it too much, unless that's not an issue?
-After about 7 minutes in the cold holding RPMs around 1300 or so, it would idle between like 600-8750ish, but it sounded like it was labored and it didn't like it was where it should be. It eventually just dies, though, if I don't keep the handle twisted. I'm hoping this is just because, you know, winter here haha. Also, what kind of gas are you using? The previous owner has 100LL gas in it, I'm assuming the same stuff as prop airplanes.
-Is having to free the clutch something you always must do after stopping, or just when the bike is getting warmed up? For instance, if I get to a stoplight after riding it for a while, or just after starting, should I expect the clutch plates to stick together and stall out, blocking traffic? haha.
-Ah yes, I meant to say "fender", not "fairing". I apologize for that. I can try to put it up on the higher set. Hoping that will at least make it not touch.
-I do not have any manuals at all. Also, I almost broke my key opening up the seat lock. I didn't, thankfully, but is there any place I can buy a blank key for that so I can copy the current one? I think it's original and it's kind of small, so I'm not sure if I can use any blank key or if it has to be that size.
-Also, what the previous owner told me about the shifting on this bike:
"I've changed the engine oil and filter about 20 miles ago with Motul 3000 20W50 mineral oil, since then the gearbox is clunky when the bike is cold, particularly when downshifting. I think it may need thinner oil next oil change to help for better gear shifting. Until it warms up, downshifting can stop at second gear, to overcome this, downshift to second gear, then up to third gear, then shift back down through second gear into first gear or neutral. It's quirky but this works best until transmission warms up"
Does this sound right? I want to make sure there isn't an issue with the clutch plates or anything before riding.

Ok, LAST question! Sorry, everyone. The neutral light occasionally shows neutral when it's in first. When I got it, it was on properly in neutral, but after playing with it, it shows neutral in first gear, and the light is off when it is in neutral. Is there something I can adjust?

rick81mhr900ss said:

I like your fuel cross over between the taps; not standard but not a bad idea. One little tip if you have an unreliable memory; I put a tiny black Sharpie pen dot on the top of each fork leg to identify which position is off for the petcocks as one is forward and one is backwards, at least on my bike. It's no fun running out of gas on a bendy road and not knowing which way reserve is/are. Your cross over will only delay things!

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The bike came like this, so all props or criticisms go to the previous person! Should I change it? I'm very unfamiliar with this bike.

rick81mhr900ss said:

I think you have a non standard, labelled, ignition pick-up cable or cable shroud exiting the left casing at the front left. This is suggests that your pups or at least their wiring, may have been replaced. The video shows the original coil block but I could not see if there were Bosch exciters or not. Does the bike has an upgraded electronic ignition?

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I wouldn't even know. What would show me if they were Bosch exciters? I don't see anywhere where there is a push start button, so I assume it's not the electronic ignition? As for the non-standard, labelled, ignition pick-up cable or cable should exiting the left casing at the front left, is there an issue, or just aftermarket?

rick81mhr900ss said:

The bike sounded lumpy in the video but it may just need a good ride to blow away cobwebs. Try set the tickover at 900 and see how happy it is. I use vac gauges to get it spot on. The front carb rubber cable cap is not in position and pulled up out of the way. On my bike pushing this little cap into position is enough to slightly change the vacuum as it straightens the cable end.

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I think it needs a good ride, but it's also pretty cold here and the bike spent about a month in transit from California to Michigan. The previous owner included some vacs with the purchase, so that may be something I'll try my hand at over the summer, with a help of my friend who knows what he's doing.

rick81mhr900ss said:

Your fairing frame has the wrong end screws. I'm guessing you should have the same as mine: Back to Classics

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You're talking about the screws holding the metal cross bar thing connected to the triple tree? If so, is there somewhere I can order those? I also need to order wiring molex crimps for the wiring coming off the turn signals. I'm replacing the california regulation ones, and keeping them, and replacing them with aftermarket ones that look more original. However, they are bare wires and don't have the molex things on them to connect to the other cable, I'm assuming coming from the wiring harness

Thank you!

Some answers:

- I was in a similar situation to you last year; I had to get the bike registered so couldn't insure it to ride it for a while. I warmed the motor up for about 5 minutes with the bike on its stand before playing with the carbs and vac gauges (this is after a 29 year hiatus). Once the bike was on the road, I took it for a good 15 minute loop then back home and tweaked the carbs once more to 1100rpm. I don't understand the comment about "notchy gear change" as only 1st gear counts when idling; once you are riding, the tickover is irrelevant except at stops as long as it is down around 1000rpm. Mine seems happiest at 1100rpm.

- As stated earlier, your 600-750ish tickover is way too low. I'd tweak the idle screw stops a little in a little on both carbs to get the tickover up to around 1000rpm as a starting point; learn to use the vac gauges - really easy and precise.

- Use premium gas and try and avoid bio/ethanol.

- The clutch only needs to be broken when the bike has not been run for a few days or more and it should not stick and stall your motor when pulled in. I only broke my clutch about once a month last summer.

- I'm home and just checked my front fender; mine is bolted to the forks on the lower bolt hole position. I still suggest raising yours to the upper bolt hole if you can.

- I'm not sure there really is a "good" manual. I have my original Haynes one from 81. There are a bunch of Internet resources that are really useful. Here's one of my favourites: Back to Classics

- I'm not sure about the keys. I suggest you take your key to a good auto shop and ask. It would not surprise me at all to find that the key is from another make.

- The description from the previous owner about oil and the gear box is interesting and suggests that the gear selector position is slightly out. There is an adjuster, eccentric screw in the gear selector mechanism that may need a tweak; the gear box should move between all gears hot or cold without issue. 20W-50 is the right oil. I use Castrol Grand Prix 20W-50.

- Your neutral switch or the brass cam may be loose. This would explain its odd behaviour. It's hidden behind the right side rear engine cover just behind the drive sprocket. Grab a flash light and go peek. I can just touch mine with a finger so check to see if anything is loose. Better still, just pull the rear casing off, being careful not to lose the last clutch pushrod piece, and take a really good look. The brass cam should be locked onto the end shaft of the gear selector drum with a little grub screw.

- Leave the gas cross-over pipe as-is. Not factory but it's also not a bad idea.

- The two Bosch exciters are small metal boxes hanging under the tank with rubber boots underneath with wires coming out. If you have an aftermarket electronic ignition then these Bosch units will be replaced with a little black box. No special buttons involved! These bikes are known to cook the ignition pick up wiring which eventually fails so it is common to see aftermarket wire repairs. You may have the original pickups and new wiring or new pickups. If you do have an electronic ignition then you will have new pickups.

- I think this is the screw type you need for your fairing cross bar but I am not certain: Back to Classics

Good luck

rick81mhr900ss said:

Avoca: I just took another look at the video. The front carb throttle and choke rubber caps are both pulled up on the cables. This suggests that someone was tweaking the carbs and forgot to push the caps back down. The rear carb is probably the same. I can not see the Bosch units. Can you remove the seat and sidepanels and take and share some pictures showing what is underneath the seat base? Also take some shots looking up under the gas tank from each side. It's common to replace the Nippon coil block, ballast resistors and the regulator when going with a new er electronic ignition but this is not always the case. Is the funny little switch on your left bar an engine kill switch? I don't have one.

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Sorry for the delay! I'll try and tune the carbs here soon. It seems like every time I free up the clutch before starting, and if it stops again, I have to free it up yet again, although it only takes 2 or 3 kicks, vs the 20 or so it takes the first time after sitting all night. Here are some pictures. Let me know if you need to see something else and I'll go out and take a few more! I do appreciate your help. Also, I seemed to have blown a fuse and my turn signals on one side stopped working, then all stopped working. I replaced the california compliant ones with aftermarket indicators that look more factory original (doesn't have the side reflector).

Here are the 81 MHR circuit diagram and component list:

Bike looks very clean . Your clutch problem sounds like contaminated discs - bike left sitting unused for too long. It may clear itself with use. If not, easily solved by taking the clutch apart, cleaning the discs, and at the same changing the oil.

A quick 'Word to the Wise' - don't forget to turn your fuel taps off when not riding! If left open, you risk hydraulic lock (rare - but dramatic and best avoided).

I replaced my old fuse box (never had the plastic cover) with a modern one, mega cheap, very well made, from Amazon so that I could use modern fuses: