Can anyone with knowledge of a very early production Monster 900 tell me why there are 3 spigots underneath the tank? It’s a ‘94 reg bike but its frame number is 499. Judging by the handwritten name and date on the underside of the tank (sorry no photo of that at present) I’m assuming it’s the original tank. The 2 spigots with the braided pipe on are the breather and overflow/water drain. In the top right is the fuel level sensor and the stop cock/fuel delivery connector is out of shot on the right. The reason I ask is the spigot which is not attached to anything appeared to be blocked off, however, it’s now started leaking fuel so clearly comes straight from the tank. My questions are; Should that spigot be blocked off? Why is it there if that’s the case? What’s the best solution to fix the leak? Just block it up with JB weld? Or something better eg live with the leak but run another pipe to the fuel filter via a T connection in the existing pipe between the tank and fuel filter so the leaking fuel just goes into the fuel filter and feeds the carbs.
I’ve an early Monster 94, I’m certain mine didn’t look like that, off out to the garage even though it’s blowing a gale……be right back. That is how mine looks, which is nothing like yours which clearly doesn’t help you. The outer left is blank the inner 2 are overflow/breathers the right one is fuel. I’ve not ever considered what the outer left did/does as it’s not ever leaked, I’m intrigued as a result of your question. Last 3 numbers are 543 on my frame Have you posted on the UKMOC page?
Have a look through the filler cap - are there two drains running down from the filler? I don't know about your bikes specifically but twin drains are common on many other bikes.
as above, it has to be to do with either drainage or breathing purposes - if you can follow up and find out how/where it emerges then you will crack the case Paul. I'm going with drain line from fuel filler aperture (overfill, water ingress etc). If it is an internally sited drain tube, and it's become perforated then it will leak of course. This has happened on 848 tanks and can remember helping solve the same on an Aprilia (i.e. - could happen on any tank with same internal draintube set-up).
That’s it, and now I have my answer. Thank you @BobDavo I have a workshop manual for the 93 model but it doesn’t have that diagram in it. From that diagram, and your others, I can see that that is the fuel supply spigot and where the fuel cock is on this tank is not where it should be. The parts diagrams show a bolt where the fuelcock is, which is the drain plug for the tank. So, it seems someone has blanked off the original fuel supply spigot, whatever they used (JB Weld?) is now leaking, they then removed the original drain plug and replaced it with a fuel cock. Well, that’s that sorted. Thank you, and special thanks to @DucatiScud for going out into the garage in the dark . BTW, I have a ‘98 monster too and that’s different again . Now, do I just blank it off or do a better, more permanent fix? Or, remove the fuel cock, replace it with a drain plug and reinstate the original fuel supply point - that would be the best (but most time consuming and costly) fix.
as MarkTMB said, (and i backed up) - try and look inside filler and determine where it's going - I don't believe it's a blanked off original fuel supply pipe, because each pipe has a purpose and isn't duplicated.
I’ll take some more photos tomorrow for everyone to see but what I now believe has occurred is that for some reason a previous owner has removed the drain plug on the bottom left of the tank (not in my photo) and replaced it with a fuel cock, they’ve then blanked off, with what looks like JB Weld, the original supply pipe. As per the diagram from @BobDavo in post 7 above the supply pipe (the unconnected spigot in my photo) connects to the fuel cock, numbered 2 in his diagram; S & D (the 2 braided pipes in my photo) are the breather & drain pipes respectively. The unconnected spigot in my photo is where the pipe from the fuel cock should connect as per BobDavo’s diagram. There is no separate drain plug on my tank but photos tomorrow will make this clear. @MarkTMB iirc under the filler cap, but above the inner filler hole is a drain for water, over filled fuel, this exits through D in BobDavo’s diagram above, and is one of the 2 braided pipes in my original photo. Underneath the inner fuel filler hole is another spigot which is the breather and which exits through S in the diag above and the other braided pipe my photo.
if they have indeed blanked off the original supply pipe, then i'm curious as to what they've used out of the remaining outlets as a replacement, as their routes aren't laid out identically. A breather pipe will continue until the highest possible point in the tank for example. I'm assuming that your bike has a Mikuni diaphragm vacuum pump still?
I couldn’t find a workshop manual for a Monster, I’m using the Haynes manual from the inferior 6-900ss mongrels. I’m perplexed by the differing spigot shapes between your Monster and mine, do you suppose they were using different suppliers given the year of manufacturer is the same. You or me could own a much rarer version, I’ll let you do the sleuthing on that question though. Of the 2 tanks I’ve looked at on ebay neither are the same. https://www.ebay.co.uk/itm/285476066781?chn=ps&_ul=GB&_trkparms=ispr=1&amdata=enc:1snKS0S20SpeUA4wn_-IE3A19&norover=1&mkevt=1&mkrid=710-134428-41853-0&mkcid=2&mkscid=101&itemid=285476066781&targetid=1816181028139&device=c&mktype=pla&googleloc=1006601&poi=&campaignid=19090194174&mkgroupid=147009364227&rlsatarget=pla-1816181028139&abcId=9303860&merchantid=101758224&gclid=CjwKCAiAvdCrBhBREiwAX6-6UtN56D8qDeSaLhegKwudDuxw6jKKAdghdH9gaF4gtCPZKoeJmVx1yBoCCc8QAvD_BwE https://www.ebay.co.uk/itm/276132743842?_trkparms=amclksrc=ITM&aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=257779&meid=66a4eb1884ae4598998eabf39af37efc&pid=101195&rk=4&rkt=12&sd=285476066781&itm=276132743842&pmt=1&noa=0&pg=4429486&algv=SimplAMLv11WebTrimmedV3MskuWithLambda85KnnRecallV1V2V4ItemNrtInQueryAndCassiniVisualRankerAndBertRecallWithVMEV3CPCEmbeddingSearchQAuto&brand=Ducati&_trksid=p4429486.c101195.m1851&amdata=cksum:27613274384266a4eb1884ae4598998eabf39af37efc|enc:AQAIAAABYMF6rapl24zPGkjYHfiSlLTuBicNRv1Nr6Iohq4bMvd7DlxPac1R4%2FnhV6ZdsOB3e44VPDg3LMjzKh6h9F%2BnyuldWK33VEcBpK6UyRXA9oDADzwEJIB%2BjrUQktYR0EluQdk0jMCISI62ak4peNZttnRbSFGqwdC47qFkTZC5xxTjp9bHcL3qg0RoXvktnjH9Rc%2F3UPI5ohSdN5JfFskKTrSLZa2qSfKWxEzsAE20FXilwWH%2FqBRmMCwRgO9sPOIjM%2BmoPHpxLPRpPUjOgezLWSIxmK9Yv3uLFa4NsbEf01E6pCzoA0cvYuuOSmSncHYjtUvpW1UEBHkQ4MS9%2BsER%2BDG35sussXt4%2F2cv3%2BQtWsMwkiPOEPUyz8uumOCEcOU9PMEnDteMnlCh0v%2BJ76P5ygKdJabUdLGuEBhYW0iKEIZfOOX%2Bsqw7ApiEMEF4w8tHoe%2BJq9bA4jXKU9bPyFcKTo8%3D|ampidL_CLK|clp:4429486 On a side note WCP I’m truly shocked and disappointed you have exhaust wrap on your Hypermotard.
What, where? I don’t have a hyper just have had a few through the workshop for service and repairs etc. Aha I remember it now, an 1100S I had in back in the spring. Yes, it had wrap on it . Not my choice, the customer’s, but he felt it helped keep the heat away from his leg.
@West Cork Paul Curiousity got the better of me….. Both the pipes I had as breather/overflow lead into the filler cap ring, the fuel on clearly goes to the fuel itself. The ‘empty’ spigot leads right up to the top of the tank internally, but appears to be blanked off by a rubber pipe clamped to it, it is around an inch from the top of the tank. The 2 breather pipes are clamped below this pipe and routed to here. There is a cradle similar to that which was used in my 851 to hold the fuel pump. (update) My tank is from a much later Monster with fuel pump delivery to the carbs. Meaning the redundant spigot would possibly have been the return pipe given how high it exits in the tank.
I have a question for you WCP, I have a fuse holder that has a single wire to it but no other wire. Have you this fuse holder on yours, it was next to the main 30 amp fuse holder it has me baffled.
Yes, the bike runs the standard Mikuni CV carbs. Thanks to the info above I can now see that at some stage in a previous life the drain plug, which should be on the left has been removed and has been replaced with the fuel cock. Quite why that was done, I’ve no idea. Maybe the original fuel supply spigot, which was blanked off (and now which has a big black pipe on it in the photo, with the other end above the level of the tank to prevent the fuel drip drip dripping out all over the weekend) had become blocked somehow and rather than clear it a previous owner just re-jigged things. I’ve a ‘98 M900 in the workshop at present too and here’s a photo of the underneath of that. I know it’s manky under there but it’s undergoing a recommission. That too has the fuel supply coming from where the drain plug ought to be but that one only has 2 spigots, with no breather or drain pipes attached to either. BTW, here’s what I believe is a date on the red M900’s tank - the bike that’s the subject of the thread. That looks like a dyslexic 12/93 to me, but maybe not ?
I will check on Tues when I’m next in the workshop. Off the top of my head however I’ll say no the 2 I have don’t have that fuse. Is blue a 7.5A fuse? Could it be a supply for something like heated gloves?
It could be it was fitted with them when I bought it but I removed them when they failed. sounds like a good shout. Yes think it’s 7.5amp
Have done a little digging it appears I may have a much later fuel tank than you that had an internal pump fitted. https://www.ducatimonster.org/threads/m900-fuel-tank-variations.353574/ https://www.ducatimonster.org/threads/fuel-tank-and-fuel-lines.353462/
