Hi everyone. I'm new to the site. I bought a 95% restored 900 sei last summer with 'only one or 2 minor things to do' Should have known better, I got emotional about the bike when I heard it started up and bought it. Been fixing the '1 or 2 problems' ever since!! Had white one in 1982 and loved it. Still love this one but I need help finishing off. Got 3 things to do. Charging light on dash wont go out, rear master cylinder and rear caliper pistons have all siezed and No.1 cyl is running hot and yellowing the exhaust. See. only a couple of minor things! Still I've learnt loads about stuff I'd previously forgotten about such as how alternators/recrifiers/regulators work, doing compression tests, all sorts of fun? stuff. Actually Utube has been a good source of knowledge, specially for seeing exactly how to do stuff. Anyway, if anyone can help with any of these 'minor' problems I'd be eternally grateful as the wife now thinks I have another woman in the garage! Cheers
A common fault with 900 sei is the charging .it gets to hot and fails a replacement is bosch and you can get recons /new from company called motobins i believe ,i bought one yrs ago was around 50 quid.
rear brakes are moto guzzi easly sourced
if been run on unleaded for a while you prob burnt valve seat .
i had a valve go due to this and had it all sorted yrs ago
now just sits in storage coverd not started since ,well cant remember
Welcome - I've got a 900 in silver which is a bundle of fun, my problem it the starter which often doesn't! .
Your hot exhaust pipe is odd. I assume this pot is running lean. If it was the carburettor (the source of many woes) you would expect the other cylinder that shares that carb to run hot as well. The spark plug would be a good indicator if this is the case. If one plug looks fine and the other lean then it must be a problem specific to that cylinder so perhaps it's an air leak. Check the exhaust and inlet for air leaks. Check the plugs are the correct type also. You might also check the timing on that cylinder.
This was just plain wrong so I've edited it:
The charging light is one of four things: wiring, alternator, or regulator. Substitution is the easiest method of diagnosis but not so easy if you have no replacements to hand. Look at the voltage on the battery when running the bike and check how this changes as you increase the revs from idle to 3000rpm. It should rise from about 12v to 13.5 to 14.5v and stay there. Let us know. Check the resistance of the rotor it should be about 2 to 3 Ohms I think. Check the battery earth lead and earth contact to the engine. Trace the wiring and check the connectors. Use your meter to check everything is connected up - buy a cheap one if you've not got one. Unlike all the other Benellis the 900 has a compact permanent magnet alternator rather than the claw pole car type fitted to other Benellis & air head BMW or Guzzi stuff.
For the brakes, firstly check you haven't got a mechanical fault like a seized pedal pivot or linkage. The rear master cylinder can be repaired with a new seal kit or replaced from the usual dealers: Selwyn MCs or Motomecca. The rear caliper is a problem if it's a bigger one than on the front - I can't see mine as I'm at work. The front ones are know as P8 and the bigger ones as P9. You can't get seal kits for the P9 any more, folk are just replacing them with P8s these days. The proportioning valve that links front left and rear brakes may be seized I don't know if you can repair these but many bikes used a straight manifold instead. I fear it is second hand or nothing for this.
Let us know how you get on
Last edited by Tornadoboy; 02-07-2010 at 01:47 PM. Reason: I'm a fool
Hi Vince. Welcome to the forum always good to see more classic owners joining. I think i remember seeing that one on ebay was it the blue one? I remember thinking why would you sell it if only very minor things left to do... sounds like they shouldnt be too much hassle to sort though. Chris (Tornadoboy) is the oracle on all things classic so I am sure he can help get you sorted. Look forward to seeing it finished!
Benelli Tornado LE #128
Benelli 254 (in bits!)
Hi Rob, here's a pic of the bike as I got it back home. It's been totally re-chromed and had a brand new set of silentium silencers put on it. Hence me wanting to get yellowing on No1 downpipe sorted. Starts real easy but I think it's a little over rich as it quickly starts to sound 'choked' but it does sound FANTASTIC. Haven't ridden it yet as I need to sort bits but having bought a proper bike ramp, I must say it's an enjoyable experience - so far. The guy who had it before me was a marine engine rebuilder and he completely rebuilt the bike but sold it before finishing the job. I now know why he sold it! Still plenty to sort. Surprise surprise I can't get in touch with him any more.
Thanks for replies lads, I really appreciate it as I now don't feel on my own.
To Col, yes it is the one on Ebay last year - Just one wire to connect - sure!!
To Chris, thanks for detailed reply, I've tested rotor continuity through the brushes and it is about 55 Ohms from the Purple lead terminal to the grounded other post. I THINK I should get 12 Volts on the purple when the bike is running but there is nothing. The 3 yellow wires each show continuity to the other blue lead and continuity back to rectifier. That's as far as I've got. I get 12.3 Volts at the battery when it's running (Battery power) I'm not convinced guy rewired it correctly.
Guy rebuilt head with new valve guides so my guess is No1 exhaust valve isn't shutting. I bought a compression test kit from a show last weekend and it doesn't work so I'm waiting for replacement. This will probably confirm the worst - that the valve isn't sealing.
I could go on... but am scared of boring the hell out of you.
Thanks again for help.
For anyone interested, I found this utube link on how alternators/rectifiers/regulators work really helpfull - even though I still haven't sorted mine, I feel I am close.
What's that brown wire hanging loose by the rectifier? I think it should piggy back on the back of the big fat red connection but that looks like the wrong unit for a 900. 12.3V is about what you get from a charged battery anyway so it does sound like you are getting nothing out of your alternator for one reason or other. Your value for the rotor resistance may well be correct I got it from a BMW site. I will check one and get back to you.
I can scan the real thing later.
Boring - Me?
Last edited by Tornadoboy; 02-03-2010 at 10:44 AM. Reason: I'm a fool & the 900 is different to all the others
Thanks for that. The diagram looks a lot better than the one I have which shows a different more simplified rectifier/regulator etc setup. Your Guzzi diagram looks a lot more like what I have but it's still not exactly what I have.
I'd appreciate a better copy when you can. Knowledge is power!!!
The brown wire comes from the starter relay. I think you're right about it going piggyback to big red (Which goes directly to battery +ve) but I was unsure about thereby putting permanent 12V on the starter relay. Also, I checked large red terminal when engine was running and it just showed 12.3V meening that higher 14ishVolts I am looking for isn't there anyway. My feeling is that the regulator should be giving 12 volts to rotor purple but it isn't.
Thanks to Richard's reply earlier, Motobins have regulators 73100 which I think is same as mine but I want to make sure before I splash £50.
-I'm also tight as well as boring!!