Regulator Batt Sensing

[TurboRestorer]

The brown wire off the regulator that is used to 'see' the battery voltage, wouldn't this be better connected directly to the battery?

[EVguru]

Only if you wanted to run the battery flat.

[penman]

Like so many things Morini, the regulator arrangement is wonderfully confusing! In its defence, there are good reasons for it being the way it is. The regulation is actually on the negative side of the regulator output, but this actually simplifies the design which is a true series regulator which doesn't waste energy by shunting it to earth. The voltage sensing is done on the switched side of the supply as you say, but this avoids any leakage to earth when the bike's switched off and the resistance of the switch and associated wiring shouldn't be enough to affect the battery voltage significantly. I wouldn't change it, as Paul says, the result might be a flat battery after a day or two parked!

[TurboRestorer]

I thought I could improve on the wiring & give me another connection point as 2 of the brown wires had melted protection sleeves. I have now fixed this issue & my lights work all the time & not just randomly, also strangley the bike runs slightly better as well. Returned float heights to 24mm precisely & E17 needles with 2nd clip position & the bike will now pull top gear! Not sure whats going on but still have fuelling issues around the 5K rpm mark but suspect that this could be main jet related as its about the 75% throttle position & the 112 is a little rich. Going to use 108-111's & see what happens.

[penman]

Still getting nowhere with my fuelling problems, as a matter of interest, do you have the rubber sealing strip between the two halves of the air box? Removing this almost doubles the area of the air intake and consequently reduces the depression in the intake. I have read somewhere that the main jet should be 98 with the seal in and 112 with it out. I'll try to find where I read that, it was a reliable source, and post something on here. Having said that, I doubt if changing the main jet will affect this problem - but this bike likes to prove me wrong so go ahead, I'm watching with interest!!

[MickeyMoto]

In the blue book....

[TurboRestorer]

Your correct, I have the RED Manual from Benji Straw (Wee-Vee) & it does state 98 with seal & 112 without, mine is without seal & 112 main jet, this is going down to 110 & see if that helps. After that I am going to adjust the ignition timing slightly (max 4deg) to see if that helps with the flat spot @ 5K, which I believe is a rich point. If you rev the engine through the 5K issue its OK but if you are in a higher gear & try to go through the 5K band it misfires & bogs down. If it was lean at that point when revving through 5K it would be worse as you have more air. Rich + more air = ok, lean + more air = not ok.

[penman]

This is all very interesting. When you have a moment (and if it ever stops raining) can you take your bike to that point when it is misfiring and bogging down as you describe - and then try closing the throttle and de-clutching? Mine behaves much the same and if I do that, the engine actually stops. I like the theory that it's at a rich point, in fact it's the best fit to my symptoms, but it does surprise me that it's so difficult to get it running well - they can't all have a nasty flat spot at 5000 rpm! Can they??

There is a whole range of different atomisers for this carburetter, different sizes and with different hole patterns. I'm guessing that the higher the holes, the more air is admitted to the spray of atomised fuel (maybe someone can say if that's right or wrong?). What I'm not sure about is how this varies as you open the throttle - does it have most effect on the taper or at full throttle. I would try changing the atomiser, but they are expensive and I'm not sure what to go for. I do have 258BD and 260BD available, but there is no appreciable difference in performance. My "gut feeling" is that it would be good to try an atomiser with fewer holes at the bottom (or more at the top!) - but again, this is an awful lot of faffing about to obtain acceptable running! Are we missing something?

[TurboRestorer]

I spoke to Dellorto about the atomisers & hole arrangement, the holes that are further up make it leaner, compare 260K with a 258BD, 258BD hole arrangement is slightly different & is a slightly leaner atomiser, didn't work that well for me, made everything too lean. The only issue I have is the statement that the main jet only affects last 25% throttle, as far as I'm concerned it must come in before that, even if its slightly before as I think it should 'feed' in to full flow gently at full throttle. What I'm thinking is that my main jet is possibly starting to come in at 75% thottle + needle/atomiser which is giving a rich point, so putting in a leaner main should make this less if I'm correct, I have fitted 110's & waiting for weather to get a bit better, just need dry roads as its been cleaned for a show later this month.

Penman: I did have an electrical problem with the lighting circuit & now thats fixed the bike does now pull top gear with std carb. settings but still wont pull over 70mph.

[penman]

TurboRestorer: I made a mistake earlier, just mis-reading the needle chart. The E24 needle starts the taper higher up, therefore earlier as the throttle rises, not later as I thought, compared to a E17 needle. This makes the mid-range go richer sooner with E24. I must say, I thought mine performed better with the E24 needle, which tends to go against the "too rich" theory - I've made so many changes though, perhaps I confused myself. I shall be interested to hear how you get on with the 110 main jet, but I suspect it'll only make a difference at or close to full throttle. My engine performs really well at full throttle and I've seen 90mph on the clock - and even then, it was me who backed off, not the bike, I think it would have gone on a bit more.

I'm a bit hazy about exactly what is going on around that magic 5000 rpm region. Under load - i.e. 6th gear on level ground or a lower gear on an incline, my engine misfires and snatches, and as I mentioned before, if I close the throttle and de-clutch, the engine stops. If it was bogging down due to richness, closing the throttle like that may not give it time to recover, so I reckon over-richness could still be the explanation - but I'm far from sure. I wish I had a box of dellorto jets, needles and atomisers to play around with!

At the moment, the Morini is in the naughty corner up the back of the garage and I won't be able to get it out until I've finished a job on the Trident, so it'll be a few days before I pick this issue up again - I needed a break from it, I'm not a Morini fan just at the minute! That will of course change if/when this problem is sorted!

[TurboRestorer]

If I can do it safely I will run the bike at 5K spluttering & stop the engine & pull the front plug to see what its like but i have to remember I now have 7's fitted & not 6's. The 6' have been contaminated with additives & ceramic doesn't give any 'reading' to interpret rich/lean.