5th gear whine

The Cagiva era Morinis
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nr.
Posts: 24
Joined: 25 May 2021 13:42
Location: Ely, UK
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5th gear whine

Post by nr. »

Hello all,

Having recommissioned the project Dart to a point where it passed an MOT, it's all been pretty straightforward so far. What a lovely engine to work on, at least for the simple stuff that I've done so far anyway. After living with a TRX850 and it's infernally complex five valve head, and a VFR800 which took three days just to get the fairing off, it's a joy to work on. I seem to have a fully functioning electrical system, which is nice, although I'm still giving the charging circuit plenty of time to disgrace itself - I can't believe I got that lucky to have that all working perfectly after 10 years in a barn. Anyway - reason for writing this - there's a definite whine in 5th gear. It's not loud, but definitely there. Is this a sign of impending doom, or just one of those things that I live with until I get the chance to split the cases over the winter and have a good look inside?

Looking forward to more evenings puttering around The Fens as I get to know the bike.

Ta,
MickeyMoto
Posts: 2415
Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: 5th gear whine

Post by MickeyMoto »

Can't help with the whine, unless a bearing is going as not been run for a while. My wife says my bikes whine in all gears, but is probably not the bike.

The charging system is Japanese! I hope it does not play up.

Good to see another Morini on the road, the Dart is probably ideal on the Fens roads.
morini_tom
Posts: 920
Joined: 05 May 2006 13:47
Location: Northampton

Re: 5th gear whine

Post by morini_tom »

I've never had a morini gearbox whine. however they have no oil feed and run on plain bushes soil it's been standing a long time it may take a bit more settling in I guess.

Is it definitely a gearbox whine? What I mean is, you say 5th gear, which it could be, or is it just that in 5th ou are more able to hear any other noises then engine is making? Tight timing belts whine.

You did put a new timing belt on didn't you? If not, do it now!

Also, the dipstick tube is curved and needs to be fitted so the handle is pointing out, otherwise the end can touch the gearbox, which might cause some sort of noise (never done it myself so don't know)

Finally, the electrics on darts are excellent so you should have no troubles provided the contacts on all the connectors are kept clean. About the biggest issue is damaged flywheels and magnets coming unbounded due to using legged pullers on the outsides as opposed to one which screws into the threaded centre. That causes a mess.

Finally, in this month's club magazine is an article on the kokusan starter system which darts have, well worth a read and take note of my advice there on checking the rubber coupling.

Look forward to meeting you,
Tom
nr.
Posts: 24
Joined: 25 May 2021 13:42
Location: Ely, UK
Contact:

Re: 5th gear whine

Post by nr. »

Thanks for all the advice on my various requests for help so far! Quick status update:
  • Timing belt was replaced before I started the engine - which was remarkably painless.
  • Fork oil was drained, flushed, and then refilled with Motul 5W. This has made an amazing difference. The oil that came out was dreadful. Completely different volumes and colour in each leg. The r/h leg had something like 350ml in there - so I suspect some of the handling quirks were due to it going solid at about 1/3rd travel.
  • Tyres - ContiScoot 110/70 on the front, ContiTwist SM 130/70 on the rear. Seem OK on the quick test rides so far. I'm a big fan of Conti, having used them on pretty much every other bike I've owned for the past 15 or so years.
  • Electrics all seem fine, with the exception of the charging circuit. There's no charging going on at all that I can tell. Rest voltage is about 13.2, which goes down to 12.9 at 4000rpm. However, there was the odd spike at around 14.5 or so, which makes me think it's probably a bad earth.
  • Rear suspension needs a good looking at. Damping is all there, but the spring rate seems to go from nothing to coilbound at the slightest hint of a bump. Around The Fens, this is a bad thing - I've been kicked out of the seat on a few occasions. I've read here that upping the rear preload can help, so I'll have a look at that.
  • Slight drip of oil from around the sump plug, so new washers are on order.
  • Oil temp gauge not moving. Not worried by this in the slightest - will replace the sensor just in case it's an easy fix, but if that doesn't do it, I'm not fussed.
  • Need to check the flexible coupling rubbery. Not sure what I'll do if it's shot, as they seem to be completely unavailable.
  • 5th gear definitely whines, and it's a bit hit and miss if it engages when changing down. Gearbox will be stripped as part of the winter overhaul.
  • Ossified old fuel and breather hoses replaced with Tygon.
  • Brake fluid changed, and pads replaced with AP Racing pads. Never used them before, but for a lightweight bike that's not that fast anyway, I'm not too concerned. Put it this way - I'm a lot more picky with the brake pads on my 675 Daytona.
And that's where we are really. It's a lovely little thing to ride, and seems to have been well looked after in the past. The bodywork has been patched up a couple of times, but whoever did it made a good job of it. The seat could really do with recovering, but that can wait. It's perfectly usable, and actually, I'd rather try to patch up and use what's there, rather than replace it. It's part of the character of the bike. Thanks for all the help and advice so far, and I hope to get along to some future meetings/trackdays/whatever to meet up and chat about things.
EVguru
Posts: 1528
Joined: 01 Aug 2006 11:13
Location: Luton
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Re: 5th gear whine

Post by EVguru »

Fitting a Freccia rear suspension unit seems to help. They used a straight rate spring, rather than the dual rate of the Dart. You can get a complete YSS unit from Brook Suspension for a good price. They are to order, so it will take a few weeks.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
nr.
Posts: 24
Joined: 25 May 2021 13:42
Location: Ely, UK
Contact:

Re: 5th gear whine

Post by nr. »

Just to follow up on this - the charging circuit shenanigans did end up being a bad earth, as expected. This became immediately apparent when I wiggled the earthing point on the front fairing mount, and next time I pressed the starter button, the passing light flashed... Easily fixed, and I took the opportunity to clean everything up in the area before bolting it all back down properly. At the same time, I fitted one of these: https://gammatronixltd.com/epages/bae94 ... BIKE-E-12V [1] - it fits nicely between the tacho and oil temp gauge, and should give me good warning when the reg/rec finally gives up the ghost.

[1] Note that you can buy them direct from the manufacturer on eBay with free postage.
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