Dart trouble

The Cagiva era Morinis
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Dart trouble

Post by mbmm350s »

Hi Wilson,
Crankcase now split, all stripped out, only damage seems to be the main bearing and everything is relatively clean without too much debris
That's good news. :D

Do you think the plain bearings (big ends and timing side main) will be re-usable or do you plan to replace - if so where did you/or plan to obtain the plain bearings from.

And a general question to the forum what is the supply availability of plain big end shells and plain main bearings for 350s like.

Thanks
Mark
seventyplus
Posts: 23
Joined: 12 Nov 2018 14:00
Location: Carlisle Cumbria
Location: North Cumbria

Re: Dart trouble

Post by seventyplus »

Hi MM, yes I did see c3 on the bearings when removed but at time of posting I didn't have the cases split and no markings visible. A "friend" did suggest the dishwasher for cleaning the cases but I'm told it can blacken aluminium. However it was the likelihood of domestic /political problems that swung me against that course and gunk and a pressure washer did quite a good job. All the fitted bearings are SKF from various countries and the large one that's breaking up has a 3/4 inch area on the inner race with bad surface damage but no corresponding area on the outer race, do I replace with SKF?
seventyplus
Posts: 23
Joined: 12 Nov 2018 14:00
Location: Carlisle Cumbria
Location: North Cumbria

Re: Dart trouble

Post by seventyplus »

Hello MM again, I've only just seen your post about the plain bearings. I've had a very close look at the flywheel side bearing and it looks fine, I've not had the rods off the crank preferring to leave well alone as the fly wheel side is fed from the same oil that passes the through the big ends and it looks fine. I'm also aware that there may be supply problems for shells, am I correct?
EVguru
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Re: Dart trouble

Post by EVguru »

Mdina are showing stock of all shell sizes, including an unofficial 'not recommended' 3rd undersize big ends.

Ideally you need to search with Morini part numbers, but they're improving the part descriptions all the time.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Dart trouble

Post by mbmm350s »

Hi Wilson,
All the fitted bearings are SKF from various countries and the large one that's breaking up has a 3/4 inch area on the inner race with bad surface damage but no corresponding area on the outer race, do I replace with SKF?
Of course you must determine as best you can the cause of the bearing failure before replacement.
SKF was likely the original fitment.
You may find this document from SKF useful.
https://www.acorn-ind.co.uk/_assets/doc ... ilures.pdf

Mark
harrymuffin
Posts: 292
Joined: 07 Apr 2014 16:06
Location: west midlands

Re: Dart trouble

Post by harrymuffin »

The crank pin is hollow and can act as a centrifugal purifier - sludge trap - which with use fills up and cuts off supply to the big end shells. You should remove the end plugs and clean out before rebuilding. I was under the impression that the drive side bearing was a Morini special and SKF stopped making them about 30 years ago. That is what NLM told me when I bought their last one as a spare. SKF was persuaded by a chap in Bristol to modify a standard bearing because of this problem, same as the gear box split bearing, by having the bore opened up so that it will fit the crank journal, there is a number for this bearing but you have to ask for this bearing specially. Can someone confirm that SKF now manufacture a bearing that is in their catalogue and off the shelf that will substitute for the original and list this number please? For your information the original bearing is 633250C 33x72x19 and the modified standard is QJ306MA (30)-(33)x72x19.
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Ming
Posts: 798
Joined: 01 Aug 2014 16:32
Location: France
Location: Central France

Re: Dart trouble

Post by Ming »

Just had a look on Google for my own interest. I found both of the above references - the first with https://www.bearing-web.com/en/bearing- ... 03558.html, the second with https://www.qualitybearingsonline.com/q ... 0x72x19mm/ and https://www.123roulement.com/roulement-QJ306MA-SKF.php
Not cheap, though (but if it's necessary...)
EVguru
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Re: Dart trouble

Post by EVguru »

Unlike the 500/501 engines, the 350 uses an ordinary deep groove ball race on the drive side.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Dart trouble

Post by mbmm350s »

Hi Wilson,

The 350/400 Dart uses Morini part 24.01.10 which is 6306 C3 which is the same as earlier 350s.

Again thanks to our Friends across Europe you can see the Dart parts book on Soren Hansen's site
http://morinist.dk/morini/engelskdownloads.php

The part Harry is referring to is "special " part for 500/501 motors.

Harry's point about cleaning out the sludge traps is a good one.
However to do this ideally you should disassemble the big ends to avoid contamination, and then make all the measurements and checks
as shown in the workshop manual.
Unless you have the required specialist tools and knowledge I would take the whole assembly complete to a specialist.
The sludge is often F*ing hard!
I think your bearing has failed rather than being worn out given the low mileage of about 24K miles.
Breaking up of cages is normally caused by some other factor, such as corrosion, admittance of foreign body or bad misalignment.

Cheers

Mark
seventyplus
Posts: 23
Joined: 12 Nov 2018 14:00
Location: Carlisle Cumbria
Location: North Cumbria

Re: Dart trouble

Post by seventyplus »

Dart finally back on the road, great, many thanks to EVguru (Paul Compton) and Morini Tom for all assistance given.
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