400cc "kit"

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simonnorthroad
Posts: 388
Joined: 16 May 2017 10:57
Location: Bath, UK

400cc "kit"

Post by simonnorthroad »

Hi,
Ive taken possession of a drumbrake Sport, which the previous owner restored but is a bit vague about the details.

He claims to have fitted an "L5 cam and "big-bore" kit, possibly 400cc though he's forgotten the capacity. Is there any such thing? I thought they were all 375cc apart from the std low CR Dart engines. There is no Gilardoni makers name on the barrel exterior or anything to indicate it is out of the ordinary. Should there be on a big-bore kit?
mbmm350s
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Re: 400cc "kit"

Post by mbmm350s »

I have some 400K (German model) Nikasil barrels the fins have a rounded shape i.e not square like on K5 so they look like original barrels with liners - i will check to see if they have Gilardoni on them. I think they work out as 390cc, but that's from distant memory
Mark
Last edited by mbmm350s on 22 May 2019 15:19, edited 2 times in total.
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: 400cc "kit"

Post by mbmm350s »

According to this site the 400 was actually 390cc, the model I have barrels for is listed as 400S. I got these around 1988 before the 400 Dart came out.
http://www.motomoriniclub.nl/models.html

Mark
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MarkB
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Re: 400cc "kit"

Post by MarkB »

My 350 Sport is actually about 400cc, Gilardoni barrels, and pistons which nobody has been able to identify; rather than the recesses in the piston heads being machined, they look cast, with rounded edges. It was used as a test bed by Alex at NLM in the early 90s.
"I'll have a V please, Bob."
simonnorthroad
Posts: 388
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Location: Bath, UK

Re: 400cc "kit"

Post by simonnorthroad »

Interesting. Ive yet to investigate the cam claims on the open road.
At the moment it doesnt even go as well as a 350 as its got 125 main jets, black plugs and gradually bogs down the more you wind open the throttle!
mbmm350s
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Location: Reading UK
Location: Berkshire UK

Re: 400cc "kit"

Post by mbmm350s »

Rounded as opposed to square finned 400cc (390cc) Nikasils are marked MOTO MORINI Gilardoni in the casting.

The only way it can be bigger than 64mm (375) and not a Nikasil is if the crankcase mouths have been bored out to accomodate
a larger liner as 64mm is about the limit on standard liners.

MarkB
For me the 400cc came from Italy as a complete kit (barells, pistons,rings,pins,circlips) not through spares importers in the UK.
I am sure I have some paperwork I will see if I can find.

Mark
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Re: 400cc "kit"

Post by EVguru »

The 375 overbore pistons give more like 366cc.

Gilardoni barrels have a larger spiggot as much as anything for addtional strength becuase there is no liner, just an extension of the barrel casting. This strength is interms of handling and avoiding damage during assembly more than anything else I think.
Gilardoni barrels can and have been machined down to fit stock 350 crankcases. The same being done to fit 501 barrels on 500 engines.

You can go to 402cc with 67mm pistons from VW Polo or Lupo. There's just enough thickness in the Iron liners and although they do get very thin at the bottom, the pistons are shorter, so you can then shorten the liner if you feel the bottom edge is too vulnerable.

I sourced pistons and had barrels machined for Pete Farrel's racer, so I know it can be done sucessfully.

You used to be able to get 500 pistons that were machined for a 17mm gudgeon pin so you could fit them to 350 rods. That very mich did require the use of a special liner.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
simonnorthroad
Posts: 388
Joined: 16 May 2017 10:57
Location: Bath, UK

Re: 400cc "kit"

Post by simonnorthroad »

Yes Ive had crankcases bored out to suit 501 barrels before now
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