Conrod kits ?

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Scottish888
Posts: 266
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

Re: Conrod kits ?

Postby Scottish888 » Fri Aug 24, 2018 3:07 pm

Just a thought,
I go to China a couple of times a year, they have a huge manufacturing industry and can make anything.
The problem with Chinese quality reality and perception is that customers ask for products to be made down to the lowest possible cost which we have all suffered from.
I have been around some of the manufacturers and discussed this with them, these guys can produce parts to the highest quality using the best spec materials if you ask them to.
Our benefit is their scale of production, we would only need a limited run but they could be useful. They naturally prefer to make for large production models with a large customer base but they will all make small batches to the quality/spec required.
I have never had to have anything produced like that but I would be happy to discuss with any firms near the areas I visit, has anyone on these forums been out there and talked with manufacturers?
You just need to look at the parts they produce on sites like made in china.com and alibaba.com, just type in motorcycle conrod or crankshaft

Jordan
Posts: 1380
Joined: Fri Dec 24, 2010 11:29 am

Re: Conrod kits ?

Postby Jordan » Fri Aug 24, 2018 9:36 pm

China has made it possible to acquire stuff that was previously too expensive to afford.
It's fun too, a bit of a lucky dip?

Some stuff I bought cheaply has proved effective and durable.
Other things have not worked at all, out of the box.

Juanpa
Posts: 2
Joined: Wed Aug 29, 2018 1:56 am

Re: Conrod kits ?

Postby Juanpa » Sun Sep 02, 2018 9:21 pm

Eldert wrote:Matt

the 24 horas engine was based on the 175 engine and crankshaft . therefore the bigend pin is narrower as a Italian narrowcase 250 or 350 pin .

Eldert

Hello, sorry to contradict Eldert, the 24 horas's crankshaft doesn't belong from 175 engine, 57,8 mm stroke, but from the 250 de Luxe, 69 mm stroke.
Thankyou very much for your big and precise information,
Juan

Eldert
Posts: 771
Joined: Sun Nov 01, 2009 3:23 pm
Location: Hazerswoude Rijndijk Netherlands

Re: Conrod kits ?

Postby Eldert » Mon Sep 03, 2018 6:15 am

Juanpa wrote:
Eldert wrote:Matt

the 24 horas engine was based on the 175 engine and crankshaft . therefore the bigend pin is narrower as a Italian narrowcase 250 or 350 pin .

Eldert

Hello, sorry to contradict Eldert, the 24 horas's crankshaft doesn't belong from 175 engine, 57,8 mm stroke, but from the 250 de Luxe, 69 mm stroke.
Thankyou very much for your big and precise information,
Juan


i said that it was based not the same as the 175 crank . the flywheels and the bigendpin have the same with . the stroke is 66 mm by the way and not 69 . the bore is 69 mm .

Eldert

Juanpa
Posts: 2
Joined: Wed Aug 29, 2018 1:56 am

Re: Conrod kits ?

Postby Juanpa » Mon Sep 03, 2018 7:47 am

Eldert wrote:
Juanpa wrote:
Eldert wrote:Matt

the 24 horas engine was based on the 175 engine and crankshaft . therefore the bigend pin is narrower as a Italian narrowcase 250 or 350 pin .

Eldert

Hello, sorry to contradict Eldert, the 24 horas's crankshaft doesn't belong from 175 engine, 57,8 mm stroke, but from the 250 de Luxe, 69 mm stroke.
Thankyou very much for your big and precise information,
Juan


i said that it was based not the same as the 175 crank . the flywheels and the bigendpin have the same with . the stroke is 66 mm by the way and not 69 . the bore is 69 mm .

Eldert

Off course Eldert you are rigth, I bad understand you, also I make a mistake because as you say, the stroke is 66, this morning I wake up with this on the head.
Sorry again,
Juan

Scottish888
Posts: 266
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

Re: Conrod kits ?

Postby Scottish888 » Fri Sep 07, 2018 12:05 pm

Does anyone have CAD drawings of the various conrods?

Regards

Scottish888
Posts: 266
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

Re: Conrod kits ?

Postby Scottish888 » Thu Sep 27, 2018 10:29 pm

Today I meausred the conrod big end width at 18mm, so I think that means I will need a 27 or 30mm pin.
I found these MAZZUCHELLI rod kits, very cheap. Does anyone know what problems MAZZUCHELLI rod kits have?

https://www.sip-scootershop.com/EN/Prod ... gIZPfD_BwE

I had a quick check of the head, could not see any light through the closed valves and the head held fuel quite well when filled.
I think my bike must need a rebore, I did not yet measure ring gaps in the cylinders, the bore does not show any visible wear (no ridge at the top) piston even looked ok but this bike has zero compression, I can turn it over easliy by hand with the plug in.
I read that others have used conrods (Honda and Yamaha etc) these rods are close in length...how can different length conrods be used?
If it is a bit shorter (134.5 rather than 135) I guess you could remove a portion of the bottom piston skirt if the .5mm was needed, no problem at TDC, how can a longer rod be used? do you need a piston with the gudgeon pin at a lower point?
Regards

Eldert
Posts: 771
Joined: Sun Nov 01, 2009 3:23 pm
Location: Hazerswoude Rijndijk Netherlands

Re: Conrod kits ?

Postby Eldert » Tue Oct 02, 2018 1:14 pm

the Honda , Yamaha and Hus . conrods where used because nothing else decent was available at that time . involved a lot of work . custom made bigend pins . narrowing the flywheel cheeks for the wider rod and rebalance the assy again .

for a road going bike i would fork out 290 euro for a rodset from the Ducati vintage store . little milling needed tho.

Eldert

blethermaskite
Posts: 477
Joined: Thu Mar 01, 2018 1:06 am
Location: northern ireland

Re: Conrod kits ?

Postby blethermaskite » Thu Oct 04, 2018 12:33 pm

Hi Eldert,
Not trying to hijack this thread.....but.....do you have experience of the rod kits from 'the ducati vintage store' it seems unclear (to me) if these kits are genuine ducati or a re-manufactured copy, you mention a little machining required ?? would you use one of these in a hard used road engine ?......I am getting close to a big end replacement for my 74 widecase 350 mk3, remarkably this will be its first big end since new, I have never needed to open this engine up in the whole 44 years I have owned the machine, (spanish/itailian hybrid engine, reved regularly to 8500rpm, std bore, only replacement parts were both rocker arms which shed their chrome at about 2000 miles way back in 1975, oil used castrol gtx from new changed at 1000 mile intervals, now using silkolene comp4 20/50)
When anyone turns their nose up at these late widecase 350s I just smile to myself.
Cheers,
George

Scottish888
Posts: 266
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

Re: Conrod kits ?

Postby Scottish888 » Fri Oct 05, 2018 8:25 am

Good news!

I contacted Samarin in Spain, they seem very helpful.
If we could organise ourselves we could have a small batch made.
Has anyone here ever made a CAD drawing imaged from a good original rod?, It would be good to scan a good rod so manufacturing companies can produce easier, we also save this cost.
If you have a new old stock or quality unused rod, could you have it scanned?
I will only have my already worn rod when I remove it from my 250.

Dear Alex

- Ref. DU-251ECM . Ducati 175cc-200cc-250cc . Special machined competition connecting rod with bearing of silver competition. Price 175 eur unit
- Ref. DU-253ECM . Ducati 350cc . Special machined competition connecting rod with bearing of silver competition. Price 210 eur unit

We can manufacture the quantity you need. From 10 units discount 10%

Transport and tax not included.

If you have any question, please feel free to contact us.

Regards.
José Marin.
Manufactured Samarin Co.Ltd.


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