Mikuni Replacement

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frankfast
Posts: 189
Joined: Wed May 05, 2010 12:35 pm
Location: New York (upstate)

Mikuni Replacement

Postby frankfast » Tue May 12, 2020 12:56 pm

Rather than rebuilding the DelOrto 29mm square slide carb on my 350 Scrambler, I'm thinking of replacing it with a Mikuni. I'm looking for advice on what type would work best - 30mm, spigot mount, manual choke instead of cable operated? I know that there may be jetting issues involved but I have no problem working that out. Any of you who have switched, I'd appreciate any advice you have to offer. There are plenty on Ebay or is there an online dealer that you would recommend? Thanks.

Duccout
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Location: Essex UK

Re: Mikuni Replacement

Postby Duccout » Tue May 12, 2020 2:46 pm

Hi, and good luck. There is a specialist in the USA called Sudco who specialises in Mikuni conversions, I'm sure they could help.

frankfast
Posts: 189
Joined: Wed May 05, 2010 12:35 pm
Location: New York (upstate)

Re: Mikuni Replacement

Postby frankfast » Tue May 12, 2020 4:26 pm

Yes, I know of them. I believe that I've purchased jet kits from them in the past. Before I talk to them, I'd like to know of board member experiences with this conversion.

Scottish888
Posts: 265
Joined: Wed Feb 07, 2018 1:47 am
Location: Edinburgh, Scotland UK

Re: Mikuni Replacement

Postby Scottish888 » Tue May 12, 2020 5:19 pm

Hi,

I bought a new 30mm Mikuni for my bike last week to solve a bad running condition.
The carb fitted easily with the rubber adaptor (40mm ID) and I kept the manual choke it is was very easy to access.
The carb sits further back due to the rubber manifold adaptor and this made an air filter very difficult to find and then fit in that limited space.
If you can get a better manifold adaptor that allows the carb to sit closer to the engine you wil be able to fit a wide rancge of filters.
I would try and buy a new bolt on manifold that sits closer to the engine rather than stick with the Ducati one, there are lots out and some may even have the dimensions you need.
You will need to make a new throttle cable but in the USA I expect you will have better service and get a cable included.
I did not try other manifolds as I think my problem is ignition so I put the Mikuni in a box and re fitted my old Dellorto till I sort the main issue.

Regards,

Alex

tobydmv
Posts: 85
Joined: Wed Apr 16, 2014 4:59 am

Re: Mikuni Replacement

Postby tobydmv » Wed May 13, 2020 2:06 am

Hi, I have a Sudco sourced Mikuni. I went with a 28. Im fairly happy with it after rejetting the pilot and raising the needle. It requires a new intake manifold and rubber coupler to connect. I bought the intake at Guzzino. They have several different sizes. The rubber coupler came from Treatland I think. One complaint I havent sorted out yet is the choke lever. The lever is on the inside, or wrong side and hits the frame tube requiring a slight angle to clear it. It also interferes with the fuel line as the fitting is also on the inside. I think the lever can be swapped over 180 but havent gotten that far with the bike yet. Too many other issues to sort out. But the carb works and its nice having a proper enrichener. I think its fair to say that it will require tuning on your part. You will have to invest in jets and maybe even needles.

I did see a NOS Dellorto on ebay https://www.ebay.com/itm/Dellorto-VHB-26-FD-NOS-Ducati-250-single-carburator-with-RIGHT-HAND-adjustments/171529835392?hash=item27eff99380:g:3E0AAOSwyTZUWZOq that I would rather have had since I have dellorto jets. I think at some point I was going to try a Dellorto from a Moto Morini 3 1/2 since its a 27mm. Those pop up on ebay all the time for a reasonable price.

Duccout
Posts: 838
Joined: Wed Feb 05, 2020 1:20 pm
Location: Essex UK

Re: Mikuni Replacement

Postby Duccout » Wed May 13, 2020 8:00 am

I don't know how the prices compare, but brand new Dell O'rto 28mm pumper carbs for Moto Guzzi can be found on eBay for £75.

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

Re: Mikuni Replacement

Postby Eldert » Wed May 13, 2020 9:39 am

that 26 mm is not a Ducati single carb . it is rubber mounted . looks like a parr twin carb to me

Eldert

tobydmv
Posts: 85
Joined: Wed Apr 16, 2014 4:59 am

Re: Mikuni Replacement

Postby tobydmv » Wed May 13, 2020 6:25 pm

Duccout wrote:I don't know how the prices compare, but brand new Dell O'rto 28mm pumper carbs for Moto Guzzi can be found on eBay for £75.


Wow, that is really cheap. Can you share a link? Recently I was researching a 30mm Dellorto for a Benelli group and the price was $200.

Eldert wrote:that 26 mm is not a Ducati single carb . it is rubber mounted . looks like a parr twin carb to me

Eldert


I'm pretty sure all Mikuni's will be rubber mounted with a coupler as well. AFAIK Mikuni doesnt make a clamp on carb to fit the stock manifold stub. Hence the new intake manifold and rubber coupler when fitting.

Jordan
Posts: 1162
Joined: Fri Dec 24, 2010 11:29 am

Re: Mikuni Replacement

Postby Jordan » Wed May 13, 2020 10:40 pm

Just to mention, there is a carburettor that doesn't need an adaptor - the Amal Concentric.
It is likely to have the greatest clearance for an air filter.
I had one on a 250 Mk3, that worked very well, although with no filter.

Duccout
Posts: 838
Joined: Wed Feb 05, 2020 1:20 pm
Location: Essex UK

Re: Mikuni Replacement

Postby Duccout » Thu May 14, 2020 7:32 am

How's this: http://www.ebay.co.uk/itm/03340-CARBURE ... SwlndZCZy6. Probably about the same price as a Mikuni. I think that the Mikuni rubber flanged manifold would work with the Dell O'rto, and the tube mounting seems the way to go - you get a rubber-mounted carb mounted fairly near the cylinder head.


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