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33mm Mikuni carb wanted for DR400S please

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Hi All,

Excuse me..I havent intro'd myself on the Newbie Board but dived straight in.

I have a DR400S with the wrong Mikuni carb fitted.

Does anyone have a 33mm Mikuni carb for this bike that I could buy please?

It has the ref no: 37210 or 37210/372 or 1320037210

This has a top to the carb which is rectangular'ish with 2 screw holes.

(Possibly a Mikuni TM33-8012)

Many thanks.

Ed

info@edgold.co.uk

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What year is the bike?

I'd make sure that you know exactly what carb you need before you buy a TM33-8012

If it is a TM33-8012 they can be bought brand new here for $217 US which is the best price I know of.

http://shop.viperizerracing.com/product.sc;jsessionid=ED3611273E970E6D3E0B222F1D6D8351.qscstrfrnt01?productId=307&categoryId=75

But I don't know if they ship to the UK so you will have to email them and ask.

I would definitely not buy a used TM33.

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Many many thanks for replying Bob.

The bike is a 1980 model. I discovered that it has been using an SP400 carb, that is the carb that is on it right now. My friend who is selling it said that it DID run but if it was left standing for a long time it wouldnt start. Apparently if an air compressor is used to give the carb a thorough clean it would run again.

The gas tank is very clean, its filter is very clean AND it has an inline filter which is very clean. The gas pipe internals are very clean so it's a mystery why the jets and carb internals get blocked IF that is what the case is.

HOWEVER the latest find is that the primary jet tube which the primary jet is recessed is missing its rubber plug that sits in its top. ALSO the pilot jet screw is missing its spring so it has been sitting in its thread screwed all of the way in!

Experience tells me that it should be wound out about 1 and a half turns? But without the spring it gets loose after 3/4's of a turn out from fully wound in.

I have looked for a rubber plug for the primary jet on the net but no luck.

Mikuni in the UK have said they could sell me a carb - they wrote:

"The only suitable carb I list has the throttle cables on the opposite side (right)

left side pull choke.

I don't know if it will fit in the space available on your bike.

Mikuni TM33-8012 (see attachment)

The carb is a 33mm pumper and can be supplied jetted to suit your bike.

£221.00 inc

£7.50 UK recorded delivery"

Bob - do you think this TM33 would work on the DR400S?

or I might try and get the SP400 carb to work...

(I attach a drawing of the carb and it is missing No. 24 & No.04, will No.24 make a big difference if it is missing?)carburetor-sp400-1980-t_bigsue0138fig8_697b.gif

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The carb in the pic is a CV (constant velocity) style carb, similar to the BST33 that the DR350S models came stock with.

The plug (#24) looks like it simply covers access to the pilot/slow jet. It appears to be inside the bowl so I don't see why it wouldn't run without it. But I cant say it will for sure.

As far as the fuel screw spring goes (#4) you definitely need that for it to run properly but I'd bet that the BST33 or TM33 spring would fit if you cant order the stock spring.

The carb will need to be disassembled and cleaned with a good carb cleaner. Any of the rubber O-rings will need to be inspected and replaced as needed.

If the O-rings and diaphragm are ok then I would think that all you would need is the spring.

Since I don't know the bore size of the DR400 stock carb I cant say if a TM33 will work or not.

I can measure the length, width, height and bore sizes of a TM33 that I have here to see if it will fit "physically" but I have no idea what size the DR400 carb is in mm so I cant say if it will be possible to jet it correctly for the DR400.

I suggest you inspect all of the rubber parts and see what it may need and go from there.

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Bob

Many thanks for your time and help. I am finding it impossible to track down an original DR400S carb so will stick with the SP400 carb. I will measure it later today and send you its dimensions. Also I will check that all rubber is intact and maybe even fabricate a rubber plug to sit over the primary jet tube as Im sure it is there for a reason. I have been looking at cmsnl.com as a supplier of carb parts - I believe they are in the Netherlands and the next best thing to ordering from the States...do you have any knowledge of this site? Im actually planning on buying this DR400S today even though it isnt running and then working on it over the next few weeks so that its ready for when the snow comes!

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No experience with or knowledge of cmsnl.com.

Do you have any idea what model/ size (mm) the stock carb is?

I will measure it later today and send you its dimensions

Post the measurements in this thread rather than a PM so others can use them for future reference. 👍

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Bob

Thanks again. Sorry I havent replied until now. Tomorrow is the day (Sunday) Im meant to be going to buy the DR400S from my mate and will have a go at getting it running again. It fired 3 times the last time I spent 12 hours at it - which involved 3 full carb strips and cleans. Im not happy at buying a bike that doesnt run but he needs the £'s and I need it for winter mountain riding (for £300/$466 USD).

I have a diagram for the proper carb from the cmsnl.com website. I can only measure the SP400 fitted to the bike when I can get my hands on it. The bike was running with the SP400 carb fitted but no longer.[it has a good spark and the battery is full charged, 6 volt]

The mate selling it has had it in bits and also tried to fit other jets etc from a carb of a bank of 4 from a GPZ750 👍.

[email=http://images.cmsnl.com/img/partslists/carburetor-dr400-1980-st_bigsue0161fig-8_1ee2.gif]http://images.cmsnl.com/img/partslists/carburetor-dr400-1980-st_bigsue0161fig-8_1ee2.gif[/email]When I was younger I would have tried to fit a shower head and a can of tomatoes as a carb if I had thought it would work but nowadays I've learnt that its best to stick to original all the way unless you have the budget of NASA. So..Id rather find a proper DR400S carb. Can you tell what carb it is by the diagram? I believe it to be a Mikuni VM33? I will try to scavenge a spring for the pilot jet off the GPZ750 carbs if they have a spring for the same and might fabricate a rubber plug to cover the tube to the primary jet, will blast it with a compressor, clean it with petrol (gas) and see what gives.

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Here are the physical dimensions for the TM33SS. Save it to your desktop and zoom in on it so you can read it.

I don't know how long the link will work for as it's from an auction.

NCS_carb_measurements.jpg

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