Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Drew400 on August 10, 2014, 05:07:44 PM
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Hello all,
Time for your expert advice on a different topic please - carburettor rebuilding.
I have inserted an image to support my questions.
The bits have all come back from cleaning, plating, etc. and are gagging to go back together. However, both my manual and my photos are slightly inadequate to help my lack of experience and memory!
I recall pulling out the main jet with the leaf spring and after that the needle jet 'fell' out of the carb body. However, I'm trying to put them back and the needle jet will only go in as far as (i.e. flush to) the bottom of its channel in the carb body. Thus, there in not the space to push in the main jet behind it. Naturally, I don't want to force it as that would presumably mean it won't fall out again if I invert the carb body. Is this making sense?
Also, my set of carb gaskets from David Silver includes some small ones (o-rings really) that I don't know what they're for, Do you?
Thank you all in anticipation of further help to my (increasingly) long-term project.
D.
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Drew, Number 2 is correct (not sure if the is round the right way) But, have you changed the O'ring on the main jet? One O'ring is for the main jet. One is for the air screw . You will need two on each side of the T pipe that is the T pipe that goes between the carb body's. You should have one on your float body. And one is for the drain screw.
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Thanks Trigger, much appreciated.
Any thoughts on why my needle jet won't slide in far enough to allow the main jet to slot in behind it?
Cheers,
D.
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Drew, i think you are on about the tube? Try putting it in the other way. I can not see clear from your picture, its not you its my eyes. The jet only goes in upto the o'ring and then the leaf spring holds it in.
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Yes indeed (the tube with all the holes in its side). I've tried both ways, although the way I've photographed is the correct way, I believe. If it would go in a bit further there would then be space to insert the jet, as you say, up to the o'ring. I'm very reluctant to push it in harder! Hmmm.
p.s. Delayed reply due to watching another Marquez MotoGP win (at least the first 12 laps were exciting!).
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Insert it like this pic
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The 400 expert has made his comment ;)
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Have you seen this before Drew?
It really is the badger's nadgers of carb rebuild documents!
http://www.docstoc.com/docs/97200467/CARB-REBUILD-101
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Thank you again, all.
Cheers,
D.
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One thing ;)
The airscrew has no O ring .... Just the spring.
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O rings are for the main jet, float valve and the drain screw. The 4 larger ones are for the fuel feed connector tubes or the inlet tee.
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Thanks again, I'm now clear on the gasket set.
I'll have another go at inserting the needle jet tube in the next few days. Maybe it's just a bit of a tight fit after the carbs were cleaned, but it's still a source of slight worry to me (I don't like pushing hard on carb bits as they all seem so delicate!).
Cheers for now,
D.
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Spot on Clem. You are right about the air screw. Drew, wipe a little Vaseline on the tube to see it it will slide in. Has the tube been cleaned?
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Thanks again Trigger,
I have cleaned the tube only with petrol and airline, but the carb body has had the full sonic and vapour blast treatment.
I'll try the old Vaseline trick when I next get into my garage. Sadly, the day job gets in the way of the rebuilding classes, eh?!
Cheers,
D.
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Drew, the tubes need to be nice and clean and all the holes checked. As Norniron once said, You may think that they are clean but, have a look with a microscope. He was right.
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OK will do, ta, D.
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Hello all,
A quick update: vaseline worked, other tips worked, etc. and a thing of beauty has appeared (albeit, we don't know yet if it works... and I have three more to go!):
Thank you again,
D.
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Well done drew. Nice work...
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Thanks Jamesh, although I can't claim credit for all of the cleanliness you can see, only some of it!
Cheers, D.
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Hello,
Has anyone got one of these? It's the spring thing from carburettor float bowl.
It fell in half (honest... no bending or anything) as I was holding it! Uri Geller, eat your heart out.
Can't see one on DS or 400fourbits websites.
Thank you in anticipation.
D.
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Opp,s You will have to find the Dutch man for one of those.
Link>>> http://www.ebay.co.uk/itm/Honda-carburetor-leaf-spring-CB500-CB550-C350-CB400-set-of-4-16061-323-004-/111428765291?pt=UK_Motorcycle_Parts_13&hash=item19f1ac066b
Or he does them at £7.50 each. If they are old they will brake.
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Ah , thank you, Trigger for your expertise and reply. I guess if one has broken, the others won't be very reliable. Maybe a set of 4 is wise.
Cheers,
D
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If you go on his site Drew and look to pay in $ it is cheaper.
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Too late, bought on e-Bay, but thanks for the thought. Cheers, D.
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You are too quick for me Drew.
This Dutch guy is a guru when it comes to carbs but, he always has two prices and the $ is always the cheaper option.
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My four things of beauty are now all fastened together and I'm doing the final adjustments before putting to one side to await the engine rebuild. However, I have a question for you experts:
Should the throttle slide be all the way down at the bottom of of its tunnel? I seem to have a small gap at the bottom of c.3mm at its highest point (see photo). I can adjust them upwards (i.e. increase the gap) but nothing doing to close the gap entirely, hence this question.
Hopefully a wet bank holiday will find many of you, like me, in front of a computer and/or engine parts as I write!
Cheers and thank you,
D.
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There should be a gap (otherwise the bike would never tick over.
I always "knew" it was 1/8th" and used a drill bit to set it.
Not sure where I got that from or how authentic it is - but always worked for me.
Steve
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Thank you Steve, you've put my mind at rest. I didn't remove the sliders from their arms when removing them from the car bodies and so I doubted I could have messed up their settings and was thus hoping for the the answer you have just sent!
Great, I can now crack on with more rebuild stuff!
Cheers,
D.
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Re the gap in the carb venturi...
When you eventually come to balance the carbs, about the last task after a re-build, this gap gets adjusted to equalise the vacuum reading for each cylinder..... All that fun to come !
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Can't wait, I think!
Thanks Clem.
D.
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Don't worry Drew. The work you have done on those carbs, everything should come in to place.
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Feeling good, my friend.
Cheers, D.