13 replies to this topic

[CTRdemon]

I bought a carb in "perfectly good working condition" off eBay and just got round to installing it.

I am having an issue with it that when the oil is put in the dashpot it just leaks down the needle and drops off.

Has anyone had this issue before and know how to solve it? Should I contact the seller and pull him up on it?

Thanks

[nicklouse]

yes in can do if you over fill it.

 

how are you measuring this.

Edited by nicklouse, 06 November 2017 - 11:31 PM.

[CTRdemon]

I am just dripping it in and it runs out. I am using 3 in 1 oil (as many recommend). I also tried with thicker 5w40 as a test but when the plunger goes in it just forces it all out.

Edited by CTRdemon, 06 November 2017 - 11:34 PM.

[panky]

You only need a couple of tea spoons full in the central tube that the piston pushes into, any more will overflow and dribble into the carb.

[nicklouse]

I am just dripping it in and it runs out. I am using 3 in 1 oil (as many recommend). I also tried with thicker 5w40 as a test but when the plunger goes in it just forces it all out.

sounds normal. the recomended is to use the same oil as your engine oil and to fill 13mm below the top of the inner tube. but just put it in and let it flow out as you slowly add the plunger. done.

[richmondclassicsnorthwales]

E-Bay are a pain in the arse  -  sorry - rant over

 

Your 3 in 1 oil is way too thin, like water.

 

20/50 is what it should be.  In the winter use a lighter grade like 10/40 or even 5/40 and just take your time placing the damper back in. Don't go bull in a china shop,

 

I don't use my classic in the winter anymore, i  have done previously, but don't need to now, so I don't. Dashpot oil is something I checked weekly, force of habit, it's only 20 seconds to look. Your oil can't go all the way through the tube if that is what your wondering.

Edited by richmondclassicsnorthwales, 07 November 2017 - 08:03 AM.

[CTRdemon]

Sorry, I should have specified it forces it all out the bottom where the needle is, not the top.

Panky & nicklouse: thanks for the tips,: that's good, I have the right amount in that case, it just pees out the bottom.

Richmondclassicsnorthwales: That is what is happening at the moment, it seems to be going all the way through the tube, out the bottom and running down the needle. I've attached a pic.

So 3in1 oil is too thin then. Should the piston be hard to move up and down in that case? At the moment it takes a little force but not too much. Is it better to use a thicker grade in the beginning to help get it running then play around with substitutions etc for better throttle response?

Attached Files

•  IMG_8775.JPG   43.07K   8 downloads

Edited by CTRdemon, 07 November 2017 - 08:32 AM.

[nicklouse]

so where is it leaking?

 

looks like it is running down the side in that picture.

 

clean it. fill with oil and leave it over night like that and see if it is really leaking.

[Dusky]

 
20/50 is what it should be.  In the winter use a lighter grade like 10/40 or even 5/40

Lol.
Oh and,dashpotoil is Just a tuning part. No "one size fits all".

[CTRdemon]

Nicklouse: it runs immediately out, no need to wait. It comes from where the needle goes into the underside of the piston (if that is what you call it).

Dusky: I did wonder because from what I've read everyone recommends something different. From what I can gather it depends on the throttle response you want and that is right for the particular engine. I just need a good "first oil" to use to get it started.

[Northernpower]

So, by holding the piston in your hand and pouring oil into the damper tube where does it leak out from?

[Retroman]

Sounds a bit like someone has had a stuck needle holder and or didn't know how to remove the needle and holder...maybe drilled down through the middle tube where the damper fits...? or brayed it with a screwdriver...?

 

If you take the needle and holder out can you look in and see daylight ? maybe from both ends ? Its the only way oil can drip directly from the needle...If you can it needs some epoxy, araldite or a grub screw.

 

   If there is too much oil around it may squirt out the tiny hole in the damper lid when the piston lifts.

It can also run down the outside of the damper tube into the bottom of the piston then creep out of the bottom holes near to the needle.

Remove everything, clean everything with carb or brake cleaner, and a lint free cloth. Make sure you do all of the piston including the inside of the at the bottom where the 2 holes are. It all needs to be spotless. Reassemble the whole shebang and just put about ten drops of your engine oil in the damper tube (not down the side)....cross your fingers all should be good

[richmondclassicsnorthwales]

Sounds very much as though someone has drilled it, which is not much use to you now. you are not going to hold any oil in that if you can see all the way through, what was anybody thinking ?. Is that from a HS4 carb ?, I don,t have any pistons for HS4, only HIF

[cal844]

Sounds very much as though someone has drilled it, which is not much use to you now. you are not going to hold any oil in that if you can see all the way through, what was anybody thinking ?. Is that from a HS4 carb ?, I don,t have any pistons for HS4, only HIF

Upon visual inspection (I haven't taken measurements) apart from the needle size the pistons can be used in the other models of SU carbs(HAS in HiF and HiF in HS )

Not saying to drive a car with mismatched carb pistons but I've used them for moving cars before

Edited by cal844, 07 November 2017 - 07:09 PM.