Suzuki 2 Strokes

Good afternoon All,
Just had the carbs and fuel tap ultrasonically cleaned after a bit of a lay up, put it all together, started 4th kick and ran up well, then fuel started pouring out of the bottom of the diaphragm. Stripped the tap and lapped in both the faces of the diagram body and cap with 800 wet/dry, no tears in the diaphragm so put it back together and it's doing the same, I've got a spare diaphragm and changed that but still the same.
Can anyone point me in the right direction, either blanking off the diaphragm part of the tap or any other suggestions. A new tap is as I'm sure you all know, is a bit pricey, if you can get one.
regards Chris

Gas is probably pouring out the vent hole in the petcock base.

The vent holes in the diaphragm & the pentagon-shaped plate have to line up with the vent hole in the petcock base.
See:


You may be missing the tiny gasket that goes between the petcock base & diaphragm — it seals the vent hole.
See tiny gasket it this pic:


Those pics are for parts that this website sells:
https://hard-to-find-parts.de/epages/af ... hn_Auspuff



Alternatively, you could use a manual petcock. I’ve had good luck with the manual petcock that Paul Miller sells on eBay.
See:
https://www.ebay.com/itm/172308959807

When using the manual petcock, you will have to seal off the carb’s petcock vacuum tap. You can use a vacuum line cap from an auto parts store.

jabcb wrote: ↑Wed Jun 09, 2021 4:02 pm Alternatively, you could use a manual petcock. I’ve had good luck with the manual petcock that Paul Miller sells on eBay.
See:
https://www.ebay.com/itm/172308959807

I have done the same with no problems.

Thanks jabcb and karlpa
Do you mean the very small one above the spring and below the filter, if so on uk models it is moulded into the diaphragm not
separate.
I think you are right it is coming out of the small hole in the diaphragm body and I can't get a replacement diaphragm anywhere.
I've had a look at the manual taps that Paul Miller sells and that looks the I'll have to go, but I still can't get my head round why it's
leaking, everything is cleaned up and aligned ?
Thanks again for the reply.
regards Chris

Yes, the very small one.
I don’t think it was molded into the diaphragm, but sticks to it because of age.

Suzuki didn’t sell diaphragm repair parts. Perhaps because there is a “trick” to getting it to work correctly.

Hi jabcb,
Thanks for the tip, I'll have another look at it, just had a thought, the O ring on the end of the diaphragm that goes into the body is worn and it could have been letting fuel through all the time so I tried to remove it, needless to say, it split so I've had a measure up and found some in the UK and ordered, the size I've ordered is 3.5mm I/D with a 2mm cross section, whether it works or not I'll post the results, it might help others in the same boat.
regards
Chris

saab9002 wrote: ↑Thu Jun 10, 2021 9:02 am just had a thought, the O ring on the end of the diaphragm that goes into the body is worn and it could have been letting fuel through all the time

Unfortunately that o ring only controls fuel flow to the carbs, which can be a problem with flooding carbs and engine, but shouldn't have any connection with fuel coming out diaphragm vent hole. The normal cause for fuel leaking out vent hole while running is a tear in the diaphragm. I know you said there is no tear in them, but I would have another close look, especially around the valve peg.

I have looked as closely as possible at both of the diaphragms I have and cannot find any tears in them (68yr old eyes) as you said jabcb the small O ring was in both cases stuck to the diaphragms, so I was in hope that after peeling them off with no damage that maybe they didn't seat into the body properly whilst stuck, and they would do as separates and cure the problem. Sadly not a chance, the only bit of good news for anyone else is that the small O ring that fits on the end of the diaphragm "shaft" should be 3.5mm I/D and 1.75mm C/Section but the O rings I got at 2.0mm C/section do work.
I would like to get these 2 taps up and running eventually but have succumbed to buying a new Suzuki replacement which works fine.
If anyone has any other ideas about repair or sourcing replacement diaphragms I would love to hear from them.
Thank you jabcb and karl pa for all your help so far.
regards Chris

I've found someone in Germany that rebuilds/manufactures Suzuki diaphragms on an exchange
basis so I've sent him the two duff ones I had and await the arrival of replacements.
I'll keep everyone informed how I get on, it could be a solution for others.
regards Chris

Sorry for the late update,but have been trying to sort out the front end of the T350R.
The replacement diaphragms are a success and the guy who does it is called Volker and his company is hard-to-find-parts
in Germany. The service he gives is great but it’s not exactly cheap but certainly cheaper than a original NOS tap.
So all good now.
Regards Chris

Hey Chris,

Thanks for the info. I had issues with my diaphragm as well, but ended up finding a new replacement assembly rather than fixing the old part. Is this website the correct one for Volker's company? (https://hard-to-find-parts.de/)

I see that he also sells kits of replacement parts, in addition to the rebuilding service. That might be a good option for those looking to save a few dollars who are in a similar situation.

Regards,

Jim

Hi Jim,
Yes that's the site, if you email him and can't speak German, let him know and he will reply in English.
Regards Chris