Bad Petcock? : RD 350

[MRDRcycle]

Hello again,

I recently checked my petcock to see if it was causing the fuel/ tuning issues I've been having. I found that only one fuel line drained gas, while the other either barely drizzled or released nothing at all.

I also turned off the gas and "wiggled" the petcock a bit. After turning it back on again, gas flowed out of the opposite fuel line, but not the one it was originally pouring out of.

After this, I covered the line that was running with my thumb and fuel poured out of the opposite side. Either way, gas only poured from one fuel line at a time.

Here is a video link if needed:  https://drive.google.com/open?id=1Afb7j16beVleaWCX3T7_mEcp1BGkMTu0

Is this normal, or should gas flow from both lines equally and simultaneously?

[quocle603]

Following. Mine is doing a similar thing as well. Someone suggested that it could be a dirty petcock. I will be cleaning mine once it stops raining.

[KANDY]

Close the one which is flowing the gas, open the petcock, see the other one start the flow.

[SUPERTUNE]

RD petcock trait.
They never flow out the both at the same time, when one line flows it sucks in air from the other outlet nipple.
Once the one fills up and has resistance, then the other line starts to flow fuel.
Chuck

[KANDY]

RD petcock trait.
They never flow out the both at the same time, when one line flows it sucks in air from the other outlet nipple.
Once the one fills up and has resistance, then the other line starts to flow fuel.
Chuck

That was my point. Good one Chuck

[MRDRcycle]

Ah. Gotcha. I was hoping I had an easy fix Time to pull the carbs apart. Thanks again for the help!

[quocle603]

There's something definitely wrong with my petcock, it's probably some rust.

[MRDRcycle]

https://video.search.yahoo.com/search/video?fr=mcafee&p=rd350+gas+tank+disassembly#id=1&vid=89bf8db146450fec2751578002707c0f&action=view 

I found this online the other day if it helps. Looks pretty thorough.

[oldguyRD1964]

I had to repair my petcock then last year had to replace tank liner... On my petcock the original brass tubes were broken and basically useless. I bought some metric brass tubes on ebay and used jbweld to glue it in. I cut one longer to have a reserve. The original had a screen/filter but I couldn't find anything and added two fuel filters. Before the tubes I cleaned the petcock with carb cleaner and a dremel tool and brass wire brush attachment.

The tank liner was it's own beast but if you do it DO NOT FORGET to have 1. a way to plug the cross over tubes. 2. air compressor to blow out the liner epoxy about 10-30 min after you pour the remaining epoxy out. I had to drill into the cross over to fix my mistake.

[Fffrank]

DO NOT FORGET to have 1. a way to plug the cross over tubes. 2. air compressor to blow out the liner epoxy about 10-30 min after you pour the remaining epoxy out. I had to drill into the cross over to fix my mistake.

How were you able to drill this?  One of my crossover tubes is clogged with rust/crud.  I've tried feeding a wire in but the bend is too tight (and the crud is too hard.)  The rust/crud also survived the electrolysis process that I used to get the rest of the tank clean.  I can't see a way to remedy this unless I cut off the cross-over tube and then drill a hole for a blind bulkhead fitting.  Would rather avoid that if possible?

[sav0r (CL MotoTech)]

You just use an L shaped drill bit.

[oldguyRD1964]

Hi, I drilled into the opening as far as the bend, then I had to drill from the outside of the tube at the bend up into the gas tank itself. Since the coating was epoxy it wasn't very difficult but it was a bit scary. Another person told me how to do it as I was trying to use 12 gauge electrical copper in my drill first to try to get it through... That might work but in my case it broke and was stuck in the tube... I forgot to mention that. However since it was copper, it was soft and I was able to get it through. I used a .99 cent store squeeze bottle to cap the ends of the cross overs originally that's a great tip others use putty and I didn't want to to that.

Once I drilled it clear I tested it and then I put some packing tape on some wire  and jammed it into the opening then mixed some jb weld carefully applied over waited 6 hours and removed the packing tape/tubing it didn't stick to it you could probably try spraying some wd or other oil as well. then I sanded a bit and luckily I found some blue nail polish at the dollar tree and low and behold it was a 99.5% match!!! how damn lucky it would match a 1973 butterfly blue!!! the color looked a bit darker in the bottle but on the bike it was perfect...

[Fffrank]

Thanks!  I'm definitely going to try something similar!