2 STROKE WORLD .net

The 2-Stroke Garage => Turning Wrenches => Topic started by: smokah on February 11, 2020, 07:46:45 PM

Title: No weld tank crossover options
Post by: smokah on February 11, 2020, 07:46:45 PM
So I bought a Chinese cafe racer tank for my RD350 but in haste my painter coated the inside and painted it before we discussed the crossover. So I'm in a bad spot. I can't weld on the tank. I've been looking at blind tank fittings and bulkhead fittings. The fitting would have to drop in to the rear of the tank and the nut would have to go underneath. I'm getting told to just drive it but I'm sure that won't go well, or very far. Thoughts?
Title: Re: No weld tank crossover options
Post by: rodneya on February 11, 2020, 09:24:28 PM
Kinda depends on what the tank looks like on the bottom. Most bikes dont have crossover tubes.
Title: Re: No weld tank crossover options
Post by: pdxjim on February 12, 2020, 12:21:46 AM
I would just run it.

As stated, most other tanks don't have crossovers, and Yamaha left it off on late models.
Title: Re: No weld tank crossover options
Post by: m in sc on February 12, 2020, 10:12:19 AM
you need it. I have a similar tank and you'll leave 30-40% on the rh side.

you can use a bulkhead fitting, feed the nut in thru the neck but you have to drill in from the bottom. i actually used 2 push to connects on my crossover at the back of the tank, but welded in some 1/8" npt connctions.

https://www.mscdirect.com/product/details/86840238

you will need a viton sealing washer on each end and TBH i'd seal the threads with case sealant.

OR, just get 2 small fittings tigged onto the bottom, it wont hurt the paint as long as you're smart about it (silicone bronze welds at a relatively low temp). put a wet rag inside the tank while you are welding to act as a heat sink against the side you are welding against,  and then reline the tank with caswell over the old sealer.

:twocents:
Title: Re: No weld tank crossover options
Post by: smokah on February 12, 2020, 12:36:08 PM
Thanks Mike. I wasn't gonna run it without the crosssover. I know you have the same or very similar tank. We have corresponded about it when I asked about getting a more free flowing petcock for it and you pointed me to the cb350 one. I'm not sure I'm comfortable having it welded due to the custom paint.
Title: Re: No weld tank crossover options
Post by: m in sc on February 12, 2020, 12:50:32 PM
one thing i considered was using a 90 degree valve stem for a motorcycle tire. taking the scherader core out and using that as a fitting and clamping  a line to it.

https://www.jpcycles.com/product/922-716/bikemaster-chrome-90-degree-valve-stem?redirectedKeyword=922-716&totalResult=1
Title: Re: No weld tank crossover options
Post by: pdxjim on February 12, 2020, 02:07:24 PM
^ that's a great idea, as long as the seals are fuel safe 👍
Title: Re: No weld tank crossover options
Post by: m in sc on February 12, 2020, 02:13:16 PM
viton and buna are good. Im not sure what they are on the stem but viton washers are easy to get or make. However im pretty sure they are ok for fuel exposure.
Title: Re: No weld tank crossover options
Post by: smokah on February 12, 2020, 05:21:56 PM
Thanks. Another possibility. I need to know how big of a hole it requires so I can see if there's enough meat there. Might just buy one to see
Title: Re: No weld tank crossover options
Post by: IR8D8R on February 14, 2020, 12:19:42 PM
Moeller Marine fuel bulkhead fitting. This one from Wholesale Marine.

https://www.wholesalemarine.com/moeller-marine-fuel-bulkhead-fitting-1-4-npt-female-to-1-4-npt-female.html

IR8D8R
Title: Re: No weld tank crossover options
Post by: smokah on February 15, 2020, 11:31:10 AM
^^^ that would work too. Expensive little buggers.
Title: Re: No weld tank crossover options
Post by: RDFL on February 15, 2020, 12:21:54 PM
Same thing on ebay for $5-6 free shipping.
Title: Re: No weld tank crossover options
Post by: smokah on February 16, 2020, 10:51:04 AM
I bought the chrome valve stems. Be here in a few days. Locating viton washers then I'll install and test them. Thanks all for the input
Title: Re: No weld tank crossover options
Post by: smokah on March 14, 2020, 12:31:27 PM
Just as a followup, the valve stems worked perfectly. The included rubber washers are stepped so finding a viton replacement was impossible. I put the rubber ones in gas for 48 hours and they were fine. Installed on the tank and no leaks in two weeks. I'm calling it a win. Got them on amazon for around $10 for the pair. Thanks for the help.
Title: Re: No weld tank crossover options
Post by: m in sc on March 14, 2020, 02:58:38 PM
sweet!  :clap:
Title: Re: No weld tank crossover options
Post by: smokah on March 24, 2020, 06:24:57 PM
This is the one I went with and how it looks mounted.
Title: Re: No weld tank crossover options
Post by: m in sc on March 24, 2020, 07:24:43 PM
thats awesome, glad it worked out  :clap:  :toot:
Title: Re: No weld tank crossover options
Post by: 85RZwade on March 24, 2020, 09:24:30 PM
Very sanitary! I like the grey, too...got a picture of the whole bike?
Title: Re: No weld tank crossover options
Post by: smokah on March 25, 2020, 10:57:34 AM
Almost ready
Title: Re: No weld tank crossover options
Post by: Dvsrd on March 26, 2020, 09:36:04 PM
Neat solution, and a very nice bike!
Is your fairing from Airtech?  "AJS4" ?
Title: Re: No weld tank crossover options
Post by: 85RZwade on March 26, 2020, 10:40:32 PM
Love that grey, almost as much as I love  :bacon:!
Thanks for the pic, it looks great
Title: Re: No weld tank crossover options
Post by: smokah on March 28, 2020, 02:50:38 PM
Thanks guys. Yes the fairing is the Dunstall from Airtech. I'm going to piece together a build thread soon. Picture heavy