Topic: Warning Noob Question...Is this a real Dunstall Tank (mount/petcock)?

[inpassing]

First I want to thank all of you for posting, I've been reading posts, looking at the bikes you've all posted, and trying to glean as much knowledge as possible.

I recently picked up a '71 CB750 in good condition, it was someones Cafe Racer project, and not my style. Since it is mechanically sound I decided to do some cosmetic work on it. The first thing I want to replace is the tank. I recently picked up a tank (pictures below) for around $150. I did some research and it looks to be a Dunstall tank, as opposed to a repo. It's clearly marked Reg Moulding, which I think Dunstall tanks were marked.

This leads to my next two questions.

1) How much work will it take to mount it to my bike?

2) Petcocks? It seems that there has been some discussion over which will work for Dunstall tanks, any clues?

3) Seats, it seems this tank is significantly longer than my present stock tank so will the present seat a Carpy job, http://www.cb750cafe.com/parts.php?id=60 need to be replaced to accommodate the longer tank?

Sorry for the shear amount of Noob in one post.

Thanks in advance!





-MD

[chimmychong86]

might be my naivety, but that looks nothing like my dunstall, for two reasons, gas cap flat to tank, and petcock holes. but then again what do i know. now for some answers.

You'll need to make brackets but it doesnt seem like there is anywhere to mount them to, so a picture of the front view would help.

for petcocks a pingle looks like it would work, but you'll need to measure holes place the tank on the bike and measure clearances for carbs before you decide on anything. also you'll have to plug up one of those holes.

check out airtech-streamlining.com they have more options and i'm more partial to them, but nothing wrong with carpy either. or you can just cut your seatpan and make your own. all of it takes time and work.

also a noob in training so wait for someone more wise to answer.
~Adam

[onagd]

Firstly welcome to the forum. There is a stack of info here and some pretty clued up people.
I am probably not going to be much help in answering your queries other than to say i had a 75 750 that i put a Dunstall seat and tank unit on back in the day, but it was a fibre glass moulded unit that fitted over the existing tank and had the seat as part of the unit. Was a great bike and a lot of fun to ride. Scared myself omce or twice on it as well.
Good luck with your project and some one here will most certainly have the answers you are after.
Regards Brett

[inpassing]

Brett, Adam, tanks for the responses.

Here are a couple shots of the front of the tank:





Also I flipped up the gas cap and saw it was marked Ceandess Wolverhampton, so if the tank wasn't made in the UK at least the cap was

[srook]

That's definitely not a Dunstall tank.  There were a bunch of fiberglass tank makers in the 70s and even more now.  I'm not sure what that tank is for but the holes look to be for a british bike.  You will have to use a thread gauge to get the tpi but petcocks on many british bikes looked like this:



You can pick these up for about $10-$15 each on ebay.  Might be worth a shot.  You could always resell them if they don't fit.  You also need the rubber/bonded washer that goes between the petcock nut and the tank to seal it.

Scott

[inpassing]

Scott,

Thanks for the advice, the PO said he was able to mount it to his Honda so I'm trying to get in touch to see just how he accomplished it, and what brand petcock he used.

-MD

[chimmychong86]

If you take your current gastank off you could do a mockup or just measure the inlets on your tank and measure the tank mounts on the bike. I'm sure someone here knows the size of those plus the frame are around here.

[inpassing]

If the weather cooperates first thing this weekend is removal of my old tank to see how the new one may fit.

-MD

[inpassing]

Petcock Problem Solved!

Hidden amongst a box of parts, a pair of Ewarts (am I spelling that right?) petcocks.



Hurray!

[754]

 I bet those threads are 19 TPI...

[inpassing]

The PO said the petcocks leaked so I hit up Brit Gaskets to see if there is a replacement valve available for them. Is 19 TPI standard on Brit bikes?

-MD