RGM norvil/dunstall alloy tank to yoke interference

joshtjeerdsma · Feb 17, 2016

I am slowly putting my combat back together and I put the fork and fork yokes back on tonight. I went to test fit the norvil/dunstall/proddy racer style tank that I purchased from RGM and noticed there is severe interference between the top yoke and the tank. I have the tank down as far as I would go and I believe I installed the yokes right. Has anybody else had issues with these tanks? It seems to be a quality tank. I will email RGM soon, but I wanted to ask you knowledgable folks first to make sure I didnt make another jackass mistake. I would hate to have to ship it back to the UK. Here are some pics. Thanks, Josh

RGM norvil/dunstall alloy tank to yoke interference

mschmitz57 · Feb 17, 2016

Would a top yoke without handlebar bosses work?
Maybe the tank is designed for clip-ons.

Rohan · Feb 17, 2016

Looks like there is a bit of room to take out some of those rubber packers under the tank mount too ?
Its not going to have to drop down very much to clear ?

SteveBorland · Feb 18, 2016

Alloy tanks always seem to vary in size & shape, probably because they are hand made.
Every alloy tank I've seen or used (which admittedly is not a huge number) has required fettling to a greater or lesser degree to get the bugger to fit as I want it.

You may need to go to clip-ons with a smooth top yoke (actually looks a lot neater as well) or perhaps add recesses on the tank for clearance. You may need to make up some longer fork stops as well. All goes with the racer image

toppy · Feb 18, 2016

The original Dunstall or other race bikes would have had clip on bars and possibly the 7" wide yokes. Dunstall made front disc brake forks of there own design that didn't use Norton Roadholder sliders an therefore possibly not Norton yokes which are heavy steel items not light alloy preferred by racer's. Reduction in steering lock is also a common issue with racing set ups and as said hand made items are very hard to accurately make. Looking for pictures of other bikes fitted with the same tank may be helpful and I have always found Roger at RGM very knowledgeable and pleasant to deal with so would email him your pictures to see what he thinks.

acotrel · Feb 19, 2016

Perhaps you might grind the angle under the rear of the handle bar mounts up to a steeper angle and also modify the stops to reduce the steering lock ? I notice from one of the photos that fitting thinner rubbers under the tank would allow it to beat itself to death where it would touch.

Rusty bucket · Feb 20, 2016

:shock: Use a hammer (very small and light), it's only metal you can outthink it.

swooshdave · Feb 20, 2016

That is normal for my tank. You have to have it set just right to not interfere. Just right. A lot of fettling is ahead for you. Once you get it, remember the settings for when you have to take the tank off.

joshtjeerdsma · Feb 21, 2016

I will try messing a bit with it. I was hoping that whatever I did to this bike would be easily reverted back to stock. I guess I made the mistake thinking this was a no mod necessary bolt on tank. I am also having trouble finding a seat to go with it. Was going to run one of the rgm manx style seats, but they are out of stock. I found a guy who is willing to trade an original steel fastback LR tank for my Norvil. Maybe this would be the easier, less modification route to go. That tank may also look good as a mild cafe racer build.

joshtjeerdsma · Feb 21, 2016

Got the tank to clear with only 1 rubber washer underneath and sliding it all the way back. The clearance at the frame mount is so slim that I think I will have to grind it down though. Now I have to mount the oil tank and see if that clears. Thanks for the input so far.

swooshdave · Feb 21, 2016

You will probably need to do the Proddy mod to the oil tank.

Also if you intend to run a Proddy fairing you will need to fabricate steering locks.

For some light reading...

search.php?keywords=swooshdave+proddy&terms=all&author=&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

gripper · Feb 21, 2016

The long range fastback tank is a PITA to fit without vibrating against the frame. It's basically a Dominator tank with a different base welded in place. It holds 4 gallons (UK gallons) I thought that was the way ahead years ago and spent good money on tank seat paint etc. got rid after about 3 weeks of use. I would speak to RGM for their twopenneth but your tank seems very high at the front. I have a Bartel Fastback alloy tank on mine and whilst it is a bit squared off compared with the original fibreglass tank, being thinner material it holds about an extra 1/2 gallon