250 petrol tank fixings

Jeffrey · Post by **Jeffrey** » Mon Apr 09, 2012 9:35 pm

hi on my 1963 ajs 250 csr basket case all the bits are going togther nicely. but i can not work out how the tank fixes at the back by the seat please help

Tolly · Post by **Tolly** » Mon Apr 09, 2012 10:47 pm

There is a large hole in the top of the frame just in front of the seat, a long bolt with a turned over top, or T piece on the top (can't quite remember which one at the moment), this top piece hooks into a slot at the back of the tank and passes through the frame where a rubber and washer is fitted before the nut. Don't over tighten the nut or you will damage the tank.

BigAl350 · Post by **BigAl350** » Mon Apr 09, 2012 10:48 pm

My 350 Lightweights have a round, thickish rubber piece (like a small doughnut) with a central hole in it which fits on top of the round hole on the frame, just forward of the front of the seat. The petrol tank has T-shaped, threaded metal piece, the top bar of which fits into the tank and the bottom, threaded part then goes through the centre hole in the rubber doughnut. The threaded part then emerges on the other side of the frame just behind the carb. There, another another round rubber piece with a hole in the middle, plus a large washer and a nut are fitted onto the threaded end of the T piece. Tighten it up and there you go.

Can send pictures if required. Most parts are available from the club if you don't have them.

Al

quote:
hi on my 1963 ajs 250 csr basket case all the bits are going togther nicely. but i can not work out how the tank fixes at the back by the seat please help
[

Janet · Post by **Janet** » Tue Apr 10, 2012 6:49 am

quote:
There is a large hole in the top of the frame just in front of the seat, a long bolt with a turned over top, or T piece on the top (can't quite remember which one at the moment), this top piece hooks into a slot at the back of the tank and passes through the frame where a rubber and washer is fitted before the nut. Don't over tighten the nut or you will damage the tank.
Mine seems to be the other way up. It has a piece sticking down from the tank that drops into a slot on the frame. This may be incorrect but it was like that when I got the bike and it never occurred to me that it was wrong.

Ian5913 · Post by **Ian5913** » Tue Apr 10, 2012 3:28 pm

Under the tank at the rear is a slot, this is where the top of the t bolt goes through. The t bolt goes through the slot (Like a letter box) and twists 90 degrees. When done up it pulls the tank down onto the frame.

The body / stem of the t bolt passes down through rubber washers top & bottom of the big hole in the frame before the rear frame top fixing bolt, and a large washer goes on the end of the t bolt and then a nut. (Lock nut)

Fitting the tank

It is possible to fit the T Bolt to the tank before fitment (Which may have happened to you here ) but the other way is to fit the T bolt into the frame through the rubber washers, fit the tank on top then twist the t bolt to locate in the tank slot. then fit the nut and washer to tighten.

When the tank is removed the t bolt normally follows the tank as its removed and is detached afterwards.

Hope this helps

The T Bolt part number for the model 14 and 8 is 044244 but differs for the CS. There are three rubber washers listed and a sleeve. (i am not sure I have all these fitted I have just protected the bolt from the frame

BigAl350 · Post by **BigAl350** » Tue Apr 10, 2012 4:51 pm

Another trick with the T bolt is to wrap some insulating tape around it and fit it into the tank. The tape will stop it moving as you line it up through the rubber "doughnut", and can also stop the T bolt from "drumming" in its tank slot.

I'll try to take some pics of the frame and hole when I'm down Devon later this week - 600-mile round-trip on my Model 8. PROPER JOB!

Al

quote:
Under the tank at the rear is a slot, this is where the top of the t bolt goes through. The t bolt goes through the slot (Like a letter box) and twists 90 degrees. When done up it pulls the tank down onto the frame.

The body / stem of the t bolt passes down through rubber washers top & bottom of the big hole in the frame before the rear frame top fixing bolt, and a large washer goes on the end of the t bolt and then a nut. (Lock nut)

Fitting the tank

It is possible to fit the T Bolt to the tank before fitment (Which may have happened to you here ) but the other way is to fit the T bolt into the frame through the rubber washers, fit the tank on top then twist the t bolt to locate in the tank slot. then fit the nut and washer to tighten.

When the tank is removed the t bolt normally follows the tank as its removed and is detached afterwards.

Hope this helps

The T Bolt part number for the model 14 and 8 is 044244 but differs for the CS. There are three rubber washers listed and a sleeve. (i am not sure I have all these fitted I have just protected the bolt from the frame

borrowashboy · Post by **borrowashboy** » Tue Apr 10, 2012 8:30 pm

mine is different again. there's no big hole going right through the frame, it's a 5/16 threaded 26tpi hole. that's it in the top of the frame. not got round to fitting my tank yet, but i can see it being born out of wedlock
cheers, bb.

Ian5913 · Post by **Ian5913** » Tue Apr 10, 2012 8:59 pm

If you have a look at the last picture on the attached it shows the basic frame and I have arrowed the part we are on about. If your frame is standard lightweight design then it ought to match this. But nothing is certain in this world. So it could well be different.

If you have this tube welded into the frame then this is what its for, a rear tank fixing point. If you have something else then I would need to see a picture.

Regards

Ian

https://picasaweb.google.com/1050863888 ... 7242756626

Jeffrey · Post by **Jeffrey** » Wed Apr 11, 2012 1:00 am

thank u all very much i understand now how it fixes frame to tank

borrowashboy · Post by **borrowashboy** » Tue Apr 17, 2012 3:32 pm

with the standard seat on, there is no way the tank will fit. with the tank on there's no way the seat will fit. now what? as i said in my earlier posting my frame has a threaded bolt coming out of the top of the frame - it doesn't go right through. basically it looks like it should have a smaller tank with a flat flange sticking out the bottom of the tank, with a hole for the bolt to go through. was there such a tank for 1959?
cheers, bb.
ps, i'll upload a picture if that would help?