Plunger suspension ride height adjustment

[roger.fellows]

I think that eliminates the slider being the wrong way up, so you're left with inadequate springs?????

[Simon.Gardiner]

....Hard to imagine anything assembled backwards....

I think you're right with that but we are clutching at straws a bit here (I reckon you need to move that slider down by something like an inch)!
The only other thing I can think of is the springs themselves, which I think involves taking at least one out and measuring it up, at this stage.

Not much help I'm afraid.

SG

[adrian.hannam]

When you go to Drags web site try typing part number 4969-39 into the search field on the top left of the page. the search will come up with the springs you want, which has "excellent stock level". If you went through their menu pages, and clicked on the part number, the link takes you to almost but not quite the right part and shows 4969-39U; the U meaning used.

[pauldridge]

Wow Adrian.. thank you so much. I have found on several occasions inaccuracies with the listings, but I guess we should all just be thankful there is a Draganfly at all. I am going to just get those on order. I have a number of other small items to purchase, so this will be my incentive to move forward. I'll keep the forum posted of the final result.

I note they show length of spring, but I am not sure measuring the old ones would be of much value, they could be the same length but have lost some of their temper? I did read several installation instructions which talked about some sort of complicated tie-down methods to get the spring nut started. However, I've had mine off to replace some of the exterior brightware, and I had no problem compressing the spring by hand to get the nut started. Perhaps that is a clue that the spring has, er, lost its spring!

[john.whiting]

Its termed "taken a set",in other words the spring has settled ..........temper is unaffected ,and if you can find someone to do it ,the spring can be annealed ,extended and rehardened and tempered........I had a friend worked for Thomas Marsh Springs,and he could just toss a spring onto the belt that went thru the furnace,and it would emerge hardened and tempered in one operation......he s retired now,and as the furnace cost over $1M ,they arent likely to let him do another one.

[johann.patek]

I have the same problems on my 56 Mk2 Sq4. When 2 up, even with a slender passenger, and hitting a hole or bump, the rear tire catches the inner part of the mudguard, bringing the rear wheel to a sudden stop. Not so good for the transmission.
As stronger springs are obviously not available, i thought packing out the original springs with a tubular packing piece to increase the preload by a certain margin. On too soft front forks this often did the trick.
Any comments to that bodge ?

[john.whiting]

You obviously need to get some stiffer springs made........however packing the existing springs is a satisfactory solution,and will also provide a travel stop that should stop the tire fouling the guard.

[john.whiting]

On the subject of springs ,to increase the rate,you need to use thicker wire.The alternative sometimes resorted to is to use less coils ,wider spaced,which ,in fact,causes a increase in the windup of the spring wire..........It may also overstress the wire and cause breakage.......You may not realize,but a coil spring is actually a torsion bar,and its important that the ends of the coil should be closed ,so the ends are anchored against free rotation.

[will_curry]

According to the 1953 parts lists the bottom spring is common across the range but the top spring
is a special for the 4's. It is quoted as being 0.312" wire rather than 0.296" for the singles and twins.

[Leejm]

The.. 312 wire springs are side car springs. The. 296 are solo. Seem most people fit side car one even if the bike is used solo. That is the general recommended way to go.