FF: Forks Avo front damper

[greg brillus]

Good point Norman, I had a good look at it and you can see the buffer rubber that you can move up and down on the shaft, and this is very much the same on the Thornton unit as well. This is the same on the Thornton front shock absorber and it is a handy "tool" to judge how much travel you are/have used up.

 

[stu spalding]

Just installed the front damper........Never had to remove that much material from an upper link before. The rear coilover is very large, bit like a series "D" unit, so I can see how installing the empty rear spring cases would be difficult. It will be interesting to see how they perform........They are also very heavy.

Hi Greg, just out of interest, did you measure the centre to centre length of this damper, fully extended. Mine was .14" over standard, which isn't much in terms of damper travel but it's a hell of a lot of metal off the top link. Cheers, Stu.

 

[greg brillus]

This damper had the same length that you quoted, this bike had the washer missing from bellow the lower stem bearing which changed the geometry slightly. The front guard had been hitting the exhaust quite badly but only at full extension. I have re positioned the front guard to help this, but it turns out that it has one of those three piece header pipes and the front pipe is sitting further forward than normal by about a half an inch. Now with the front forks fully compressed the front guard just touches the pipe with the steering on that angle of lock, which I seriously doubt you would ever encounter out on the road, so I am happy to live with that. Just need to make up the rear steering damper bracket now and jobs done. Also On this installation I used the longer eyebolts, which I think I've used on every kit I have fitted.

 

[John Cone]

I thought i had read that the front AVO damper now comes complete with the top shroud or am i mistaken?

 

[greg brillus]

This new one does have a shroud on it, but the diameter is not helping. Perhaps these are made from an existing shock absorber used for other applications which they chose to use rather than create a slimmer design.

 

[timetraveller]

The diameter of the shroud is dictated by the diameter of the lower body. The problem is that Stu is using a damper. which originally did not have a shroud and which has had one fixed on by the use of three screws near the top. However, the diameter of his shroud seems to be the same as the more recent dampers and the only issue seems to be that his damper is slightly longer than the most recent ones.

The way in which I measured the depth of the cut out in the top link as to use a digital vernier to measure the diameter of the tube on the front of the link and then the thickness across the diameter where the cut out is. The difference is the depth of the cut out, just over one eighth of an inch. I provided the dimensions above so that anyone else should know when to stop cutting and I have put them into the instructions which go out with each damper. Using this forum is the quickest way to spread this type of information.
As an aside, and I have no connection with the company, I have found AVO to be a vry friendly company, willing to lend dampers and make modifications in order to help with the development work.

 

[BigEd]

J ....... The rear coilover is very large, bit like a series "D" unit, so I can see how installing the empty rear spring cases would be difficult. It will be interesting to see how they perform........They are also very heavy.

The AVO coilover is as one would expect is relatively heavy as it quite robustly built and also has the spring fitted. I discussed this with Rob Staley and Rob sent me these figures. When the coilover is compared with the weight of an original damper plus to Vincent spring unit the coilover is quite a lot lighter. Useful if you are looking to save weight especially as a proportion of suspension unitweight is unsprung.
Rob measured the weights (in grams) of the dampers etc he had in stock:
Unit Grams
Vincent damper 707g
Armstrong damper 757g
Koni damper 839g
AVO damper 1183g
AVO coilover 2210g
One Vincent spring unit* 1307g

(*Original cases & eye-bolts, but Armstrong spring and alloy adapters, so probably bit lighter than original spring & brass claws.)

Total weight of original rear springs and dampers: 3321 gms, (7.32 lbs)

So AVO coilover weight saving over original components: 1111 gms (2.45 lbs)

AVO front damper increase in weight over Vincent damper: 476 gms (1.04)

 

[stu spalding]

I thought i had read that the front AVO damper now comes complete with the top shroud or am i mistaken?

Hi John, the thing to watch with the AVO damper is that the clutch and valve lifter cables can become trapped between shroud and top link. Mine has the screws holding the shroud on, the front one of which has a clip to hold the cables out of harms way. Cheers, Stu.

 

[vibrac]

Do you need the shroud? what about a simple rubber jacket like a small version of the bantam gaiter?

 

[Simon Dinsdale]

I bought one of the early Vincent front Avo dampers that didn't come with a shroud. I phoned Avo and asked if they would sell me one of the black silicone rubber shrouds that come with their standard dampers for other makes and they sent me a pair in the post for free. I had to make an adaptor ring so it would fit the top Vincent fitting which is off a standard Vincent damper. The shroud is very flexable and would just move out of the way for any top link when the damper is fully extended. Sorry I don't have a part number and it was several years ago. I pinched the photo below off the Avo website which shows some dampers with this shroud as standard.