Windscreen Mechanism (potential repair kit)

(Edit 5 Sep 2021 - Crowdfunding is almost completed for the test pieces and no further donors will be required after 30 SEP 2021)

Some of you may well be aware of the issue with the ST1300 windscreen mechanism in that it eventually begins to wear and very soon afterwards WILL fail completely.

ALL model years will eventually suffer this fate and of course, it is not mileage related but is purely down to how often and in what situation you adjust your windscreen. There are (apparently) models with over 100,000 miles which are still going strong yet some, with as little as 25,000 have failed – my own decided to give up the ghost at 25800 miles.

There are inherent flaws in the layout and design of the mech but it is still rather quite a simple affair. Two helical wound metal cables (with a nylon/plastic interlay) are driven by a corresponding helical geared shaft which in turn is driven by a 12v car windscreen wiper motor. The nylon part of the cable is of a slightly larger diameter than the metal element by about 0.5-1.0mm and it seems this is part of the failure sequence.

The cable only travels back and forth about 180mm at about 90rpm for about 5 seconds (full travel in either direction). The big problem is the same bit of each cable is constantly in contact with the same (2) areas of the shaft splines. This repeated, up and down action causes the plastic/nylon element to become worn by the helical gear which is cut at a 90-degree (corner) angle.

The next thing to happen is the metal cable contacts directly with the gear and for some inexplicable reason, Honda seem to have chosen a cable which is made from a harder material than the gear itself – this is something I am addressing in my repair solution described later, and so the permanent damage occurs very soon after the nylon damage.

Lubrication (of the correct components) can help but is not a permanent solution – there isn’t one really, unless you choose to leave your windscreen fixed at one height.

Some things you can do to help it last longer are:

1. Make sure you slow down to around 30mph before altering the screen height - not much fun on motorways/highways or dual carriageway I know! The faster the speed, the more resistance and the more load involved on the mechanism, so slower is better as the load is less.

2. Keep the sliders/screen carrier blocks lubricated (and the channels they run in).

3. Do not lubricate the cables themselves nor the gear shaft – it won’t help the nylon grip!

The parts that fail are a splined helical driveshaft (gear) and the two associated cables which are driven by it. These are the only parts which need to be replaced but of course Honda, in their infinite wisdom, decided to have the whole mech sold as a single unit. The cost, if you can find one, is almost £460.00! I bit the bullet and bought a new one as I needed to cannibalise my old one for this research and investigation.

BEWARE of second-hand models on eBay, you have no idea when it will fail – could be the first time you try it and at around £200 each second hand, it’s a big risk in my opinion!

The Proposed solution.

I have managed to find a cable supplier here in UK and, in my local area, a toolmaker is making test pieces for me (August 2021) and my current aerospace engineer specialists will produce the gears following a successful test. The simple idea is to have the gear made harder than the cable!

It is worth mentioning at this point that manufacturing the gear involves a process called Electrical Discharge Machining (EDM) or more commonly known as ‘spark-erosion’ whereby a very fine wire is used to erode an intricate patterned recess in the base of the gear to provide a perfect fit onto the drive shaft of the wiper motor.

No other process can achieve this fine machining. The cost of having just the EDM part of production is prohibitively expensive here in the UK (£40 per unit) and that does not include the cost of having the gear made! I recently bought an aftermarket gear from a friend who had bought several, manufactured by a guy in the USA some years ago and that was almost £100. No one else makes the cables though and they are an integral failure point!

So, to the point of this blog … I am looking to find out how many of you would consider investing in one of these repair kits - either as an ‘immediate repair’ or for an ‘insurance spare’ for the future. My intention is to provide a fitting service whereby you send me your existing unit (just the screen carrier blocks) and I repair and return them to you.

I will need your old blocks because although you can cut the old cables free to gain access and reuse the carriers, unless you have the tools and the equipment, you cannot crimp the new cables into the screen carrier blocks. The tool to do this (correctly) is over £300 – I am prepared to invest in this and whatever else is necessary and will carry out the work, so your new unit is ready for you to refit to your machine. If/when the project goes ahead, I will provide videos on the site to show how to remove/refit the unit in due course. For those of you with access to a crimper and the ferrules etc. I may sell the kit as a DIY spare too.

The new style cable (without the nylon insert) will be the sacrificial part in this and if it wears in the future, the replacement cables will be a few pounds each.

Now, to make this viable I need to purchase in bulk – you won’t believe it, but the cost comes down considerably from thousands to hundreds of pounds/dollars if I purchase sufficient gears. All the initial cost is in the tooling and modelling process and I would need to purchase at least 500 units to make it viable. There are over 8000 ST1300s still out in the world currently so that is not a big ask percentage wise – they will all fail at some point!

REST ASSURED of two things:

1. This is a once in a lifetime attempt by me to sort this – If it doesn’t fly the first time, I will not be revisiting this again.

2. I will not go ahead with this until I have thoroughly tested the prototype gear and cable and I am fully satisfied the project is worth proceeding with. This will involve considerable outlay by me for tooling and set up costs.

I will (at some point) need some commitment and for that you will want to know the cost to you. So, I would estimate the kit (consisting of one gear and two new cables) would cost £150 and the fitting would be £25 including return postage. So, you are looking at a cost of £175 including UK shipping. If I get sufficient support that (£150) cost could come down to around £125. Bear in mind that a second-hand unit costs almost double that! I will offer the service worldwide too, but shipping will be additional – approx. £10-15 max worldwide.

I will post results of the test online BEFORE I ask for any financial commitment (and make any subsequent orders) and I will not make any orders until I have deposits from every potential customer.

What I need at this time is an indication from you if you would be willing to help me make this happen. I need to be specific and to that end I need to know if you would purchase this repair kit and service – no guarantee needed but a strong commitment perhaps?

Once/if I get sufficient positive responses, I will commit to having the test kit made and once it has tested successfully, I will ask for a deposit of 50% which will only be refundable if the project falls through for whatever reason.

So to recap …

Your bike’s unit will (eventually ) fail - if you continue to use it.

There is no other alternative – that I know of.

The new design (cable and uprated gear hardness factor) should solve the issue.

Max cost will be around £150 (fitted) and if costs do reduce, maybe £135?

Subsequent cables will be available at around £15 per pair and are in fact designed to be the weaker component - to preserve the gear element.

Commitment is paramount at this stage and if this is successful and you miss the boat, you will need to pay considerably more for any repeat order – if I actually place one.

This is a once-only attempt at gathering support – if I don’t get sufficient response, then I won’t commit to production and testing.

ACTION REQUIRED

If you would like to be added to the donor list then please email me at bikequipsteve@gmail.com before 30 September 2021 when the donor list will finally close.