Manky Monkey Motors

Hi folks...
Well after some exciting and excellent advice concerning disk brakes, calliper carriers etc we have the bits ready for the reliant axle we have.

However on looking closely at the swinging arm housing for the Universal Joint on the Guzzi... there just aint enough room to allow the prop shaft to be angled over to the reliant diff which sits in the middle.

I've been reading on MMM about how to shorten one side of the axle to allow the diff to move over and align with the output of the Guzzi gearbox but is there another way?

The Guzzi UJ runs in a bearing housed in the swinging arm.... Can I use a different arrangement of UJ to allow me to angle over a prop shaft from the gearbox to the diff?

Anyone who has made a trike from a Guzzi who could advise me would be most welcome otherwise it looks like shortening one side of the axle to move the diff over a bit.

Any advice?

Martin

Mate of mine had his Cali triked with an angled prop shaft, and he had all sorts of trouble with it - in the end he had the axle shortened.

Do you have the room to add a second UJ in?

I think (but could be wrong) the main problem is that most bikes do not use a UJ (Hookes joint) but a CV joint (constant velocity) or double cardan joint at the output.
With a UJ the prop shaft speeds up and slows down as it revolves. The greater the angle the greater the variation in speed. UJ are used in pairs, one each end of the prop to counter this. If you have a  CV joint one end and a UJ at the other the prop will try to vary the speed of the axle with every rotation. The greater the angle the prop is at the faster something will break.
Best way is to narrow the axle one side and if possible fit a CV joint at the axle end of the prop instead of the normal UJ
Just my thoughts. Please correct me if I am wrong. I'm here to learn    :D

Thanks everyone for the input.
I'm here to learn like many others. I used to teach engineering and in another life I was a self employed turner and welder so I know that I can do the engineering bit if required but I just wanted to sound out others' wisdom first before getting heavy with the axle.

It is indeed a "double cardan joint" that runs within a cup that forms a major part of the swinging arm. If I wanted to take the joint out at about 15 to 20 degrees then I'd almost certainly have to re-engineer the right side of the swinging arm (looking from the rear of the bike frame) and I really don't want to do that.

So... no room for another joint but I half expected this to be the case so it looks like shortening the axle. No a big problem once its up on the bench... I just wanted to be sure before next weekend when I'd scheduled the work to begin. Besides if I align the diff up properly then I can use the original guzzi prop shaft and splined components (plus a little turning).

I'll look and wait a bit more to see if anyone else has any more suggestions.

Thanks everyone... when I get some pictures I'll post them of the work so that other members can learn from what I make.

Martin

My trike uses the bike prop shortened and mated to the Reliant prop - like so......   (BTW not my build so feel free to say what you like about it!)

I build my wife a trike using a Kawasaki  GT750 the best way forward and the advice of Chris Island from Desperate Dan's was to shorten one side and it work's very well and also looks more tidy.

Thanks for that image. It helps and explains a lot to me. I like the idea of marrying up the guzzi prop shaft to the reliant diff input. There is some nice engineering with the guzzi splines that I want to make full use of. It also shows me that the shortened axle is the way to go rather than trying to swing the prop shaft over,

Martin

Yes... thanks for that advice and the words from "Dans". The more I read the more I am convinced that shortening is the direction to go. I'm starting to look forward to getting to grips with the axle now. All I need to know is the off-set of the guzzi output shaft and then I'm good to go.

Martin

Does anyone know what the gearbox output off-set is for a Guzzi Cali 1000 (1996).
The distance of the output shaft to the right) from the centre line of the frame?
Because that's the amount I need to shorten the axle by.

Martin

I don't know about the Guzzi, but the Kawasaki gt 750 frame isn't symmetrical, it's offset to allow room for the shaft and uj, so be careful when measuring up for centre lines. On the same drift, but more a question to the experienced on here, is this assymetricism unique to shaftees?
Huw

That's a good point. I might have to offer up the axle on a couple of stands to ascertain the correct position. From sight the frame seems symmetrical at the bosses where the swinging arm bearings are located. Easy enough to lift the axle up to check I suppose but it would have been nice is there were someone with this type of experience who could comment about the measurements for a Cali 1000.

Martin

In case it helps, there's an album of pics on photobucket - not of the build taking place, they're ones that I took for someone.  Hope this link works cos I'm having some odd computer probs and can't pick up the easy link!

http://s195.photobucket.com/user/BikerGran_photos/library/GT550%20Trike%20conversion?sort=4&page=1 (http://s195.photobucket.com/user/BikerGran_photos/library/GT550%20Trike%20conversion?sort=4&page=1)

Thanks for the pictures BikerGran... everything and anything is a help. I've been convinced that the off-set shortened axle for a Guzzi trike is really the way to go.

AND THE GOOD NEWS.... its 85mm (3.34" in real numbers) that has to be removed from one end of the axle.

I found a PDF of the geometry of the swinging arm and the prop shaft is 85mm offset from the centre line of the bike.

So now I can start playing in my workshop. Yep - I have a lathe, welding gear and I know how to use em so I'm set to go next weekend.

Check out the pics, they may be of assistance, and are of another forum members Guzzi to Reliant axle build. Morrag

And a couple more..........................

This axle appears standard and not shortened, so.................

I knew there was another Guzzi here! Who's was that Mr M?

I think the problem Martin has is that he wishes to retain the swing arm (or at least some of it). I assume he's going the bolt on route with rear suspension.

I see that one has a couple of UJs - mine doesn't, which may possibly be why I've had trouble with my shaft drive.  It's been fixed twice and I've currently got a rattle which may mean it's going again!

I had wondered if the first time was down to lack of maintenance (I asked the trike builder to grease it while he had it all apart but there were so many other things he didn't do that I just wondered) and then I thought maybe I was just putting too much strain on it towing my fairly well loaded trailer.  Now I'm starting to wonder....

Can be found on page 18 of "Trike Tech" under 'Waynes Guzzi', Mr.M, ok, Morrag

Wow... "Morrag"... I am not worthy...
Thanks very much for the images and taking time to comment.
Looks simple doesn't it but.... my brother has had a bloke convert his existing swinging arm into an A frame to support the axle and the place where the guzzi UJ joint is housed is an integral part of that structure now.

If I wanted to put a different UJ in place and pull the prop shaft over to the centre line I'm worried that I'd have to almost destroy the right hand side of the swinging arm to create the sort of room your images have.
In the images you sent me, the frame is nicely spaced around the area where the UJ can be mounted... loads of room. I don't thnk I have that luxury with the modified swinging arm we have ended up with.

I might hold off on shortening the axle for a bit while I have a serious think about the arrangement again.

I found an image of something very similar but the UJ housing is on the other side on my brothers frame. The UJ housing also hosts a bearing for the UJ which I was thinking is quite important for the life of the joint!

Thanks very much.

Martin

You know what... I subscribe to a couple of other forums for shooting, archery and home brewing and none of their forum members offer a fraction of the positive advice and welcome I have found her on "MMM". In fact some are without doubt some of the most ignorant individuals I've ever met on-line. So this is so much like a breath of fresh air just being able to discuss bikes and engineering without being slapped down all the time.

"Olds" you are of course right... it's not a "real trike" as some might say. My brother wanted to go the "bolt-on" route and use the existing swinging arm. Personally I'd have fabricated something more like an external swinging arm that would have left the inside area as free as could be. But we are where we are at the moment and I'm having to work with quite limited space.

Looking at the image I found earlier - it looks very similar to my brothers. It may be that the maker of the frame I found the image of earlier recognises the job (for a Guzzi 1000) and could offer up a few words of wisdom. I'm certainly not too proud to listen and learn. Its a nice solid job and from a welders perspective - nicely done.

Regards

Martin

Aww, we love you too mate.  :-*
Keep saying- nobody knows it all, but we all know a little bit & your little bit might be the very piece of the jigsaw someone else needs. The more info we share, the more friends we'll have to share this hobby with. 
Personally, I know nuffink, but I'm learning all the time here.

As its a similar layout to the Guzzi, this is my Honda Silverwing trike, with a detail of the prop. shaft, hope it's of some use, Morrag

Couple more pics that will show the general layout, and I used a symmetrically shortened axle,6" narrower than standard................

Morrag,
I've been away a bit but now back on the tail of the Guzzi trike saga.
I've come to terms about using the centre mounted diff and angling over the prop shaft. I was wondering about having a prop shaft made to take the load but I note on your Honda trike that you have a "skinny" prop shaft... is this the original one?
I'm worried if the original Guzzi prop shaft and splines from the gearbox output can actually take the load of the reliant axle...

What do you (or others) think?

First I have to say that I know NOTHING about the engineering side of things - but my mate had his Cali triked with an angled shaft and had a lot of problems, finally got the axle shortened to avoid this.  But I don't know whether it might have been more to do with whoever did the conversion not knowing how to do it properly.

There's nothing wrong with shortening one side and lengthening the other, if you want to retain the original width (I would).
However, there is a limit to this - shaft stiffness and tube wall thickness needs to be up to it.
If you're messing around with the axle casing tubes I recommend binning the originals and buying some thicker metal - especially if you can turn stuff, best move imade.
Huw

as long as one ends sliding, and its inline your ok, if it keeps fecking up its usually a design fault, for eg, not inline correctly....

The prop is an amalgamation of the Honda prop. and an aftermarket industrial item, and more than man enough for a Honda "V" twins 50 Bhp, or your Guzzi's output. The prop shaft does not have to run in a straight line, and indeed some offset is desirable to reduce the brinneling effect of the univ. joints. Finally, unless you intend to put much larger horse power through the axle than that planned, then the standard tubes are more than adequate, ans are best,safest! modified by the cut and liner method, as pulling the existing tubes risks fracturing the diff. casing,even with judiciously applied heat, they have been in there a long time!, so, and for what its worth, that's what I do............... :) :) :) :) :) :)  Morrag

Have to slightly disagree morrag, I've seen numerous bent axles on this and other forums - admittedly because of poor design, usually mounting too far in to the middle.
Also, removing old tubes is a cinch, no risk attached. You just slice off at the casing and run a bead of weld or two along the inside of the bit still in the diff. The bit cools and taps out easy peaty.
You do need some skills and a lathe to make up the new axle admittedly, but moorem seems to have both, hence my advice. I'd also advise re driling the hubs for 100mm and 12mm studs, rather than bending the originals.
Huw

Well, each to his own me old son, its the result that counts ultimately...Morrag

Ai too true.
The problem with this custom stuff is while building one machine you're seeing other stuff which sparks your imagination. I have a yam turbo engine and frame which I intend to be build no2 (soft tail).
Just seen a vw reversed unit which also looks pretty good, but I'd like a v6....
Note to self, finish one project first.
Huw

Now that's sound advice, just wish I took note of it on occasion!! ;D ;D ;D ;D ;D ;D ;D

Well after a break from the build to have a new "A" frame fabricated by FASTrikes (Father and Son Trikes) in Basingstoke we are finally on the road to a real project.
Fastrikes made a fantastic job of undoing the rubbish that was put together north of the border. They recovered the original swinging arm and made a fantastic job of mating the reliant axle we supplied to their fabrication.

Everything simply slid into place, plenty of room for the UJ and prop shaft.

I've just modified the hubs to accept a couple of Rover wheels (I'll post some pics soon of that mod).
Drilled out and installed 12mm studs
New bearings & oil seals fitted.

Going back to my brothers this weekend to start bolting on the carriers, calipers and a couple of other minor bits and pieces.

Next job is the prop shaft. I'm marrying up the Guzzi UJ to a Robin shaft. It'll be spring loaded to keep pressure on the UJ against the gearbox drive output haft which is a sliding fit on the Guzzi.

So it's actually starting to look like a trike!

Basibstoke?
I'm curious to see what it looks like now!

Now that's interesting - the spring loaded bit.  I have a GT550 trike with shaft mated to the Robin shaft and I've some problems with the motorcycle end of the drive - what's the actual reason for the spring loading?

Not sure about the guzzi end bg, but your 550 prop should have a spung and keyed front end, this would keep pressure on the short splined gearbox output, thereby allowing any change in prop length brought aboutby the swing arm design.
Mine was solid, not sure of i'll spring load it, but my frame is solid hardtail

Ah yes you're right, I'd forgotten that!   Had also forgotten that I worked out that my probs were likely caused by lack of lubrication (someone didn't do the job I paid them for)

Thought I'd post a bit of the engineering here for a look.

These are the hubs I've modified so that a Rover wheel will fit the hub and be properly supported and not just held on by the studs:

Fairly simple to do if you can weld and have a lathe.

I'll grab some more pictures of the trike this weekend as we mount the modified axle onto the bike.

Then its the prop shaft to do - by the way it is a swinging arm which is why the prop shaft has to be sprung loaded against the Guzzi output shaft.

The disc sits on the larger diameter an the smaller diameter sticks through the disc bore to locate the rover wheel. It all fits really well.

Before I go from here for now I'd like to thank everyone for their excellent commentary, images of trike parts and assemblies and good humor. It has all been a real help in getting my brothers project moving.

The output shaft of the Guzzi is short and there is no means of clamping the UJ. It is made to slide to accommodate the movement of the swinging arm.

Disc in position. A nice snug fit.

Hub assembled in axle

Looking good so far. Checked run-out with a DTI and it was less than 0.0015"

Offering up the axle to the swinging arm frame from Fastrikes.
Everything slipped in just nicely.

Wheels on for a quick gloat.

That's a nice arse.

Thanks. It would not be where it is now if it were not for MMM and its very helpful members.

 ;D It's what we do.

Well its been some time since I posted an update.... family, holidays and kids off to university take priority but we have started again.

Well after my ancient switched DC welder blowing up on me, prompting the purchase of a new DC 150 amp inverter welder, we got the drive shaft welded together. I used the splined shaft from the Guzzi and welded a splined sleeve into an EN8 steel collar that was welded into a Reliant drive shaft. All very stable and welded with low-hydrogen rods so the well will be about as tough as I can manage from a home workshop.

It is handy being able to weld!

As soon as I can I'll post some pictures of the drive shaft.

Next up... brake hydraulics. We are opting for braided stainless flexible pipes from the Guzzi foot brake cylinder to drive the rear brakes via a T piece mounted on the rear axle. We found a company in Pitsea - Essex who will make them while you wait and he is about half the price of some other suppliers. I don't know how the feeling is about giving out suppliers details here so if anyone want to PM me then I'll send the details.

Again... more pictures to come in a little while.

Martin

Nice to see you back Sir & to hear things are back on track.
No problem if you'd like to recommend a company you've had good service from -we've got a section just for that. Check the Links for Commercial Purposes bit.

Back again after a break.
Got the prop shaft welded and in position. Original splined shaft driving a reliant stub through a splined male sleve welded into a boss. Seems to be OK. Checked the synchronising of the UJ's and by shear luck I got it right. I own up to not checking the spline alignment before fully welding the assembly. Not even half a spline out of line... phew that was close. I'd have hated to have had to try and cut that weld to reposition the boss splines.

Another view of the drive shaft from a different angle showing alignment back to the gearbox from the reliant axle:

Now to a problem and I'd really welcome some advice here.

Having had a fairly nice time with the disc conversion where everything went absolutely fine and dandy after some excellent advice from member I am stumped with a hydraulic problem.

The MotoGuzzi foot brake is a dual linked system. Front and back. I figured that with careful bleeding I might be able to get away with the cylinder being able to drive both rear pistons (now eather side) and of course the front as well.

It does but... the damn rear hydraulic pistons keep popping back in after the pedal pushes them out and so I have a very spongy brake pedal action.
I've bled it to bits and even inserted residual pressure valves either side leading to the rear discs. The calipers keep retracting though. When the foot brake it activated and pumped the pistons extend but then retract back in and so need pumping again.

Anyone any ideas please?

The picture below shows my attempt at inserting two residual pressure valves (2PSI) but the pistons still retract.

You should only need one valve and it should be as close to the master cylinder as possible. Don't recognise the make but I assume that they are fitted the correct way round.
One other thing, are you sure the calipers are mounted square to the disc face. If not, when the brakes are applied the mount or disc may twist slightly and when pressure is released they twists back forcing the pads out again.

Hi Olds....

I agree but I've had some conflicting advice. So I thought I'd go for the overkill advice first.
As far as I could find out these valves are usually installed where the master cylinder is lower than the slave. It should not be a problem with the Guzzi because it is much higher than the discs front and back.

The conversion is  GTI calipers as per MMM and for which I received excellent advice from the forum.

When I first installed the brake lines the rear brake pistons sprung back into the cylinders. I bled the lines to hell and back but the still insisted on springing back in.

Aha I thought... keep the pressure on. So I had the valves put in but the damn caliper cylinders, and particularly the right side, insist on springing back in after the foot brake is pumped. After it is pumped 3 - 4 times it grips but then you can see the pistons squeezing back in when the foot brake is released.

I can put a single valve back inline further near the master cylinder but I'm wondering if I'm missing a trick with the VW calipers. Might it be a problem of needing the handbrake applied for slack to be taken up as some self adjusting brakes do on other calipers?

This is the master cylinder by the way... 5/8" piston.

If you still think a single valve will work then I can try that.

Any more thoughts?

We put residual valves on my Pop, (I don't pretend I knew that was the problem. That was down to a far cleverer Monkey than me). The brakes were bleeding back overnight, so the pedal needed a couple of pumps the next day to bring it back up. We also fitted a one way valve. Would that help?

Hi Manky,

Thanks for coming back to me.
I don't think it is a draining problem because I can watch the rear pistons springing back in as I take my foot off the brake. I quite like the idea of a one-way valve though.

Martin

Sounds almost like the rubber dust ring is pulling the pistons back in. Are the calipers the correct size for the thickness of disc ? I'm not sure to how your calipers work as far as handbrake/adjustment goes but many have an adjuster inside the piston that is actuated by the handbrake. Try actuating the lever on the caliper a few times.
Problems like this are why I stayed with the standard drums. They work.

Wot olds said- if they're girling like the rover ones you need to put a spanner on the handbrake lever and give it the vinegar stroke..

Hi Minimutly,

I suspect that you and Olds are probably right. That will be the next job when I get out there.

I'll report back later.

Thanks.