rare quad

seen on the german ebay:

http://cgi.ebay.de/Husaberg-550FE-Quad- ... _500wt_947

regards

Taffy

I ought to mention that I'm tuning a Husaberg Quad for the road at the moment. the engine is being stroked and I've been asked to do everything!

I even have the inlet tract downdraughted. I'll be asked to send it off at the end and have the fuel tank made (it's a cannondale chassis) and an exhaust system nmanufactured. hopefully the owner will justify some dyno time! that would be fun! I'm hoping for 70BHP from a 666.

regards

Taffy

I've been asked to take a shed load of photos of the quad actually by the owner. don't forget that it's a dirt quad and what I haven't mentioned is that I've had to convert it to road use. we've lowered all the suspension and checked the rear axle/s/a pivot/ sprocket centre alignment by raising lowering the engine.

the engine fitted in between the s/a bearing houses. the cannondale usesd 17mm shaft and the husey 16mm.

the swingarm needed a bearing kit with bushes which we got and then we could see that the s/a was loose to the engine so to get it down to 16mm we designed new bushes with the thicker shoulders on the inside shoulder near the engine.

we also had the problem of sprocket alignment and noticed that we were as much as 7mm out of line. It looked like a completely stepped sprocket would be needed but we machined the the boss off the husabergs left cover that is for the kickstart and announced that we were going leccy boot only.

this, along with grinding 4mm out of the frame spare in that area allowed the engine to move over the 7mm. so when we did the inside shoulders we not only took the 16mm into account but adjusted the shoulders accordingly!

now we have a clutch cover 1mm from the frame and a tight s/a complete with 16mm pin and sprockets lined up. BTW we put shouldered hats in the frame for 16mm as well AND we made the shaft.

so that was that sorted.

so we had let the rear suspension travel dictate everything. we have 15mm drop onto the wheels. 35mm of travel is to see all three axles in line. then we have a further 60mm of travel to finish.


we then came to a double problem:
1) the carb needed a clear run but the top beam on the MX style shock was right across the mouth of the port let alone room for a carb.
2) it was only when we knew the wheels free position of the swing arm that we could look at a short shock.

the question was whether we could get and use a short enough - and therefore low enough - shock? so we cut the cross beam out and then started trying to source a short shock. preferably one that had done cantilever action. the best we could find was an ohlins off a 600ss ducati. we didn't want to go daft initially and get a 'posh' shock so this suited us.

the ducati shock is 330mm long compared to the usual MX shock of 400mm long. so we now fitted a mock steel shafts to represent the rear shock length if we were to get it to see if the carb could still be clear over the shock mount.

evidence showed that the carb and inlet would have to be mounted in a downdraught style. so we bought the shock and had all the excess alloy above the shock mount taken off. tests weren't conclusive as the shock mount could be lowered screwing the travel of S/A ratio to shock but making the carb have a clear run OR the correct position and a huge downdraught for the carb and inlet manifold.

we checked the shock and considered that we had 17mm of unused shaft which was daft so we had the shock sent away, rebuilt and upgraded to what we 'think' a quad needs, and shortened by 13mm.

shock back, and mounted we saw that the carb downdraught will now likely be quite sharp so I have organised a MK1 42mm carb with the design being well suited to that angle.

shock positioned correctl and the cross beams position marked it is now being welded in place.

when it is back later this week we can sit on it and jump up and down on the seat etc to get the ride height on the rear sorted. at present the bike has an 'uphill' look with the front still being MX set up.. so to do the ride height etc we'll sort the rear with the tyres on blocks. that done we can order the correct spring strength AND also a shorter spring (in one of course!) because the 13mm off the shock has meant that the spring is heavily preloaded just to get the nut started on the thread.

we felt it critical that the beam be welded in before we machine the back face of the head where the home-made inlet stub will sit. we made two slightly 'bishop's mitred' screw heads to pivot the inlet stub on and the gap underneath is 7mm so we will be machining the back face of the head out by that amount at the top to get the clearance over the shock.

we're going straight to a cone filter as well and 'hope' that there's enough room under the tank and seat which we weren't supplied with!

the front end will look after itself. we did do preliminary measurements but basically it is easier to get the rear ride height all sorted and then go to the front end with a clean remit and buy the shock we want at the length we want for the job.

the only piece of advice we felt we could have done with was the 'correct rid heights and sags for a road based quad with cantilever rear ends'?

the engine? that's the boring bit!

regards

Taffy

don't know yet bud, I have no source for pistons as you know and JBS is not talking since the gasket issues of a year ago. 102mm would be obvious but I have to source my own liners which isn't a problem but i also have to source head gaskets and pistons as well. so that's three jobs for on ebike? any suggestions?

regards

Taffy

phukin hell. brill tech write up and not one reply and instead all i get is drivel!

jeez! let's all talk about gearing again can we!!!!!!

some of you boys need to expand your thought processes.

regards

Taffy

I need to get some photos. you can't expect children to behave without toys. :twisted: :twisted:

we fitted the rear shock and found that even with a ratio of 2.95 to 1 shock to wheel movement it's actually way more shock movement than we need. could have still been 10mm shorter shock I reckon.

we fitted a WP type spring on the showa unit that has a length of 150mm. this is way shorter than original and just what we wanted. it now utilises the middle thread area of the pre-load rings. the spring is a 110KG which is way heavier than anything I'd have expected on a Quad. the sag is 10mm onto the wheels and then a further 28 (for 38mm) with rider aboard.

we have now measured up what we need for the front shock to get the ride height right BUT we have a dilemma.... we took the measurements to the wheel centres because we have no friggin idea what the tyre squat ratio OR the wheel sizes that the owner is going to want? so the front shock lengths will be dictated by those factors.

the head is being machined at the top face and into it by 7mm. the engine tune begins shortly. it's gonna be a monster!

regards

taffy

but the piston is like the modern LDC engines with the valve pockets out of the edge of the piston. no good bud!

I'm now chasing head gaskets so that's a start right?

regards

Taffy