My Trike

[triker-taz]

Hi all been out on the old trike today (cant pass up these nice days) and just after any info you guys and gals can give me as lots of you have been doing this for a long time and have built many a machine, and I'm only a new boy at this.. . I got my trike (which will be in the trike section soon..) at the start or the year it is based on an XS750 with a narrowed capri back axle (hard tail) and a bandit front end and although its great fun round town it is quite hard work on longer journeys (if I could sort this I could go on a few more runs ) Its great up to speeds of say 45/50 but at 50 or over I do seem to get alot of vibration, I dont have a rev counter fitted so dont know if it could just be over revving but dont think so as I have had it over 70 and it never went bang  (just lost a few fillings), is it just the nature or the XS750 lump ... are they prone to a lot of vibration I have considered trying to some how rubber mount the engine to see if this would help any ideas would be greatfully received because if I could sort this it would be much more fun to ride longer distances and I could get to more rallys and fun days ..

Thanks..

P.S what sort of pressure do you guys and gals run your front and back tyres at have tried various settings but dont seem to make much difference (still get catapulted out the seat at pot holes )

[Trikerrob]

Mines hardtail mate i run the rear tyres at 12 when i am solo, could the vibration be from your prop 

[triker-taz]

What do you run the front at?? and did think of that will have to have a look.. but it is only about a foot and half long.. ( the prop that is not the trike))

[Manky Monkey]

Hiya Taz.
Yup, I'll sort through your trikey stuff & pass it on to Yodie to make up into a page in the Motors bit.
I've owned several XS750s, as well as 4, (I think), XS650s & an XS850. I also owned an XS1100 for 3 weeks. The 750 & 850s are triples so just naturally lumpy, but not to the point where you can't ride them! If I remember right, mine would smooth out at motorway speeds & cruise at 70 -80 quite happily.
A hardtail will always exagerate any vibrations. Rob's right, it could well be your prop that needs balancing. I've mentioned it here before, but it's worth trying a large jubilee clip around the prop tube. Gradually moving it around the prop may well ease the problem as the worm drive part of the clip will act as a counter weight. Does your prop run straight, or at an angle? Too much of an angle will put the universal joints under a lot of strain & prematurely wear them -which would show as vibration. Are your Capri wheel bearings O.K? Do your rear wheels need balancing?
I run normal bike pressures in the front tyres, (30 -35 PSI), with 15 in the rears. Too much at the back & your trike will skitter all over the road.

[triker-taz]

Cheers for that will hopefully get to have a look tomorrow if the rain and the beer holds off (got  the other half's work xmas drinks thingy to go to) thinking about it where the prop connects to the axle one of the four bolts does have a nut on it (presume the threads are stripped) do you think this could be enough to throw the balance out and cause the vibration.

[Manky Monkey]

Nah, it'd take a bit more than that. Might be worth checking the prop's actually running true. Jack it up & spin it to see if it wobbles.

[toad]

it could be that the uj,s are out of line!check to see if the centres of the bearings line up. ie if one of the bearings at the front is at 12 oclock then one of the rears should be the same if not that will more than likely be the cause!

[triker-taz]

Ah.. could that cause it I never knew that... well you live and learn will go and look now  Back in a mo

[Manky Monkey]

Yup, the yokes that hold the UJs on either end of the prop should be in line with each other.

[triker-taz]

Just checked and NO they are not in line ...But the front one looks like its on a spline (think its the one off the bike) so will take the prop off and see if I can line them up by turning it on the splines .. .. Will try and get a pic and post here..

[Manky Monkey]

An easy fix if that's the problem. Certainly worth a go.

[triker-taz]

OK first pic is how it was  .. and second pic how it is now  ..... better but not perfectly in line, just have to see if it works.. ..Does it have to be the fixed yokes in line.. Because if I turn it another 90degrees they do line up even better..

[Manky Monkey]

Yeah, the fixed ends of the prop. The Reliant ones are actually angled, so we just line 'em up as best we can, but then our props are so short, balancing isn't really a problem. If they're not in line, they'll be fighting against each other as the prop turns & creating vibration -just like you're experiencing. Re-aligning them might not fix it. but certainly won't do any harm.

[triker-taz]

So like the second pic then..

[Manky Monkey]

Yuss.