Front end vibration

[Jeff t]

Coincidentally I have checked the disk without the tyre and it’s bang on the tyre though probably moves between 5 and 10mm when you spin the wheel, so I have let the air out and I am going to over inflate then lower back to what it should be see if it trues up.

[hullygully]

are they after market split Indian rims Jef?

[Jeff t]

No SIP tubeless, tried the tyre last night and not much difference. Where I am at now is, I’ve changed the springs, secured top buffer, removed some weld splatter on the inside of the forks as one of the links was a bit tight.
Everything looks spot on now apart from two issues, tyre seems to run out by about 5mm although disk is spot on and the wheel is slightly off centre which you can’t adjust.
I’ll put back together and try it

[hullygully]

is your disk hub spindle horizontal in links?

[Warkton Tornado No.1]

No SIP tubeless, tried the tyre last night and not much difference. Where I am at now is, I’ve changed the springs, secured top buffer, removed some weld splatter on the inside of the forks as one of the links was a bit tight.
Everything looks spot on now apart from two issues, tyre seems to run out by about 5mm although disk is spot on and the wheel is slightly off centre which you can’t adjust.
I’ll put back together and try it

I suggest that you swap that wheel assembly for anything with less run-out until such time as the cause of the issue is found.

Talking of run-out, if the faces of the disc are not true - as in warped - that will be a judder more easily distinguishable than the harsh vibration likely with over-sprung suspension.

As you say "the wheel is slightly off centre which you can’t adjust" which is a design fault/feature of the otherwise excellent SIP rims. It makes you wonder just how far axially offset the wheels can get when you factor in the double-row layshaft bearings that also do the same

[nsaints]

What type are the softer engine mounts and where do you get them from ?

I used the mounts listed as SIL from Scooter Restorations, replacing the BGM ones

I've BGM fitted to my TV as well.
I'd need to confirm but fairly sure there's also some vibration starting around 40mph, but disappears above 50mph

There is no vibration throughout the rev range on the GP with SIL mounts

[Jeff t]

Well just been out and it’s miles better, I changed the springs but I think what made the difference was the engine was touching the frame. I have a Casa engine bolt where you can lower the engine and the air intake was touching the frame so lowered it off a bit. Thanks to all those who offered help get some miles on now and see how it goes.

[Warkton Tornado No.1]

Well just been out and it’s miles better, I changed the springs but I think what made the difference was the engine was touching the frame. I have a Casa engine bolt where you can lower the engine and the air intake was touching the frame so lowered it off a bit. Thanks to all those who offered help get some miles on now and see how it goes.

Really? The weight of rider counteracts any issue with the inlet touching the frame.

Anyway, I'm glad the problem is diminished, but my thoughts remain with the springs being the issue. Unfortunately, so many remade parts are not fit for purpose.....

[Jeff t]

Well obviously can’t be certain, i used BGM springs so I guess they could have made the difference, main thing it feels a lot better.

[Jeff t]

The issue goes on but to sumarise I have an issue with a hydraulic PM tuning disc brake, i’ll not go through all the history but i have a judder when braking at slow speed. Ive ruled everything else out and i’m at the point where i have removed the wheel to see if I can workout whats happening.

First thing i found which won’t have helped is the head of the wheel studs on the hub are catching the caliper, on this type of brake the wheel studs are cap head bolts.

Difficult to explain but if I tywrap the brake lever so the load is consistent the issues I need help with is the disc is a shark fin shape like on a crosser and when the fin is roughly in the center of the caliper it tighthens slightly when under light load and then releases again as the fin moves on and so on with each fin.

When there is no pressure on the caliper the wheel is free so the top of the fin is clealry not touching anything and when measuring there is a good 5mm clearnce at the back of the caliper.

Question is would you expect the braking to increase so tighetn up as described as the amount of metal in contact with the brake pads increases due to the shark fin design.

Obvioulsy I’ll put back togetger and hope it was the studs catching the caliper but think thats just wishful thinking, realy lost with this one.