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Re: Front end vibration

PostPosted: Tue Apr 26, 2022 5:08 pm
by 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.

Re: Front end vibration

PostPosted: Tue Apr 26, 2022 5:24 pm
by hullygully
are they after market split Indian rims Jef? :?

Re: Front end vibration

PostPosted: Wed Apr 27, 2022 8:45 am
by 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

Re: Front end vibration

PostPosted: Wed Apr 27, 2022 9:55 am
by hullygully
is your disk hub spindle horizontal in links?

Re: Front end vibration

PostPosted: Wed Apr 27, 2022 3:19 pm
by Warkton Tornado No.1
Jeff t wrote: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 :lol:

Re: Front end vibration

PostPosted: Wed Apr 27, 2022 4:05 pm
by 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

Re: Front end vibration

PostPosted: Mon May 02, 2022 4:59 pm
by 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.

Re: Front end vibration

PostPosted: Mon May 02, 2022 7:13 pm
by Warkton Tornado No.1
Jeff t wrote: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..... :roll:

Re: Front end vibration

PostPosted: Mon May 02, 2022 7:53 pm
by 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.