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 Post subject: NS400R wheel runout
PostPosted: Fri Jun 23, 2017 4:50 am 
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Joined: Sun Oct 28, 2012 6:38 pm
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Location: Spielberg, Austria
After my first ~300km with the NSR I have found one problem.
The front wheel starts to vibrate at 140km/h - no handlebar shaking, only vibration which is visible if you look down on the fork.

Removed the tire from the rim and checked the runout - limit according Honda is +-2mm (total 4mm!) in radial and axial direction which is quite a lot.

Can`t measure the runout as I`m waiting for my dial gauge stand, but should be within +-2mm but it will be close to that.

Is there any experience with the original Honda wheels?
Are they "round" from factory or is it standard that they are close to this +-2mm?

Bike is not 100% "crash free" but no signs of a big impact.

I mounted the wheel again and balanced it new but can`t test it as there was a thunderstorm at 6AM today, so I had to take the car to go to work :smt013

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My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda NS400R NC19
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: NS400R wheel runout
PostPosted: Fri Jun 23, 2017 10:27 am 
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Joined: Sat Feb 04, 2012 7:36 am
Posts: 1964
Location: Eastern Ontario Canada
I have a similar issue with mine, but at low speed. When decelerating there is a bit of a shake in the front end. I have replaced the tires and will ride it to test soon. I'm using Dynabeads for front balancing this time. I suspect the old front tire had a flat spot from storage as I seldom use the bike. If it still shakes I'll service the forks. This problem only surfaced a short while ago. High speed riding has always been very smooth.

Do you have new tires on your bike?

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1985 RZ500
1985 RZ500 Project Bike
1986 RG500 ATR
1986 NS400R
1987 TZR250
2007 DL650 VStrom
2014 Triumph Thruxton
1979 Pontiac Trans Am with modified 1969 Olds 455 (7.5 L) 400++ HP, 500++ Ft/Lbs


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 Post subject: Re: NS400R wheel runout
PostPosted: Fri Jun 23, 2017 11:18 am 
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Joined: Sun Oct 28, 2012 6:38 pm
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Location: Spielberg, Austria
Yes, new BT45`s

It`s not the standard shaking as I know it from a lot of old bikes, it`s more a front-rear vibration which is clearly visible when looking down to the fork.
I can`t really feel it in the handlebars, the whole bike is vibrating but no issue with stability.

Had similar issues on my CBR600 also at the same speed range, there I balanced the front wheel new and it was gone.

By the way, I recogniced that the anti-dive system is actuated by the left brake caliper.
Maybe I should check the brake rotors.
Could be that they are not straight and the (movable mounted) brake capliper starts to vibrate at this speed.
Maybe this is also what I can see.

Changed the mounting side of the rotors as they were mounted on the "L"ight and "R"eft side :smt018

_________________
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda NS400R NC19
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: NS400R wheel runout
PostPosted: Fri Jun 23, 2017 3:35 pm 
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Joined: Sun Oct 28, 2012 6:38 pm
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Location: Spielberg, Austria
Update:
Managed to go out for a test ride after the next thunderstorm went behind the next mountains.

It`s stable up to ~170km/h, seems that the wheel was not balanced.
Did not add too much weight (5g before, 10g now) but maybe the tire was not in right position (yellow spot at the wrong side) together with too less weight.
Or the weight was not removed from the old tire and the new one was not balanced at all...

At least I found the answer - it doesn`t matter if the tire is bumping up/down/to the side like crazy when turning on the balancer.

And balancing on the my self made balancer worked fine again, no need for dynamic balancing.

_________________
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda NS400R NC19
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: NS400R wheel runout
PostPosted: Sat Jun 24, 2017 1:39 am 
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Joined: Sat Feb 04, 2012 7:36 am
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Location: Eastern Ontario Canada
Now you need to test it to top speed :smt003

_________________
1985 RZ500
1985 RZ500 Project Bike
1986 RG500 ATR
1986 NS400R
1987 TZR250
2007 DL650 VStrom
2014 Triumph Thruxton
1979 Pontiac Trans Am with modified 1969 Olds 455 (7.5 L) 400++ HP, 500++ Ft/Lbs


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 Post subject: Re: NS400R wheel runout
PostPosted: Sat Jun 24, 2017 6:17 am 
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Joined: Sun Oct 28, 2012 6:38 pm
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Location: Spielberg, Austria
Thats true, I never tested the top speed up to now :smt003

By the way, I have used my old workshop helmet yesterday.
My Shoei helmet seems to filter "bad noises" from the engine which is sometimes not that bad as every engine is making some funny but uncritical noises.

Besides that the bike is very loud :smt003 there is a rattling noise on the left side.
Sounds a bit like the normal clutch noise but it`s on the wrong side.

As far as I know on the left side there is only the generator which usually doesn`t make any noise and the shifting mechanism.
And then there is only the gearbox (bearings) and the crankshaft bearings.
As the noise changes with the engine speed when opening the clutch it can only be the crankshaft or the clutch basket...

Is there also some "mechanical" noise on your bike (left engine side)?

_________________
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda NS400R NC19
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: NS400R wheel runout
PostPosted: Sat Jun 24, 2017 2:49 pm 
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Joined: Sat Feb 04, 2012 7:36 am
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Location: Eastern Ontario Canada
The Honda does make some odd noises. I think they're normal, but other guys that ride my bike usually say they hear strange noises.

A rattle on the left side may be the ATAC actuator. Maybe it's a good time to check it and it's adjustment.

_________________
1985 RZ500
1985 RZ500 Project Bike
1986 RG500 ATR
1986 NS400R
1987 TZR250
2007 DL650 VStrom
2014 Triumph Thruxton
1979 Pontiac Trans Am with modified 1969 Olds 455 (7.5 L) 400++ HP, 500++ Ft/Lbs


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