The shakes
Moderator: Modsquad
The shakes
The vibrations of the bike at idle seem much quieter if I’m holding the rear brake.
When holding the bike with the front brake only, or not holding the brake at all, engine vibrations shake the bike substantially more than when the rear brake is engaged.
Not a big deal, but wondering if anyone else noticed, and if so, knew why.
When holding the bike with the front brake only, or not holding the brake at all, engine vibrations shake the bike substantially more than when the rear brake is engaged.
Not a big deal, but wondering if anyone else noticed, and if so, knew why.
- kramnala58
- Mod Emeritus
- Posts: 2864
- Joined: Sun Jun 09, 2013 7:49 am
- Color: White is faster
- Location: Niagara Falls, USA
Re: The shakes
Sorry, I have a Thai bike and the idle stop really helps to get rid of the vibration.Urbanian wrote: ... wondering if anyone else noticed ...

2010 Honda PCX 125 in Thailand (White) - "White Lightning" Sold in Sept 2017
2009 Yamaha Majesty YP400 in USA (Metalic Titanium) - "The Throne" Sold in June 2020

2009 Yamaha Majesty YP400 in USA (Metalic Titanium) - "The Throne" Sold in June 2020

- maddiedog
- Benevolent Overlord
- Posts: 3646
- Joined: Tue Nov 01, 2011 7:04 pm
- Year: 2011
- Color: White
- Location: New Mexico
- Contact:
Re: The shakes
I notice the same.
I added barend weights, all that did was make the weights rattle.
My best guess as to why the PCX vibrates at stop is because it's a single-piston bike. I've ridden some bigger single-piston bikes (usually call them thumpers), namely a Buell Blast, several KTMs, and a Harley once.. They all vibrate even worse than the PCX does. From my experience, some vtwins, all inline 4's, and all parallel twins are all much smoother because there's another piston offsetting the vibration of the first piston.
I added barend weights, all that did was make the weights rattle.

My best guess as to why the PCX vibrates at stop is because it's a single-piston bike. I've ridden some bigger single-piston bikes (usually call them thumpers), namely a Buell Blast, several KTMs, and a Harley once.. They all vibrate even worse than the PCX does. From my experience, some vtwins, all inline 4's, and all parallel twins are all much smoother because there's another piston offsetting the vibration of the first piston.
Currently ride: Nothing right now - mostly mountain biking with my boys until they're old enough to ride
Previously rides: 2011 Honda PCX 125, 2005 V-Strom DL650, 1974 Vespa Ciao, 2011 Honda PCX 170 (tons of mods - takegawa 170cc big bore kit, gears, etc), 1996 Honda Nighthawk 250, 1987 Honda Spree, 2000 KTM 125SX, 2003 Honda Silverwing, 2007 Genuine Buddy 125, 1998 Honda PC800, 2008 Buddy 125 (white), 2008 Buddy 125 (red), 2001 Honda Reflex, 1987 Honda Elite, 1988 Honda Spree, 2007 Yamaha Vino, 2007 Honda Metro, 2x 125cc pure-chinesium dirt bikes

Previously rides: 2011 Honda PCX 125, 2005 V-Strom DL650, 1974 Vespa Ciao, 2011 Honda PCX 170 (tons of mods - takegawa 170cc big bore kit, gears, etc), 1996 Honda Nighthawk 250, 1987 Honda Spree, 2000 KTM 125SX, 2003 Honda Silverwing, 2007 Genuine Buddy 125, 1998 Honda PC800, 2008 Buddy 125 (white), 2008 Buddy 125 (red), 2001 Honda Reflex, 1987 Honda Elite, 1988 Honda Spree, 2007 Yamaha Vino, 2007 Honda Metro, 2x 125cc pure-chinesium dirt bikes
Re: The shakes
V-twin vibration is largely dependent on the included angle.
A ninety degree angle gives perfect primary balance and can be smooth as silk.
Anything else and it shakes like a prehistoric tractor engine.
Honda V4s, BMW boxer twins are also seriously smooth and the Z1300 six is like a gas turbine.
A ninety degree angle gives perfect primary balance and can be smooth as silk.
Anything else and it shakes like a prehistoric tractor engine.
Honda V4s, BMW boxer twins are also seriously smooth and the Z1300 six is like a gas turbine.
Four decades on two wheels has taught me nothing, all advice given is guaranteed to be wrong
- Alibally
- Official Moderator
- Posts: 1761
- Joined: Thu Nov 03, 2011 5:47 pm
- Year: 2019
- Color: Black
- Location: Edinburgh, Scotland
Re: The shakes
BMW use lanchester balancer to smooth the engine vibration. See http://www.ashonbikes.com/bmw_engine_balancer
I've see it on car engines before and it works great, but its another thing to time up when rebuilding one.
I've see it on car engines before and it works great, but its another thing to time up when rebuilding one.

- you you
- What's a wot?
- Posts: 10001
- Joined: Sat Jun 30, 2012 5:37 pm
- Location: Between Lulu and Chichi
Re: The shakes
Alibally wrote:BMW use lanchester balancer to smooth the engine vibration. See http://www.ashonbikes.com/bmw_engine_balancer
I've see it on car engines before and it works great, but its another thing to time up when rebuilding one.
They don't use lanchester shafts
- Alibally
- Official Moderator
- Posts: 1761
- Joined: Thu Nov 03, 2011 5:47 pm
- Year: 2019
- Color: Black
- Location: Edinburgh, Scotland
Re: The shakes
Technically not. The F800 instead uses a third ‘slave’ conrod to drive a bobweight, but the results are the same. It's based on a similar principle of counterbalancing any vibration.

- you you
- What's a wot?
- Posts: 10001
- Joined: Sat Jun 30, 2012 5:37 pm
- Location: Between Lulu and Chichi
Re: The shakes
Alibally wrote:Technically not. The F800 instead uses a third ‘slave’ conrod to drive a bobweight, but the results are the same. It's based on a similar principle of counterbalancing any vibration.
Not technically not, absolutely not. A lanchester balancer is a rotating balance shaft. Not in any way shape or form what the f800 uses.
Mind you I think BMW use balance shafts on the k series?
-
- Regular User
- Posts: 149
- Joined: Thu Jan 03, 2013 5:41 am
- Location: Sydney Australia
Re: The shakes
My shakes only when the brakes are held at the lights. When I've stopped and let go of the brakes, it idles very smoothly
Re: The shakes
I agree.SmellyTofu wrote:My shakes only when the brakes are held at the lights. When I've stopped and let go of the brakes, it idles very smoothly
Mine idles very quietly, and the few vibrations I notice are located on the handlebars. If I hold the rear (or combined) brake, then the vibrations move to the seat, that is right to my back end.
I personally don't like it so I usually hold the front brake at traffic lights. But who knows, there's a chance that someone around here likes and actually enjoys that kind of vibrations in their "rear"

-
- New Member
- Posts: 20
- Joined: Fri Nov 09, 2012 6:10 pm
Re: The shakes
Mine have the same symptoms. hen no brake is applied it will shake more than when the brake applied. But i only noticed it after reeding this post. i was never aware before of this issue.
