Anyone know how a scooter engine mount works?
smart51 - 17/2/13 at 02:05 PM
... Or what it does?
Here's a link to one on eBay with a picture.
PIAGGIO FLY 125 4T 2008 08 ENGINE SUSPENSION MOUNT BRACKET CHEAP UK POSTAGE | eBay
The tube at the bottom has bearings in it and a long bolt goes through it to mount it to the frame and is the main pivot. The tube above it is
another pivot. The top part fastens to the engine casing/trailing arm. Why so much articulation?
The reason I ask is that I'vebuilt a three wheeler with a scooter rear end. In high speed corners, there feels like a bit of flex in the rear
end. I'm thinking of making something more rigid to combat the extra forces of a trike that a scooter doesn't have because it leans into
corners. To do it properly, I'd like to understand what the scooter part is trying to do. clearly they wouldn't have made it complicated
if simple is good enough. any ideas?
[Edited on 17-2-2013 by smart51]
Peteff - 17/2/13 at 02:21 PM
Is there a rubber mount in there as well, it looks like it has a damper built into it ?
Slimy38 - 17/2/13 at 02:39 PM
Is it anything to do with the articulation in rising rate motorcycle suspension?
http://www.promecha.com.au/leverage_linkages.htm
I remember when the bearings in my bikes linkage were worn the bike felt extremely 'flexible' on the back end.
smart51 - 17/2/13 at 05:08 PM
quote:
Originally posted by Peteff
Is there a rubber mount in there as well, it looks like it has a damper built into it ?
The round thing, top left is rubber with holes in it. it allows some movement but limits it.
smart51 - 17/2/13 at 05:11 PM
quote:
Originally posted by Slimy38
Is it anything to do with the articulation in rising rate motorcycle suspension?
http://www.promecha.com.au/leverage_linkages.htm
The coil overs are right at the back, so not rising rate as per that article.
quote:
I remember when the bearings in my bikes linkage were worn the bike felt extremely 'flexible' on the back end.
It feels like something that should be fixed is moving above a certain load. I've checked and it is all tight. My assumption is that the higher
lateral force of a trike may be causing something in the linkage to move in a way it shouldn't.
[Edited on 17-2-2013 by smart51]
nick205 - 17/2/13 at 07:38 PM
I'm sure you've checked, but is tyre pressure playing a part? The extra load from the cabin scooter might be affecting the way the tyre
behaves under higher and more lateral loading.
smart51 - 17/2/13 at 07:55 PM
The rear tyre pressure affects the ride noticeably but it hasn't affected the feeling of flex in the rear end. That's not to say the tyre
isn't playing a part.
I'm still trying to figure out how the 3 pivot swing arm works. I can't find a description on the Internet. The rubber bush allows the
engine to move up and down a little. I guess it allows some movement when getting on and off the throttle.
on_eighty_runner - 3/3/13 at 02:29 PM
I had a runner sp180 and at idle there is a fair bit of vibration from the engine.
The engine pivot is offset from the frame pivot to allow vibration fore and aft to be permitted via the larger soft rubber do-nut.
The right and left sides are welded on each piece to keep the engine pivot parallel with the frame even if it moves fore/aft and up/down.
This is not fitted on the 50 cc's for vibration and obviously cost reasons.
there are lots of 125 piaggios around, have a look at one after a cold start and its all clear, you'll see it all jumping around.
You could try hard mount, but there may be later fatigue problems.
It was a very fast scooter but I do remember the back end a bit loose at times when hitting a pothole on a corner.
Crankshaft snapped on the a46 at 80 mph, engine rebuilt and stolen and written off the next weekend!
Steve