Hi all, put together first motored bike. Sprocket alignment is good, chain alignment is good, wheel is fairly straight. Low speeds not much vibration, higher rpm more vibration. When bike is stationary with engine running not much vibration, when I Rev engine,quite a bit of vibration. Is this normal? Has anyone rubber mounted these engines to the frame. Do you think that might help? Any and all suggestions appreciated.
Vibration
- Thread starter Jeffrey
- Start date
FurryOnTheInside
In Memoriam
Okay please read through the "related threads" at the bottom of this page, and also use the search function (in the top right corner under your name), to search for the word vibration.
Read lots then come back and tell us which engine exactly you have, ie eBay crappy time or a brand name engine or what.
You will read that rubber mounts only make things much worse.
I have done this:
Two holes in line with the con rod, 3/8" wide and 15mm deep. I was advised that up to 18mm deep would be about right, but I'd like to go slowly, since I haven't finished my bike yet (so the engine has never been run) so this is just a starting point for me and the crappy time engine I have. I have some work to do still to lighten up the piston/pin. This work I'm doing is to do with so-called "balance" and not crappy/ damaged crank bearings which can be an issue too!
Read lots then come back and tell us which engine exactly you have, ie eBay crappy time or a brand name engine or what.
You will read that rubber mounts only make things much worse.
I have done this:
Two holes in line with the con rod, 3/8" wide and 15mm deep. I was advised that up to 18mm deep would be about right, but I'd like to go slowly, since I haven't finished my bike yet (so the engine has never been run) so this is just a starting point for me and the crappy time engine I have. I have some work to do still to lighten up the piston/pin. This work I'm doing is to do with so-called "balance" and not crappy/ damaged crank bearings which can be an issue too!
Yeah, I saw the threads after I posted question. New to this, u know...bike has a flying horse, don't know if that ebay junk or name brand. I'm guessing name brand Chinese junk..anyway, I figured it out. Front motor mount had vertical play in it. I was only looking for side to side play. It is alot smoother now..100% better..thanks for the reply
I am curious how does rubber make it worse?
For cars the engine and transmission is mounted in rubber to isolate the vibration of the engine from the vehicle itself. When the mount crushes and goes bad it sits metal on metal putting vibration into the vehicle as well in some cases a loud rattling vibrating noise.
For me I was going to use high temp locktite on all thread installed into the block and then pass it through the rubber mount through my mount with a stainless washer, lock washer, and nut.
The muffler clamp like mount around the seat tube I was thinking of actually coating the whole clamp minus the threads in some of that elastic rubber plasti-dip in black so there would be no need to try and fit rubber between.
FurryOnTheInside
In Memoriam
As I understand it: Rubber allows the engine to vibrate.
Rather than isolating the vibration we want to lessen it as close to the source as possible. The aluminium case/cylinder/head has hardly any mass, so we need to attach the mass of the bike directly to the engine so that it in effect becomes part of the engine. This increased mass (inertia) lessens the vibration and stops the engine shaking itself to pieces.
Baconator101
Active Member
I used them...once... at the very beginning they did tend to let the motor wiggle even if it was uncomfortably tight. (Lucky I didn't strip motor mount holes) but then I sandwiched the rear one between two motor mounts, and the front stayed the same. It's worked out excellent in my situation. Excuse all the grime.
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Interesting. Might need to try it.
Probably not like the look with the hump in the mount but I guess I could take the rubber mount and cut the ears off and mount it flush and use the rubber D to fill in the space for a finished look. I how ever think I will still dip the rear U bolt mount in plasti-dip black rubberized coating just to give it some give to not damage my paint too much.
