Hello All.

[DAMIEN1307]

Thanks.... as a newbie, i thought I had read that using rubber under mounts was not a good idea and the only option was an aluminum or metal sleeve of in some installations, leather. I have my CNC mount to my aluminum frame un padded. I guess I need to add the rubber

It just needs to be thin is all, it helps give it a better grip without increasing vibration harmonics which tend to shake things loose and break things.

The problem with rubber is that some folks either use thicker amounts or actual rubber block motor mounts on these which will pretty much destroy your hard work and increases vibrations.

 

[Tommy Griffin]

Thanks.... as a newbie, i thought I had read that using rubber under mounts was not a good idea and the only option was an aluminum or metal sleeve of in some installations, leather. I have my CNC mount to my aluminum frame un padded. I guess I need to add the rubber

Never use any sort or rubber or leather between mounts. Its not like a car frame that’s supposed to have controlled movement, the engine never moves. Solid mount 100%. Anything else would squish and leave a gap.

 

[DAMIEN1307]

Never use any sort or rubber or leather between mounts. Its not like a car frame that’s supposed to have controlled movement, the engine never moves. Solid mount 100%. Anything else would squish and leave a gap.

That, I will disagree with you on Tommy...Provided your using only the thinnest sheet of rubber like i mentioned previously and know what your doing when affixing your mounts and not overtightening things, it does not cause a problem...It is not thick enough to cause a problem with vibration harmonics resulting in more vibration between motor and bike. (Using all of the usual lockwashers, and/or locknuts and blue locktite of course)...lol.

It is simply there so as to get a decent grip and nothing more, especially with people with aluminum frames when some folks tend to overtighten the mounts and crack their frames...I only use steel frames myself but the same principle applies.

Im also not constantly re-adjusting nuts/bolts etc. like most folks on here and I have been building and running motorised bikes going onto 11 years now.

I got into this when i retired for my second and last time as an ASE certified master tech for cars and motorcycles...(My first retirement in 1989 was as a Police LT. in Mass.)...My worst two problems i ever have had with these bikes was a cracked frame after 5 years and 6000 miles on one bike, (still have the motor), and 2 weeks ago losing a stud which is now replaced with good American made bolts...lol...DAMIEN

Ps...I might add that when i am building my bikes, there is a buddy with me who works at the White Sands Missile Range where you might have guessed, gets to play with rockets and military drones and is an actual mechanic for these "devices" as well as a military expert in metallurgy...My mounts and brake caliper adapters to my frame are made out of 7075 T6 grade aluminum that are used at the base for rockets and F-16s and drones, they will outlast the bike...lol...I even have a couple of "Adel" clamps affixed to certain items and they never budge...lol.

 

[Freddy Snottgrass]

I have always heard not to use rubber between the engine and the frame, HOWEVER...

The manual I got from my latest engine, a Zeda, on page 5 of 14 says:

"Vibration is a serious concern with all the single cylinder bicycle engines, so it is a good idea to use rubber pads (about 3mm thick) between the mounts, the clamps and the frame"

 

[Karl Snarl]

I just weld in motor mounts. Makes it really easy to swap engines and align the chain. Plus the hold steady and no worry of a nut coming loose. An it is part of the frame, so less worry about it cracking the frame.

 

[DAMIEN1307]

I have always heard not to use rubber between the engine and the frame, HOWEVER...

The manual I got from my latest engine, a Zeda, on page 5 of 14 says:

"Vibration is a serious concern with all the single cylinder bicycle engines, so it is a good idea to use rubber pads (about 3mm thick) between the mounts, the clamps and the frame"

Never use any sort or rubber or leather between mounts. Its not like a car frame that’s supposed to have controlled movement, the engine never moves. Solid mount 100%. Anything else would squish and leave a gap.

My Zeda 80 instructions state the following as well, (My instructions are from May 2020)...And mounting this way has caused zero harm whatsoever...DAMIEN

• Rework the mounts so they are a good fit in the frame. Adding rubber pads (about 3mm thick) helps reduce
engine vibration and helps the mounts to grip the frame.

Spacers and longer mounting studs are available from
ZEDA.

NOTE: The Rear Engine mount must always be at right angles to the Seat Stay

• Do as little re-working of the front mount as is possible, better to re-arrange the rear mount to suit the frame.
See images this page for ideas. If you need further help, call the ‘Help Line’.

The person that wrote this manual is also from Australia, same as this forum is also from Australia and whats written below is written by him...His instructions, as far as i can see, will apply to the good building of any brand 2 stroke, stock, China Girl motor.

CAUTION! DO NOT REFER TO THE INTERNET FOR “HELP”!! The information about these motors
that is offered on the internet is usually WRONG! Yes, I know people will tell you that, “This idea is great!”
Well, the author of these notes has been building engines (including small competition two stroke engines)
for over 50 years (yes I’m an old fella!), and am yet to find, on the ‘net, a ‘good idea’ that I did not already
know about.

Here is a copy of that Zeda installation PDF for anyone who is just getting started in building their CG...Just click on it and it will immediately download to your computer for offline usage.

 

[Freddy Snottgrass]

I don't even bolt mine down so I have easy swaps. I go through a lot of engines and frames for some reason.

 

[Axl Myk]

Never use any sort or rubber or leather between mounts. Its not like a car frame that’s supposed to have controlled movement, the engine never moves. Solid mount 100%. Anything else would squish and leave a gap.

Except some people prefer to protect the paint.

 

[Deleted member 33209]

I'm brand new to the hobby but I'm starting to think that this rubber topic, like engine break in, ethanol gas, what ratio to use, has lots of sides that are often both right (which makes it's frustrating as a newb lol)

 

[DAMIEN1307]

I'm brand new to the hobby but I'm starting to think that this rubber topic, like engine break in, ethanol gas, what ratio to use, has lots of sides that are often both right (which makes it's frustrating as a newb lol)

Just look to see if the writer of a post can post documentation with what they recommend or condemn...A good example of this is with ethanol or ethanol free gasoline...Folks who claim its just fine cite "If they use it in race cars its ok to use"...They do not read anything from the opposing sides that provide documentation of why it is harmful to 2 cycle motors.

Always ask for documentation or look for it if the poster has already provided documention in these postings and then read it for yourself....DAMIEN