To "rubber" or not

all my Grubee engines run super smooth. i've run them stock out of the box and heavily modified, and in my opinion they're the smoothest engines out there.

BUT, i respect camlifter's experience, and if he says the ones he had vibrate, i have to believe him.

maybe he just got some from a bad batch, or some other unknown factor, who knows? maybe the molecules in the frames he uses reacts violently with the resonance of the engine...

whatever it is, i ain't arguing. if i did, it'd turn into a chevy vs. ford pissing match. :)
 
true that. everyone has there brand, and i don't want to argue either, it would never end. i prefer the of brands but there getting harder to get.
 
I can describe my mount. I have an older Huffy Santa Fe and I stacked up washers so that there wasnt any slop between the mount and frame. I also wedged some washers under the plate part of the mount and held them in place with (cough,cough) JB Weld. I didnt use any kind of lock-tite anywhere and havent had any loosening issues anywhere, so I dont believe solid mount amplifies vibes. This was my first build and I read everything I could on mounting and concluded solid mount is the way to go.
 
biknut said:
This is how I mounted mine and so far in 500 miles I've been very happy with it. Although I feel it reduces vibration, the main advantage is hockey pucks are easy to work with and make it easy to adjust the size of your mount to accommodate different size frames.





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Hockey pucks. Awesome. I tried something close to that but I think I'm in trouble.

I just did my first build on a Schwinn cruiser where the down tube didn't leave the cranks in a vee, but closer to horizontal, then it curved upward to meet the top, or nut, bar, as it's called. So the frame was way too big for the 48cc Skyhawk that I was trying to install. I solved this by overextending the mounting studs. Somebody just said, there's your first mistake.

I transferred the longer, factory back studs to the front, and bought two new bolts for the back, only about 3/4in longer, 8.8 grade I'm told. Then I made two filler blocks out of something called Trex. It's decking, as in on your back deck, it's two inches thick, and it's made out of hard rubber and soft plastic. You can scratch it with your fingernail. The front block fills in between the engine case and the frame, is about 1- 1/2in thick, and is cut to fit the curve of the tube; the rear block is square, 2in thick, and goes between the case and the metallic, floating factory block that fits to the frame there. This engine runs pretty smooth, smoother than I expected, and mounted like this I can feel very little vibration going down the road.

Until it snaps and falls apart, which is what I am getting from the discussion. It may not, but suddenly it seems like a bad idea to overextend the factory hardware and provide a flex point for the twisting and the vibration.

Short of welding new mounts, which I am not inclined to do on such a cheap ride, is there really any way to fit one of these engines to a frame that doesn't have that pervect vee to work with? So many cruisers are designed that way now. How about wood blocks, anybody have experience with those? Speak up, homey. How about tapping the engine case for larger, case-hardened studs? How about a third attachment point to the nut bar?
 
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superbob said:
Short of welding new mounts, which I am not inclined to do on such a cheap ride, is there really any way to fit one of these engines to a frame that doesn't have that pervect vee to work with? So many cruisers are designed that way now. How about wood blocks, anybody have experience with those? Speak up, homey. How about tapping the engine case for larger, case-hardened studs? How about a third attachment point to the nut bar?
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This is how I do it... This is made from 1/4" steel & good quality 'U' bolts. It's very solid!
It's very important to make sure the rear mount is square to the frame & the front mount angles are correct to also be square with the frame so that the engine is as solid as possible (& won't be able to vibrate.) ;)
vmbbasebike2.jpg

vmbbasebike1.jpg

vmbbasebike3.jpg
 
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bairdco said:
whatever it is, i ain't arguing. if i did, it'd turn into a chevy vs. ford pissing match. :)
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Yeah I know what you mean Bairdco, no reason in starting a big ruckus over how much better Ford is than Chevy, that would just go & go & go......!

Just kidding around here fella's.......LOL!

Peace...
 
I found out to late the best route to go is when mounting the engine to go too an auto parts store and i got a rubber exhaust insulator. It brought down on the vibration considerably wish i would've done it sooner now I gotta come up with something cuz my thread on my motor mount broke.
 
txlixard469 said:
I found out to late the best route to go is when mounting the engine to go too an auto parts store and i got a rubber exhaust insulator. It brought down on the vibration considerably wish i would've done it sooner now I gotta come up with something cuz my thread on my motor mount broke.
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Apparently you haven't been paying attention to the previous posts. Your rubber insulator is why your mount broke. Throw the rubber away and mount the engine solid to the frame; then you won't be breaking mounts and fasteners.
Tom
 
The mounting bolts broke before i put the insulator on I've gone thru at least 4 mounting bolts and 3 regular bolts bought at home depot. I geuss either way I am doin something wrong so I'm trouble shooting my options and ur right I wasnt payin attention to the other posts , I do what I always do and give my 2 cents without reading the rest :( one of my many defects. I'll learn one days .
 
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Are you buying grade 8 steel bolts? No sense in not spending the money on it.

Seriously - it's a motor hitting at least 5500RPM, you really want that to not come flying off your bike. I don't trust aluminum, and I don't know who would.

Grade 8 (5 at the MINIMUM) steel stud bolts, make sure it's a flush connection against the frame, and you won't have any problems.
 
I have a raw that is yet to be installed. been reading a lot of posts, I suppose that I picked the right engine. the weird thing, that nobody seems to know for sure, is why they all have the same outer casings?.... is this true?
 
Dogtown Burner said:
I have a raw that is yet to be installed. been reading a lot of posts, I suppose that I picked the right engine. the weird thing, that nobody seems to know for sure, is why they all have the same outer casings?.... is this true?
Click to expand...

i pulled this from another forum.
Well basically the "happy time" engine was a term coined by a guy called Augidog (one of the "fathers" of MBc) and the term just stuck. There are several factories that all manufacture the happy time engine, each factory has a slight difference to them (Dax will be able to explain more).

As for its origins: The chinese version is a enhanced copy of an older russian design from back in the 50's, these engines are called the "D" type engines. Heres a good thread about them: http://www.motoredbikes.com/showthre...+engine&page=2.

Then the chinese got a hold of the design and created the modern day happy time, there have been a few upgrades to its design, and the engine is slowly getting better and better. I was told that the Russian engine is a copy of a British design during the war! So the happy time engine has evolved a **** of a lot since then!
Click to expand...
 
Thank you VERY much for the educational response. And so hilarious. Amazing- an English engine by way of china. Which makes me wonder, did the brits copy the moped kings of Italy? Is this a Vespasian? Hahaha. Anyhow, question answered. My interpretation is: Yes, the outer casings are the same, but due to the fact that they're produced at 4 factories there are going to be small differences in parts, and therefore performance and quality will differ. Not knowing about their quality Control over there, it's basically a crap shoot. And perhaps the Ford vs Chevy syndrome starts at that point.
 
I notice on the worksman frame that the China 2 stroke doesnt clamp up as nicely as I would like.
Any suggestions? I read the thread. Saw the shims. Anymore info on these, or advice from someone that's clamped a stock China 2 stroke into a stock worksman INB frame?
 
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Ok, here's some advice if you go along with the general consensus of this thread, that is, that you should use metal shims rather than rubber in your engine mounts...
Silicone RTV the metal shims in!
My metal shims fell out going down the road.
So Ive used silicone RTV to hold them in place so they dont drop out.
 
MaxPower said:
I think we can all agree that drilling a hole through the frame is about the worst thing you can do.

We can also agree the best way to mount is using manic mechanics mount. It looks like there is some rubber between the mount and the frame although the second picture has no rubber.
mount.jpg

MotorMount01.jpg
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my buddy is interested in trying one of these mechanic mount setups. He says he saw a post somewhere around here that shows a kind of template for it. Anybody got info on where we can find that post?
 
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