New Engine Questions

[crassius]

engines may or may not be assembled - makes a good question to ask in email before buying - kits are one size fits all, so they don't fit most bikes without some extra effort - if your bike looks like a 1960s chinese 5 speed road bike, it'll fit well

like many folks, I could throw a kit on a bike in about 3 hours, but never do it in less than 2 days because I want the finished product to look like it was made to be that way, and all the initial adjustments are done

 

[micromaster22]

engines may or may not be assembled - makes a good question to ask in email before buying - kits are one size fits all, so they don't fit most bikes without some extra effort - if your bike looks like a 1960s chinese 5 speed road bike, it'll fit well

like many folks, I could throw a kit on a bike in about 3 hours, but never do it in less than 2 days because I want the finished product to look like it was made to be that way, and all the initial adjustments are done

Im familiar with kits and building, my engine died so i bought this one. I was just curious if the engines alone come assembled or if i have to add the bottom and top together. I guess we will wait and see! Thanks again for all your help.

 

[Tyler6357]

I think that has a 47mm bore and 38mm stroke. I noticed that the listing says it's both, haha. Under "unit specs" it says 47mm bore/38mm stroke but if you scroll down under specifications it says 47mm bore/40mm stroke. I wonder which one it is? Is it a GT with a 38mm stroke or a PK80 40mm stroke?

 

[crassius]

nothing on a site can be taken as true - most stuff is posted by non-english speakers, and is just copied from other sites

once you have it in hand, you can measure it

 

[KCvale]

yes, PVC at rear mount is important - a piece cut in half (or sometimes a third for skinny tubes)

I completely disagree with this advice.
I suggest you mount your back mount directly to the seat post metal to metal, and then work out a front mount that is metal to metal.

If you have vibration from a cheap engine take it out at the handlebars as putting plastic between the engine and bike can and WILL fail.

 

[crassius]

guess we'll disagree on this

I have gotten 3 to 5 bikes a year in for repair over the last 10 years or so with nice tight rear mounts that just snapped the seat tube in half - the fix is easy, just cut a piece of seat post & hammer it down past the break then drill thru to add two bolts

but why bother when a piece of PVC will prevent that break

 

[KCvale]

guess we'll disagree on this

I have gotten 3 to 5 bikes a year in for repair over the last 10 years or so with nice tight rear mounts that just snapped the seat tube in half

2 questions for you...
Did you build them, and were they ~$100 bikes to begin with?

 

[crassius]

none that I built - no recollection of what bikes they were, but I get that problem in regularly

I do prefer cheap bikes tho for the thick, heavy frames that will take hitting potholes at 35mph.

 

[KCvale]

Well, we agree to disagree about putting anything between the bike and the engine.

All my builds get my 'Shove Test'.
Hold your engine head with one hand, the bike top bar directly above it with the other, and then shove the engine back and forth AS HARD AS YOU CAN.

If the engine moves AT ALL that is a fail and you best redo your mounting,

 

[Deleted member 27811]

Well, we agree to disagree about putting anything between the bike and the engine.

All my builds get my 'Shove Test'.
Hold your engine head with one hand, the bike top bar directly above it with the other, and then shove the engine back and forth AS HARD AS YOU CAN.

If the engine moves AT ALL that is a fail and you best redo your mounting,

There's 2 shove tests KC...#1 is the one you mentioned....#2 the one where you shove the darn thing HOME...called the homey test. (carry on)