gy6 transplant?

[b22turbo]

hey everybody,i have a moto roma buggy with a 157fm engine.can anyone tell me the difference between it an the more common 157QMJ engine.

my engines on its last legs and was wondering if the QMJ engine would work as a direct transplant with no mods to the wiring an so forth.cheers

[dude]

I'm a new guy too. I hope you have better luck getting answers to your questions than I did with mine. This might just be a really slow,unoccupied website.

[b22turbo]

jst to let anyone know,i was told the fm engines are primarily for scooters an that someone may have changed my engine in the past.

i bought a 190cc qmj engine which fits straight in an gave me a lot more torque,power and fun,well delited!!

[olderthan]

good for you now go have fun

[b22turbo]

i certainly will,bt i burst the rear engine mount when i went airbourne at the top of a hill last nite,no take long to fix tho,

can u tell how ur 1500 spring works and the benefits of it?cheers

[JakeTheSnake]

B22- "i certainly will,bt i burst the rear engine mount when i went airbourne at the top of a hill last nite,no take long to fix tho,"

b22, I did the same thing grabbing air on my mini-buggy, snapped the cast aluminum right at the chain adjuster fork. I have a quick fix for that using a set of old brake shoes off a smaller car, a table mounted wheel grinder to shape em to fit, and a couple bolts. The bolts even act like shear pins when do again. lol Yep I like being airborne and done did again, luckily I carry an extra set of bolts in my tool compartment for this very reason. Let me know and I'll throw some pics up on the fix.

[b22turbo]

mine snapped in exactly in the place,first nite i had the new engine in

that would be great if u could post pics especialy if they act like shear bolts.cheers dude,

[olderthan]

1500 spring helps hold you in gear longer & helps on down shifts does not change top end but helps on low end torque-more help comes from mods to varitor lower wts= more
lower end torque higher wts=more top end

[JakeTheSnake]

B22- This break and fix occurred last fall, it’s held up very well with the exception of my need to get my buggy in the air, and as I said, your bolts act like shear pins when you have need for flight. lol Have some spare bolts in your tool compartment if you got one. Last fall I was running her fast and hard on some jumps, I hit one close to full blast, caught some major air, but then came down hard. As soon as I hit the ground I knew something broke. The cast aluminum at the chain adjust fork snapped and the only thing that saved me from a total engine bottom out was what the Chinese call an engine strengthen board. It held on by a thread. So I got the idea the make 2 of my own engine strengthen boards out of old brake shoes. I have a family friend that runs an auto repair shop, so I went over and grabbed a pair of small worn brake shoes off of him, not sure what they came off of just had an idea of what might fit on the circular cast aluminum area of the output shaft. Got ‘em home, ground off the rest of the pad, if you can find a set worn down to the metal, it’ll make it easier. I then shaped ‘em down to fit on a table grinder, measured up the pre-drilled holes from where the engine a strengthen board was, actually I only needed to drill one hole where as the holes for the brakes shoes caliper pins lined up for the bottom bolt on the board and the top bolt for the chain adjust fork. If you notice the hole for the chain adjust fork on the brake shoe is slightly above the broken cast hole, so I took 2 links of chain out to compensate for chain slack on the adjustment, and brake shoe metal is strong but it’s also very rust prone. I ran it for a while to see if the fix would hold, and it did, then I took it all apart and painted the brake shoes for rust prevention. You’ll also need some washers at the top to even out the spacing at the top by the chain adjust fork, and a washer at the bottom for the play of the big hole of the brake shoe. It’s also a good idea to take some of the lip off of the aluminum cast for better brake shoe fit. This all saves you from having to buy a left side crankcase piece and a cvt/engine tear down to repair it. It’s Western Pennslytuckian engineering at its best, and works like a charm. See the photos for reference to my story and Good Luck!

[b22turbo]

cheers for the info.ats the same place mine broke,looks like a good fix u got there,

i started fixing it after u gave me a rough idea yest on how you did yours,so ive done the type of strenghin boards as you have done an ive joined them up to the rear engine mount on the casing,ive had to shift the tensioner for the chain aswel so ive realy puttin mysel to a bit more than i could have done after seeing ur pics,bt hopefully it shouldnt give me bother now.ill stick some pics up if i get the chance,cheers again

[olderthan]

jakethesnake
nice repair job!!

[JakeTheSnake]

@B22, Thanx on the fix. Can't wait to see some pics on how ya made out on your repair.

@Olderthan, Thanx on the repair.

[olderthan]

we all need to figure ways to fix problems and share the info

[b22turbo]

well thats the fix,seems to be standing the test anywae.so il be stripin it for paint shortly,only problem i found was puttin the airbox back in place it was a bit if a tight fit.was plannin a unifilter so anywae so itl look a bit tidier then.

[JakeTheSnake]

Nice job on the repair. I see what you mean by relocating the chain adjuster. Looks like you are good to go.

[b22turbo]

cheers,put mysel to a bit more work after seeing ur easier fix tho

now another question,now that ive got a bigger engine in do i need to open up the exit on the muffler,was reading another thread and they said about cutting off the tailpipe?

[JakeTheSnake]

Well B22, I'm assuming that your 190 is a standard GY6 bored out. So your current muffler should be ok, and the fact that 250 muffler setups wont fit up to a GY6. There are things you can do such as gutting it out to improve air flow. This involves cutting the exhaust end cap off at the seam, removing the packing and baffle, then welding the the cap back on. You can also cut off the muffler at the point where the tail pipe meets it and put on an EMF Shorty slide on, make sure you get the right size for slide on. If you plan on putting on a UNI air filter, doing either one of the prior mentioned muffler mods will compliment air flow, but plan on re-jetting your carb, and that would be based on your elevation and if your burning fuel lean or rich. You can monitor that by the color of your sparkplug and idling and running engine behavior.

[b22turbo]

spot on thats great info.i put a holesaw in the end of the muffler lst nite so going to weld a slightly larger bit of pipe in now,il look into the re-jetting,the spark plug couldnt look any better bt sometimes when you go to park up after a burn about she stalls bt turn the key an she'l fire straight bak up,thanks again jake ur a dude.