70cc speed kit please help

<HTML>hello everyone. in case you didn't read my previous posting regarding the 70 cc speed kit i'll sum it up. i purchased a kit (new cylinder/head,piston,15mm carb, and a biturbo exhaust) for my 92 tomos golden bullet tt lx and upon installation and running the piston and cylinder got grinded and destroyed. i thought maybe i ran the throttle too high prior to being broken in and oiled correctly. well either that or i was told it could be a flesh coating problem by the manufacturer. so after being tired of not having a moped for a week i bought a replacement cylinder/piston and just installed it this weekend. we absolutely made sure it was installed correctly and made sure it was even running a bit oil rich to start with and then ran it at idle speed. then it broke again. same exact spot on the piston is grinded. this time the cylinder was spared with maybe a little repair necessary.

does anyone know if it's just my moped make and model that is incompatible with the speedkit? because we installed the same kit on my friend tom's 00 tomos targa lx and it works fine. maybe the piston drops too far into the ped or something like it wasn't made to be compatible with the kit i don't know.

could this possibly be a manufacturer's error since we installed the same thign the same way on another ped with no error? and if so should that be covered even though there's no warranty?

with all this i've dropped $400 into this kit that is just not working. i'm planning on reinstalling my 49cc and cutting my losses. i'd like to have 70cc but don't think i should purchase another piston if the same thing is going to happen.

so if anyone has any information on this ordeal it would be greatly appreciated.



RE: 70cc speed kit please help

<HTML>It might help if you gave a little more info on what the and where the damage exactly is and what it looks like. Are the springs broken? Is the crankshaft still ok? (it could be bent/broken). It is possible that the piston fals deeper into the cylinder because the crankshaft/driveshaft of your ped has a longer stroke (well, could have, I don't know), in that case the pistonsprings could get hooked under the mantel of the cylinderbarrel, break and jam everything. If you mount the piston the wrong way around a pistonspring could get hooked in an intake- or exhaustportal. The pistonpen could have been loose, the crankshaftbarings could be worn so that the driveshaft can move side to side and jam the piston into the side of the cylinderbarrel, it could be a whole lot of things really.

A lack of oil shouldn't be an immediate problem, I once drove 150 miles on my Honda MT5 without oil. When I went to look why the engine was running so shitty and then I found out the oiltank was empty and the oilglass was broken..</HTML>

RE: 70cc speed kit please help

<HTML>Here I am again, if the mopedstore that sold you the speedkits garantees you it's compatible with your ped and you don't want to risk destroying a speedkit again (and maybe your crankshaft along with it) than maybe it would be a good idea to let them (at the mopedstore) install the speedkit. If it breaks down again you could demand repairs because they garanteed it.</HTML>

RE: 70cc speed kit please help

<HTML>I had the same problem on my 'ped. I was told that the oil injection dosen't inject enough oil. I had to add additional oil to the gas. But I was afraid of reliability so I took all of the stuff off and made it 49 cc's again


RE: 70cc speed kit please help

twowheelers /

<HTML>The problem with these so called "speed" kits is that they aren't a selection of balanced components. You've got a 70 cc cylinder that needs to be filled with LOADS of fresh mixture on one side and a tiny 15 mm carb that is suppose to provide the stuff on the other side. Unfortunatelly it's not a perfect match. As the cylinder isn't getting enough fresh air and fuel to power and more importantly cool the whole thing down, sometimes (at warm climates) the piston simply expands faster than the cylinder and effectivelly seizes. To prevent that, people usually run rich on fuel/air and oil mixture. But that doesn't solve the problem, it just eases it. For that kind of power and thus fuel/air demands the 15 is way too small. 18 mm is a minimum.</HTML>

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account