motoclay

iTrader: (3)

Hey guys,

I got a weird one. Yesterday i raced my Losi 8T with a HPI .25 motor in it. Its the motor that comes from the Savage RTR. I was desperite and needed a motor and it was all i had. It was new, had been broken in, and ready to race, i thought?? I had a .28 in the truck before so i adjusted the clutch to come in a little sooner (softer springs) cuz i knew the motor would have less power and i didnt want the clutch to slip. I tried running the original clutch set up, but it slipped way to much. So i got the clutch tying up about right, but then, i noticed that the motor just would not REV!!!! It would just go flat. No snap, no top end, just really tame, like having half throttle or something. Put on couple different pipes, one was a JP-2, same results. Try to lean it up, to get it to scream, and it would lean bog up top, never got hot, just wasnt running????? Had 2-3 different guys asking the same questions, we all took a stab at tuning it up, but just could not get it to rip. Any ideas????? Its a new motor, should be decent for now until i can get a new race motor, but why wont this thing rev??????

Thanks in advance!

pdmustgt

Either the clutch is engaging way to soon, air in the fuel line, plugged fuel filter or something in the carb plugging it. Check air filter

motoclay

iTrader: (3)

bumpity bump bump

kevinmajor

iTrader: (3)

It sounds like an airleak. It will make the engine starve for fuel and lean bog like you described. Check the fuel line, gas tank, fuel filter, the neck of the carb, engine backplate, etc.

motoclay

iTrader: (3)

another thing, the motor will bench tune fairly well. It idles like a dream, has great throttle response on the stand, but once you put it down, is where you notice the problem. If it was an air leak, wouldnt it got LEAN sitting there, and idle irratic??

pdmustgt

Check your clutch then

JAMMINKRAZY

iTrader: (17)

+1 this is probably the problem.

motoclay

iTrader: (3)

what am i looking for in the clutch?? I was thinking that maybe the motor just cant pull the gearing. 13/48 (stock Losi gearing). I know the springs are right now, because before it would just slip and never tie up. Now it ties up and hooks, but it just wont rip. I figured it would work, but if i put stiffer springs in, it revs, but still not to what i feel it should or is capable of, and its slipping the shoes, which i dont want??

pdmustgt

Is the car trying to move at idle?

motoclay

iTrader: (3)

nope, the clutch is not hung up. i rebuilt the clutch for the motor, i have green and gold springs on it. with aluminum shoes, all Team Losi hardware. 13/48 gearing. all stock gearing in diffs and drives.

JAMMINKRAZY

iTrader: (17)

Hmmm interesting. if it revs in the air but not on the ground it seems like the clutch, but if you just rebuilt it then idk. Mabey it is your gearing. Mabey try a 14 or 15 tooth bell.

motoclay

iTrader: (3)

i was thinking that too, maybe just cant swing the gear?? i dunno, .21s can i dunno why this .25 wont go. Are HPIs horrible engines??? 150 bux if i was to buy it out right, i just happen to have a new savage that i got in a trade, so i thought, wth, ill run that motor, should do fine, but nope??

pdmustgt

It's not a bad engine it's better than the hpi .21 that came on my savage. It's not a high end engine but it should do fine. Going to have more low end torque.

The only reason why we are saying it's the clutch. Because you say it revs fine on the bench. But on the ground it won't go

motoclay

iTrader: (3)

it will move, and run a decent speed, but it just seems to be flat? Ya know, you can nail it and it dont just leap into action, its real tame like a slipping clutch, but it ties up good and loads the motor about right, but then it just doesnt SCREAM on top, like i know it should!!

motoclay

iTrader: (3)

still lookin for other suggestions?????? I really want to make this motor work, cuz i know its capable, ne one ever run this motor before?