Terra Moto Krusha Carby Tune?

[Terra-Moto-123]

Hey everyone,

Just wondering if anyone has any info regarding the carby on a Terra Moto Krusha? i.e. Make/Model number, a tuning manual, or any tuning/jetting exeperiences you've had with them?

Just tryin to get mine sorted. Its bogging down when you snap open the throttle from idle and backfiring/popping when engine-braking downhill.

Cheers!

 

[Flarry]

Back firing is usually caused by the exhaust pipe not being on properly where it connects to the engine and leaking or the same thing with the air filter.

Not sure on your other problem (bogging down), could be a cause of it not being warmed up or not getting fuel...

Not sure what carby's terra moto use, have a look at it and see if it has any brand name stamped on it, if its a mikuni you could probably find it on the mikuni webiste/forum.

 

[Terra-Moto-123]

Cheers for the reply mate.

I've already checked and tightened the exhaust and air filter.

I've made sure the bike was warm before i played with anything.

I've fiddled with the pilot air screw a bit....it was initally only about a 1/4 of a turn 'out' from fully seated...ive since wound it 'out' 1 turn and it appears to have improved the bogging issue and (to some degree) the backfire as well. So leaning the pilot up appears to have improved things...but im just not sure if the pilot is the issue? Perhaps i've compensated for the needle or the main circuits being out by leaning up the pilot???

Not sure where to go next? Anyone experienced in tuning/jetting carbys got any hints?

Cheers

 

[mickalomaniac]

yeh dude, its just running too rich down low, if you leane it out that should sort out your bogging down and the back firing... Back firing is mainly cause by too rich mixture... its caused by too much unburnt fuel entering the exhaust...as far as getting your carby set up its kinda personal to how you ride... if its too lean it wont rev out and you'll loose power... and well you've seen first hand wat its like when its too rich

 

[Terra-Moto-123]

Cheers mate.

I figured the pilot was most probably running rich...but im just not 100% confident what the other circuits are doing? Backfiring and blogging down can also be caused by lean conditions. Leaning up the pilot may just be compensating for the other circuits being out? At idle and during engine braking the throttle slide is fully closed...right?....fuel/air is delivered via the pilot circuit....but theres still 'some' air/fuel mix being drawn through the main & needle circuits...right? So, if the main & needle circuits are running rich perhaps?...leaning up the pilot could appear to 'fix' the problem!

What circuit would you think is dominate when you snap open the throttle from idle? Would'nt it be the main? Are there any other transient effects that im just not thinking about? i.e. how does a sudden rush of air (as you snap open the throttle) effect the fuel/air mix? How does this effect the off-idle response...bogging issues....etc?

At this stage im guessing all circuits are running rich? perhaps its a safe way to tune these engines so they last forever...better to be rich than lean! The bike is still being run-in so im thinking ill sort the tuning/jetting issues as time goes on.

If anyone with experience can think of anything i may be over looking....hints and tips would be great!

Cheers,