Loss of acceleration

[snicholls]

Hello,

I have a yamaha jog 2010 with only 600km on clock. I have had a 70cc big bore kit put in, a new datona racing cdi(un restricted), new exhaust all installed with the aim to get it up to 70km/h(to keep up with trafic). All of which i have had no joy. It would do a maximum of 60km/h(tops). It had a lack of power. That is until the other day i got on and kick started it, as it was having trouble starting(cold morning). Once I got it going it flew, with heaps of acceleration and max speed of 70 to 80km/h. Loved it. This was what I expected with putting all the extra modifications on. It went really well for two trips and now it is back to no power and only getting 60km/h tops.

I guess the question is does any one know why out of no where I got my power and how do I get it back? Could it be the air filter or something else??? Apparently it does not have a fuel filter.

Any help/suggestions would be of great help.

Steve

[Airhead]

I dont see why for a while it was powerful and next time not so. Could it be something to do with the variator, rollers or whatever these things have? All of which is beyond my experience

[2 Wheels]

I dont see why for a while it was powerful and next time not so. Could it be something to do with the variator, rollers or whatever these things have? All of which is beyond my experience

Paul, mabey it ran lean for a while and was going like a train.

I wonder did he do the necessary adjustments to allow for the 70 kit and exhaust !

Dam, them little scotters would wreck your head, lol

[snicholls]

Thanks for that guys. I got all of the adjustments done by the yamaha bike shop where i bought the thing. It has been back several times for them to look at it. They have tuned it, adjusted the carb etc. I gave them a call about this and they are at a loss. They suggested removing the air filter and taking it for a run to see if it was starved of air. I have not had a chance to do this yet.

I have found that if i kick start it instead of the electric start I get more performace. It seems at the moment to consistently get better top speed(which is great). I still notice at the upper speeds i get a drop in acceleration if i accelerate to much. I have to find the right revs and stick on it. If i rev a little to much then it seems to drop in power. Which is leaning me towards the air filter??? I am only a beginner with all of this stuff.

I agree these little scooters can do your head in

[FLYIN BRIAN]

if i accelerate to much

This sounds like fuel starvation. If you roll off the throttle slightly does it seem to pick up?

I firmly believe you need a fuel filter. Only a matter of time before you run into trouble without one. It may already the cause of your trouble. You should check the fuel system to make sure there are no restrictions to flow whether dirt in carb, kinked fuel line or dirty petcock. Also make sure the fuel system is venting properly.

[snicholls]

Yes if I roll off the throttle I will get a slight increase in speed. Maybe 5km.

I will check those suggestions on the fuel side of things on the weekend. Thank you for the suggestions.

[Airhead]

Yes if I roll off the throttle I will get a slight increase in speed. Maybe 5km.

I will check those suggestions on the fuel side of things on the weekend. Thank you for the suggestions.

that sounds like it needs a bigger main jet, was one fitted with the big bore?

[snicholls]

Not that I know of. I will have to chase it up with the bike shop who installed it.

Thanks

[Airhead]

Not that I know of. I will have to chase it up with the bike shop who installed it.

Thanks

Get it done ASAP or your engine will suffer overheating and possible damage to your new piston

[snicholls]

I just rang the shop and they said that they have already put one in. Happy days with respect to that anyway. Thank you.