Relatively new to karting here, I am trying to determine the health of my lo206. The other day i noticed i was not hitting the rev limiter at the end of the main straight. The cylinder wall looks beautiful.
I measured the valve lift at 0.242 exhaust and 0.247 intake.
I see max allowable is 0.255 so my numbers concern me a little. Does any one think I have a worn cam?
I can’t comment on the valve numbers specifically, but have you done a leakdown or compression test? For the latter you will have to use an external starter so that it cranks the engine fast enough to disengage the compression release…
One of the most common causes of power loss is warping of the valve seat, so I wonder if that’s what’s happened here.
I will be doing a leak down test later this week
Valve lift is measured at the valve, directly off the valve spring retainer at zero valve lash setting.
What is your valve lash set at?
Recheck cam lift with zero lash and your dial indicator set on the valve spring retainer. But, I don’t believe you have a cam wear issue. The .255" number is max allowable lift.
Did you verify your slide is opening fully when you press pedal to full throttle? The engine is off of the kart now, so…
Did the axle shift, causing the rotor to drag on the brake pads?
Do check leakdown if you can.
Also, when you say
[quote=“Alex_Cherewyk, post:1, topic:6316”]
The other day i noticed i was not hitting the rev limiter at the end of the main straight.
[/quote] had you always been hitting the limiter at the end of that straight? Is that how you have your gear ratio set?
I checked to see if I had any slack in the throttle cable when the throttle pedal was fully depressed and I had no slack. So I am quite sure I am getting full throttle but I will check for full slide travel next time I’m at the track. The axel did not shift I checked it about midway through the day. Yes my gearing is set up to hit the rev limiter abit at the end of the straight.
Very unlikely that you have a cam wear issue.
How much has your rpm changed?
I agree with James. May be time for a valve job. Also look the carb over. Check float level.
Yea, you’re making the 206 way too complicated. Check the leak down and lap the valves in if it’s a a little high. Recut the valves and seats if it’s really high.
Most RPM drop on a 206 is chassis/track related.
Fuel related maybe?
If someone put ethanol fuel in a pure gasoline tank that would rob some power.