Motor temp / plug color

[skiracer]

So riding my 250 yesterday; 85 degrees, 78% humidity. Rode about 40 minutes. When I got back to my shop I noticed the first bend on the pipe was blueish and the rest of the pipe was really hot. I checked the  plug color after the motor cooled down and I found it to be a real nice light brown, perfect burn. So my question is, if my jetting is right why did the motor get that hot?  Yes I was riding hard, but I didn't think I was pushing it that hard. Any thoughts?

1976 250 MC5 Original Owner
1976 Penton 175 XC

[firstturn]

Make sure your pipe isn't plugged up.

Ron Carbaugh

[skiracer]

thanks Ron, pipe is clear...

quote:Originally posted by firstturn

Make sure your pipe isn't plugged up.

Ron Carbaugh

1976 250 MC5 Original Owner
1976 Penton 175 XC

[firstturn]

Check your timing.


Ron Carbaugh

[skiracer]

Too far advanced, yes?  My thoughts too.  

quote:Originally posted by firstturn

Check your timing.


Ron Carbaugh

1976 250 MC5 Original Owner
1976 Penton 175 XC

[Mike Rosso]

Is your head pipe sealed with high temp RTV at the cylinder exhaust manifold?

Mike

[skiracer]

No.  I have never sealed my 250 or 175 motors.  I just slide the pipe into the slip joint of the exhaust manifold.  Have done it that way since the bike was new.

quote:Originally posted by Mike Rosso

Is your head pipe sealed with high temp RTV at the cylinder exhaust manifold?

Mike

1976 250 MC5 Original Owner
1976 Penton 175 XC

[Richard]

Retarded timing could cause exhaust header overheating (ignition firing closer to top dead center). Fuel still burning when exhaust port is open.

[skiracer]

So, the piston is set at less than the standard 2.55 BTDC, right?  I am going to check the timing this week. Thanks for the input.

quote:Originally posted by Richard

Retarded timing could cause exhaust header overheating (ignition firing closer to top dead center). Fuel still burning when exhaust port is open.

1976 250 MC5 Original Owner
1976 Penton 175 XC