High speed ping

[85xr600+]

I just bought the bike back from a guy that I sold it to in 1989. He bored it out to ? cc. All I know is that he used a wisco piston.

Overall, it runs better than it ever did when I owned it. It pulls like a tractor.

But..

1. I'm getting a loud ping when she's opened up full throttle in 4th + gear.

2. And the thing feels like it's in need of a front end allignment?

Clues:

I ride on mostly New England power lines & trails

I'm running 10 40 Spectro oil

I ride fast

I use high octaine gas

It has a K&N air filter

It has a Supertrapp exaust(P.S. I'm need of a header)

Please tell me what I'm doing wrong and point me in the right direction.

Thanks for your help

Nubie with old school 85 XR 600+?

[YZ400Court]

Sounds like the main jet is too lean.

[Moredesert]

How high is the octang your running. The book says 92 min stock. I ran 95 + with a stock engine. Go with a fatter main jet if the octang is good. You can run 100 + for high compression.

[qadsan]

Originally posted by 85xr600+:

...But..

1. I'm getting a loud ping when she's opened up full throttle in 4th + gear...

I had a loud pinging at full throttle from my XR650R. It turned out the be the skid plate making the noise, but it sure sounded like engine noise. It's just something else to check out. Don't forget to adjust your valves and make sure they're in spec. YZ400Court already addressed the other potential reason for your pinging.

[Moredesert]

qadsan has a good point, Everytime I went to Mexico I herd noises and pings no matter what octang I ran. The skid plate and big hand guards I had made it worse.

[XR6's_rule]

Your friends high-comp piston is probably making the bike ping due to the higher compression. Before you gochanging your jetting or fuel, check for intake/exhaust leaks & check your valve clearances.

[85xr600+]

Thanks guys. I'm going to check all of your suggestions. Until then. I'll keep on riding and keep it out of the ping zone.

Thanks again for your help!