1991 kdx 250 help

[adamryan30]

Hey guys just joined the forum and new to owning a kdx. Just got a 1991 kdx 250 from a neighbor for free as it's been sitting in garage for a while so obviously carb needs to be cleaned. But I checked the compression and getting a reading of only 90 psi. Seems very low. Questions is compression that low, would it keep a bike from starting?

[KDXohio]

Could still run...not well.
Definitely in need of a rebuild!

[adamryan30]

That's what I was figuring...should I just redo the top end or you think bottom should be rebuilt as well? Also completely off topic but what size gas tank do these have and what kinda mileage are people getting out if a tank?

[radonc73]

I would just do the top end. The bottom end should be good. Mileage has never been an issue for me. If you fill the tank you will have plenty of gas for an entire day of riding IMO.

[KDXGarage]

No way to accurately diagnose it over the internet.

Does it not crank at all? There are several things to check if so.

[SS109]

Do a leak down test to see if the crank seals are good. They can go bad from just sitting for long time.

[KDXGarage]

My brain needs a leak down test. This thread was 5 months old when radonc replied.