Cam

[harrynorris]

After Taking This Yz 250f Top End Apart,i Took My Timing Chain Off And I Noticed The Exhaust Cam Would Rotate Alittle Back And Forth Till The Lobes Hit The Valves,but The Intake Cam Is Like It's Stuck I Cannot Turn It,and When I Took The Cam Out I Had To Peck It Alittle To Get It Out Of The Holder,the Bearing Seemed Fine But When I Installed The Cam Back In,it Still Will Not Roll Freely,i Even Put Alittle Pressure On It And Still Doesn't Want To Roll Freely,i Was Thinking It Should Be Like The Exhaust Cam,where It Would Role Till The Lobe On The Cam Hits,any Idea Will Be Appreciated

[jbrooks26]

Sounds like you don't have the cam lined up properly in the bearing. If you get it sitting back too far the lobes will hit on the casting in the head and not allow it to turn freely. It can get stuck there if you try too hard to turn it in one direction. You probably did not get the cam clip lined up with the bearing when you put the cap back on and the clip is probably actually sitting in front of the roller bearing on the cam. This happened to me once. Hope this helps.

Josh

[suzuki2stroker]

do the bearing surfaces still look shiny? or do they look kinda scrached?

how much valve clearance is there? any?

i spun the cam bearings on mine, the bearings looked scrached, there was aluminum melted to the cam and little burrs of aluminum in the oil feed hole.

[YamahaRider351]

id have to say your valve clearance is out of spec

[chiaj144]

Make sure you torqued the cams to the appropriate spec my buddy tightened his too much and had the same problem.

[harrynorris]

i think it is in the valves,i could not even get a guage between the cam and lifter,i took it to the shop to get looked at

[suzuki2stroker]

you had no valve clearance. the lobes were dragging on the buckets. reshim the valves and you should be fine.