lpd Posted June 6, 2007 Report Share Posted June 6, 2007 I had a knock in my engine that was diagnosed as lay in crank between bearings. The bearings are new, but the crank shifts back and forth a little causing a knock/vibration. Any suggestions....would a shim suffice? Quote Link to comment Share on other sites More sharing options...
peterb Posted June 9, 2007 Report Share Posted June 9, 2007 Hi there, Do you mean there is end play on the crankshaft? There should be none. Any play here is usually a sign of worn main bearings. As you have fitted new ones, there may be something more sinister! Were the bearings tight in the crankcase housings? Were the bearings a tight fit on the crankshaft? What year TXT200 is it? Bye, PeterB. Quote Link to comment Share on other sites More sharing options...
lpd Posted June 9, 2007 Author Report Share Posted June 9, 2007 I had a fellow look at it and he figures it either the bearings are the wrong size or improperly installed or could be the crank is out of true. I'm hoping for the bearings. With the clutch taken out and if I pull on the crank shaft it has play...bearings don't move with the crank. Quote Link to comment Share on other sites More sharing options...
peterb Posted June 10, 2007 Report Share Posted June 10, 2007 It seems like you have end play on the crankshaft, and if the crankshaft bearings are not moving at the same time, then the crankshaft stubs are moving through the inside diameter of the bearings. This is not so good and not the norm on Gassers. If the bearings are the right size, they should be 6206 C3 - important to get the C3 clearence bearings, then there is wear on the outside diameter of the crank stubs for some odd reason. Are you sure that the play is on the crankshaft? Can you measure the endfloat with a DTI, there really should be virtually zero movement. The photos you have posted are for a 249 TXT 2000, is this your bike? These have no history of crank problems. If the bearings are the correct size, I would try fitting the motor together with a bearing loctite on the crankshaft bearing ID's. Hope this helps. Bye, PeterB. Quote Link to comment Share on other sites More sharing options...
kevin j Posted June 10, 2007 Report Share Posted June 10, 2007 Had the same issue with 2000 GG200, and have two friends with same noise. One is about a 98, and the other is around 2000. Sounded like knock, replaced top end, then found crank moves left and right on the helical gear. On compression stroke it moves one way, then on firing it moves the ot4ehr way. It is not the 'oil hole bearing failure' issue the 200's had. Test: with engine warm, listen to noise, then tilt 45 degrees or more to right, then 45 or more to left. One way it disappears, when the force is overcome by gravity of the crank weight. I think it was tilting left. Crank on mine moved total .010 or more in the ID of the bearing race. Bearing radial is perfect, but concern is of course wearing the crank journal OD. Struggled to find info from dealer, importer, and GG enduro bike dealers, to no avail. Bad new: have to split the cases, replace the bearings. I used GG bearings (expensive, would go industrial supply, but didn't want to change more than one variable at a time) and high temperature (higher than normal working temperature) red loctite on the right side bearing only. Bearing to crank, NOT bearing to case) This is purely opinion, I just wasn't sure if gluing both sides might put some thrust loads on the bearing as the engine heats up. A light press on the left bearing does allow some creep with hot/cold cycles to relieve stresses. MORE bad news: It helped a lot for only a month or two. The noise is back! For now, since it is not ridden too many hours, and ridden mildly (me) I run it. Does notappear to hurt anything, but is embarassing to ride. Don't you ever maintain that thing? Next winter I will split again and look into some sort of spray buildup on the right journal. kcj Quote Link to comment Share on other sites More sharing options...
lpd Posted June 10, 2007 Author Report Share Posted June 10, 2007 Thanks all for the help. I had the bike serviced about a month ago. Main bearings replaced?? Seems the wrong bearings may have been used or just an issue with how they were installed. I've since located a really good mechanic as I can do basics, but tearing an engine apart is abit above my learning curve...I know my limitations. Had the same issue with 2000 GG200, and have two friends with same noise. One is about a 98, and the other is around 2000. Sounded like knock, replaced top end, then found crank moves left and right on the helical gear. On compression stroke it moves one way, then on firing it moves the ot4ehr way.It is not the 'oil hole bearing failure' issue the 200's had. Test: with engine warm, listen to noise, then tilt 45 degrees or more to right, then 45 or more to left. One way it disappears, when the force is overcome by gravity of the crank weight. I think it was tilting left. Crank on mine moved total .010 or more in the ID of the bearing race. Bearing radial is perfect, but concern is of course wearing the crank journal OD. Struggled to find info from dealer, importer, and GG enduro bike dealers, to no avail. Bad new: have to split the cases, replace the bearings. I used GG bearings (expensive, would go industrial supply, but didn't want to change more than one variable at a time) and high temperature (higher than normal working temperature) red loctite on the right side bearing only. Bearing to crank, NOT bearing to case) This is purely opinion, I just wasn't sure if gluing both sides might put some thrust loads on the bearing as the engine heats up. A light press on the left bearing does allow some creep with hot/cold cycles to relieve stresses. MORE bad news: It helped a lot for only a month or two. The noise is back! For now, since it is not ridden too many hours, and ridden mildly (me) I run it. Does notappear to hurt anything, but is embarassing to ride. Don't you ever maintain that thing? Next winter I will split again and look into some sort of spray buildup on the right journal. kcj Quote Link to comment Share on other sites More sharing options...
lpd Posted June 10, 2007 Author Report Share Posted June 10, 2007 It seems like you have end play on the crankshaft, and if the crankshaft bearings are not moving at the same time, then the crankshaft stubs are moving through the inside diameter of the bearings. This is not so good and not the norm on Gassers. If the bearings are the right size, they should be 6206 C3 - important to get the C3 clearence bearings, then there is wear on the outside diameter of the crank stubs for some odd reason. Are you sure that the play is on the crankshaft? Can you measure the endfloat with a DTI, there really should be virtually zero movement.The photos you have posted are for a 249 TXT 2000, is this your bike? These have no history of crank problems. If the bearings are the correct size, I would try fitting the motor together with a bearing loctite on the crankshaft bearing ID's. Hope this helps. Bye, PeterB. Yep the 250 is mine. It has less than 4 hours of riding on it. I've been wanting more power after borrowing my buddies 280 and my other friends 321 while my bike is on the fritz. The extra power sure helped on the big hill climbs, although the 321 was a little intimidating at first for a 150lbs fella. Quote Link to comment Share on other sites More sharing options...
peterb Posted June 11, 2007 Report Share Posted June 11, 2007 Those 321's are pretty good on the trails, lots of riders use these and the older 370's for blasting across the tracks up the hills over here in NZ, good pulling power. I always found the 321 was easier to manage when fitted with a D34 needle, not so quick off the bottom end. Good luck with the bearings. Bye, PeterB. Quote Link to comment Share on other sites More sharing options...
lpd Posted June 12, 2007 Author Report Share Posted June 12, 2007 Just found this note on a tech page.... Tech page Endplay of crankshaft in center cases (all models): 0.02~0.03 mm. Note: Use different thickness center case gaskets and/or bearing shims to correct endplay. Quote Link to comment Share on other sites More sharing options...
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