HoboCop 0 Posted May 6, 2009 Hey Everyone, I picked up an old '81 Yamaha XT250 a while back, and I've been working on it ever since. I was trying to adjust the valves, and it seems like the Exhaust Valve was fine, but the Tappet on the Intake isn't budging. Does anyone know what size this would be, or where one might pick up the right tool for this? Thanks in Advance! Share this post Link to post Share on other sites
Joliet 0 Posted May 6, 2009 Hey Everyone, I picked up an old '81 Yamaha XT250 a while back, and I've been working on it ever since. I was trying to adjust the valves, and it seems like the Exhaust Valve was fine, but the Tappet on the Intake isn't budging. Does anyone know what size this would be, or where one might pick up the right tool for this? Thanks in Advance! You can't loosen the lock nut or is it the valve adjuster screw you can't turn once you loosen the lock nut? The lock nut should be a standard size hex nut and the adjuster screw should be either a slot screwdriver or an allan wrench type. How about a picture of it? Intakes are supposed to be .0020-.0039 and exhaust .0047-.0067 Here is a link to schematics for most bikes. http://www.bikebandit.com/houseofmotorcycl...0h-1981/o/m8319 Share this post Link to post Share on other sites
HoboCop 0 Posted May 6, 2009 Thankfully the locknut came off fine with a regular socket, but the valve stem/ tappet/valve adjust screw itself isnt budging. Its a very small tappet on the top of it that will help me move it, not a screwdriver slot. Thanks for the clearance info, I have the clymer manual for it but doesn't specify what size the valve tappet will be, but it looks like it would be something tiny, around 3-4mm. Also i'm sorry if my terminology isnt 100% here, but I appreciate the help given Share this post Link to post Share on other sites
dirt dame 561 Posted May 6, 2009 Thankfully the locknut came off fine with a regular socket, but the valve stem/ tappet/valve adjust screw itself isnt budging. Its a very small tappet on the top of it that will help me move it, not a screwdriver slot.Thanks for the clearance info, I have the clymer manual for it but doesn't specify what size the valve tappet will be, but it looks like it would be something tiny, around 3-4mm. Also i'm sorry if my terminology isnt 100% here, but I appreciate the help given Is it a square top tappet? They make special little wrenches for those, but if there is enough room, you can get a really tiny open end wrench in there. I'm not sure why it's seems seized up if the nut is loose. Share this post Link to post Share on other sites
tntmo 901 Posted May 6, 2009 Thankfully the locknut came off fine with a regular socket, but the valve stem/ tappet/valve adjust screw itself isnt budging. Its a very small tappet on the top of it that will help me move it, not a screwdriver slot.Thanks for the clearance info, I have the clymer manual for it but doesn't specify what size the valve tappet will be, but it looks like it would be something tiny, around 3-4mm. Also i'm sorry if my terminology isnt 100% here, but I appreciate the help given I think there is a special tool available from Motion Pro for that little square on top of the tappet, I used to have a homemade tool for it made out of a square drive deck screw. Here's the MP tool. http://www.motorcycletoolchest.com/Motion_...t_p/08-0073.htm Share this post Link to post Share on other sites
HoboCop 0 Posted May 6, 2009 Is it a square top tappet? They make special little wrenches for those, but if there is enough room, you can get a really tiny open end wrench in there. I'm not sure why it's seems seized up if the nut is loose. The nut is just locking the Valve Screw down into the rocker arm. If it were to budge, I could unscrew the entire Adjust Screw. Here, i'll use this as a referance: http://www.dansmc.com/tappets4.jpg The Tappet is what I called the Valve Adjust Screw, the Locknut only serves to keep it secure. I can fully remove that and then the Screw is threaded into the Arm, which is where I am supposed to turn it from. Haha, I'm sorry if I'm bad at trying to explain it Share this post Link to post Share on other sites
Joliet 0 Posted May 6, 2009 Give it a shot of penetrating oil (several times) and let it soak for a couple of days. A new valve adjust screw only costs a few dollars, if it is really tight in there, I wouldn't hesitate to use a quality pair of channel locks to get the old one out and discard it and install a new one. Ken Share this post Link to post Share on other sites
HoboCop 0 Posted May 6, 2009 Give it a shot of penetrating oil (several times) and let it soak for a couple of days. A new valve adjust screw only costs a few dollars, if it is really tight in there, I wouldn't hesitate to use a quality pair of channel locks to get the old one out and discard it and install a new one. Ken I left some Penetrating oil in it for a couple days, still didn't budge. But thanks, I'll be looking into that tappet set or i might just lock it down and get a new one if it gets messed up. Share this post Link to post Share on other sites
socalhodaka 104 Posted May 6, 2009 I sell Motion Pro tools. I will PM you with a price. Kelly Share this post Link to post Share on other sites
