87-92 LT250r engine Reliability Guide

87-92 LT250r engine Reliability Guide
Posted by Nekrofilliak on 08 Mar, 2013 13:39
Hi, I want to everyone know the tips to build a reliable LT-250R engine.
Most of tips come from Carl ( Iceracer )

LT250r 87-88 Reliability guide

Engine crankcase recommendation

sealant: Threebond 1194 only since silicone will get eaten by gasoline.
seal: use Loctite on every seal to prevent from moving
bearing: use oem only

Crankshaft recommendation

Never hammer on crankshaft, use special tool to remove
cold down the crankshaft before install to help seat on the engine bearing

Top end recommendation

Use Heavy duty thrust washer and RM bearing only
Be sure exhaust bridge is correctly relieved. ( see picture)

Gasket recommendation

Use OEM Head gasket only
Use Cometic aluminum base gasket number: B0047032AFM. Only then add Threebond 1194 to prevent leak
Use Threebond 1194 on intake gasket/boot to prevent leak

Piston recommendation

piston manufacturer: Wiseco only

To improve wrist pin bearing lubrication,
drill a 10 mm hole on the intake side centered 15 mm down the lower ring groove (see picture)

To improve exhaust bridge lubrication and prevent top ring seizure,
drill two centered 1.5-2.2 mm hole on the exhaust side, one centered between the two existing hole and one below the second existing hole at the same distance than first drilled (see picture)

#2 Reply
Posted by LT250RWV on 19 Mar, 2013 18:37
Good info What about suzuki bond or yamaha brand instead of the Theerbond 1194 oe is it equal

#3 Reply
Posted by BadMoonRacing500 on 19 Mar, 2013 19:11
Quote from: LT250RWV on 19 Mar, 2013 18:37
Good info What about suzuki bond or yamaha brand instead of the Theerbond 1194 oe is it equal
same

#4 Reply
Posted by James Dandy on 26 Sep, 2013 19:01
Love this thread. I started the alum washer VS YZ piston thread just to explore further. I knew it would get everybody involved. I'm definitely gonna use the aluminum washers. Not the re-pinned YZ deal. I was always a fan of cometic gaskets, so I'm gonna buy a cometic set, and an oem set. I'll make sure the cometic set has the aluminum base gasket. Great idea on the loktite seals. How much harder is it to remove loktited seals? I have a parts motor that the crank seal on the flywheel side had came part way out. When I noticed that I thought, there must be an adheisive to prevent that!

#6 Reply
Posted by James Dandy on 05 Oct, 2013 18:53
Good question dangerous. I'm in the middle of my first LT motor, on all my dirtbikes, I only used cometic. They've always had a good rep. I'm going with exactly what this says to do tho. Unless somebody else chimes in here...

#7 Reply
Posted by Nekrofilliak on 24 Oct, 2013 12:02
maybe i am too late but, locktite on seal is mandatory , it is recommended by Suzuki ans is witted in the service manual. for the head gasket. i recommended oem because the oem head gasket is covered with a thin rubber seal BUT , last time i order a oem head gasket it was not covered with rubber and was identical to the cometic . So i don't know if Suzuki still product the rubber covered head gasket

the aluminum cometic base gasket is really a must , use it with case glue ( threebone) on both face. remember when using case glue , you must clean carefully before. apply a thin layer of glue on each surface , so for the base aluminum gasket you must apply glue on the gasket , under the gasket , on the engine crankcase and on the cylinder base . install the gasket and cylinder, lightly hand torque the bolt and wait 20 min , then torque to specification.

silicone not work hewer sine silicone will get eat by gasoline

#9 Reply
Posted by Kylerj133 on 22 Mar, 2015 00:43
anybody know were to get the cometic base gasket? I cant seem to find the part number thats listed..

#10 Reply
Posted by GrkGuy on 22 Mar, 2015 08:34
-TThey used to be in the site store, or just call them cometic, they are AMF gaskets. Just make sure you get right thickness for your bike.