Installation of KTM Australia s Racing Four Stroke Head Kit This kit is available from KTM Australia for a limited time for $143 and upgrades the head internals of any 2000, 2001 & 2002 model 400 and 520 to 2003 specs. The kit includes: New heat treated cam bearings Forged and balanced integral cam gear Updated Water Pump Seal Carrier - easier to remove All O-Rings, gaskets and seals needed Cam chain joining link Now for those of you who aren t fiddlers like me or if you are less than mechanically minded then Bolton Motorcycles in Kyneton will fit the kit for you for only $130.00. TOOLS YOU WILL NEED: Small chain breaker - this is the tool required to do the hardest part of the entire job. We had to modify a mountain bike chainbreaker to fit. What you are looking for is a very plain C shaped breaker that will push then pin straight out the other side. See pic1. Loctite 515 Sealant to reseal your rocker cover. Loctite 262 Stud Locker for your cam gear bolts. Ball Pein Hammer to pein the joining link. Small wheel puller to remove the cam bearings. KTM 400/520 Engine Manual. Pic 1 After having done two of these upgrade kits now, I think I can say that I am confident at doing them. Doing the first one I was terrified of making a mistake, and consequently worried myself stupid. Well, my bike started and runs quieter than before. The 2nd kit I did took about 4 hours from the time the engine was out of the bike. As long as you take your time and keep everything clean and orderly you will do fine! YOU DO NOT HAVE TO REMOVE THE ENGINE FROM THE CHASSIS TO DO THIS JOB, I CHOSE TO SO THAT I COULD PERFORM NUMEROUS OTHER MAINTENANCE ITEMS. START FROM PART 2-ENGINE DIS-ASSEMBLY IF YOU DONT WANT TO REMOVE THE ENGINE.
1. 1. Bike Dis-assembly From this... 1. Remove the seat and petrol tank. See Pic 1 2. Drain radiator fluid by undoing the drain plug on the RHS of the engine. 3. Remove both radiators (2 bolts each), I left all of the hoses atached to the radiators so nothing got lost. See Pic 2 & 3 4. Remove the RHS number plate(2 bolts) and remove the rear muffler(2 bolts and 2 springs). 5. Remove centre exhaust mounting bolt as well as the 2 springs that attach it to the headers. Remove centre exhast. 6. Remove the 2 springs that hold the header pipes to the front of the engine an remove the header pipes. See Pic 4 Note: I am now going to purchase myself a spring puller from somewhere like Ballards as these springs are a bitch to get on and off! 7. Remove rear wheel and chain. Note: I took this opportunity to show my chain some love by giving it an oil bath. 8. Remove both frame guards. 9. Remove case protector, you will have removed 1 bolt already by taking the LHS Frame Guard off, the other is located on the inside of the frame in front of the air box. The bolt runs through the centre of your top chain roller. Note: While I am on the subject of chain rollers, I took this opportunity to throw my bottom chain roller away and put on the chain slipper from the 2003 model which supports the chain better and all but eliminates chain slap. The slipper and steel insert cost less than a roller too! 10. Undo the remaining 2 bolts in your clutch slave cylinder. Wrap the slave cylinder in a plastic bag or rag to keep any crap from getting in to it and let it hang out of the way. See Pic 5 11. Remove the black plastic cover on the RHS of the carbie. Undo both throttle cables. Note: Inspect the bottom throttle cable for wear, mine was badly frayed! 12. Undo the decompressor cable from the head. 13. Undo the crankcase breather hose from the motor and the carby. Note: I decided not to reattach my crank breather hose to the carb. If the bike goes arse up oil can travel staight into the carb mouth and clog your jets and needle. I routed the hose over to the other side just above the chain. Pic 1 Pic 2 Pic 3 Pic 4 Pic 5 To this.
14. Undo rear brake reservoir and move out of the way. Leave it connected though. 15. Disconnect the battery lead from the starter motor. Undo both battery leads and remove the battery. 16. Undo all of the electrical connections from both the motor and carby. 17. Remove bottom shock bolt. 18. Undo and remove the swing-arm bolt. Pull the swingarm out. Note: With the swingarm off, now is a good time to re-grease the swingarm bearings. 19. Undo the hose clamps holding the carby in place. 20. Loosen the two top bolts that attach the rear subframe to the main frame. 21. Remove the bottom two bolts that attach the subframe to the main frame. 22. Pivot the subframe upwards to release the airbox boot from the carby. Secure the subframe in this slightly raised position, it will make removing the engine a hell of a lot easier. 23. Remove carby. Note: I had a REAL difficult time getting my bike restarted, probably due to a stuck float level. This happened because I left my carby on it s side for a week with no fuel in it. So a word from the wise - keep it upright! 24. Remove the bottom engine mount bolt first, then remove the front one. It will take a little persuading to get out because the weight of the engine is on it now. 25. To get the engine out of the frame is a tricky job, and one best done with 2 people. It can be accomplished on your own but it is fiddly. The steps I used are as follows: Wiggle the engine back as far as you can, at least until the front cases clear the front engine mounts. Then tilt it forward to drop the top of the engine below the frame. Tilt the engine out of the frame towards the LHS (sprocket side).
2. 2. Top End Dis-assembly From this... To this. 1. Remove the oil line that runs from the case to the head. Take note of the 2 different banjo bolts, the gold colored one goes into the head and the silver one is for the case. Each bolt has 2 copper washers. 2. Undo the 4 water pump housing bolts and remove the housing(see Pic 6. Remove the old gasket and clean both surfaces so that the new gasket will seal well. 3. Remove the circlip on the cam shaft and the water pump impellor will pull straight off, but be careful not to lose the pin that locates it which is directly behind the impellor. 4. Undo the rocker cover bolts. Note: The bolts are of varying lengths, so make sure you take note of where they belong! The 2 55mm bolts that are located next to the rocker shafts are located will have wear marks on the shanks from the shaft guides rub on them. THIS IS NORMAL. 5. To remove the rocker cover you will need to break the 3 bond seal. I used a peice of dowel and tapped my way around the heaad to break the seal (See Pic 7). Once the seal is broken you can lever it off from the RHS. 6. I cleaned all the mating surfaces as I went. My head was fairly crudded up from excessive use of 3bond. 7. You will now be able to see what it is that you are going to all of this trouble for (See Pic8). You should be able to slide the aluminium water pump seal carrier off the cam shaft (See Pic 9). 8. Lock the engine at TDC by removing the allen bolt in the front RHS case, remove the copper washer and re-install the bolt to lock the crank. 9. Undo the centre bolt of the cam chain tensioner. Note: The cenre bolt of the cam chain tensioner is spring loaded, so be ready to keep a hold of it when you undo it. 10. Remove the remaining 2 bolts from ths cam chain tensioner and pull out the assembly. Pic 6 Pic 7 Pic 8 Pic 9
11. You are now ready to break the cam chain. Note: It is VERY important to prepare the engine to do this. The engine must be at TDC. You will find 2 indentations on the cam sprocket. These must run parallel to the surface of the head. Both cam lobes will be facing downwards and the decomp assembly will be visible along the top of the cam also. 12. Tie off the cam chain so that it cannot slip down into the case (See Pic 10). I used a couple of big tie wires. Note: It is very important keep tension on the cam chain. You do not want it to be able to move of the bottom sprocket Pic 10
13. Before you break the cam chain it is imperative that you cover up your internals to prevent anything from falling down into the cases! (See Pic 11) 14. Breaking the cam chain will vary depending on what sort of breaker you have. Just take it slow and steady and be very careful to keep track of where the pins and plates go when they come off! 15. Once you have broken the cam chain just recheck that the chain has some tension on it so that it will not move. (See Pic 12) 16. Lift the cam out of the head. Using a small wheel puller, remove both bearings. 17. The auto decomp assembly is removed by lifting the spring out of its notch and sliding the shaft out. 18. Removing the 2 cam sprocket bolts will require the application of heat OR a sharp crack with a rattle gun as they have stud lock on them. Note: Heat the bolt heads gently so they do not lose their temper. 3. 3. Re-assembly 1. Install the bearing closest to the cam lobes. I used a small hammer and a flat hard surface. Be careful to keep the cam straight while tapping the cam shaft. Note: Always use a piece of wood between your hammer and the bearing or camshaft and NEVER hit the outside race of the bearing, ALWAYS use the inner race to drive a bearing into position. 2. Install new cam sprocket using Loctite 262 on the bolts. Note: Make sure the auto decomp stop is on the same side as the depression in the cam for the decomp assembly. 3. Install the auto decomp assembly and tension the spring by half a turn, making sure the decomp returns on its own. 4. Install the 2nd bearing. My bikes plug spanner worked a treat for this. (see Pic 13) Pic 11 Pic 12 Pic 13
5. Install the 2 water pump shaft seals into the aluminium seal carrier. Note: Theseals are installed with the spings facing outwards. The seals are a very tight fit, so be careful fitting them. Putting them in the freezer for a few hours will help make fitting them easier. I pressed them in with the vice. 6. The large o-ring goes on the back (side without the 2 threaded holes) of the water pump carrier. 7. The smaller o-ring goes into the outside groove closest to the impellor. 8. Slide the new washer on to the cam shaft so it sits next to the bearing. 9. Note: wrap a piece of duct tape or similar over the end of the cam shaft, covering the groove where the water pump circlip sits. This will protect the new shaft seals from damage as you slide the carrier on the shaft. 10. Place the cam into the head making sure that the washer sits in its groove. I gave the cam lobes and decomp assembly a smear of new oil too. 11. REPOSITION THE CAM AT TOP DEAD CENTRE. 12. Pic 14 - This shows all of the new parts installed and the cam once again at TDC. Note: Make sure you position the cam at TDC ie. with the lobes facing down and the decomp assembly visible. Pic 14
13. Lay the cam chain back onto the sprocket. 14. COVER UP AGAIN - SEE PIC 15 15. Double check that the cam is still at TDC. 16. Install the joining link. Press on the joining plate and pein over the ends of the link. (See Pic 16). The ideal tool for this job is of course a chain joining tool. I used a pair of vice grips to get the plate started on the pins and then used a small g-clamp to finish pressing the link into place. With a solid object on the other side of the link to stop it moving I then peened the ends over with a small ball-peen hammer. Pic 15 Pic 16
17. Make sure both the head and rocker cover mating surfaces are clean. Put a thin bead of Loctite 515 sealant on to the head only. Slip the rocker cover back into place, tapping gently with a rubber mallet until both surfaces mate. You will see the Loctite ooze out when the cover is home. Just check to see if the sealant has oozed out all of the way around. Clean up the excess out of the water pump housing. Note: Make sure that the correct rocker cover bolts go back in the correct positions. 18. Re-install water pump impellor and circlip. (See Pic18) Pic 17 19. Re-install water pump housing with the new gasket. (See Pic19) 20. Remove the crank lock bolt, put the copper washer back on and re-install. 21. Now put the motor back where it belongs! Pic 18 Pic 19