KDX220 Crank Seals

[Kwackermad]

I've recently taken my crank case cover off a couple of times and there's been a small pond of fuel/oil in the cover which suggests there's a leak from my crank seals. Can anyone confirm that this sounds correct? Also, is it a difficult job? I'm pretty handy mechanically but've never done it before - has anyone out there changed theirs? If so can you please advise me on how to tackle it and if i need any special tools (pullers etc).

Cheers

 

[glad2ride]

The 1989 - 1994 KDX200's had an issue with the steel bearing insert expanding due to heat at a different rate than the surrounding aluminum. This caused some leakage. I don't know if that is possible on a KDX220. If it's not possible, then yes, it definitely sounds like a crankcase leak. You will need a rotor puller to pull the rotor. You will also need to split the crankcase halves to change the seal. I have used a steering wheel puller to split the cases before. Compared to other KDX tasks, it is pretty difficult, and it seems few have tried it themselves instead of taking it to a dealer. Go slow and triple check your work. :-) Good luck with it.

 

[KDXLance]

I recall a post some time ago where carb overflow and water from river crossings was sucked into flywheel cover from hot engine meeting cold water.My point is, just be sure crank seals really do need changing.It is a big job and there are usually other symptoms of leaking crank seals.

 

[droopie69]

I've recently taken my crank case cover off a couple of times and there's been a small pond of fuel/oil in the cover which suggests there's a leak from my crank seals. Can anyone confirm that this sounds correct? Also, is it a difficult job? I'm pretty handy mechanically but've never done it before - has anyone out there changed theirs? If so can you please advise me on how to tackle it and if i need any special tools (pullers etc).

Cheers

I noticed this on my 200 and Jeff Fredette (and others) said it was behind the magneto. There are three equally spaced indentions. All 3 were slightly leaking on mine. A little JB Weld and let it sit over night. Put it back together...no more leaks!

You need a flywheel puller. Once you pull the magneto plate off, it's pretty obvious. I cleaned the three holes really well with brake clean, then JB Welded them up. No more leaks! Thanks Fredette!

 

[Core87]

If your seals are leaking and you are going to replace them, it would pay to do your main brgs at the same time, as it is a bit of a major. I would also get an engine builder to check the big end and conrod, sometimes its best to spend a little to save alot. especially on an older motor.
Just my 2c

 

[blackduc98]

I noticed this on my 200 and Jeff Fredette (and others) said it was behind the magneto. There are three equally spaced indentions. All 3 were slightly leaking on mine. A little JB Weld and let it sit over night. Put it back together...no more leaks!

You need a flywheel puller. Once you pull the magneto plate off, it's pretty obvious. I cleaned the three holes really well with brake clean, then JB Welded them up. No more leaks! Thanks Fredette!

Droopie69, can you do this without splitting crank cases? I'm asking because I also discovered some grey-ish goop (probably fuel/water mix) when I removed magneto cover. If I can fix it without splitting the cases then I'll do it soon. If not, then I'll wait until winter.

BTW, what kind of tools do you need? The manual shows a flywheel holder tool. Do I have to buy it from kawi, or are there alternatives?

 

[droopie69]

Droopie69, can you do this without splitting crank cases? I'm asking because I also discovered some grey-ish goop (probably fuel/water mix) when I removed magneto cover. If I can fix it without splitting the cases then I'll do it soon. If not, then I'll wait until winter.

BTW, what kind of tools do you need? The manual shows a flywheel holder tool. Do I have to buy it from kawi, or are there alternatives?

No need to split the cases....very easy to do. Pull the mag cover, pull the flywheel, pull the mag/stator plate. You'll probably see the three indentions are wet. I had no idea what to look for, but as soon as I pulled the mag/stator it was obvious.

You do need a flywheel puller. I've seen new ones on **** for $12. It's easy to use. Take the nut off the flywheel, screw the threaded part of the puller in, then tighten the bolt on the puller. The flywheel comes right off. It literally would take 30 minutes to do the whole thing and have it back together, except you should let the JB Weld cure good before putting it back together.

Also, do put it on too thick so that it obstructs putting the mag/stator back on. ALSO, the phillips head screws that held the mag/stator on rounded out, so I went to Lowe's and got some allen head screws. I also advanced my timing to the fathest advanced mark. My bike rips now.

 

[blackduc98]

You do need a flywheel puller.

Besides a puller do you also need a flywheel holder too? The manual shows a tool which holds the flywheel so that you can remove the nut. That's the tool I'm asking about.

Also, do put it on too thick so that it obstructs putting the mag/stator back on.

Did you mean to say "do not put it on too thick"?

 

[glad2ride]

You probably will need a holder, or an air tool.

Use the rope trick Fredette mentioned somewhwere, or a Steahly Off-Road lockup device.

Roughen up the three indentions before applying the J-B Weld.

 

[adam728]

You can do it without the puller. You can take out the spark plug and thread some rope in there to keep the engine from turning. Or you can put it in 6th gear and stand on the rear brake while cranking on it. Both have worked for me. Air tools would have been nice...


Edit -
I meant without the holder, not without the puller. That would be a feat to accomplish!

 

[chris_psmith]

I wrote up how I did my 220 if it helps, also have some photos if you are interested, actually managed to split my case twice, the second time as I had mixed the crank oil seal with the output shaft seal (both same OD) which you only discover when you come to the final operation of putting the bush over the shaft and finding it won't go through the hole!!! :bang:

Not had any problems since the rebuild.

Crank Case Splitting

Before starting you will need some special tools:
1. Fly Wheel Puller – Only cheap and not worth trying to find another way around it (£7.50 from e-bay).
2. Crank Case Splitter – Can be made with a length of box section, two long M6 bolts and one M8 with nut. Put two holes in the bar the same distance as two bolt holes on opposite sides of the flywheel cover and a hole in the centre to take the M8. Use two spacers on the M6 bolts to ensure that they form a tight frame and are fully home in the case threads (i.e. clamp the bar down against two spacers to make everything rigid, if you don't it is very easy to put a side load on the case and possibly split it when you try and force the case apart – I used two long nose sockets for spacers). Pass the M8 through the bar with the nut underneath, and then tighten the nut forcing the M8 against the crank end.
3. Fly Wheel holding tool – Can be made using the same piece of box section as the case splitter but fitted with two M8 bolts and nuts. Drill two holes in the bar at the same distance as the two holes in the flywheel, fasten the two bolts to the bar and double check that the length of bolt left sticking out can not come into contact with the electrical windings visible behind the flywheel.
4. Bearing puller – You will need this to get the crank bearing off the shaft, it needs to be able to get between the bearing and the crank so needs a thin wedge shape to work.
5. Bearing heating tool – lots of ways to do this, I used a slug of aluminium machined down to fit inside the bearing (enough undersized so that it doesn't get stuck in when you heat it), and a handle to hold it without getting burnt.
6. Cylinder nut torque tool – 12mm ring spanner with a socket welded to it so you can use the torque wrench.

Disassembly
Strip the engine down, all straight forward enough if you follow the manual (Head off / Barrel off / Right hand cover off). A note of caution, when you take the right cover off it is easy to loose track of some of the washers as they may come off stuck to the cover or stay on the engine, falling off later when you are not looking – small washer over the kick start shaft and washer behind the clutch bush, also watch out for the white plastic tube that is on the gear shifter, had me a bit confused when I spotted it lying on the bench.
Take time to photograph everything and make lots of sketches as the manual is not as clear as the notes you will be able to make.
The first difficult bit is how you remove the fly wheel nut, the clutch centre nut and the crank main drive nut. The best way I found (with hindsight) was to remove the four bolts from the clutch, remove the square clutch plate and replace it with four washers, then bolt the clutch assembly back down. This will give you the ability to lock the engine with the fly wheel holding tool described above. Hold the crank main drive nut with a 22mm socket and release the flywheel nut (17mm from memory), then insert the flywheel holding tool and release the crank drive nut, then the clutch centre nut, then remove the four clutch bolts and clutch assembly.
Insert the fly-wheel puller (left hand thread into the flywheel) and pop the wheel off.
Remove the screws that hold the winding and sensor in place – take extra time to make sure you have a screwdriver that fits the heads correctly, if you strip the heads it will be a big job to get them out!
Remove the shift shaft and the circlip on the transmission output shaft cog, remove the cog and washer.
Attach the case splitter and carefully tighten the nut to put force on the case/crank, when it gets tight, tap round the case with a soft hammer / mallet, then tighten again, keep doing this and it should start to come apart. I ended up tapping the case on the housing that sticks out at the front whilst holding the splitter frame as this is the only place you get any force in the direction you are trying to split (but I was very careful!). Make sure the case gap stays equal throughout the process to ensure nothing gets snagged, may need to tap the trans output shaft to keep the back end straight.
When the case is apart, massive relief! Pull the two shift rod shafts up and then lift out the two gear sets, lift the red plate off the changer drum (as you can be sure it will fall off and get lost later), check where the case bushes are (should be two bushes in the right hand cover and two bushes in the crank cases), it was at this point I also noticed the one of the woodruff keys had fallen off the crank, so check you have removed the woodruff keys from either end of the crank shaft.
Remove the bearing from the crank using the puller and some heat from a propane torch, don't be tempted to start hammering at the gap between the crank and bearing as from this point in you have to take lots of care to make sure you don't disturb the crank alignment.
It was at this stage that I had an issue; I hadn't taken the crank drive nut off! The only way round this was to take it to work and get it removed with an impact driver, they pushed the crank out of the case half for me while I was their so I can't help on how to do that part of the job.
The remaining crank bearing stayed in the case, this was easy to remove with some gentle heat and some pressure on the back of it to pop it out.

Assembly
Assembly is simply the reverse of disassembly, well not actually! Oil the con rod bearings then put the crank in a freezer for as long as possible, I would say at least over night. Put any new bearings and seals in the freezer for at least a couple of hours.
Apply a gentle heat to the case halves where the seals / bearing go and carefully push in the seals and bearings into the cases. Add some high temp. grease to the bearings. (I tapped the new bearings in using the old bearing as a bush).
Re-assemble the gear train and all other parts that came out of the case, ensure you put the red disk back on the shifter and the two bushes in the case, put a thin coating of semi-hardening gasket sealant on one case half, check and double check you have everything in place, then check again, make sure the shifter is in place and working, put high temperature grease on all seal surfaces and the mating shaft ends. Have a few mental run-throughs of how you will assemble the cases; make sure you have supports to hold the case flat, a soft hammer, sockets to match the case bolts (8mm) etc. Time is the most important thing in the assembly.
When you are ready, heat the aluminium bearing tool until its nice and hot, then hold it inside the bearing to transfer the heat (making sure you don’t touch the new oil seals), keep doing this until the two crank bearings and the trans output bearing are nice and hot (I may have been too cautious with this, but the thought of waving a propane flame on my nice new bearings and seals didn't appeal too me).
When you are happy they are hot enough, remove the crank from the freezer and drop it into the case half (do make sure you have it the right way round, you will be dropping the thin end that takes the flywheel and the arrow on the piston top should face forward (I lost sleep over this one dreaming that I had re-assembled the crank cases with the crank back to front). Then put the other case half on and tap lightly around it too take up the position and get all the shift shafts / drive trains etc stared in their holes (this wasn't too hard), keep tapping the case until the gap has closed down to engagement of the case bushes. Insert the crank case bolts and carefully (but quickly) gradually tighten the bolts down to keep the gap constant as you tighten them down. This wasn't difficult, just tense, and required minimal force on the crank.
I believe you can get away without the Kawasaki tool to keep the alignment of the crank so long as you are careful and don’t put too much force on the crank, this was the single biggest concern I had throughout the build, but there seems to be enough people around that have done this now without engine failure later to suggest it is OK, heating and freezing removes a lot of the force that would be needed to do it the way Kawasaki describe in the manual using the special tool.
When the cases are back together it is just simple spannering to rebuild the engine. Remember to re-assemble the clutch with the washers instead of the square plate to allow you to tighten the three nuts described earlier.
When it comes to tightening down the cylinder you will need a ring spanner with a socket welded to it (as described already on this forum - thanks it worked a treat), you will also need two torque wrenches to work out the equivalent torque value, as the spanner extension will change the torque value, set one wrench to the correct value and adjust the one with the tool fitted so they both click at about the same time.

I hope that is of help to someone, I have quite enjoyed the strip and build, would have preferred not to have the time pressure of being booked in for a race the next weekend, but that’s life. If it explodes I will be sure to let you know not to try this. I have photos I can post if anyone is interested.

 

[blackduc98]

Dear chris_psmith, if you've got pics that would be great. A pic is worth 1000 words.

Regarding torque wrench tricks: you don't really need 2 torque wrenches to figure out the correct setting. Final torque is directly proportional to the length of the torque wrench. So if you add an extension, you can simply calculate what setting to use in order to achieve desired torque. Here is the basic relationship: wrench setting / wrench length = actual torque / (wrench length + extension length). For example, let's say your torque wrench is 50cm long, and your extension is 10cm long, and you set your torque wrench for 25 N-m. Actual torque applied to the fastener is going to be (50 + 10) * (25 / 50) = 30 N-m. To convince yourself that this is true you can try this on e.g. rear axle nut with and without torque wrench extension, and aim for a setting much lower than the nut is designed for in case you make a miscalculation. There are several web sites with a handy torque calculator, like this one for instance: http://www.norbar.com/torquewrenchextensioncalculator.php

BTW, when I was torquing down my cylinder, I discovered that I didn't really need to weld anything in the way of torque wrench extension. It turned out that the open end of a 12mm box wrench fits perfectly onto a 3/8-to-1/2 ratchet drive converter. So I attached this converter to my torque wrench, and placed the other end of said converter into the open end of 12mm box wrench, while placing ring end of same wrench onto the cyl nut.

 

[chris_psmith]

Interesting bit on the torque extensions, probably easier, but I am lucky enough to have two wrenches.

Most photos of case split are at:

http://kdxrider.net/forums/modules....hp&PHPSESSID=6be8d3414662c90f47cfb6128795b7ae

I will add a picture of the special tools I made up, this site wont let me add attachments (let me know if you want the original larger ones e-mailed to you).

Good Luck
Rgds Chris