KTM top end rebuild for Axel

[tntmo 910]

A few weeks ago, Axel dropped off a sad looking KTM at my house and asked me to get it going and to test it out for him. I cleaned it up and did some basic maintenance stuff to it, and after getting it running it's smoking pretty bad. Oil smoke, so much that the exhaust gets wet with oil. It's a 2003 KTM 525MXC, a model I've heard is awesome but so far this one is only awesome for laying down a nice layer of mosquito repellant on RPMX track this weekend.

So, my mechanically minded friends, I need some references for the best places to get parts and service for this beastie. I'm thinking it's time to get the head checked out and install new valve seals. While I'm there, check the cylinder and replace piston and rings. I haven't done a KTM top end but I know the cam chain needs to be split and then re-linked....special tools? Anyone care to assist with the operation?

More to come.....

[Goofy Footer 539]

I have a leakdown tester and cold beer!

I'd love to check it out and see the inside of the beast.

[Suspenders 43]

I can get Axel some parts.

ProX piston kit is probably best bang for the buck with the lower compression ratio a bit over 11 to 1

They run just under $135. If that is a good price I would be happy to include in one of my orders.

Anything else I can do to help out let me know.

George

[paulmbowers 236]

A few weeks ago, Axel dropped off a sad looking KTM at my house and asked me to get it going and to test it out for him. I cleaned it up and did some basic maintenance stuff to it, and after getting it running it's smoking pretty bad. Oil smoke, so much that the exhaust gets wet with oil. It's a 2003 KTM 525MXC, a model I've heard is awesome but so far this one is only awesome for laying down a nice layer of mosquito repellant on RPMX track this weekend.

So, my mechanically minded friends, I need some references for the best places to get parts and service for this beastie. I'm thinking it's time to get the head checked out and install new valve seals. While I'm there, check the cylinder and replace piston and rings. I haven't done a KTM top end but I know the cam chain needs to be split and then re-linked....special tools? Anyone care to assist with the operation?

More to come.....

You need Bob Hulka. Search CAFlash on KTMTalk. Has more spare parts, rebuilt parts than anyone. Knows all the right parts to use, too- the right plating, pistons, etc. He'll also tell you to use Kibblewhite valves. I'd contact him and have him put together a kit for a top end- probably swap out heads & he may want the piston/cylinder as cores.

Tell him I said hi- use my name or my Fake Name.

[tntmo 910]

Does anyone have a chain splitter for the cam chain?

[tntmo 910]

Does anyone have a chain splitter for the cam chain?

[tlking6 0]

Does anyone have a chain splitter for the cam chain?

I have the splitter-re peening tool. Your welcome to borrow it.

[Uncle Champ 116]

Carguy did his KTM, I would think he has the chaintoolthingy.

[robertaccio 412]

"Does anyone have a chain splitter for the cam chain?"

special KTM tool (part No. 590.29.020.000, $138.49) just in case you need that info

[tntmo 910]

I have a leakdown tester and cold beer!

I'd love to check it out and see the inside of the beast.

I've never used a leakdown tester so that would be nice to do before it gets pulled apart.

[Spaugh 1]

you can use a dremel to split the chain and most of the standard motion pro type chain tool sets they sell for your drive chain have a small thing for putting the new link in.

get kibblewhite valves.

new cam chain master link.

wossner piston.

and new gaskets.

or cut bait while you are ahead

[tntmo 910]

or cut bait while you are ahead :torch:/>

I brought this up to Axel. I think he got the bike for a decent deal, but by the time it's ready to go there is probably more invested in the bike than it's worth. I think he is in the mindset that it will be a reliable machine after the work is done.

[Spaugh 1]

or cut bait while you are ahead :torch:/>/>/>

I brought this up to Axel. I think he got the bike for a decent deal, but by the time it's ready to go there is probably more invested in the bike than it's worth. I think he is in the mindset that it will be a reliable machine after the work is done.

my bro kept his bike in my garage for the last 8 years. Almost the same bike. His was 2003 525 EXC. he let it sit and rot for 5 years and wanted me to make it run. I could have made it work but it was going to be a major project. He sold it to someone on SDAR for 1000$ a few months back.

Reminded me of the old movie with Tom Hanks where he buys a fixer upper house. My favorite scene was when the bathtub fell through the floor and he starts laughing hysterically. Sometimes laughing is all you can do.

[carguy 1]

Got the chain tool and a new master link. Might want to think about upgrading to a 540. Not much more and only need to rejet carb. Dave Hopkins did the work for me, DJH Nibble white valves a must.

[paulmbowers 236]

Got the chain tool and a new master link. Might want to think about upgrading to a 540. Not much more and only need to rejet carb. Dave Hopkins did the work for me, DJH Nibble white valves a must.

Ya know?

I've been through the RFS mod process. I've had a 540, now a 560, cams, bored carb, etc etc- bike breathes fire. And I wouldn't do it again.

Don't get me wrong- I love the thrill of twisting the throttle, and with my ample girth it makes the bike really fun on open trails and desert. But on tighter stuff, smaller trails where the power is not needed it becomes a hinderance. Bikes comes on too hard too fast, even with my masterful throttle control and incredible bike handling technique.

The factory 540 cylinder is no longer available- it was the cool ticket- had more cooling passeges, etc.

Was I in Axel's spot, I'd revive it bone stock. And put on black plastics, of course.

[Crawdaddy 96]

Reminded me of the old movie with Tom Hanks where he buys a fixer upper house. My favorite scene was when the bathtub fell through the floor and he starts laughing hysterically. Sometimes laughing is all you can do.

Faced with a similar dilemna I dropped back and punted on my 520......sold it to TNTMO for the SDAR bro price......

You're spot on Brad......classic flick/scene....the preceding kitchen scene/quote could apply to some engine rebuild situations, "Actually it's a little over done for my taste.....let's not go there again"

[AATA 0]

A few weeks ago, Axel dropped off a sad looking KTM at my house and asked me to get it going and to test it out for him. I cleaned it up and did some basic maintenance stuff to it, and after getting it running it's smoking pretty bad. Oil smoke, so much that the exhaust gets wet with oil. It's a 2003 KTM 525MXC, a model I've heard is awesome but so far this one is only awesome for laying down a nice layer of mosquito repellant on RPMX track this weekend.

So, my mechanically minded friends, I need some references for the best places to get parts and service for this beastie. I'm thinking it's time to get the head checked out and install new valve seals. While I'm there, check the cylinder and replace piston and rings. I haven't done a KTM top end but I know the cam chain needs to be split and then re-linked....special tools? Anyone care to assist with the operation?

More to come.....

You need Bob Hulka. Search CAFlash on KTMTalk. Has more spare parts, rebuilt parts than anyone. Knows all the right parts to use, too- the right plating, pistons, etc. He'll also tell you to use Kibblewhite valves. I'd contact him and have him put together a kit for a top end- probably swap out heads & he may want the piston/cylinder as cores.

Tell him I said hi- use my name or my Fake Name.

+1. Exactly what he said! This is your best option for anything related to the RFS engines. You can find him all over KTM talk. He has multiple engines, top ends, whatever ready to go and is very reasonable.

[bikeslut 1]

Axel is not a member here, but wanted to pass on how much he appreciates all of you. From riding with a lot of you, to meeting Tom and George wrenching for him.

He was a long time rider but had hung up his boots for two years, and has dived back in, now that he has people to ride with and help with his bikes.

Thanks guys

[Goofy Footer 539]

So the "best practice" here would be to take the head off and send it to one of the RFS gurus for Kibblewhite valves and new valve seats?

But what if only one valve is out of commission? Couldn't you take the head to a local shop to have them cut the valve seat and then you could replace/install the valve? A valve compressor tool is ~$30-40 (sicvic built one if I recall). One could clean the head themselves and save some money there too? While all new valves/seats would be primo, to save money in this situation could Axel only replace the damaged ones?

(Assuming only one or two valves would be damaged.)

[Goofy Footer 539]

tntmo, there are some RFS top end rebuild videos from RMATV in this thread that might be helpful. You're free to use the leakdown tester - but you may have to bring beer to my garage to get it!

SicVic's Top End rebuild thread

[tntmo 910]

tntmo, there are some RFS top end rebuild videos from RMATV in this thread that might be helpful. You're free to use the leakdown tester - but you may have to bring beer to my garage to get it!

SicVic's Top End rebuild thread

You have brought so much beer to my garage, it's about time I returned the favor. I have a homemade valve spring compressor that I've used several times.

[paulmbowers 236]

So the "best practice" here would be to take the head off and send it to one of the RFS gurus for Kibblewhite valves and new valve seats?

But what if only one valve is out of commission? Couldn't you take the head to a local shop to have them cut the valve seat and then you could replace/install the valve? A valve compressor tool is ~$30-40 (sicvic built one if I recall). One could clean the head themselves and save some money there too? While all new valves/seats would be primo, to save money in this situation could Axel only replace the damaged ones?

(Assuming only one or two valves would be damaged.)

Ick.

No.

Do the job right. If one valve is worn, the others won't be far behind. In one seat is beyond spec, the other has the same mileage, and won't be far behind.And if one is worn well beyond the others, something else is wrong- maybe a worn cam. If the rings are shot, it's likely the cylinder bore is worn, too. If the cylinder is worn, likely is the piston. If the timing chain is worn, then the timing is off. If the timing chain is worn enough that the timing is off, so likely are the cam bearings.

The point of demarcation is the top end and the bottom end. Often a top end can be done without splitting the case to do the crank bearings. But rarely can one only do a small part of either.

If I were to consider buying a bike and the owner tells me he replaced one valve or one cam bearing, I won't buy the bike. It's sloppy work, and indicative of further sloppy work.

[tntmo 910]

If I were to consider buying a bike and the owner tells me he replaced one valve or one cam bearing, I won't buy the bike. It's sloppy work, and indicative of further sloppy work.

Chances are if you bought a bike with only one valve replaced, the owner wouldn't even mention opening up the top end. That sounds like something that gets done in order to get a machine running and sell it as quickly as possible.

Yes you could just replace one valve, but a good mechanic starts doing the "might as well" jobs. Since we have the head off, might as well pull the cylinder and check the piston. Might as well check the connecting rod.

Might as well jobs tend to make the repair bill a lot higher, but they make you feel confident that the machine is well taken care of.

[Suspenders 43]

I think that is smart!

[paulmbowers 236]

I'm smart! Not like everybody says!