KTM - timing/cam chain tensioner problems

[crs]

New KTM 2013 EXC-F 250.

From the start, the bike didn't like to idle from a cold (well, cold for Thailand!) start - and you'd hear cam chain 'slap' at times when at idle/low revs riding. Apparently the standard KTM cam chain tensioner isn't good - so this is a common problem. It's hydraulic and varying oil pressure means it doesn't always put enough force on the chain at idle - or even sometimes at higher revs (= speed) - so, apart from the noise, the chain can get worn or jump.

Out riding the other week and the bike cut out. Managed to get it started again but it sounded like a sewing machine. Towed it home and fitted a Dirt Tricks aftermarket tensioner the next day (which I'd previously ordered). This tensioner is hydraulic too - but has a spring inside to add extra pressure. Sounded pretty much the same - like the chain was tight on the tensioner. All fitted right according to instructions though - and no other twin cam to compare it too so... Thought best to just ride the thing. Bike ran OK for a few hours but later, after starting to ride faster, it cut out again. Got it started but ran rough and kept cutting out. Had to pickup the bike home.

Put the original tension back in today and checked the timing (which still looks right to me). Engine turns fine - but won't start. (Checked plug, fuses, etc too). Now, I need a good mechanic in CM or CR - because I want this sorting ASAP(!!!) and it's time to hand this to someone professional. I'm thinking German Joe - though I've never used him. I need a good English speaker - because I don't want anything getting 'lost in translation' for this job. Any other thoughts/suggestions for mechanics appreciated. I'm more than happy to pay a fair rate for fast work that gets the job done properly... Because dry season is coming(!!!). Thanks for any help.

Note, this KTM engine apparently has an issue with low oil pressure (DJHCycleSport.com RC4 Installation Instructions). I've been using 10w-40 syn' oil when recommended is 10w-50 or 10w-60 - because of price. This might have made a difference to how the hydraulic tensioner(s) worked. (Today, I put 10w-60 in it though.) Also, I'm sure this mess is all tensioner related/started, but there seems to be another problem now that i don't understand - and, possibly, this 'no-start' problem is actually unrelated to the tensioner problem. I've found out about the DJH tensioner - which is just manual - so I'm going to order and fit that, whatever. I would say that is the way to go, especially if you want to run cheaper (far cheaper in Thailand), lower viscosity oils.

 

[bill]

I looked at the Dirt Tricks website and could not see a camchain tensioner listed for your model, nor on the DJH website either.

They only list up to 2010 or 2011 models that I can see.

 

[crs]

Same engine. They only added f.i. as any major change after that. Old websites that need updating, by the looks of things. Check other retailers that stock these parts or KTM related forums for info.

Anyways, the first cut out was with the standard tensioner fitted - and it wasn't tensioning the chain right, that's for sure...

EDIT: e.g..

http://www.ktm-parts.com/DJH1400-OR-p-PPECV,350ENG,SBM250FEN.html#.UlFHohb22Rg

http://www.rockymountainatvmc.com/A.../25928/Dirt-Tricks-KTM-Timing-Chain-Tensioner (The 250 2012 and 2013 are virtually the same bike.)

 

[crs]

Tried again with a charged battery and can get the odd splutter and backfire - but it doesn't want to run. Haven't checked all through the ignition system, but it's sparking at the plug. I'd guess at a fuel problem, but there's no f.i. warning light flashes (obviously haven't got the KTM Diagnostics Tool - KTM Chiang Mai might do, if I try there). Maybe the timing has got messed up somehow...

 

[Loop]

Jeez..feel for you mate.

I hope the problem is not related to the "not ready to race" issue when you first got it.

 

[crs]

^ The valve clearances? They're all in spec' - just... Actually, I should have checked them again today. Checked them a few weeks back - but good idea incase this tensioner stuff could have changed things(?). Valve clearance can make a bike hard to start.

Engine cranks by hand no problem...

 

[LUFC]

Have you got a spare inline fuel filter for the "snap" connector?

If yes, change it. If no, take out the inline fuel filter and try starting it. If it starts don't ride it with no filter!

I don't think its tensioner related at all, they are noisy but I have NEVER heard of one actually failing and it would have to be timed way-off to not start.

I have spare filters if you need.

 

[crs]

^ Checked the inline filter (fuel screen) at the snap connector - looked clean but blew it out anyway. Will try that though - and might as well check the fuel filter in the tank too.

I'm pretty sure the timing chain went wrong... Bad, bad noises. What's happened though as a result - I don't know. I shouldn't have tried it over and over.

Will open the thing up again in the morning to check valve clearances and look again for any visible damage.

I don't see how anything has got too fkd, if it turns over OK - but .

 

[crs]

Anyone know if they do have a KTM Diagnostics Tool at KTM Chiang Mai?

 

[LUFC]

Joe and Herman are both excellent mechanics. I wouldn't put much faith in KTM CMai diagnostic abilities.

 

[crs]

Yes, I wouldn't want them to work on it, but for some stuff you need that KTM diagnostics tool to hook up to the bike.

(Just tried taking out fuel screen. Same.)

Cheers.

 

[johnnysneds]

Have you checked your valves? Bent possibly due to incorrect timing. "Sounded like a sewing machine"

Hope I'm wrong mate..

 

[crs]

Just getting the engine out...

 

[crs]

Well, it looks like your guess was right, Lew.

The shim had kicked out and this is what I saw. Can't get the cylinder head off yet because they've made it real tight getting into the interior bolts - and the bolts have been over-tightened. Bust the only 13 socket I could get in on them - so will have to go buy another. (Not sure if I can get the valves out without special tools for clamping/compressing anyway.) Will have to see what lurks underneath tomorrow! At least the cams, cams cover, cams seat all look OK.

Nearside exhaust valve spring top and lever are damaged. The clearance on this one always was only just in spec... I guess not just enough! Whether the tensioner stuff and this valve clearance issue combined into a problem, triggered off each other, or are totally separate - I don't know. If anybody else gets a KTM 250 4t, best to check/sort the valve clearance and get a manual tensioner...

 

[Loop]

Hopefully minimum cost and only some blood,sweat and tears to get it tearing up the dirt again Chris.

 

[crs]

Hopefully... Will have to see what I find tomorrow. I would also like to know exactly what made the bad happen. I guess that it is just down to the clearance issue - and not the tensioner... But can I rule the tensioner out? Not sure...

Having a proper KTM dealer nearby would have been very handy - this stuff should have been their problem. But, I knew how things were when I bought the bike so... Suppose I get to learn how to work on it - which would have happened sooner or later. And I do have a big bore kit handy - but that'd maybe take too long to sort, what with rainy season nearly done.

 

[LUFC]

Looks like that valve has dropped so it may be a case of valve meeting piston.

 

[MastaMax]

Chris I know a very good mechanic in Chiang Mai if you are interested. I don't think he has a lot of experience on FI but it seems your problem isn't related. If you are interested in his contact you can PM me.

 

[crs]

Looks like that valve has dropped so it may be a case of valve meeting piston.

Yep.

The piston doesn't look too bad (IMO - please say if you think otherwise), so I'll leave that and just replace the valve, valve cap, valve seal, rocker arm, cylinder head gasket and get some smaller shims. (though I might replace all the Ti valves with a full s.steel set + springs to suit). But, the question is, what caused this to happen...

Looking back, this started with the original tensioner in - which might have not have helped an already tight clearance. The valve must have got gradually knocked down through the valve spring top - and that's what made the engine stall and the 'sewing machine' noise start. This just continued after I'd fitted the DT tensioner (the Dirt Tricks tensioner likely didn't make any difference - the bad had already started). I didn't know enough to recognise what had actually happened - so it just got worse till the shim jumped out or something - and then the engine wouldn't run.

The questionable valve clearance, the dodgy standard tensioner - plus maybe an over flattened cylinder head gasket (had to air gun the bolts out - well over torqued) is the 'nice' reason for this happening. The nasty reason is if the cam or crank profiles are wrong, bearings are wrong - or some other internal bit just isn't how it should be. I'll fix on the premise it's the 'nice' reason - if not, it'll fk up again - and then this is beyond me.

 

[crs]

Chris I know a very good mechanic in Chiang Mai if you are interested. I don't think he has a lot of experience on FI but it seems your problem isn't related. If you are interested in his contact you can PM me.

Cheers, Max. Going to try fix it on my own for now, but if things get any worse then I'll need someone else, so will get in touch then. Wish I'd bought your WR now... Just the reason for why I thought it better to spend some more and get a new bike, has gone and happened anyway!

 

[Loop]

I had something similar happen to my old F2 Ducati.

Some time later at the front of the pack in a race at Phillip Island the valve guide from the previously damaged valve cracked and dropped into the combustion chamber resulting in a large amount of oil gushing in as well as it bouncing around until i could stop the engine.

Not saying it will happen to you...but maybe something to think about? if the valve is bent you can pretty much guarantee some sideways force has been put on the valve guide.

It may also pay to put an extra base gasket in if the tolerances have been so close that the valve has hit the piston? i know big job but you don`t want it hitting again.

 

[crs]

Shit, after reading that Lew, I went and cleaned it up some, and saw I need to replace the valve guide too - with the old one needing to be pressed, knocked, machined out somehow. (Doesn't say how to do in the repair manual.) The old guide has been well smashed - I went and gave my exhaust a shake - and out rattled the remains of the bottom part of it. Oh this is just getting better and better! If this was an old, dirt cheap project bike, I'd find this sort of interesting - but on a brand new KTM...
:kboom

 

[KMA]

Jeez Chris, at this point I think I would be loading that thing up and taking it to KTM in CM for warranty replacement etc..

 

[crs]

Jeez Chris, at this point I think I would be loading that thing up and taking it to KTM in CM for warranty replacement etc..

If I thought that would be straightforward, I would. I will look into the warranty ASAP, but with me already working on it myself, and not having bought the bike from them, I can't see them wanting to cooperate.

 

[bill]

Maybe you can shoot an email/pics to DJH and/or Thumper racing. Might give you some more ideas.
If you find enough wrong with the head/valves, then EMS to an experienced KTM engine builder might be the go, especially if you were thinking of changing to SS valves and need new guides and seats recut.
Anyway, whatever they suggest is free info at least.

 

[KTMphil]

Very strange with such a new bike

 

[Loop]

It sounds like the valve clearances to the piston need to be checked.

A fairly big job but you put some plasticine on the top of the piston (few mm`s thick),reassemble the top end and crank it over a few times by hand without the spark plug in and then take the head off again and make sure there`s the right gap between the two.

Very strange a new bike has done this,especially a KTM

edit;valve guides are usually pressed in and out using heat on the head from my experience.
So the head is heated to expand and then a press is used.... when it cools it makes a tight fit. I`m no mechanic but just from what i remember my engineer did.
He made them up from brass tube that he drilled and machined down to size.

 

[crs]

The warranty is a no go as I've been inside. I can't find out much about removing the valve guides, but I'd guess it needs machining out by the looks of it.

Bill, I'm going to talk to Thumper Racing and send stuff to them if they're up for the work. I've already got a 300 big bore kit of theirs that I was going to send back to them (+ cylinder) because I don't know a machinist here who can understand enough english to follow the rebore instructions. Also, they can remap the ecu. (Was going to wait till it needs a new piston but seems the time has come early.) I'll send the cylinder and cylinder head, inc' all the insides, then they can check the lot and see what they think happened and fix what needs fixing.

EDIT: I'll ask them to check that, Lew - and any other stuff that KTM should have got right in the 1st fkn place!

It's going to take some time what with postage.... There's not been a drop of rain since it's happened either... MoFo....

Anybody got a bike for sale? I might buy something then sell it when I get mine fixed. XR or better...

 

[Loop]

Here.. What's the proper way to remove and install valve guides? ThumperTalk

 

[crs]

Here.. What's the proper way to remove and install valve guides? ThumperTalk

Yeh, read about that way, but also read this re. a '09 450 SX:

'the old guides have to be machined out, new guides installed to the correct height and then reamed to the proper valve to guide clearance. valve seats will most likely need to be re-cut.'

Even if you don't need to machine, if I did find somewhere to heat it up (I have no oven - this is Thailand), I could see a fair chance of the head getting damaged as I tried to knock the guide out. Best left to someone else, I think.

EDIT: Lew, I think your guess that the clearance between this valve and the piston could be wrong is the most likely cause. I don't see how it could be anything bottom-end related like a crank bearing, as only this one valve has any damage. (When I checked previously, the valve clearance was actually less on the right exhaust valve.) Anyway, as long as it isn't bottom-end related, if I send all of the top-end to Thumper Racing, they should be able to figure it out, hopefully.

 

[LivinLOS]

Jesus man.. Thats a whole bunch of unlucky for a new purchase..

Smokers.. No valves.. No problems Tho best not be telling that to Max !!

 

[MastaMax]

Jesus man.. Thats a whole bunch of unlucky for a new purchase..

Smokers.. No valves.. No problems Tho best not be telling that to Max !!

I read that... :annie

Chris I feel your pain, when my bike had issues after just a few hours I put a new cylinder and piston so I didn't have to think about it anymore and I'm happy the bike runs as good as new. Shit can happen, I just wanted to sort it out as fast as possible, after all we all know it's a pricey hobby.

 

[crs]

Yeh - unlucky... But shit does happen.

I keep trying to think if I could have done something to cause this - but can't. If I'd dropped something by accident inside the cylinder head that could have made the valve jam, I would have found it by now. All I found was the shim loose in the bottom of the head - and I really don't see how I could have knocked that out of place myself. The timing was still right, I'm sure - checked cam marks with it locked at TDC every time I went in there... Valve clearances were in spec... Wondered if something could have got in via the exhaust - but can't see that as possible.

Forgot - you had bad luck with your new bike too, Max... KTM - should be better. Yeh, the cost is one thing, but what really pisses me off is that this could take quite some time - and dry season seems to have started. Still waiting to hear from Thumper Racing - they're always busy. If anyone knows of an OK bike for sale with papers, please let me know.

 

[LivinLOS]

Chris I feel your pain, when my bike had issues after just a few hours I put a new cylinder and piston so I didn't have to think about it anymore and I'm happy the bike runs as good as new.

Exactly the same with the YZ.. Didnt know the bike and let it overheat pushing water out (also put on a super cooler now).. I could have had the barrel recoated / rebored but didnt want to wait..

At least for a yammie the barrel is just a couple hundred.

 

[crs]

I am not alone: 2x here with same/similar problem. Lucky for them, they had warranty take care of it in no time. Fk . KTMTalk: Board Message

EDIT: Problem caused by valve not running smooth in the valve guide. After reading that, it'll cost more but reckon I should replace all with steel valves. Have read a few times now about the valve guides not liking the Ti valves.

 

[crs]

All on its way to Thumper Racing now... They reckon to replace with a standard valve and that it's likely just down to a poor factory install. So, that's me and Max who've both recently bought new KTMs - and they both had problems they shouldn't of had. KTM

Just hope it keeps sweet when I get it back together again... (Might get a bit of porting work done while it's there as well, if not too pricey. )

 

[LUFC]

Really terrible luck Chris, I hope Thumper do a good job for you.

Jons WR250 is for sale..

 

[Loop]

How long after changing the tensioner did all this start?

Wasnt it running well/properly before that?

 

[crs]

@LUFC
Yeh, will cost a bit, but Thumper should sort things. More worried about the postal service...

@Loop
Yes, I thought I was having a problem with the standard tensioner then the Dirt Tricks tensioner at first, but what happened to me sounds just like what people describe on KTMTalk - a problem with the valve and valve guide. First time something happened, was with original tensioner in. I think maybe the shim flipped out then and so the 'sewing machine' noise started. Things got more worn till it really bust. I wish I could have recognised bad engine sounds better when it happened!


1. The bike was still timed correctly after this had happened, 2. only one exhaust valve was damaged. If the timing had jumped and then jumped back somehow, I'm pretty sure both exhaust valves not 1 would show damage. (Clearance was actually tighter on the other side.) The only other things I could imagine causing this is a bad cam profile/cam seat effecting just that valve or bad valve to piston clearance just in that area - like u said.

 

[bill]

@LUFC
Yeh, will cost a bit, but Thumper should sort things. More worried about the postal service...

I guess I'll doing something similar when the topend is due for an overhaul on the 500, and again when the bottom end/top end is due.
I'm yet to research it, but documenting the contents of the EMS package with the Post office might avoid tax when it returns.
If so, that would allow one to insure the contents for the full replacement amount, instead of a lowball value to avoid tax.