Monsterlover does a big bore kit.

[Monsterlover]

Lots of KTM content here and really no Duc content so sorry about that.

But, if you're like me, you like seeing the insides of engines no matter who made them.

A few years ago I bought a low mile low hr (750 miles, about 30 hrs) 2010 KTM 450 EXC Champions Edition.  Basically a 450 dirt bike with stuff to make it street legal.

I immediately converted it into a supermoto and have been riding it that way ever since.  Im now up to 3850 miles and 107 hrs.

If I wasn't power hungry I would have left it alone.  It runs fine and since it never sees dirt/dust/trails I can stretch the maintenance quite a bit.  I think KTM wants you to put another piston in it somewhere in the 100-120 hr time frame.  I've seen pistons that were trashed at that hr level and, as you'll see in the pics, mine is just starting to scuff a little.

What drove this is a growing love of trackdays.



I like riding this bike there but I think it needs a little more power.  It's currently 35 or 40ish.  I'm doing a Thumper Racing big bore kit.

I tried to get the KTM 570 kit which turns a 530 into a 570.  A 530 crank would make my 450 accept that kit but it's not available world wide any more.  I called Thumper and they spent 30-40 minutes on the phone answering questions.  After talking with them I settled on a 520 kit which uses the existing short throw 450 crank.  It should be a rev monster.

Their combo-

520 kit
overbore the carb from 39-41 (its a flatslide too boot!)
use the cam from a 2012+ 500exc

They're getting 60HP with this setup.  In a 265 pound bike that should be pretty fun.

While I was out there working on removing the cylinder (goes back to Thumper Racing) I decided to fix a nagging problem I've had for years.  The electric starter will turn the bike over but most times not fast enough to active the CDI and light it up.  I end up having to use the kick starter.  I'm lazy and that's annoying so I found the fix on Advrider.  There's a clutch that can be tightened. . .


Having a lift makes all the difference.  It's really nice to raise or lower things to the level that's comfortable.  Pulling the carb on these bikes kind of sucked until I learned you could unbolt the bottom of the subframe and hinge the whole thing up.  That pulls the airbox boot off the carb and gives plenty of room to disconnect everything and pull it off the head.










The right side cover is easy to remove.  Pull the clutch cover, and remove all the side cover bolts as well as the hose on the water pump.  This clutch gear lives behind the clutch basket so that's gotta go as well.  Pull the pressure plate and disc pack.  Bend the tabs up on the security plate and remove the hub nut with an impact gun.  Pull the hub and basket and there she is.








I have no idea how this ended up grouped with all the rest of these pictures but here's one of my cats fatting out on the window sill


So here's the right side all buttoned back up.  Note that one of the side cover bolts is dual purpose.  To hold the side cover on there is a fat washer that sits between the bolt and the cover.  If you remove this washer and reinstall the bolt with the engine at TDC it will engage a groove or divot in the crank shaft and serves to keep the engine locked at TDC.  Smart.






I already had the valve cover off and as you can see there's a dot on the cam gear and a mark on the head casting that when lined up tell you you're at TDC.  Getting there is a pregnant dog.  I used the kick lever to roll things over (spark plug removed. . .) and if you go a hair too far it falls off the cam lobe and moves like 90 degrees too much.  I got it with trial, error, cursing and praying.  It fell into place just before I resorted to sacrificing a chicken.  I hurried up and locked the crank in place with that bolt.



After this I pulled the cam chain tensioner.  I did not have a 21mm socket or wrench in my collection and the english versions didn't fit well enough to make me comfortable.  What to do?  I turned to my trusty KTM tool kit.  Son of a pregnant dog it had the wrench I needed!  It's a double ended wrench that actually fits 4 sizes of fastener.  Smart.  And it worked like a charm.





The only thing holding the cam in place is a retaining plate bolted from the opposite side of the head casting.  After that's out the cam wiggles out a bit and drops down after the journal is clear of the bearing.  That gives enough slack to pull the chain off it.  I zip tied that so it didn't get dropped down into the case.






Here's the cam.  Note the cool little decompression device on there.  Spring loaded so that the exhaust valves are held open a bit.  Once the engine hits a few hundred rpm (500? not sure) the spring is overcome and the rockers follow the actual cam profile.  I think the compression stock on this engine is 12.5:1








The underside of the head and cylinder.  More carbon that I would have thought but not all that bad.  Zero wear on the cylinder.  Factory cross hatch is alive and well as it should be.












More carbon that I would have thought on the piston.  What I find strange is that it's all on the right side between the intake and exhaust valve.  Any idea what that's about?  I got nothing.  The skirt is coated on the piston and some that ive seen at 100 hours have the coating worn away totally and have heavy wear marks.  Mine looks pretty good I think.  There is only a hint of scoring starting.  If I had to guess, I think this piston could do another 70-100 hours if kept on the street an maintained the way I have been.






I only took this so I remembered which way the wrist pin clip went.  I guess it matters and if it's put in backwards it can work its way out.



I'm not sure if this piston is cast or forged.  It's very high quality for a factory job.  KTM claims their bikes are "Ready to race" right off the showroom floor and I believe it.








A shot of how the bike sits now.  The carb and cylinder are ready to go off to Thumper.  Once I have everything here I think I can have it running after a solid afternoon of wrenching.  Stay tuned. . .

[blalor]

Looks like a fun project.  $775 doesn't seem to bad for 50% more power.

I've been shopping for a dual sport.  I'd like to pick up some off-pavement skills and fall a few times to go get over that fear. :-)  I've pretty much settled on a WR250R, but I keep coming across KTMs on ADVrider that look interesting.  But it sounds like maybe KTMs are a bit too race-bred for me, if they're wanting a new piston every 100 hours.

[Monsterlover]

Looks like a fun project.  $775 doesn't seem to bad for 50% more power.

I've been shopping for a dual sport.  I'd like to pick up some off-pavement skills and fall a few times to go get over that fear. :-)  I've pretty much settled on a WR250R, but I keep coming across KTMs on ADVrider that look interesting.  But it sounds like maybe KTMs are a bit too race-bred for me, if they're wanting a new piston every 100 hours.

I'm sure the WR is great. KTM is a great option too. As with anything it's all in the use and maintenance. If you can't keep your air filter clean on a regular basis then engine life suffers no matter who makes the bike. You can only ride dusty trails and submerge the bike in streams so many times before you move into the aggressive user category.

The boot between my air filter and carb was absolutely spotless. That's probably why the piston looked so good. 100% street helps in that regard.

I wouldn't shy away from KTM. Stick with a 2011+ bike (exc if you want street legality) and you will already have all the upgraded parts right from the factory (oil system stuff)

Do you have a dealer near you?

[Kopfjager]

Well, I'm never getting my bottle opener now. 

[koko64]

 

Cool project.

[DesmoDiva]

Looks like fun.

Stop beating on your thumb.

[Monsterlover]

Looks like fun.

Stop beating on your thumb.

I wondered if that would get noticed. I was reaching for something and my thumb glanced of a piece of metal. That was the result!

[blalor]

If you can't keep your air filter clean on a regular basis then engine life suffers no matter who makes the bike. You can only ride dusty trails and submerge the bike in streams so many times before you move into the aggressive user category.

Ah, interesting.  Basically FOD. 

I wouldn't shy away from KTM. Stick with a 2011+ bike (exc if you want street legality) and you will already have all the upgraded parts right from the factory (oil system stuff)

Do you have a dealer near you?

Not too far away, it appears.  I'm looking for something used and cheap, tho; I'm hoping to find a not-too-rough WR for around $3k.  A DRZ400 is also a good (and cheaper) candidate.

[Monsterlover]

Either of those will roll on dirt

[Speeddog]

The more I see of their stuff, the more I'm impressed.

Make sure you take care of where the cam chain is if you need to turn the crank.

[clubhousemotorsports]

Nice thread!
Ktm's are good to go in my book too, put together well and not over complicated.

I would be surprised if the HP was not a tad higher stock, I just had a 07 husqvarna 450smr on my dyno and it came in right around 45 hp, yours should have been similar.

The piston looks like a Pistal or mahle both very good products. Looking forward to see how it comes out.

[Monsterlover]

You and me both!

[1.21GW]

 

[Monsterlover]

Looks like a fun project.  $775 doesn't seem to bad for 50% more power.

I've been shopping for a dual sport.  I'd like to pick up some off-pavement skills and fall a few times to go get over that fear. :-)  I've pretty much settled on a WR250R, but I keep coming across KTMs on ADVrider that look interesting.  But it sounds like maybe KTMs are a bit too race-bred for me, if they're wanting a new piston every 100 hours.

Note that it's a little more than $775 with the cam ($215ish) and the carb work ($200)

I got the carb and cylinder sent off to them a couple days ago....

[Speeddog]

Note that it's a little more than $775 with the cam ($215ish) and the carb work ($200)

I got the carb and cylinder sent off to them a couple days ago....

So $1190 plus labor at $0.25/hr.