KTM Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
27 Posts
Discussion Starter #1
I believe I figured out why my bike is not starting. I'll try to explain in detail. Please understand I may not say everything right I am still a noob. Also to respond to all your questions as to why I don't got to a shop or a mechanic. 1 I am a broke college student and 2 I enjoy working on motorcycles. So if it takes me a month or a year to figure something out so be it because I'll just gain knowledge. Anyway so here's why I think my bike won't turn on and if anyone can point me in the right direction I'd appreciate it. Today I took the valve cover off of my 08 450 exc-r. This was my first time taking the valve cover off on this KTM I bought it less than a month ago. Anyway I took the valve cover off so I can adjust the valves (or shims) because my shim kit came in today. Upon taking off the valve cover I noticed a huge red flag. On the exhaust side of the valves clutch side. There is supposed to be 2 long black bolts and on the brake side there's 2 silver bolts of course you undo these to loosen the rocker arms and remove the rocker shaft so you can adjust the shims. Anyway I noticed noticed on the clutch side where there's supposed to be 2 of the Long black bolts I only had one on the exhaust side and the other bolt was some cheap Home Depot bolt that was maybe an inch. I knew it wasn't the right bolt. I have a spare engine for my bike that I like taking apart and putting back together just to understand how things work. So at first I didn't pay any mind to it. I used my feeler gauge and checked the intake shims first. Everything was in spec. Great. I then tried the exhaust side. None of my feeler gauges could get threw at any size. I then thought well maybe its out of spec let me remove the rocker arm then remove the rocker shaft. If anyone else has worked on ktm engines with shims you know the shaft is supposed to come out pretty easily. I did everything right TDC, Special tool so it can stay locked in tdc. I was there for 3 hours trying to pull the exhaust rocker shaft out and nothing it wouldn't budge. The intake shaft came out pretty easily and on my spare engine both shafts came out like easily as well. So my questions is to you guys. What can I do ? Is there anyway I can just replace my head with my other engines head by bolting it on ? The spare engine has everything on it its not in pieces. Or should I keep trying to take the exhaust rocker shaft out? Is there any reason why this is happening? Thanks
 

·
Dirt Wizard
Joined
·
3,777 Posts
I suppose it could be bent maybe?
Usually you just screw a bolt into the end of the rocker arm pin/shaft and just pull it out.
Good to hear you're prepared to tinker.
It's got blown how the bike was even starting before if the valves were riding.
You can swap cylinder heads and rocker gear as one if you can't get the pin out.....pretty sure.
 

·
Super Moderator
Joined
·
915 Posts
@DW if @joshb973 replaces the head unit (head plus rocker gear) he could have the bike running and providing transport while he takes his time to get the current one disassembled. Am I right to think that or have I missed a trick here? As you know I am pretty good at disassembling stuff, not so good at putting them back together lol!!
 

·
Registered
Joined
·
27 Posts
Discussion Starter #4
@DW if @joshb973 replaces the head unit (head plus rocker gear) he could have the bike running and providing transport while he takes his time to get the current one disassembled. Am I right to think that or have I missed a trick here? As you know I am pretty good at disassembling stuff, not so good at putting them back together lol!!

yeah lol thats my question as well. It should be a simple unbolt and bolt new head unit on correct? While my spare head is on. I can do fix or do a upgrade on my current rocker gear correct?
 

·
Registered
Joined
·
27 Posts
Discussion Starter #5
I suppose it could be bent maybe?
Usually you just screw a bolt into the end of the rocker arm pin/shaft and just pull it out.
Good to hear you're prepared to tinker.
It's got blown how the bike was even starting before if the valves were riding.
You can swap cylinder heads and rocker gear as one if you can't get the pin out.....pretty sure.

yeah thats what I tried. When I did that on the intake shaft it came out smooth. Also on my spare engine they both came out smooth thats why I am stumped. So you think I should be able to just unbolt it and put on my spare head?
 

·
Dirt Wizard
Joined
·
3,777 Posts
Can't see why not, as long as they're both same capacity and similar year models. Just take the cam chain off and make sure they're both at the same position.
Make sure the head and barrel are nice and flat, new gasket and should be fine.
You are definitely better off keeping second hand heads and cam together as a paired set than swapping them around in my opinion.
Yes @AusPete . Definitely worth doing it up as a spare.
If it were me Josh, I would fix the whole spare engine and have it ready to swap out if it doesn't have anything to clinically wrong with it.
Josh, can you spin the rocker pin around inside the arm?
 

·
Registered
Joined
·
27 Posts
Discussion Starter #7
Can't see why not, as long as they're both same capacity and similar year models. Just take the cam chain off and make sure they're both at the same position.
Make sure the head and barrel are nice and flat, new gasket and should be fine.
You are definitely better off keeping second hand heads and cam together as a paired set than swapping them around in my opinion.
Yes @AusPete . Definitely worth doing it up as a spare.
If it were me Josh, I would fix the whole spare engine and have it ready to swap out if it doesn't have anything to clinically wrong with it.
Josh, can you spin the rocker pin around inside the arm?

on the spare engine I can but on the current engine on my bike I can but it still won't come out. It won't fully spin it will turn maybe a inch so I don't know why it won't come out. Also my spare engine the top end is fine. However I pulled the bottom end to take a look and there's black plastic shredded threw out the bottom end thats on my spare so seems like a gear got loose and shredded everything up. So that will need a rebuild but im not worried about that right now lol
 

·
Dirt Wizard
Joined
·
3,777 Posts
It's blown it's oil pump gear by the sounds, they're made out of black plastic.
If the rocker arm pin spins around easy than it's most likely not bent, but if it won't pull out its got a worn ridge somewhere. Have you tried wriggling the rocker arm as your pulling the pin?
 

·
Registered
Joined
·
27 Posts
Discussion Starter #9
Yes I tried that It still didn’t come out and you think it’s a plastic oil pump gear .
 

·
Dirt Wizard
Joined
·
3,777 Posts
A few of those plastic oil pump gears did fly apart.
Every ktm 4 stroke dirt bike I have ever opened up had a plastic oil pump gear........Actually yours is the 08 with the split oil sump set up. It will have 2 of them plastic gears. The engines with the 2 original plastic gears running on each other were prone to failure.
You use to be able to buy "Blais" metal/alloy gears as an upgrade. Or I think ktm made an upgraded plastic gear set that didn't fly apart.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #11
A few of those plastic oil pump gears did fly apart.
Every ktm 4 stroke dirt bike I have ever opened up had a plastic oil pump gear........Actually yours is the 08 with the split oil sump set up. It will have 2 of them plastic gears. The engines with the 2 original plastic gears running on each other were prone to failure.
You use to be able to buy "Blais" metal/alloy gears as an upgrade. Or I think ktm made an upgraded plastic gear set that didn't fly apart.

yeah they do still make them and what do you think would be the best way to remove the head? I think I may have to remove the cam as well.
 

·
Registered
Joined
·
27 Posts
Discussion Starter #12
Swappped the head and the carb she's turning on now I ran her today. She runs a little off and bogs out in 2nd gear. Any Suggestions ??
 
1 - 12 of 12 Posts
Top