ADVrider

Go Back   ADVrider > Bikes > Thumpers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 10-20-2010, 04:31 AM   #61
LukasM
Beastly Adventurer
 
Joined: Nov 2006
Location: On a RTW ride - currently Central Asia
Oddometer: 5,333
Great thread Tseta, good on you for having such cool winter projects and getting to learn a lot in the process.

If you ever need some specialized engine work that you want to outsource, I can highly recommend you get in touch with Glenn Woodman aka GWR. Very experienced LC4/EXC guy who used to work in Mattighofen and now builds engines for a few race teams at world class level (lots of sidecar stuff which is a killer stress test). He also has a few really expensive tools that nobody else outside of the KTM factory has.

Check out the RFS stroker crank he just did for me, this used to be a full circle crank that was lightened, polished, welded pin and balanced for a custom piston.

__________________
RTW trip blog: https://www.facebook.com/AroundTheWorldWithLukasM

LukasM screwed with this post 10-21-2010 at 06:41 AM
LukasM is offline   Reply With Quote
Old 10-20-2010, 05:33 AM   #62
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Quote:
Originally Posted by LukasM
Check out the RFS stroker crank he just did for me, this used to be a full circle crank that was lightened, knife edged/polished, welded pin and balanced for a custom piston.


Thanks for the tip about GWR.

-T
Tseta is offline   Reply With Quote
Old 10-20-2010, 05:43 AM   #63
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
I promised I would post up some of the dimensions of the engine stand that I made. I have to emphasize that the stand is quite rough. Also, it doesn't allow for the engine cases to be split while the engine is still attached to the stand.





























I didn't really design the stand or dimension it on paper before I started building it. The (obviously) important bits are the center-to-center distance between the engine mount holes and the width of the attachment forks. I would suggest to make the mounting holes quite oval.

Cheers,

Tseta
Tseta is offline   Reply With Quote
Old 10-20-2010, 09:11 AM   #64
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Bypass piston and spring checkup.





I think these two snippets from the official KTM LC4 engine manual do a good job of explaining where the bypass piston and spring are located and how they are checked.

However, the specifications for the spring length seem to vary. The technical data for a 1998 LC4 says that the bypass spring length should be 25mm at the minimum.



This is also reflected upon the parts fiche description for said spring.

Year/Model: 1998,
Component: ENGINE CASE 400/640 LCE-E `98
Item #: 50
Part Number: 58038023300
Description: PRESSURE SPRING L=25MM D=1MM


This is what the drain plugs and the bypass piston look like inside the case:



And here with the drain plugs removed. You can still see the actual bypass piston (shiny, silver color) inside the passage.



You can remove the bypass piston plug from the bottom of the engine (even while it is attached to the frame) with an allen key.



The spring will probably fall out once the plug is removed, but the piston may still stay inside the case due to oil stiction. A small pen magnet may help in pulling the piston out.



Here are the components laid out. Note that the piston has a "pocket" for the spring. The piston goes in the engine with the closed end first.



The spring in this engine measured 23.5mm.



This would be OK if you only took a cursory glance at the manual, but closer examination (as laid out above) shows that this spring is not adequate. One should also check the piston itself for any scratches or such. It should move quite smoothly (but not too loosely...) in the bore.

Hopefully this brings more clarity than confusion to the bypass piston issue.

Cheers,

Tseta
Tseta is offline   Reply With Quote
Old 10-20-2010, 09:16 AM   #65
wrk2surf
on the gas or brakes
 
wrk2surf's Avatar
 
Joined: Dec 2007
Location: THE exact center of California/Bass lake/Yosemite
Oddometer: 6,172
my sxc motor rebuld included a stuck bypass that had to be scraped out using the hole showing the piston with a pick... sometimes a blast of air will pop it out... keep it goin
__________________
Thanks for the 2014 support:BELL HELMETS, SCOTT USA, Kriega USA, Carbon-pro.com, GPR stabilzers, Renazco Racing, Sidi/Motonation, Masters paint and body, Magura , motolab , Tripy GPS, Loctite and Dunlop tires .
wrk2surf is offline   Reply With Quote
Old 10-20-2010, 11:47 AM   #66
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Well crap...

Good news and bad news.

The good news is that I finally found the damage and where the small metal bits shaped like corners of gearwheels came from.

The bad news is that they are the kickstarter gears.

58033022700 KICKSTARTER GEAR 35-T $102.11
58033023200 RATCHET GEAR 24-T $294.99



These gears are missing quite a lot of their teeth. It explains most of the metal flakes found in the engine. I still think though that the pin is a remnant from the previous owner's bearing change. How stupid of me to not check these sooner...

(Pics later.)



Although I have learned a lot from this project, it has also caused a lot of grief and perhaps depression as well, for both me and the owner of the bike.

-T
Tseta is offline   Reply With Quote
Old 10-20-2010, 12:31 PM   #67
makazica
Studly Adventurer
 
makazica's Avatar
 
Joined: May 2008
Location: Zagreb, Croatia
Oddometer: 736
Crap indeed!

But no going back now, you're gonna have to assemble it for whatever it's future is going to be..... Hopefully the owner will have the same opinion as you have, to keep the bike for a long time. Even if it takes some time to gather money for parts.

M.
makazica is offline   Reply With Quote
Old 10-20-2010, 01:50 PM   #68
gunnerbuck
Island Hopper
 
gunnerbuck's Avatar
 
Joined: Nov 2005
Location: N.V.I, B.C.
Oddometer: 3,750
Check ebay

There are several sets of kickstart gears listed on here that will work:

http://motors.shop.ebay.ca/i.html?_n....c0.m270.l1313
gunnerbuck is offline   Reply With Quote
Old 10-20-2010, 10:10 PM   #69
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Stripped gears...











Experience has shown me that shipping across the pond is always a huge hassle, mostly due to the strict customs regulations and heavy duties that have to be paid here in Finland.

-T
Tseta is offline   Reply With Quote
Old 10-20-2010, 10:57 PM   #70
bmwktmbill
Traveler
 
Joined: Jul 2005
Location: Traveler
Oddometer: 4,765
Hello Tseta,
That's a great write up on the bi pass valve.
Now I understand exactly how it works.

Not much left except the cylinder head!!
Thanks and good luck
bill
__________________
'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
Cormack McCarthy-The Crossing

The faster it goes the faster it breaks.
And high performance=high maintenance.
Bill Shockley
bmwktmbill is offline   Reply With Quote
Old 10-21-2010, 01:34 AM   #71
makazica
Studly Adventurer
 
makazica's Avatar
 
Joined: May 2008
Location: Zagreb, Croatia
Oddometer: 736
How about german or austrian e-bay?

M.
makazica is offline   Reply With Quote
Old 10-21-2010, 06:39 AM   #72
laramie LC4
crash test dummy!
 
laramie LC4's Avatar
 
Joined: Sep 2004
Location: Tucson, Az
Oddometer: 2,330
Quote:
Originally Posted by Tseta
Although I have learned a lot from this project, it has also caused a lot of grief and perhaps depression as well........
-T
WOW, that is EXACTLY how i felt. seemed the deeper i delved, the more expensive the project became. throw into that a couple "KTM" original tools and things get spendy. i fell feel for your guy....

laramie
__________________
DON'T TRUST CUT 7! HE IS A CROOK! ASK ME HOW I KNOW.

'12 LC8 990R, '02 LC4 640, '05 WR 450f (part-out), '98 XR400R, '76 KE100, '05 525 (Step-Child)
laramie LC4 is offline   Reply With Quote
Old 10-21-2010, 08:34 AM   #73
Tseta OP
Lost
 
Tseta's Avatar
 
Joined: Nov 2008
Location: Finland
Oddometer: 669
Quote:
Originally Posted by bmwktmbill
Not much left except the cylinder head!!
Yeah, about that...

I took a look at the cylinder head today. I checked the sealing surface flatness with a straightedge and a feeler gauge - no problems there. The valve guides were checked with a plug gauge - 7.02 mm was the largest I could fit (KTM specifies the wear limit at 7.05 mm) so things are ok there as well.

The valves themselves are a different story. The manual says that the valve sealing areas (valve seats) should not be pocketed. I don't completely understand what this means.

The intake and exhaust valves look like this:









It looks almost like the sealing area is a little bit recessed into the valve body itself. Is this what the manual is talking about with the valves being pocketed?

-T

Edit: Gunnerbuck, thanks for your idea about E-bay and for searching the correct gears from there, even though I am not able to order from across the pond.

However, I was able to snatch a similar gearset from German E-bay, like Makazica had suggested. Hopefully it will arrive without hassles.

Tseta screwed with this post 10-21-2010 at 09:36 AM
Tseta is offline   Reply With Quote
Old 10-21-2010, 10:39 AM   #74
toolfan
Broken Hearted
 
toolfan's Avatar
 
Joined: Jun 2006
Location: NoPo (pdx)
Oddometer: 9,543
Valve seats are in the head, not on the valve.

You can lap valves/seats if they aren't too bad...
toolfan is offline   Reply With Quote
Old 10-21-2010, 12:57 PM   #75
DaBit
Gnarly Adventurer
 
Joined: Nov 2008
Location: Netherlands
Oddometer: 345
Quote:
Originally Posted by laramie LC4
WOW, that is EXACTLY how i felt.
Everyone, I suppose. I felt that way also when I dug into the engine to fix 'only' a head gasket. It ended with another cylinder head, cylinder, piston, etc.

I didn't split the cases. When there is no absolute need, don't. You will always find something out of spec, and then there is the 'I am here already, let's replace those bearings and seals also'. In the end you would have been better off buying a low-mileage replacement engine. For example: at the local second-hand site I found a 2007 one with a few thousand km's on it for EUR 1200,- asking price. Going price would be EUR 1000,- or so, I suppose. Sell the old engine for a few hundred, and total cost is quite attractive compared to all the various bits and parts.

Anyway: I still have my 'spare engine'. It's not much spare engine anymore since I used it as a parts supply. But if you need something special....
DaBit is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 11:39 AM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014