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 11-27-2012, 06:01 PM   #31
gunnerbuck
Island Hopper
 
gunnerbuck's Avatar
 
Joined: Nov 2005
Location: N.V.I, B.C.
Oddometer: 4,040
That noise does sound strange and gives reason to look further...

Here are some rebuild threads that may prove helpful:

http://advrider.com/forums/showthread.php?t=628511

http://advrider.com/forums/showthread.php?t=632893

http://advrider.com/forums/showthread.php?t=633753
gunnerbuck is offline   Reply With Quote
Old 11-27-2012, 08:06 PM   #32
bmwktmbill
Traveler
 
Joined: Jul 2005
Location: Traveler
Oddometer: 4,962
YIKES!!!!

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 11-28-2012, 12:17 AM   #33
beek-02
blazing a trail
 
beek-02's Avatar
 
Joined: Sep 2009
Location: California City, Ca
Oddometer: 113
Quote:
Originally Posted by sam_2555 View Post
Cheers Gunner. That's a photo defect on the valve there.

I've just been turning the engine over to check the whole barrel for any obvious scoring and can hear a fairly loud clunking coming from the gear box. It sounds a bit like the auto-decomp which is why I didn't pick it up before. I'll post more details when I strip back the engine further.

Here's a youtube vid of the noise: http://www.youtube.com/watch?v=69yQLcdKFWE
Dollars to donuts it has a bad crank/connecting rod. I bought an lc4 a bit back with a bad crank and although I did get it to fire/run, it barely ran, and not for long. I ended up buying a pro x con rod kit to rebuild the crank and then came across another motor that I got lucky on. I don't need the con rod kit if that is the way you decide to go shoot me a pm. The crank on these is about as mechanical as it gets. It has to be shimmed to the proper clearances for the main bearings and will have to be redone if you put a new crank in. If you go the route of rebuilding the crank a good reputable shop should be able to mimick the current width of the crank and not require any shimming, (repeat should). This is only good if the main bearings are still good. Also, check/replace the seal on the clutch side cover that goes over the end of the crank. This is the seal that directs the flow/pressure of the oil through the crank and to the con rod.

A whole other direction is to get a crank with a longer stroke and build a big bore. I think you can go up to almost 700cc with the right combination of crank and piston. Of course this gets a lot more expensive as it would require a longer cylinder to get the right compression. Munn racing might have more info on the big bores, I know he has a lot of knowledge on the lc4, or at least used to. There aren't as many out there building the old lc4's now that the new FI 690 is out there.

Good Luck and keep us posted,

Beek
__________________
"Opinions are like a$$holes. Everybody's got one and everyone thinks everyone else's stinks."
beek-02 is offline   Reply With Quote
Old 12-02-2012, 01:12 PM   #34
sam_2555 OP
Adventurer
 
Joined: Nov 2012
Oddometer: 21
More progress(?)

Thanks for the help guys. Gunner, those threads are really useful, I've started reading all of them and not quite finished any yet. I've learned a fair bit by just going through them though.

Beek, thanks for your input. If it is the crank that's bad I'd like to go the big bore route but finances might limit me a bit. We'll see, if I need a new crank or if it'll cost a fortune to get this one sorted I'll look into it more.

Mean while, I've been taking more parts off. I got a mate to make a flywheel holder for me from a rough drawing I gave him and it worked like a charm. The clutch nut was a pain to get off though, I ended up flattening out the entire tab washer not just the bit that was bent over the nut. Got it off in the end though and saw this little beauty when I did:


Now correct me if I'm wrong but that's a SKF roller bearing isn't it? So it would appear that the upgrade has already been done. This would lead me to one of two conclusions, either the previous owner was a fan of preventative maintenance OR the main shaft bearing failed and it was replaced. Going off the position of the oil drain plugs this is a pre 2001 engine so the bearings are definitely not OEM.

Another question is, what is this stuff around the bottom of the barrel? You can see where the piston travel stops and theres some discolouration around there. It's the same on the other side but not as bad. Is this just a coating that's worn off in places or something else?


There is some fairly minor scoring on the piston skirt as well but since I've never done anything like this before I don't know what could have an adverse effect and what is acceptable. You can feel the scores with your finger and if you drag a nail over them it gets caught on the biggest score, I guess that's the best description I can give really.



There aren't any marks that I can see at the crown just those up the skirt.

I've been thinking about carburation recently as well. When I get this thing back together and running on the old BST I think the next upgrade will be fuel injection. It'll cost about 100 more than an FCR but for the tunability and potential performance gains I think it'll be worth it. Plus I might learn some stuff along the way, which is never a bad thing. What say you advriders?

One more thing, when I eventually got the clutch off the oil on the shaft smelt really bad. Is this normal? It really didn't smell like engine oil, I've smelt something like that before but can't remember what it was now.
sam_2555 is offline   Reply With Quote
Old 12-02-2012, 06:18 PM   #35
gunnerbuck
Island Hopper
 
gunnerbuck's Avatar
 
Joined: Nov 2005
Location: N.V.I, B.C.
Oddometer: 4,040
Did the oil have a rotten gas smell to it? Sometimes if the carb float/needle are not doing their job fuel leaks past, goes through the intake and ends up bleeding through the piston/ring seal and into the base... Are the discolored patches on the cylinder wall sticky like fuel varnish?

The cylinder itself looks serviceable {unless you have visible scoring that doesn't show in the pic} but could probably use a hone, at the same time the shop could measure it to make sure the bore is within spec...

The score marks on the piston skirt should not be much of an issue as it is the rings that seal the bore, they should probably be changed for new ones...

At the point you are now you can diagnose the crank, lift the rod up and down to see if the bearing has excessive up and down slop.. Use a feeler guage to then measure the side play.... You can spin the crank and hold a pointer to the gear end of the shaft to kind of observe if it has excessive run out, a dial guage will give you a correct # if it looks to have a lot of wobble...

You can now spin the gearbox with the mainshaft and shift through all the gears a few times to see if you pick up on any of those clicking noises...
gunnerbuck is offline   Reply With Quote
Old 12-02-2012, 11:42 PM   #36
bmwktmbill
Traveler
 
Joined: Jul 2005
Location: Traveler
Oddometer: 4,962
Sam,
Are the rings free or are they stuck?
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 12-03-2012, 04:34 PM   #37
sam_2555 OP
Adventurer
 
Joined: Nov 2012
Oddometer: 21
Gunner, I've checked the side play on the crank at less than 0.7mm and max in the manual is 1.1mm so that seems good and no radial play at all. I haven't checked the cylinder discolouration yet but will do tomorrow.

Bill, the rings are free and the gaps in them don't look too big. I reckon when I put it back together I'll measure the assembled end gap and if they're out of tolerance I'll replace them.

I found the clicking noise. It's coming from the kickstarter assembly. As the kickstarter intermediate gear spins something in the assembly is clicking. I've got no idea what it could be, any educated guesses? Ratchet gear maybe? The engine has never had a kickstart fitted that I know of, the guy I bought it off said he took it off because it wouldn't fit around the fairings.

Before I can split the cases to have a look at the kickstart assembly I need to get the gear off the end of the crankshaft. The manual says this nut is torqued to 170Nm! What should I use to get it off? Remount the flywheel and nut and use those maybe?
sam_2555 is offline   Reply With Quote
Old 12-03-2012, 04:59 PM   #38
clintnz
Trans-Global Chook Chaser
 
clintnz's Avatar
 
Joined: May 2004
Location: Rotoiti, New Zealand
Oddometer: 3,392
Quote:
Originally Posted by sam_2555 View Post
Gunner, I've checked the side play on the crank at less than 0.7mm and max in the manual is 1.1mm so that seems good and no radial play at all. I haven't checked the cylinder discolouration yet but will do tomorrow.

...

Before I can split the cases to have a look at the kickstart assembly I need to get the gear off the end of the crankshaft. The manual says this nut is torqued to 170Nm! What should I use to get it off? Remount the flywheel and nut and use those maybe?
Check that big end carefully, I couldn't feel much play in mine when I did a rebuild but it was obviously well shagged when I removed it. Having said that my piston was also well worn by that point, your fairly unmolested piston should give some hope that the engine isn't too buggered.

To get the crank gear nut off just put the piston pin back in & put a block of wood under each side between it & the cases to chock it. Leave the base gasket on to protect the surfaces & use good size blocks of wood. It might have been Gunnerbuck I learnt that one off actually This is about where an engine stand comes in real handy - if you have fabrication capability its well worth spending an hr or 3 knocking something up.

Maybe check your crank end float before you split the cases too so you have a baseline just in case.

Cheers
Clint
__________________
'03 KTM 640 LC4 Enduro

The wilderness, the desert - why are they not crowded
.................................................. .....with pilgrims?
clintnz is offline   Reply With Quote
Old 12-04-2012, 08:30 AM   #39
gunnerbuck
Island Hopper
 
gunnerbuck's Avatar
 
Joined: Nov 2005
Location: N.V.I, B.C.
Oddometer: 4,040
Do you have the kick start lever? It comes in handy to hold the spring tension when you loosen the stopper bolt at the back of the engine, it also comes in handy to wind the spring tension back up upon reassembly...

If your not using the kick start you could always just remove and run without the intermediate gear to eliminate the problem... Personally, I would tear it down and fix the issue...
gunnerbuck is offline   Reply With Quote
Old 12-04-2012, 10:09 PM   #40
wrk2surf
on the gas or brakes
 
wrk2surf's Avatar
 
Joined: Dec 2007
Location: THE exact center of California/Bass lake/Yosemite
Oddometer: 6,463
have you checked the regulator and also have you clipped the ignition wire on the plug end..
__________________
Thanks for the 2015 support: BELL HELMETS, SCOTT USA, Kriega USA, SEATCONCEPTS.COM , Galfer USA, Carbon-pro.com, GPR stabilzers, Sidi/Motonation, Masters paint and body, Magura , Motolab , Loctite and Dunlop tires .
wrk2surf is offline   Reply With Quote
Old 12-09-2012, 07:06 AM   #41
sam_2555 OP
Adventurer
 
Joined: Nov 2012
Oddometer: 21
wrk2surf the reg has never been connected as the bike never ran I didn't think it would need it's own battery charging circuit. I've tried a few different HT leads and a few different caps, I even tried stripping back the insulation and wrapping the bare wires around the spark plug end.

I finally managed to get the nut off the end of the crankshaft a couple of nights ago using Clint's method. I got my girlfriend to undo the nut whilst I held the engine down. All the gears slid off their shaft nicely, no need to buy a puller. I took the oil pumps out and they look fine.

The only thing I can guess would be making that noise in the kickstart assembly is the ratchet gear. I'm going to see if I can just remove everything on the kickstarter assembly with no ill effects. A new ratchet gear would cost 130, so I'm definitely not getting a new one and I'm never going to use the kickstart so if it's possible I'll pull the lot out.

I don't have the kick start lever but I shouldn't need it if I'm removing the whole assembly apart form the shaft should I?

Whilst the head's off anyway I'm going to have the seats recut so I can fit 32mm exhaust valves. I'm also going to clean up the casting a bit to remove any large imperfections. Does anyone know what kind of power gains you can expect from increasing exhaust valve size? Or what else changed between the black and grey heads? I've searched for this Sommer 'special red head' that I saw mentioned in a couple of threads but found no actual info on it.

I'd like to measure the crank end play before I split the cases so I know where I am before any work is done, as advised by Clint. Any tips for doing this without a dial indicator? I've done the standard google search and all I found were some videos on youtube for car crankshaft end play. Any advice would be really appreciated.

Thanks a lot for the continued support guys, your help and input really has been invaluable.
sam_2555 is offline   Reply With Quote
Old 12-09-2012, 07:34 AM   #42
gunnerbuck
Island Hopper
 
gunnerbuck's Avatar
 
Joined: Nov 2005
Location: N.V.I, B.C.
Oddometer: 4,040
Quote:
Originally Posted by sam_2555 View Post
wrk2surf the reg has never been connected as the bike never ran I didn't think it would need it's own battery charging circuit. I've tried a few different HT leads and a few different caps, I even tried stripping back the insulation and wrapping the bare wires around the spark plug end.

I finally managed to get the nut off the end of the crankshaft a couple of nights ago using Clint's method. I got my girlfriend to undo the nut whilst I held the engine down. All the gears slid off their shaft nicely, no need to buy a puller. I took the oil pumps out and they look fine.

The only thing I can guess would be making that noise in the kickstart assembly is the ratchet gear. I'm going to see if I can just remove everything on the kickstarter assembly with no ill effects. A new ratchet gear would cost 130, so I'm definitely not getting a new one and I'm never going to use the kickstart so if it's possible I'll pull the lot out.

I don't have the kick start lever but I shouldn't need it if I'm removing the whole assembly apart form the shaft should I?

Whilst the head's off anyway I'm going to have the seats recut so I can fit 32mm exhaust valves. I'm also going to clean up the casting a bit to remove any large imperfections. Does anyone know what kind of power gains you can expect from increasing exhaust valve size? Or what else changed between the black and grey heads? I've searched for this Sommer 'special red head' that I saw mentioned in a couple of threads but found no actual info on it.

I'd like to measure the crank end play before I split the cases so I know where I am before any work is done, as advised by Clint. Any tips for doing this without a dial indicator? I've done the standard google search and all I found were some videos on youtube for car crankshaft end play. Any advice would be really appreciated.

Thanks a lot for the continued support guys, your help and input really has been invaluable.
Just remove the kickstart idle gear off the countershaft clutch end to take the kickstart out of the system, no need to split the cases...

Is there a lot of end play in the shafts evident when you move them by hand?
gunnerbuck is offline   Reply With Quote
Old 01-09-2013, 08:27 AM   #43
sam_2555 OP
Adventurer
 
Joined: Nov 2012
Oddometer: 21
Progress

I haven't done anything with the engine for a few weeks, christmas, family and uni deadlines have been sucking up all my time.

I've just dropped the cases off at my local light engineering works to get the end float on the crank measured before I split the cases. Once I've split the cases I'll take the crank back to the shop to get the run out checked.

Gunner, I know what you're saying about the idle gear but I want to get inside and have a look about. It would be much easier to just remove the idle gear but there might be some underlying cause as to why it's failed. I've never seen anything about the ratchet gear going in one of these engines so I really want to get in there and have a look around.

I got the exhaust valves out myself using an extractor I bought off ebay. I'm NEVER buying a cheap valve extractor again. By the time I started taking out the first inlet valve the extractor was pretty bent, then it totally gave up and bent so much it was unusable - I got a full refund though so all is not lost and the seller didn't want it back so I might be able to salvage something out of it. The inlet valves are being removed at the shop, since everything is apart anyway I thought I may as well lap them in. I'm ordering 32mm valves and springs to match, water pump rebuild kit, full set of carb seals and a full gasket and seal set today.

I won't get anything else done until all the bits arrive and even then progress will be slow until I finish my exams at the end of this month. After that though the Triumph will be sold and I can devote some serious time to this project.

Not much of an update I know, but I hate those threads where the OP just gives up posting and you never get to know the end of the story.

Cheers,

Sam.
sam_2555 is offline   Reply With Quote
Old 01-09-2013, 09:57 AM   #44
kyns
Beastly Adventurer
 
kyns's Avatar
 
Joined: Feb 2009
Location: Finland West coast
Oddometer: 1,936
Cool, so you haven't given up and made a paper weight out of it yet.

I'm interested to see what is the problem, IT SHOULD RUN... beats me...

I still think splitting it, will not help with the issue...

Where are you located ? Can you plate that thing ?
kyns is offline   Reply With Quote
Old 01-09-2013, 10:21 AM   #45
gunnerbuck
Island Hopper
 
gunnerbuck's Avatar
 
Joined: Nov 2005
Location: N.V.I, B.C.
Oddometer: 4,040
Quote:
Originally Posted by kyns View Post
Cool, so you haven't given up and made a paper weight out of it yet.

I'm interested to see what is the problem, IT SHOULD RUN... beats me...

I still think splitting it, will not help with the issue...

Where are you located ? Can you plate that thing ?
I would agree with you, he is already past the point where the problem lies but he is game to go over the whole engine...


A chipped kickstart gear on this page from Tsetas rebuild:
http://advrider.com/forums/showthrea...=628511&page=5
gunnerbuck 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 01:05 PM.


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