KTM 620RXC...Anyone?? - Page 37

Adios Pantalones · 10-07-2012, 02:04 PM

Thanks to all the good info here, some all the way back to 06 in a Gaspipe post,

I ditched the old edelbrock and coughed up for a new FCR 41.

Long story short... it's a new bike.

96, 620, kick only. 5000mi on it. It went from an good, old used bike that ran kinda crappy to the beast it should be.
I can stop shopping for the replacement bike!

Sudco set it up right and got it to me in 2 days. I am officially ready for desert season!

rz35027 · 10-08-2012, 09:40 PM

Quote:

Originally Posted by Adios Pantalones

Thanks to all the good info here, some all the way back to 06 in a Gaspipe post,

I ditched the old edelbrock and coughed up for a new FCR 41.

Long story short... it's a new bike.

96, 620, kick only. 5000mi on it. It went from an good, old used bike that ran kinda crappy to the beast it should be.
I can stop shopping for the replacement bike!

Sudco set it up right and got it to me in 2 days. I am officially ready for desert season!

Setup that undersprung suspension (if it's still stock) and all of a sudden it will transform again...

Adios Pantalones · 12-01-2012, 09:15 AM

Quote:

Originally Posted by rz35027

Setup that undersprung suspension (if it's still stock) and all of a sudden it will transform again...

Yeah, still stock, Marz/Ohlin. Suggestions?

Adios Pantalones · 12-01-2012, 09:18 AM

Did a pretty good soil sampling last weekend, cracked the orig. front fender and brace. No OEM available.

Any ideas on good fittting aftermarket fender?

katumo_jtb · 12-01-2012, 01:04 PM

OEM fenders from later year KTM's will fit. The bolt pattern is the same, you just need to make sure you get a fender with the "nubs" that hold the mask in place. I'm using a fender from an '04 625 on my '95.

John

Adios Pantalones · 12-01-2012, 01:25 PM

Quote:

Originally Posted by katumo_jtb

OEM fenders from later year KTM's will fit. The bolt pattern is the same, you just need to make sure you get a fender with the "nubs" that hold the mask in place. I'm using a fender from an '04 625 on my '95.

John

Awesome, thank you.

2wheelwilli · 01-30-2013, 04:29 PM

Ok i need rxc help, mine is a 1995 rxc620 kick only, i need to find a battery where can i get one, my speedo stoped working so im useing my GPS till i find one... this bike is a blast.....

mik-ktm400rxc · 05-04-2013, 03:12 PM

I have a mystery starting issue on a ktm rxc 400 96'.

I changed the water pump seals on my bike and set the valve lash gap to the specified .1 mm on my way out. I had the cylinder and head rebuilt last summer and decided the recently ground valves should be re-gapped cus' of em settlin' into the re-ground seats, theoretically. It seemed the valve-lash was too tight.

Now.... it won't start. It has spark. I didn't mess with the carb. IDK WTF.

I have tried tightening and loosening the valve lash to various degress without success. It won't even backfire. There is nothing at all happening when I kick it, no hesitation, no nothing.

I don't know what I coulda done while I was in there. Could I have messed with the valve timing/spark timing when putting the head back on? I had to move the wheel a bit to get the water pump back on... That's my guess. Could it be sparking on the wrong stroke or at the wrong time? How would I check it? Correct it?

Gracias amigos para su tiempo, everyone on here has been a huge help in the past and I look forward to your diagnosticating regarding this matter.

katumo_jtb · 05-04-2013, 03:38 PM

The recent changes were timing gear and valve lash, so it's probably one of those, as you said.

Are you sure you adjusted the valves at TDC on the compression stroke? You can lock the engine at TDC with the crankshaft bolt on the underside of the case. Also do you have auto-decompression? Are you sure the auto-decomp was down when you measured the exhaust valves? Also, I thought the spec was .15mm, not .1mm. However, I'd guess you're further out of spec than that, if that's the problem, but you should definitely make sure.

The valve timing is the other possibility. If it were off, it would make valve adjustment confusing as the cam could be in the wrong place at TDC. Unfortunately the only way to tell is to take off the head cover and look. It's pretty easy to tell if it's off. Lock the engine at TDC with the crankshaft bolt and see if the dot on the timing wheel is even with the edge of the head.

Good luck!

mik-ktm400rxc · 05-04-2013, 06:00 PM

That's what I was thinking. Would this also throw the timing for the spark off? So that it would be sparking during the stroke or some other innapropriate time?

katumo_jtb · 05-04-2013, 09:02 PM

The timing gear being off wouldn't throw off spark timing as the spark happens relative to the crankshaft position, which hasn't changed; the sensor for spark timing is in the stator cover. But it would cause the valves to open and close at the wrong time relative to spark and compression, which would make it tough to start.

mik-ktm400rxc · 05-04-2013, 09:22 PM

Quote:

Originally Posted by katumo_jtb

Also do you have auto-decompression? Are you sure the auto-decomp was down when you measured the exhaust valves? Also, I thought the spec was .15mm, not .1mm.
Good luck!

I have the auto-decomp. I set the lash with-out messing with the decomp-cable, as the cable is attached to the valve adjustment cover, which was off to set the lash. I shouldn't need to do anything beyond removing the cable?

Also, I didn't mess with the timing gear (I think) I just pulled the cover off the head and replaced the water pump. But when I replaced the water pump I had to move the back-wheel, and therefor the timing gear, to re-install it. I thought I kept everything in the same orientation as before, but am uncertain if I did. So the deal with that is i am worried I turned the timing gear around once before reinstalling the valve/head cover, and if that could affect things....

katumo_jtb · 05-05-2013, 02:15 AM

OK, I misunderstood, I thought you had the timing gear off. Since you didn't, there's no way the valve timing could be off. It doesn't matter if things move around with the valve cover off, the cam is locked in place with the timing gear and the cam followers just sit on top of the cam.

With auto-decomp, it's not only the cable that could lift the exhaust valves but the extra inertial lobe on the camshaft. I don't have auto-decomp so maybe someone else can comment, but it's possible your valves seemed too tight because the decomp lobe on the cam was opening them slightly at TDCC. I think you can hear a little "clack" when the auto-decomp lobe comes down after TDCC. Maybe try adjusting the exhaust valves again and wait for the "clack" -- if your exhaust valves look way too loose this time, that's your problem.

10-07-2012, 02:04 PM	#541
Adios Pantalones AdventureDeficitDisorder Joined: May 2005 Location: San Diego, not Mex, but I can smell it from here. Oddometer: 2,198	New FCR 41 on the 620 Thanks to all the good info here, some all the way back to 06 in a Gaspipe post, I ditched the old edelbrock and coughed up for a new FCR 41. Long story short... it's a new bike. 96, 620, kick only. 5000mi on it. It went from an good, old used bike that ran kinda crappy to the beast it should be. I can stop shopping for the replacement bike! Sudco set it up right and got it to me in 2 days. I am officially ready for desert season! __________________ To do is to be. Socrates To be is to do. Plato Do be do be do. Sinatra

12-01-2012, 09:18 AM	#544
Adios Pantalones AdventureDeficitDisorder Joined: May 2005 Location: San Diego, not Mex, but I can smell it from here. Oddometer: 2,198	Did a pretty good soil sampling last weekend, cracked the orig. front fender and brace. No OEM available. Any ideas on good fittting aftermarket fender? __________________ To do is to be. Socrates To be is to do. Plato Do be do be do. Sinatra

05-04-2013, 03:12 PM	#548
mik-ktm400rxc 4-stroke nOOb Joined: Nov 2011 Location: Utah Oddometer: 9	A new mystery for those diagnosticians out thar' I have a mystery starting issue on a ktm rxc 400 96'. I changed the water pump seals on my bike and set the valve lash gap to the specified .1 mm on my way out. I had the cylinder and head rebuilt last summer and decided the recently ground valves should be re-gapped cus' of em settlin' into the re-ground seats, theoretically. It seemed the valve-lash was too tight. Now.... it won't start. It has spark. I didn't mess with the carb. IDK WTF. I have tried tightening and loosening the valve lash to various degress without success. It won't even backfire. There is nothing at all happening when I kick it, no hesitation, no nothing. I don't know what I coulda done while I was in there. Could I have messed with the valve timing/spark timing when putting the head back on? I had to move the wheel a bit to get the water pump back on... That's my guess. Could it be sparking on the wrong stroke or at the wrong time? How would I check it? Correct it? Gracias amigos para su tiempo, everyone on here has been a huge help in the past and I look forward to your diagnosticating regarding this matter.

05-04-2013, 06:00 PM	#550
mik-ktm400rxc 4-stroke nOOb Joined: Nov 2011 Location: Utah Oddometer: 9	Yep That's what I was thinking. Would this also throw the timing for the spark off? So that it would be sparking during the stroke or some other innapropriate time?

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12-01-2012, 01:04 PM	#545
katumo_jtb bogus journeyer Joined: May 2009 Location: Kali, People's Republic of Oddometer: 441	OEM fenders from later year KTM's will fit. The bolt pattern is the same, you just need to make sure you get a fender with the "nubs" that hold the mask in place. I'm using a fender from an '04 625 on my '95. John

01-30-2013, 04:29 PM	#547
2wheelwilli n00b Joined: Jan 2013 Location: Roanoke Rapids NC Oddometer: 5	Ok i need rxc help, mine is a 1995 rxc620 kick only, i need to find a battery where can i get one, my speedo stoped working so im useing my GPS till i find one... this bike is a blast.....

05-04-2013, 03:38 PM	#549
katumo_jtb bogus journeyer Joined: May 2009 Location: Kali, People's Republic of Oddometer: 441	The recent changes were timing gear and valve lash, so it's probably one of those, as you said. Are you sure you adjusted the valves at TDC on the compression stroke? You can lock the engine at TDC with the crankshaft bolt on the underside of the case. Also do you have auto-decompression? Are you sure the auto-decomp was down when you measured the exhaust valves? Also, I thought the spec was .15mm, not .1mm. However, I'd guess you're further out of spec than that, if that's the problem, but you should definitely make sure. The valve timing is the other possibility. If it were off, it would make valve adjustment confusing as the cam could be in the wrong place at TDC. Unfortunately the only way to tell is to take off the head cover and look. It's pretty easy to tell if it's off. Lock the engine at TDC with the crankshaft bolt and see if the dot on the timing wheel is even with the edge of the head. Good luck!

05-04-2013, 09:02 PM	#551
katumo_jtb bogus journeyer Joined: May 2009 Location: Kali, People's Republic of Oddometer: 441	The timing gear being off wouldn't throw off spark timing as the spark happens relative to the crankshaft position, which hasn't changed; the sensor for spark timing is in the stator cover. But it would cause the valves to open and close at the wrong time relative to spark and compression, which would make it tough to start.

05-05-2013, 02:15 AM	#553
katumo_jtb bogus journeyer Joined: May 2009 Location: Kali, People's Republic of Oddometer: 441	OK, I misunderstood, I thought you had the timing gear off. Since you didn't, there's no way the valve timing could be off. It doesn't matter if things move around with the valve cover off, the cam is locked in place with the timing gear and the cam followers just sit on top of the cam. With auto-decomp, it's not only the cable that could lift the exhaust valves but the extra inertial lobe on the camshaft. I don't have auto-decomp so maybe someone else can comment, but it's possible your valves seemed too tight because the decomp lobe on the cam was opening them slightly at TDCC. I think you can hear a little "clack" when the auto-decomp lobe comes down after TDCC. Maybe try adjusting the exhaust valves again and wait for the "clack" -- if your exhaust valves look way too loose this time, that's your problem.