Cheers to everyone here for keeping the legend alive and for all the exciting discussions and troubleshootings.
I’m an avid reader for a few years now, but never posted myself. Well now it’s time.
My father passed on to me his 447 XS, it‘s a chopper conversion by the Germans from HM, also called Stiebler. It’s a wild bike.
He was owning it for 30 years and It was sitting in a barn for most of that time. And it never ran fine. And he didn’t ever get it to run properly apparently.
It used to always have a weird mix of ignition and charging issues (both, not ignition issues caused by not charging). Sometimes running better sometimes worse, always backfiring through carbs, one time even blowing the carbs off! We took a closer look and noticed all sorts of issues and worn parts, some of them being a faulty reg/rec conversion resulting in not charging the battery, crappy ignition and, hold tight:
Wrong pistons for the crankshaft that was installed, resulting in a larger combustion chamber and less compression(6 bar)!!
Back to old regulator + rectifier and took the engine apart to change to the right pistons. We tought the pistons might be the main issue. First she was running sweet and charging, dad even kickstarted by hand with 8-9 bar compression, but during the first ride it died and then again running poorly, backfiring through carbs a lot and would die at idle at some point. And then never fired again.
Before it died it was similar to how it ran when I got it in the first place.
Then we did another overhaul:
Cam chain tension set, valve clearance set, timing to slighty after F-mark(slightly retarded).
And it doesn’t do a thing when kicking like a m*****f******.
Multiple occasions each time 20 kicks without pulling throttle, with choke, no sign of life at all!
Only one single firing with kickback after pushing a tiny bit of gasoline directly into the cylinder.
It’s got compression, fuel, spark – so WTF?
Three thoughts I wanted to share that I noticed.
1. Advance unit is sticky – one time I checked timing and was wondering why it’s completely off at full advance, turns out the advance unit got stuck somehow. Am I correct that it does not play a role when starting at idle/low rpm??
2. The pin that is holding the ATU is not pointing perfectly straight up when at TDC, it is off by 2-5 degrees clockwise. Maybe the chain jumped?!?! But if it jumped, wouldn’t this throw off timing and making it impossible to time to F mark?
3. Spark plugs always wet when taking them out after another kicking session without any firing. Maybe the spark is good when testing, but when mounted in the cylinder and under compression?!
What do you guys think? What else am I missing?
I am worried that there’s something fundamentally wrong with engine/cam/cam chain timing. When we assembled it we paid close attention to the mark at the cam.
THANKS for any thoughts on this, I am lost and I want to rip my XS around.
Chris
I’m an avid reader for a few years now, but never posted myself. Well now it’s time.
My father passed on to me his 447 XS, it‘s a chopper conversion by the Germans from HM, also called Stiebler. It’s a wild bike.
He was owning it for 30 years and It was sitting in a barn for most of that time. And it never ran fine. And he didn’t ever get it to run properly apparently.
It used to always have a weird mix of ignition and charging issues (both, not ignition issues caused by not charging). Sometimes running better sometimes worse, always backfiring through carbs, one time even blowing the carbs off! We took a closer look and noticed all sorts of issues and worn parts, some of them being a faulty reg/rec conversion resulting in not charging the battery, crappy ignition and, hold tight:
Wrong pistons for the crankshaft that was installed, resulting in a larger combustion chamber and less compression(6 bar)!!
Back to old regulator + rectifier and took the engine apart to change to the right pistons. We tought the pistons might be the main issue. First she was running sweet and charging, dad even kickstarted by hand with 8-9 bar compression, but during the first ride it died and then again running poorly, backfiring through carbs a lot and would die at idle at some point. And then never fired again.
Before it died it was similar to how it ran when I got it in the first place.
Then we did another overhaul:
- complete new DIY wiring harness
- New coils, condensers, points
- New ignition switch ,fuse box, battery (only 15 amps main fuse is "old" taken from a Harley)
- checked plugs and plug cables
Cam chain tension set, valve clearance set, timing to slighty after F-mark(slightly retarded).
And it doesn’t do a thing when kicking like a m*****f******.
Multiple occasions each time 20 kicks without pulling throttle, with choke, no sign of life at all!
Only one single firing with kickback after pushing a tiny bit of gasoline directly into the cylinder.
It’s got compression, fuel, spark – so WTF?
Three thoughts I wanted to share that I noticed.
1. Advance unit is sticky – one time I checked timing and was wondering why it’s completely off at full advance, turns out the advance unit got stuck somehow. Am I correct that it does not play a role when starting at idle/low rpm??
2. The pin that is holding the ATU is not pointing perfectly straight up when at TDC, it is off by 2-5 degrees clockwise. Maybe the chain jumped?!?! But if it jumped, wouldn’t this throw off timing and making it impossible to time to F mark?
3. Spark plugs always wet when taking them out after another kicking session without any firing. Maybe the spark is good when testing, but when mounted in the cylinder and under compression?!
What do you guys think? What else am I missing?
I am worried that there’s something fundamentally wrong with engine/cam/cam chain timing. When we assembled it we paid close attention to the mark at the cam.
THANKS for any thoughts on this, I am lost and I want to rip my XS around.
Chris
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