Can a sprag clutch wear out?
- Thread starter racepaul
- Start date
It's a 2002 EC400FSE and it is original part. Here is finnish gasgas sparepart sellers page where it can be found: http://ahvalaracing.markkina-avain....p/Select/List&E158116O=40&x158116=Select/Card
Tech info on sprag:
SIAM RINGSPANN
Freewheel with cage SF44/16K
Part number: 3673044.001
Torque: 380 Nm
Shaft diameter: 44mm
External diameter: 62mm
stainlesscycle
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that's a strange i.d. for a sprag. i've googled extensively and don't see any aside from that one..
I fitted a LeoVince silencer to my gasser and it made a HUGE difference in kickstarting! Now I can kickstart my bike easily no matter if it's cold or hot 
Still haven't got new sprag to my starter but it's okay because I can kick it It was pure pleasure to be able to ride the bike. Still must find and repair a oil leak and then it's time to get some mud flying 
Still haven't got new sprag to my starter but it's okay because I can kick it
It was pure pleasure to be able to ride the bike. Still must find and repair a oil leak and then it's time to get some mud flying
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mikethebike1127
New member
A bit late in relying to this but here goes......this will maybe help with slow cranking problems. My 450 cranked over very slowly when I bought her. I always blamed the starter motor so I eventually changed it out for a modified DRZ item. Motor span over slightly quicker but the problem was still there. I laid the bike down on its right hand side, removed the fly wheel/started gear casing and hit the starter button. Starter and the upper gear/cog were spinning as the should but everything below was sluggish!!!. I removed said cog and found there was a 17mm hex on the back. Stuck it in the vice and backed out the hex......this split the inner and outer gear. Inside the two is some friction material (a la clutch plate/brake pad). I can only assume this whole cog is a safety devise which allows the two cogs to spin independently should the motor kick back on start up thus preventing casing damage. I then cut a disc of thin cardboard (shoe box), placed it between the cogs and nipped them back up in the vice. Threw everything back together, pushed the started button and hey presto....the bike has started first push of the button since.
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I had the dreaded slipping happening on the starter clutch / torque limiter on my EC450 2009 model.This is the answer in most cases. I went through all of this last year. I suspected the torque limiter from the start but I was told by mechanics that it would be the sprag. After spending money on parts and tools I wasn't happy the first time I hit the starter after doing the job only to hear the starter freewheeling again.
There is a simple test to determine whether you have a sprag problem or a torque limiter problem. Remove the torque limiter and draw a line on it like in the photo below. Put it back in and press the starter button until you hear the freewheeling sound. Pull it out and i'll bet the marks don't line up any more.
If you find that you're torque limiter is slipping you can disassemble it and add a washer to increase the pressure on the gears. You can see the washer I added to mine here. It's a bit tricky to line up the 3 large gears when you put it back together. Don't bother trying to line them up when you press them back together. If you put the small gear in a vice you can turn the upper and lower gears individually with a big pair of multi grips until they line up with the centre gear.
I used a bearing puller like this one to do the job.
I noticed that the front plate of the torque limiter that sits immediately behind the circlip was slightly concave around the circlip/washer, which was reducing the pressure on the friction plates. I removed the circlip and pulled the stack of plates off and noticed the other side was identical - the plate stack is symmetrical, and because the other side sits behind those concave washers it was in perfect condition.
So I reassembled with the plate stack reversed, squashed it together in a vise with a couple bits of wood to protect it so I could fit the circlip, and now my bike starts beautifully. I did not need to shim it at all!
Your post was very helpful in identifying the problem so thanks very much!
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