annmariec Posted November 23, 2012 Report Share Posted November 23, 2012 A friend of ours just purchased a used 125 sherco, 2006 model year. We know the former owner, he never had a problem with this as far as we know. twice today, the bike suddenly revved to or near the limiter with no provocation by a novice rider using very little throttle (once was a crash, once was a nice save by a very rattled rookie!); then Mike (my hubby/our mechanic) rode the bike and eventually was able to repeat it. When it screamed, he could snap the throttle several times until it shut back down. no binding whatsoever at full lock either direction. the throttle cable had a small amount of excess freeplay which he removed. still could make it stick and scream. cable is good otherwise. We found that, when an adult rider is sitting on the seat-less seat area (not on the fender), the tank actually could pin the throttle cable. Zip tied the cable (loosely) to a segment of frame that keeps it away from said pinch point. Not certain if the bike reved out again after that adjustment. Obviously, the new rider is nervous to get back on her bike, and Mike is nervous to let her ride it again until we're certain the problem is solved. has anyone seen anything similar? any ideas what could be happening? HELP???? Quote Link to comment Share on other sites More sharing options...
theshercorider Posted November 23, 2012 Report Share Posted November 23, 2012 (edited) Something to do with the throttle cable is likely to be the cause as you say. Has any work been done recently on the bike that could effect anything? Make sure the throttle assembly on the bars hasn't been forced a bit along the bars. Can cause friction between the throttle tube and bars and give a sticky throttle. While your checking its worth cleaning out the throttle body. Also for what they cost it is probably worth replacing the throttle cable, they can wear over time and when not cleaned and lubed they can get spots where friction can cause them to not run smooth. Would be a good idea to strip the carb and take out all the jets and choke assembly and give them a clean and blow out with an air line. Also have a check of the manifolds to make sure there are no air leaks at all. I can't think of anything else off the top of my head, it's getting late Edited November 23, 2012 by theshercorider Quote Link to comment Share on other sites More sharing options...
copemech Posted November 23, 2012 Report Share Posted November 23, 2012 Well, other than the obvious issues with cables and such, I would check to insure the SUHMIC(spousal unit and head mechanic in charge) had not washed the bike without checking the airbox.!!! What happens is, if you get anywhere these things with a hose or pressure washer, you WILL slosh water up and over/into the air filter and it will wash through the filter carrying dirt and grit with it. This stuff will lay up in the lower section of the airbox untill you go out and slosh it around a bit, then the grit and slosh will be induced into the carb and the grit will bind the throttle slide, even if momentarily. If this does occur, be sure to pull in the clutch, as that is your bailout tool! Then pull out the blanket, for the SUHMIC will be on the sofa for a while! If this has not happened yet, it will, so beware! Quote Link to comment Share on other sites More sharing options...
dombush Posted November 23, 2012 Report Share Posted November 23, 2012 This happened to me once on a CR500, one of the most frightening experiences of my life. As has been said above there are two main sources of such problems.... The cable itself and the slide sticking in the carb. Copemech has covered the slide sticking subject. Also caused by poor / missing air filter. A list of the possible cable related checks might be:- Throttle housing too far up the handlebars leading causing jamming against the handlebar end and the grip. Freyed inner cable at the twistgrip housing end. This can be found by removing the snap-cap on the Domino twist-grip housing. ANY freying here is bad. Also check that this area is free of dirt / excess grease and that the cable "drum" rotates freely. Damaged / poorly seated outer throttle cable entry into the twistgrip housing. This area should be held "in line" by a strong rubber boot when handlebars are turned. Any rocking of the cable outer here is bad. Similar issue at the carb end of the outer cable. Where the outer cable joins the "swan neck" of the carb there should be a rubber boot to stop water getting in at this joint. Check that it isnt easy for the cable outer to slip out of the "swan neck". This could easily be caused by poor cable routing or if the swan neck has been oriented poorly when the carb is refitted. Check the routing of the cable with the rear mudguard and tank off. The cable should take a reasonably straight path and not be over constrained on its route. Check for areas of the cable that have worn through the outer plastic sheath to the steel reinforcement below. This is bad. Lastly, remove the slide from the carb removing the 2 screws holding the slide cap on. Withdraw the slide and look at the cable inner and return spring. Spring in good condition?? , ANY cable freying here is bad. Hope you find it... confidence is everything for young riders (and older ones!!) Quote Link to comment Share on other sites More sharing options...
htrdoug Posted November 23, 2012 Report Share Posted November 23, 2012 Borrow some parts from your temporarily dormant 280 to isolate the issue,see if you can swap throttle cables over,if that doesn't correct it then swap the carb,doesn't have to be jetted perfectly,just not leaner than the 125 carb(I am unsure which carb is on the 125s that year) Problem persists with different carb-look for air leaks in engine,problem goes away-repair or replace old carb. You might consider relocating kill button to a location that can be reached by your thumb without removing your grip from the bars,might give a new rider some peace of mind that she can keep it from running away from her. Twin kill buttons would work just fine. 1 Quote Link to comment Share on other sites More sharing options...
baldilocks Posted November 23, 2012 Report Share Posted November 23, 2012 not sure if the layout is the same but i filed a groove into the upper side of the head steady on my 2007 so the cable didnt get nipped by the tank. i have had those symptoms on a yamaha before but lubing the cable cured it. Quote Link to comment Share on other sites More sharing options...
annmariec Posted November 24, 2012 Author Report Share Posted November 24, 2012 thanks all! SUHMIC knows about perssure washing et al, as he taught me. he did not, however, take the whole bike apart and work over every inch of her as he did my new-2-me used bike a few weeks ago. Just got distracted and didn't get there ... so, he says to pass along a thank you! the iarbox was clean but the air filter was dry and there was dirt binding up teh carb slide. also found some other minor issues along the way. in the mean time, my friend the new rookie got a few hours ride time on my Gas Gas 80, which has been good for her as well! And, I got about an hour on the Sherco 125 once SUHMIC was pertty sure it was fixed but he wanted it ridden more before the new rookie took it in hand again. conclusion? I LOVEEE my GG80 and do not like the powerband of the 125. But luckily the 125s momma DOES like it and she happily rode her again this evening. Quote Link to comment Share on other sites More sharing options...
annmariec Posted November 24, 2012 Author Report Share Posted November 24, 2012 (edited) Borrow some parts from your temporarily dormant 280 to isolate the issue,see if you can swap throttle cables over,if that doesn't correct it then swap the carb,doesn't have to be jetted perfectly,just not leaner than the 125 carb(I am unsure which carb is on the 125s that year) Problem persists with different carb-look for air leaks in engine,problem goes away-repair or replace old carb. You might consider relocating kill button to a location that can be reached by your thumb without removing your grip from the bars,might give a new rider some peace of mind that she can keep it from running away from her. Twin kill buttons would work just fine. Impressed you remembered my GG280, thanks Doug! <AHHH doug ... I didn't ercognize the username at first. Nice to see u here Mr May!> We are relocating her kill switch as we did mine as well, thank you also for that suggestion. I hadn't thought of twin kill swiches, but that's an idea! Edited November 24, 2012 by annmariec Quote Link to comment Share on other sites More sharing options...
jfc Posted November 24, 2012 Report Share Posted November 24, 2012 To help with confidence how about a lanyard type (kill switch) Quote Link to comment Share on other sites More sharing options...
ham2 Posted November 24, 2012 Report Share Posted November 24, 2012 I know I'm a bit late to the party with this topic but I recall a friends 02 Sherco with a sticking slide in the carb' body,a truly frightening experience for an adult never mind a young rider . In that particular case it was the grit and water scenario just as Copey described. It was surprising how insignificantly small the grit and water droplets were to cause the (huge) problem but I suppose any water or grit in any carb' is a bad thing. It certainly tightened up my carb cleaning routine. Quote Link to comment Share on other sites More sharing options...
htrdoug Posted November 24, 2012 Report Share Posted November 24, 2012 Now you can harass Chris about "How can a guy who owns a auto detail shop..." I've been told by a young man who has plenty of experience with them that the Sherco 125 got much better response in 2011. Quote Link to comment Share on other sites More sharing options...
annmariec Posted November 24, 2012 Author Report Share Posted November 24, 2012 we'll not harrass Chris too badly. Hey doug, how would you do twin kill switches, where, and to what benefit? And to everyone -- WHY did they move kill switches to the center of the bars??? Our 84 and 91 trials bikes both had them just to the right of the left grip which seems like SUCH a more logical location. Quote Link to comment Share on other sites More sharing options...
htrdoug Posted November 24, 2012 Report Share Posted November 24, 2012 Center of bars kill switch is not easily contacted by accident while riding,and easily reached no matter which side the bike is lying on. Kill buttons just ground the circuit,so you could hook 5 of them in parallel and they'd all work. You can leave the center mounted on in place and just tap in a second one out by the left grip. Quote Link to comment Share on other sites More sharing options...
copemech Posted November 30, 2012 Report Share Posted November 30, 2012 thanks all! SUHMIC knows about perssure washing et al, as he taught me. he did not, however, take the whole bike apart and work over every inch of her as he did my new-2-me used bike a few weeks ago. Just got distracted and didn't get there ... so, he says to pass along a thank you! the iarbox was clean but the air filter was dry and there was dirt binding up teh carb slide. also found some other minor issues along the way. in the mean time, my friend the new rookie got a few hours ride time on my Gas Gas 80, which has been good for her as well! And, I got about an hour on the Sherco 125 once SUHMIC was pertty sure it was fixed but he wanted it ridden more before the new rookie took it in hand again. conclusion? I LOVEEE my GG80 and do not like the powerband of the 125. But luckily the 125s momma DOES like it and she happily rode her again this evening. All good to hear, now Stay away with the hose as well, may be worse due to the water volume! Best practice is to build a foam plug, pull fender and remove filter before washing and install plug in filter hole. (takes 1 minute) Then blast away! Hand dirty mudguard to spousal unit for cleaning! BTW, as time goes on, you will find a 125 more tractable without revving the crap oit of it, They are docile! Quote Link to comment Share on other sites More sharing options...
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