silverwood Posted January 27, 2013 Report Share Posted January 27, 2013 Hi guys, I have a rather unkempt '03 2.5. I bought it recently for a good price and have slowly been sorting things out as I go along. This is my first trials bike, mx before, so there's a lot of learning on both the spannering and riding sides! I've been having issues with the bike's running. After a carb strip and clean the bike is back to being crisp but after a ride is back to being fluffy and wooly off the bottom end. It normally clears once revs are up but as I'm trying to learn the low speed balance stuff it's not very handy... I've been putting this down to a partially blocked pilot jet which fits with what I see when I strip it down. However it seems to be a recurring issue. I've read that the airbox and silencer design is poor and can let water and muck into the airbox. Is it so bad that it could be affecting almost every ride? Conditions are very wet at the moment so there is more muck being thrown by the rear wheel which may tie in. Has anyone else had a similar issue? Are my thoughts in the right direction? A second wee issue is the clutch which is a bit temperamental. I've been ignoring this so far as it's a problem I've been able to ride around as I was getting used to the bike but now I need the clutch more often. Can you bleed the clutch in the same way as you would bleed the brake? It feels as if there's air in the system which needs a couple of pulls of the lever to clear. Again any thoughts or suggestions would be great! cheers, ferg Quote Link to comment Share on other sites More sharing options...
broadie Posted January 27, 2013 Report Share Posted January 27, 2013 Hi ferg The pilot jets are normally too small at around 30 you you want about a 36 as a starting point. Your clutch can you can bleed I'd change the fluid he it was mine. Quote Link to comment Share on other sites More sharing options...
tony27 Posted January 27, 2013 Report Share Posted January 27, 2013 If the pilot jet appears to be getting partially blocked after every ride it may that you are either missing the screen filter in the side of the standard dell orto carb or if are running a keihin you need a inline filter On the dell orto there is a cover that the fuel line is connected to, remove that & there should be a fine mesh screen in there. If you think you're getting water in the airbox there are a couple of things to check/do. Is there a small black splash guard fitted at the front of the airbox that sits over the front of the airbox where the carb connector fits? This is the piece http://www.splatshop.co.uk/sherco-air-box-deflector.html Sherco also put out a bulletin about taping up under the rear guard down to the airbox to seal up that area http://www.shercousa.com/pdfs/Engine_Stops_Running_in_Wet_Conditions.pdf A question for you, how do you remove the carb from the airbox, if you undo the connector from the carb & leave it on the airbox it is very difficult to get sealed up again, easiest & safest way is to leave it connected to the carb & undo it from the airbox which is really the only way refit the airbox with the splash guard fitted Quote Link to comment Share on other sites More sharing options...
copemech Posted January 28, 2013 Report Share Posted January 28, 2013 Better describe "clutch which is a bit temperamental" !!!! Quote Link to comment Share on other sites More sharing options...
silverwood Posted January 29, 2013 Author Report Share Posted January 29, 2013 Better describe "clutch which is a bit temperamental" !!!! It feels like there's air in the system although whether that is the case remains to be seen. The plates have been sticking as I think the bike had been standing for quite a while before I bought it. After a warm up and some revs it frees up. However to get the clutch to engage often takes a couple of pulls at the lever rather than being there as soon as you need it. Any other suggestions then? The oil when I changed it was silver, which I've read about on here before, but looked mental! On the wee black splash guard I'm missing one of those! I am running an inline fuel filter and have cleaned out the tank which has helped. I am removing the carb and airbox as two separate pieces with the airbox as one and the carb with the rubber connector as the other. They don't seem to want to come out as one which I think I had read on here was the optimum way of going about things. The carb is the dellorto but I haven't seen a screen mesh and have had to change the fuel line which had gone brittle and horrible. Will have a look again and check the pilot jet for which size it is. Seems like there'll be another order going in to Splatshop again! Thanks for the help so far guys, really useful stuff Quote Link to comment Share on other sites More sharing options...
copemech Posted January 30, 2013 Report Share Posted January 30, 2013 Right then, a number of issues to cover here. If the actual clutch lever feel is consistant, it is unlikely air in the system. If the lever feel varies on application, I would be looking at poor seals in the master cyl and a rebuild kit for it. It is somewhat normal for the plates to stick after sitting, yet this worstens with oil degredation and if your old oil was that bad then it may take several changes to clean things up. There are a number of reccos for oil on here, or ATF, but ck to see what Splatshop recco is, as I use Maxima at the mo but? If you are getting floaty idle and surge, the carb is still suspect and hopefully you are sure the system is flushed and no water or condensation. The pilot jet is critical it seems and needs to be clean and correct. As mentioned, it seems 35-36 range is not uncommon nowa in UK fuel, so you prolly need to know exactly where you are at in addition to insuring it is totally clean. There is a round part held by a 10mm head bolt where the fuel line enters the carb. Under that is the banjo screen, and it works well if intact. No need for inline filter on those as redundant. Generally, dirt and water may pass through the bore of the carb due to poor filter maintenance ans such, but it does not generally the float bowl that way. Most this either comes in along with the fuel, or from the bowl vents on either side which are open to atmosphereic pressure and must breath. I recco short tubes of around 50mm length here as crap deflectors and to help prevent water entry when washing the bike and such. Aside from carb issues, I think the age of the bike alone makes the crankshaft seals suspect and I would change them out for the Viton ones from Splatshop, all has to do with alcohol in our fuels. Duck tape at the mudguarg/ airbox junction with a drip flap formed in front as well, and if really mudy, put a strip along the side as it runs along airbox to mudguard. NEVER wash the bike without pulling mudguard and either blocking off filter hole or removing it after and cleaning up the mess you have made in the bottom of the airbox! Ta, let us know how you get on, MC Quote Link to comment Share on other sites More sharing options...
silverwood Posted February 1, 2013 Author Report Share Posted February 1, 2013 Evening ladies and gentlemen. Managed to get the carb off today for a look. The screen filter is there which is good. It was quite dirty but seemingly doing its job. On the pilot jet front the one in the bike is a 33. Would it still be advisable to go up to a 36 or so? The carb wasn't particularly dirty this time on strip down with no visible water or dirt in the float bowl. The pilot jet did look a touch restricted but the hole is so small it's hard to tell accurately. On the airfilter front I'm quite good on making sure they're cleaned, changed and oiled regularly so there shouldn't been an issue there (famous last words...). Crankshaft seals seem to be popping up in every thread on here! Are they really that common a failure? The issue I'm having does seem to go away after a carb clean and only come back after a while. It's not something that is always present but something that develops. I'm hoping that this means it's not something as serious as the seals going! Quote Link to comment Share on other sites More sharing options...
copemech Posted February 2, 2013 Report Share Posted February 2, 2013 Ok well, I think it is kinda like this on the jetting thing. Back when your bike was new, it seemed we all got along quite well with jets in that range. Seems fuel has changed over the years, and of course the alcohol is a big part of it. This could effect the seals as well. Your jet issue with possible dirt is a constant given as they are sensitive. I use a fine wire to pass through the hole gently as a cleaning tool that is hopefully non abrasive, then cleaner and air and such through all the other passages as well. Evertyhing here is critical, and it will get dirty again in time, depending. Many times you may never spot the culprit! I like my pilot jet large enough to where I can actually get some range out of the fuel trim screw as compared to simply running it out to the effective limits of around 3.5 turns and leaving it there where more is not better and less sucks. I can actually adjust mine on the day and the temps, and comes in closer to the 2.5 range mostly, may need more in cold temps, and less when warm you know. I am at 38 on our fuel. Too large and you will get a blubbery transition to the needle at 1/8 or less throttle. Go by local referance if you can, for your area, but I think 36 is common in UK now. If it runs well with a clean carb, then all is well, yet I will tell that the odd occasional unstable operation at lower revs is a symptom of a seal issue. The seals are not all that difficult to change with a bit of proper gear. That in itself is a minor repair, not an overhaul. Quote Link to comment Share on other sites More sharing options...
silverwood Posted February 9, 2013 Author Report Share Posted February 9, 2013 (edited) Thanks again for the replies and advice so far guys. Have had an incredibly frustrating day. Ordered a 36 pilot jet and mud deflector from Splatshop through the week. Fitted them both today and popped it all back together. I checked and my main jet seems to be roughly in line with what others are running. Can't remember the number now and I didn't write it down. I was all ready to try it out but it simply wouldn't start. Will pull it apart tomorrow and try again as I may have missed something simple. The spark was good with a strong kick and the plug was reasonably wet but I'll start again to make sure of no stupid slips. Getting quite frustrated with the bike. I love the spannering side of things but I equally love riding and so far I've done far more of the former! The full title for my bike is The Recalcitrant Sherco. I hope it redeems itself and I guess (hope) most of the issues I'm facing are due to previous owners but it is making me think longingly of a solid, dependable 4rt.... Feel free to sing the Shedco's Sherco's praise in order to change my view! On another point, is the bleed nipple on the clutch slave cylinder meant to be a 7mm fitting? I have never seen a 7mm nut and don't have a spanner in that size. Will have to order one for the toolbox and the fluid change will have to wait for that Edited February 9, 2013 by silverwood Quote Link to comment Share on other sites More sharing options...
copemech Posted February 10, 2013 Report Share Posted February 10, 2013 Thanks again for the replies and advice so far guys. Have had an incredibly frustrating day. Ordered a 36 pilot jet and mud deflector from Splatshop through the week. Fitted them both today and popped it all back together. I checked and my main jet seems to be roughly in line with what others are running. Can't remember the number now and I didn't write it down. I was all ready to try it out but it simply wouldn't start. Will pull it apart tomorrow and try again as I may have missed something simple. The spark was good with a strong kick and the plug was reasonably wet but I'll start again to make sure of no stupid slips. Getting quite frustrated with the bike. I love the spannering side of things but I equally love riding and so far I've done far more of the former! The full title for my bike is The Recalcitrant Sherco. I hope it redeems itself and I guess (hope) most of the issues I'm facing are due to previous owners but it is making me think longingly of a solid, dependable 4rt.... Feel free to sing the Shedco's Sherco's praise in order to change my view! On another point, is the bleed nipple on the clutch slave cylinder meant to be a 7mm fitting? I have never seen a 7mm nut and don't have a spanner in that size. Will have to order one for the toolbox and the fluid change will have to wait for that A Sherco is probably the easiest bike to maintain and parts are comparitvly inexpensive. I know it may sound daft, but you did'nt put the floats in upside down did you? Fuel on with enough in tank so you do not have to go to reserve? 7mm sounds about right, yet I have never had to bleed one that way. Even if there is air in it, removing the M/C cap and bellows and gently stroking the lever should let any air migrate up and out. Quote Link to comment Share on other sites More sharing options...
silverwood Posted February 10, 2013 Author Report Share Posted February 10, 2013 (edited) A Sherco is probably the easiest bike to maintain and parts are comparitvly inexpensive. Probably very true but it's just the continual cycle of repairs at the moment that's dragging me down. That added to the rubbish rides are making it hard! Was low for an hour or two after last night but I'm back and upbeat now and ready to get it sorted! It is a very pretty bike but it does push me to nasty thoughts at times. I should however be blaming former owners rather than the bike I suppose. I think it is probably something dumb like that. The bike did proceed to dump its half tank of fuel over the garage floor last night which further points to a bout of ineptitude. I was very keen to get it together and get out for a ride yesterday so I've probably missed something simple in my haste. I can but learn... Will have a shot with the cap off the clutch reservoir. Had a read up on the Beta fix. Is it a worthwhile procedure for the Sherco? Edited February 10, 2013 by silverwood Quote Link to comment Share on other sites More sharing options...
copemech Posted February 11, 2013 Report Share Posted February 11, 2013 [/size] Probably very true but it's just the continual cycle of repairs at the moment that's dragging me down. That added to the rubbish rides are making it hard! Was low for an hour or two after last night but I'm back and upbeat now and ready to get it sorted! It is a very pretty bike but it does push me to nasty thoughts at times. I should however be blaming former owners rather than the bike I suppose. I think it is probably something dumb like that. The bike did proceed to dump its half tank of fuel over the garage floor last night which further points to a bout of ineptitude. I was very keen to get it together and get out for a ride yesterday so I've probably missed something simple in my haste. I can but learn... Will have a shot with the cap off the clutch reservoir. Had a read up on the Beta fix. Is it a worthwhile procedure for the Sherco? It is all a learning curve in a way. Start off on a decade old bike that may need attention, then add your lack of specifics, it is all good. So, just how did it spill fuel overnight? Lets get her back to running first insuring the carb is good if possible. Is the bottom end full of fuel now? Tips: The float arms should be LEVEL with the bowl parting surface when inverted, measured at 18.5 or so mm. The tabs on the floats go down in the bowl, and the floats should have Alto marked on the top as I recall. Insure they are not heavy and full of fuel as one would sink. And the work freely on the rods. See if you can get it going and get back about the clutch as well. Quote Link to comment Share on other sites More sharing options...
silverwood Posted February 12, 2013 Author Report Share Posted February 12, 2013 Well I was correct on the stupidity side of things.... The new mud deflector has made getting the carb and airbox on much more difficult. I guess in the struggle the fuel line was trapped and torn without me noticing. Cue half a tank of fuel seeping out over the floor in a steady, unnoticed drip. It went back together, however stupid isn't joined by simple. At first it wouldn't start. I pulled the plug and checked the spark it was producing. I compared it to a fresh one and they were similar; producing a nice big spark with a good full kick but nothing with a weedy kick. Bike back together and she started up. Success! er.... no. Warming her up she started to bog, eventually dying. I changed the plug over for a new one. Again she started but then after a minute or so began to die. I left the bike and came back after ten minutes. She would fire on the choke but would soon die just as before. The only thing I can liken it to is on a mx bike when the plug fouls and the bike won't rev cleanly and dies. Whether this is the case or not I'm not sure. At a 36 have I gone too high on the pilot jet? Is this fouling the plug a bit like on an mx bike? The plugs don't look like a fouled mx plug however. The old plug was a nice light brown colour and quite dry. I haven't pulled the new plug out yet to see how that looks but it seems to quick for the plug to go off in this way? Equally why would the bike start on the choke and run, even for a few seconds if the plug was fouled? I am confused and sad Quote Link to comment Share on other sites More sharing options...
copemech Posted February 13, 2013 Report Share Posted February 13, 2013 Well, some progress it seems! No the 36 is not soo large to cause any of that. From what you describe, it sounds as though it is running out of fuel With the running on choke thing, this is still an indication of no fuel. Start again with basics, pull the tank and open the tap to insure good flow, even a blocked vent can prevent flow to carb. See if you can get a spanner on the bowl nut to break it loose to insure flow and float valve are allowing sufficient flow to bowl. Insure the vent tubes on either side of the carb are open so fuel can flow into the bowl. With your pics, things still look a bit grungy to me, and with carbs cleanliness is next to godliness. you should be able to eat off it when you are through, inside and out. Get on with it! Quote Link to comment Share on other sites More sharing options...
tony27 Posted February 13, 2013 Report Share Posted February 13, 2013 If it's starting on the choke & bogging when the choke is switched off then the pilot jet circuit has some form of blockage somewhere If my memory serves me correctly I ran my fuel inlet so that the hose was just missing the vent The easy way to refit the airbox with the deflector is to fit the carb then slide the deflector into place then slide the airbox through the hole in the deflector & into the joint, it gets easier with practise & the deflector does form to the correct shape over time Quote Link to comment Share on other sites More sharing options...
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