copemech Posted May 21, 2009 Report Share Posted May 21, 2009 Gday all, I should have said that Jon, I knew that... of course the leakdown test by itself only tells you if there is a leak. Anyway - I was wondering are the Sherco mufflers repackable? (In that they come apart for cleaning and repacking) For the record I have had a few earlier (1999 - 2001) Sherco front and mid pipes in my cold parts cleaner tank for cleaning with no adverse results afterwards and it works well. For you other guys in Aus I use Hunters' Carbo Clean in a 25 litre plastic bucket. Also really good for cleaning your barrells and other engine and carb parts but nothing plastic. If you can get some it might be worth a try to make sure the inside bits of those pipes are really clean. At least then you have a known good point to work from. Cheers, Stork "Are they repackable?" Well, if you can cut out all the welds, and are handy with the TIG torch, it can be done! Not very practicle though. I do think that the longevity of these things is somewhat determined by the oil used, as it seems the hard carbon buidlup is the most offensive and clogs the baffle tubes. The oil that is still oily will eventually move out on its own. Quote Link to comment Share on other sites More sharing options...
neo Posted May 22, 2009 Author Report Share Posted May 22, 2009 Hey Stork,...Thanks for your additional input....I knew I'd forgotten someone in my list of Knights in shining armour Right Gents, I know Jon has mentioned this Leakdown (pump-up) test in other threads. And since then I've been itching to give it a go. But the soapy spray idea has convinced me really it's worth doing. So last night I set about making a "pumping point" out of a drilled out spark plug and an inner tube vale stem. So with any luck tomorrow, being a rainy day, I'll finish it, plug up the holes and pump her up......Question is how many PSI?....or is it the more the merrier And how slowly should this pressure drop? Best of balance. Neo Quote Link to comment Share on other sites More sharing options...
stork955 Posted May 22, 2009 Report Share Posted May 22, 2009 Gday Neo, 3-5 psi is plenty. It should hold a vacuum (if you can do that) for around 15 minutes or more also. Id just use a bicycle pump. Remember to block off the exhaust port and the inlet manifold securely too. You may find caps off spray cans, deodorants etc will plug the holes nicely. Soapy water brushed on with your missus' pastry brush will help find the leaks. Don't get caught using her indoors' kitchen gear. Take the flywheel and stator off too so you can get at the crank seal on the maggy side. Mark the location of the stator before removal! Good luck. I'm itching to see how it goes. Stork Quote Link to comment Share on other sites More sharing options...
tony27 Posted May 22, 2009 Report Share Posted May 22, 2009 Seeing as you need to block off exhaust port anyway making a plate with the fitting in it & testing with the piston at bottom of bore is the way I'd do it I turned up a plug to fit in manifold whenever the carb is out instead of a rag & that would be the way to go if possible Good luck with the testing & hopefully you get to bottom of it Quote Link to comment Share on other sites More sharing options...
neo Posted May 24, 2009 Author Report Share Posted May 24, 2009 (edited) Hi All, This is what I discovered ......nothing!!....no leaks found at all Ok I've pictured my "Leak Down Kit" so I explain how I used it. Fitted the "pump up" vale (as pictured) in the spark plug hole. The yellow cap fits perfectly (with a bit exhaust paste) into the exhaust port (comes from a plastic petrol container which is very common in Aus). Then bolted the header pipe back on to hold the cap firm. I made an inlet plug out of some PVC waste pipe. Heated one end, put a bit of silicone in it the clamped it in the vice. It fitted snugly into the rubber inlet manifold. I also inserted a thin tie cord into a reed vale to make sure the valve stayed open. I then removed the flywheel and stator (great suggestion Stork!) and the bash plate.....then I got ready with the soap spay. Lastly I put that yellow pipe on the oil breather, then into the little plastic container filled with soapy water....My theory here was that if the right hand seal was leaking the air would make it's way out via the oil breather and been seen in bubbles. So...first problem.....I have no bicycle pump ...what the hell, use the electric tyre pump . So a quick burst with that...oops she's hit 10psi already..."what the hell"... start spaying all over....Nothing Hmmm.... "What concerns me about all this process is the bike normally starts hunting when it's hot. But this engine is cold" Ok lets tun up the pressure oops she's hit 20psi now...what the hell... start spaying all over again....Nothing Ok lets tun up the pressure oops she'd hit 35psi now ...what the hell... start spaying all over again....Nothing She held that 35 PSI...and dropped to 32 PSI some 20 mins later....And I reckon the only reason it dropped at all was because I kept taking pressure readings On the plus side....this is one hell of sealed engine I have .....On the negative side....I still don't know what's wrong with this bike Gday Neo, don't worry about the hunting while warming up - keep in mind that the engine is probably just off choke but not at operating temperature yet, so don't go looking for a cure for this as you will only upset some other aspect of its running. Stork what I meant by warm engine is an engine that's not really hot...say less than 15 mins of riding. Even today the engine was hunting very mildly shortly after staring. I rode her for half an hour like that. Then 2 hours later I rode her again and she was as good as gold So all I can say now gents is...."next idea please" Best of balance. Neo Edited May 24, 2009 by Neo Quote Link to comment Share on other sites More sharing options...
stork955 Posted May 24, 2009 Report Share Posted May 24, 2009 If it held 32 psi it must be OK. Maybe though the leak (if it has one) doesn't happen until its hot. It might pay to get it real hot and repeat the test, although it will take a bit of time to set up it still may reveal something. Worth a try anyway. Cheers, Stork Quote Link to comment Share on other sites More sharing options...
copemech Posted May 25, 2009 Report Share Posted May 25, 2009 I think that putting that much pressure on a lip seal would actually help them seal! I think one would need to T in a sensitive low pressure guage to do this properly at low pressures such as a tire guage. Mine is a glycerine filled unit with 0-15 in 1/2 psi increments i think. And then on the other hand, the entire question is weather or not it is sucking air, so one would really need to perform this with a handheld vacume pump or summat. Once again at relatively low vacume. Neo, patronize me again by gently removing the carb and loostening the bowl screws(may need other hands to hold) then gently remove the bowl and pour it into a clear pyrex bowl to see what comes out and settles in the bowl. No outside debris allowed. Then put it back all nice and clean, and ride it without the vent tubes installed. Quote Link to comment Share on other sites More sharing options...
neo Posted May 25, 2009 Author Report Share Posted May 25, 2009 Hi Gents, Looking at the design of the main seals there are two sealing edges. One sharp (angled, pointing outward) and the other much wider and flat. So I'd guess that these seals would only seal better if pressure was being applied from the outside, causing that sharp edge to press harder onto the shaft. Getting the engine really hot then working with that header pipe is not my idea of fun and I'll have to find a non plastic cap for that too.....Otherwise things could get melted and messy ....But I might try this next weekend. Wife allowing....as it's our 23rd anniversary this weekend But I tend to agree that if it held 32PSI it can't be that bad. Also remembering it would need a fair volume of air to lean out the mix on every stroke. Supporting this theory is the fact that both the throttle cable and the Carb cable tube are not sealed at all....yet most bike are not effected by air leaking past the slider. Cope I'll empty the carb into a glass bowl again....It's always best to go back to basics when all else fails. But I know it can't be those vent tubes. As they've only been on there these past couple of month. And questioning my own prognosis....Can anyone think of any faults that would be just like an engine running lean? .....Next time it starts hunting should I stop and take a look at the colour of the spark plug?....or would a glass windowed spark plug help me here? Best of balance. Neo Quote Link to comment Share on other sites More sharing options...
ham2 Posted May 25, 2009 Report Share Posted May 25, 2009 Gents,here's a long shot but I get the feeling Neo is heading down this way....when faced with a Sherco with poor running problems and the owner has thoroughly checked off all the mechanical / carburation procedures (just like me) then we are into the realms of black magic .Yes, Sherco coil -itis...after a long lay of I'm about to resurrect my poor running Sherco by getting the stator coil re-wound. I'll keep you posted. Quote Link to comment Share on other sites More sharing options...
neo Posted May 25, 2009 Author Report Share Posted May 25, 2009 Hmmm....maybe....maybe not Something I forgot to mention...... It was only when I took the plastic cover off of the flywheel that I realised that since owning this bike for 2 years the fly wheel cover had never been removed....not since the previous owner sealed it on with silicon. So it was like going back in time.......Before my eyes was an untouched shining flywheel....almost too good to use a rattle gun on And the stator coils were just as clean and shiny as the flywheel too.....so it's hard to believe that this baby would give me trouble....but I'll keep an open mind for now. Are your symptom similar to ours Ham? ....Let us know how you get on? Best of balance. Neo Quote Link to comment Share on other sites More sharing options...
stork955 Posted May 25, 2009 Report Share Posted May 25, 2009 Gday Neo, heres a thing - are you sure its running lean when it plays up? I reckon do what Cope says and if it plays up have a good look at the plug, (start with a clean one to get a good base point). It may be overly rich. I was thinking of this on the weekend with another Beta in our club - its just a little bit "flat" and its rider told me he has the needle fully down (circlip in the top groove). Needle jet and Jet needle wear methinks. Not saying your bike is like this but there may be over-richness contributing here. Cheers, Stork Quote Link to comment Share on other sites More sharing options...
copemech Posted May 26, 2009 Report Share Posted May 26, 2009 (edited) Gday Neo, heres a thing - are you sure its running lean when it plays up? I reckon do what Cope says and if it plays up have a good look at the plug, (start with a clean one to get a good base point). It may be overly rich. I was thinking of this on the weekend with another Beta in our club - its just a little bit "flat" and its rider told me he has the needle fully down (circlip in the top groove). Needle jet and Jet needle wear methinks. Not saying your bike is like this but there may be over-richness contributing here. Cheers, Stork I can well see this one being a bit flat, cause with the needle down it would limit fuel in the throttle range. Yet I would not think the needle position would normally have much anything to do with the idle properties if things were right... meaning no abnormal float levels as the needle is in front of the throttle valve and there should be no true vacume there at idle as vacume is maintained only upon the back side of the slide. There is a transition port installed just behind the needle, which should take over at a crack of the throttle and before the needle gets off the straight part. The actual idle circuit port in the bore is so exceptionally small(possibly even smaller than the low speed jet itself) that anything could disturb it. This is the critical one, and must be backflushed with cleaner and blown out with air, several times to insure the circuit is clear all the way back to the airscrew as I recall, which should be removed when backflushing the circuit. I know I am forgetful, but Neo, tell me again what jetting is in this and what needle. What fuel tank vent(standard hose?) along with what came out of the carby this time. Edited May 26, 2009 by copemech Quote Link to comment Share on other sites More sharing options...
neo Posted May 26, 2009 Author Report Share Posted May 26, 2009 Gday Neo, heres a thing - are you sure its running lean when it plays up? Well I suppose I don't completely. All I know is when she's hunting I adjust the air mix (on the PWK) clockwise and the hunting stops (well almost) for a while then a few mins later she runs poppy (rich) and I adjust the airmix anti-clockwise and that makes it run smoother again. This variation can go back and forwards before it settles down or before I give up adjusting it and just ignore it...which make me ride like crap I might invest in one of those glass window spark plug to see whats happening. Best of balance. Neo Quote Link to comment Share on other sites More sharing options...
ham2 Posted May 26, 2009 Report Share Posted May 26, 2009 Neo, strange (annoying) things happen when the stator starts playing up on a Sherco, its not always just a case of open/closed circuit . I'm sending my stator off to be tested...................Wayne Quote Link to comment Share on other sites More sharing options...
copemech Posted May 27, 2009 Report Share Posted May 27, 2009 Well I suppose I don't completely.All I know is when she's hunting I adjust the air mix (on the PWK) clockwise and the hunting stops (well almost) for a while then a few mins later she runs poppy (rich) and I adjust the airmix anti-clockwise and that makes it run smoother again. This variation can go back and forwards before it settles down or before I give up adjusting it and just ignore it...which make me ride like crap I might invest in one of those glass window spark plug to see whats happening. Best of balance. Neo Well, once again, temp and baro changes throughout the day can change things. I mean, I even keep a thumbscrew type adjuster on the dellorto fuel screw to adjust accordingly. In stoich theory, the airscrew would be almost 15 times more sensitive to changes stated for a proper mix range, normally considered 1/2- 1 - 1/2 on the screw range for best range of adjustment sensivity. Thing I cannot reconcile is the continuous need to richen the mix by reducing incoming air through the screw. The restricted exhaust theory may come into play simply by inducing more partially burnt mix into the combustion chamber returning through the exhaust port and having a low oxygen content thrown into the mix, which requires an enrichment of the primary fuel/air source. This should normall yield lower performance on the bottom end and possibly more high end ? Need to see if Clav can report on his findings still. Yet while we wait, what about Neo, his fuel dump, and even the try of the 24 on the bike? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.