ask greeves Posted January 13, 2007 Report Share Posted January 13, 2007 (edited) Good on you Mr RRansom, Sorry for my abrupt bedside manner. Be careful you don't fall into the usual bad cenario, strip down something were it's not necessary. I personally would have tried the obvious fixes before taking the drastic step of removing and stripping the engine. 1/ Make sure the carb was snapping back closed 2/that the engine wasn't 'loaded up' with fuel/oil and on starting 4stroking giving the impression that the revs were rising, as the engine cleared. 3/all these things assume that you've correctly fitted the new barrell /piston 4/ Have you got a flywheel extractor to remove the ignition flywheel, these engines were designed so that the main bearing oil seals can be changed in situ. Bill Pye probably's going to love you, when you turn up with a basket load of 309 engine. Just a thought, why did it rev up in the 1st place, did you catch the throttle cable ! Edited January 13, 2007 by ask greeves Quote Link to comment Share on other sites More sharing options...
rransome Posted January 14, 2007 Author Report Share Posted January 14, 2007 To tell you the truth it wasn't me riding it, it was my mate he went over a jump and fell off twisting the throttle wide open when the bike fell by the time i got to him the damage was done. This might sound dumb but to change main oil seals am i going to loose my transmission oil. and if so how much does it Hold when i put it back. Quote Link to comment Share on other sites More sharing options...
ask greeves Posted January 14, 2007 Report Share Posted January 14, 2007 Fantics are so good, you don't even have to know the amount of oil necessary for the transmission, haven't you ever changed the transmission oil ! there is an oil level plug just below the gearchange lever. When you remove the cover you'll see it. Unfortunatley rransome your asking all the wrong questions, you've got no idea off the basics, like the amount of oil, but your prepared to attempt the difficult. Personnally I started my mechanical engineering with mechano, then progressed to lego, then push bikes, then motor bikes, then cars now aeroplanes. I've found the secret is, put it back together in the reverse order that I took it to bits and never force anything. Cleanliness is of utmost importance, not personal cleanliness, some of the best trials riders have been known to whiff abit, but cleaniness of the reassembled internal engine parts. I personnally think that your best friend will turn out to be Big Bill. To get the job done properly with all the correct parts Big Bill will probably work out cheaper in the long run. Quote Link to comment Share on other sites More sharing options...
rransome Posted January 14, 2007 Author Report Share Posted January 14, 2007 I have thought about taking it to bill's on many occasions, But i feel as if that is giving in, I removed the engine and distmantled the top end to have it re-bored and then re-built it my self. And I would rarter like to do the rest of the work myself with guidence from people along the way. I fing that actualy working on the bike and the eventual satisfaction that will come with knowing that i have saved anothr fantic just as much fun as riding it. Quote Link to comment Share on other sites More sharing options...
lee harris Posted January 14, 2007 Report Share Posted January 14, 2007 (edited) MMMmmm? Ok throw your hammer away. Then throw the pliers, mole grips, big iron levers and anything else away you may be tempted to use!!! Lets just try the oilseals for starts as Greeves was greeving about! Take off the kicktart lever on the right. Take off the flywheel cover. Becareful and the gasket MAY be re-usable. Holder the Flywheel witha flywheel holder and toosen the nut. Alternatively use an air gun and a hammer/air ratchet. You will not need to hold the flywheel in this case. SPECIAL tool number 1 needer. Crank Flywheel puller. Screw into the flywheel tighten the nut, maybe tap with a leather mallet and wammo, the flywheel is off. DONT HIT IT WITH A HAMMER. NEVER. EVER. look for the marks on the ignition backplate, If there are none there, make one. When you reassemble, make sure they line up PERFECTLY. Now you see the RH Oil seal. Come back to that later. Left side. remove the gear lever . Loosen the case cover screws evenly and remove the cover. TAP gently the six screws holding the clutch in place. LEAVE THE STEEL HAMMER in the bin. Foild a piece of surgecally clean Rag 16 times and wedge it between the crank gear and the clutch basket. Loosen and remove the cluch screws. Use that air pistol again to LOOSEN the clutch center nut or use a clutch hub holding tool. DONT TRY to wedge it with a BIG BAR OR TYRE LEVER; YOU WILL BUGGER SOMETHING: oops caps lock again! Fold down the lock tab on the crank nut and use that air gun again to loosen the crank nut. If you have no gun, refold your wifes knickers again and wedge it in there (no the engine) to stop the nut rotating. Remove both nuts and then a flat two or three screw puller to remove the left hand crank flywheel. Stop if you dont have the right puller. NO LEVERS BARS OR HAMMERS Now you can see the LH crank seal. To remove the seals I use two spokes with the nipples on the end. Grind the bent end to form two hooks. Push these into the centre of the seal and turn them outwards. I then bridge the two spokes using a thick steel bar and then get the mole grips on the bridge...I know you threw them away.... and pull. Wamo, the seal is out! try that for starters Edited January 14, 2007 by Lee Harris Quote Link to comment Share on other sites More sharing options...
fantic156 Posted January 14, 2007 Report Share Posted January 14, 2007 (edited) MMMmmm?Ok throw your hammer away. Then throw the pliers, mole grips, big iron levers and anything else away you may be tempted to use!!! Lets just try the oilseals for starts as Greeves was greeving about! ETC : Informative with a splash of humour. Made I laugh Edited January 14, 2007 by fantic156 Quote Link to comment Share on other sites More sharing options...
ask greeves Posted January 14, 2007 Report Share Posted January 14, 2007 (edited) I would do as Lee says on the magneto side oil seal, but on the clutch side i would remove the whole assembly, which is held on with 3 alan screws, also change the large outer o ring and the small inner o ring behind the inner spacer. The chief mechanic is pointing at where the oilseal and retainer is situated. Edited January 14, 2007 by ask greeves Quote Link to comment Share on other sites More sharing options...
rransome Posted January 14, 2007 Author Report Share Posted January 14, 2007 Thanks very much for the instructions i have printed then out so i can follow them as i do it. I am planning to tackle the job next sunday. I intend to take pics as i go to refer back to so ill post some on here. Quote Link to comment Share on other sites More sharing options...
lee harris Posted January 14, 2007 Report Share Posted January 14, 2007 But pete, you always did have more experience on the proper bikes...im still used to stripping beamish suzuli lumps Quote Link to comment Share on other sites More sharing options...
blocky Posted January 15, 2007 Report Share Posted January 15, 2007 Very good explanation Lee... AND it made me chuckle. I am VERY slowly putting together some instructions for doing the crankseals on a TX250 on my website which is pretty much the same on most Fantics I believe. If your interested the link is http://www.blocky.sitesled.com/ then go to TECHNICAL Quote Link to comment Share on other sites More sharing options...
rransome Posted February 1, 2007 Author Report Share Posted February 1, 2007 Hello There. Thanks for all the advice on this topic it has been very usefull, I have now replaced the seals. I removed the engine from the bike and completley striped it down even split the crank case to check for debris. I have replaced all o rings and gaskets with new it wasn't a difficult job just took a bit of time. Re-built it back exactly the same as it came apart and everything turns over like a dream. Engine is now back in bike but not started as i ran out of time, Just carb, tank and wiring to put back and then we will see. Im going to start it on saturday morning so i will post with either more question or a possative answer. Thanks Quote Link to comment Share on other sites More sharing options...
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