Fatbloke Posted October 2, 2011 Report Share Posted October 2, 2011 Hi guys, The wife's mates son has an RS125 which he siezed up and spent £600 having it repaired only for it to happen again. She has asked if I could have a look at it for him as he has run out of money and doesn't want to go back to the same place for them to do it again? If I find anything obvious I will go back to them for him but thought i'd ask on here first. Are there any known issue's with these? Air leaks, fuel starvation? If anyone can give me a starting point I would be very grateful, Ta Fatbloke. Link to comment Share on other sites More sharing options...
Stu13 Posted October 2, 2011 Report Share Posted October 2, 2011 No well known issues with this bike but to be honest if I had just paid someone to fix it and it happened again I would be straight back to them wanting it sorted for free. It seems they must have missed something or did they only do part of the work? Link to comment Share on other sites More sharing options...
Fatbloke Posted October 2, 2011 Author Report Share Posted October 2, 2011 Not sure of the full story yet, I will pop over and talk to him tomorrow. I'll get it back here and have a quick look and see if there is anything obvious first. Fatbloke. Link to comment Share on other sites More sharing options...
Devon Posted October 2, 2011 Report Share Posted October 2, 2011 I own a couple of this, and build the engines for these. Id say check that the oil pump works, and if it does work it might not be set up properly so you may need to adjust it to allow more oil in. Id also check the there is actually oil in the tank and that its getting to the pump. There arent really any known issues for this bike apart from what is usually expecting from a two stroke. take the top end and check what damage there is in the barrel, you may be lucky and this kid didnt keep trying to get the bike running after it siezed then there may be little or ni damage that cant be sorted with a quick rub of an emery cloth. PM me any questions and I will do everything to give you advice as I have a few mates that are also like me obsessed with these amazing bikes Link to comment Share on other sites More sharing options...
Fatbloke Posted October 2, 2011 Author Report Share Posted October 2, 2011 Thanks Devon, i'll keep in touch Link to comment Share on other sites More sharing options...
Acid Posted October 2, 2011 Report Share Posted October 2, 2011 Obsessed Rs125 owner here too Ive two of them One I owned (2001) since new with 7400 kms from new and another 2001 with 30k + (speedo stopped last year)that gets death everywere and is amazing fun on the north coast, trackdays. Link to comment Share on other sites More sharing options...
Fatbloke Posted October 3, 2011 Author Report Share Posted October 3, 2011 Well, its now in my workshop and has de-valued my house by at least half!!! Never have I seen a sorrier looking pile of poo in my life. Watch this space for RS125 parts as I think it will be dismantled and flogged off in bits. Why did I agree to look at it???????????????????? Arse. Fatbloke Link to comment Share on other sites More sharing options...
oktrg500 Posted October 3, 2011 Report Share Posted October 3, 2011 Obsessed Rs125 owner here too Me too. I'm about to build my own now, after having helped my nephew racing one for two seasons. My build thread is here. @Fatbloke: Sorry to hear it seizing up twice. I hope you don't break it for parts. Keep up with service intervals, run a sensible jetting - and these things are both fast and reliable. Some pics of the piston could give a clue about what happened. Could you supply some more info about the bike? Model year? Restricted? If not, which restrictions has been removed? Carb model and size? Airfilter stock, or aftermarket? Size of main jet and position of the needle? Exhaust stock, or aftermarket? CDI stock, or aftermarket? (Usually HPI or Zeeltronic) Woodruff key stock, or advanced? Cylinder head and cylinder stock, or modifyed? Spark plug type? Give some more info, and we can give a shot at what the cause could be. Piston and rings I buy from PJME. Cylinder replate is around £130, if repair is required. Link to comment Share on other sites More sharing options...
Fatbloke Posted October 3, 2011 Author Report Share Posted October 3, 2011 Thanks dude, I can't face it tonight so i'm drinking beer in the house catching up on the racing from the weekend. I have got tomorrow off so will have a peek then. It seems to have locked the gearbox as it's jammed in a gear and won't find neutral so I had to carry the bastard thing into the workshop! I think it's all standard but i'll find out when it comes to bits. Living the dream Fatbloke Link to comment Share on other sites More sharing options...
oktrg500 Posted October 3, 2011 Report Share Posted October 3, 2011 I can't face it tonight so i'm drinking beer in the house catching up on the racing from the weekend. I hear you. I'm drinking beer myself It seems to have locked the gearbox as it's jammed in a gear and won't find neutral so I had to carry the bastard thing into the workshop! Seizure and jammed gear at the same time? Enjoy the beer tonight and let us hear when you have disassembled the top end. Easy to maintain these engines. With a little practice, the engine can be removed from the frame in 30-40 minutes. My guess is the seizures are related. Link to comment Share on other sites More sharing options...
Fatbloke Posted October 4, 2011 Author Report Share Posted October 4, 2011 Right then, its in bits. The bike is a "98 on an S plate. It has Mitaka on the barrel which i presume is after market. Ive taken the clutch cover off and the resin cog on the end of the crank is proper fu**ed and the gearbox is solid. The barrel and piston seem ok except lots of carbon build up on the piston crown. When I drained the gearbox oil about 100ml came out so where did the rest go to??????????? Could the carbon build up be from burning gearbox oil? If so how did it get there, crank seals? HELP!!! Does anyone want to buy a nice clean RS125, in bits??????? Fatbloke. PS I thought I had seen every bodge in the book however........the riders RHS footpeg has broken at some point and won't stay in place so the lad has wedged 5, yes 5 galvanised roofing nails into the hanger to keep it in place!!!FFS what have I let myself in for. Link to comment Share on other sites More sharing options...
Acid Posted October 5, 2011 Report Share Posted October 5, 2011 relax the Rs engine is dead easy to fix the resin cogs lead to the balancer shaft, easy fit and setup when the engine was rebuilt was it a top end rebuild ? mikita is an aftermarket head. crank case seals are an easy fix, better to fit new ones anyhow if the engine is an 98 and they are bound to be perished. gearbox is locked due to engine being seized, (im guessing). dont panic we will get you there !!! Link to comment Share on other sites More sharing options...
Fatbloke Posted October 5, 2011 Author Report Share Posted October 5, 2011 Thanks matey, The top end is fine and shows no sign of locking up so it's just the gearbox thats solid. How easy is it to split the cases? Ta Fatbloke Link to comment Share on other sites More sharing options...
2T Institue Posted October 5, 2011 Report Share Posted October 5, 2011 Thake note of the circlips in the gearbox they have a curved thrust face and they must be installed the correct way round. I would invest in the manual will make that and timing the balance shaft easy. Link to comment Share on other sites More sharing options...
Devon Posted October 5, 2011 Report Share Posted October 5, 2011 the big yellow plastic cogs are for the balance shaft so when you do put them back on, the one on the crank side has to be at TDC, The gearbox is really easy to take apart and rebuild, theres a few videos on youtube of a guy whos done tutorials of taking the RS engine apart the crankcases are easy to split, make sure all of the bolts are removed and then around the crankcases are little places that you can put something to help split them, there will be some resistance with the seals and bearings but they will split easily, just make sure when you do split the cases that you dont use too much brute force as the cases can easily get damaged. Link to comment Share on other sites More sharing options...
wazrs257 Posted October 5, 2011 Report Share Posted October 5, 2011 It could be that bits from the balance-shaft drive gear have found their way into the gear-box and have jammed it. Sounds like a full engine strip is required, although this could be a good chance to educate the lad! You should find all the parts you need HERE. Don't bother removing the gear-box gears from the shafts unless they are damaged. Link to comment Share on other sites More sharing options...
Devon Posted October 6, 2011 Report Share Posted October 6, 2011 Its really hard to get the gears off, ive been trying to find a set of circlip pliers to strip the gearbox shafts and rebuild Link to comment Share on other sites More sharing options...
Fatbloke Posted October 20, 2011 Author Report Share Posted October 20, 2011 Right then, the cases are split and its not looking good at all. My guess is the crank seals have failed causing the gearbox oil to leak into the barrel and get burnt off. It must have looked like the bloody red arrows display team!! Anyway, the gearbox has locked and smashed one gear into several bits, broken the teeth off most of the other gears and damaged the casings. The gear shafts are even bent! Good skils I think, ive never seen anything more broken. Anyone got a spare engine? If not I'm going to break the thing and recoup some cash for the poor sod. Fatbloke. PS, if you need any bits let me know Link to comment Share on other sites More sharing options...
Devon Posted October 21, 2011 Report Share Posted October 21, 2011 I have a few spare engines, They need properly rebuilding though, ive just put them together for storage, when im bored I split them and then put them back together for practise. Depending on the condition of the crank I would be interested in haveing it off you. Chuck some pictures up of the engine and perhaps it could be a pretty easy fix, Ive got a few spare gearboxes, and I can pretty easily source you one Oh the only other issue with my engines are that they are all tuned :/ so not to everyones liking Link to comment Share on other sites More sharing options...
Fatbloke Posted October 22, 2011 Author Report Share Posted October 22, 2011 Tried to take some pics earlier, as below. <a href="http://s908.photobucket.com/albums/ac287/fatbloke692/?action=view&current=P1040206.jpg" target="_blank"><img src="http://i908.photobucket.com/albums/ac287/fatbloke692/P1040206.jpg" border="0" alt="Photobucket"></a> <a href="http://s908.photobucket.com/albums/ac287/fatbloke692/?action=view&current=P1040207.jpg" target="_blank"><img src="http://i908.photobucket.com/albums/ac287/fatbloke692/P1040207.jpg" border="0" alt="Photobucket"></a> <a href="http://s908.photobucket.com/albums/ac287/fatbloke692/?action=view&current=P1040208.jpg" target="_blank"><img src="http://i908.photobucket.com/albums/ac287/fatbloke692/P1040208.jpg" border="0" alt="Photobucket"></a> Hope this works, I'm a techno spastic, Fatbloke. Link to comment Share on other sites More sharing options...
Acid Posted October 22, 2011 Report Share Posted October 22, 2011 fixed that for you Link to comment Share on other sites More sharing options...
crumpy Posted October 23, 2011 Report Share Posted October 23, 2011 ooh nice job you've got yourself there. I seized my RS125 a few years back chasing a Lamborghini down the A3 (lol). To be fair it was about 5,000 passed it's 10,000 service which includes a top end rebuild. The Mikita barrel and piston kit cost me £110 if I remember rightly and I managed to do it in one long evening afterwork with a friends help. I'll be fucked if I can remember anything useful though. good luck, you'll get her rolling again. I have a few spare engines, They need properly rebuilding though, ive just put them together for storage, when im bored I split them and then put them back together for practise. That sounds like the best way to kill time ever. good idea. Link to comment Share on other sites More sharing options...
Fatbloke Posted October 23, 2011 Author Report Share Posted October 23, 2011 Thanks for that, told you I was CRAP!! Its a good jigsaw isnt it? Fatbloke. Link to comment Share on other sites More sharing options...
Fatbloke Posted December 14, 2011 Author Report Share Posted December 14, 2011 Right then, it's been stuck in my garage for 2 months now and despite me chasing bits up for him it appears that he has no interest in it. So. Whats it worth in bits?? There is a virtually new Mitaka top end, the bottom end is mostly scrap and the rolling chassis needs a good clean up but is ok. Plastics are a bit tatty but all there. Give me some ideas please, Ta Fatbloke. Link to comment Share on other sites More sharing options...
2poke Posted December 14, 2011 Report Share Posted December 14, 2011 ive gotta gear box sitting in my garage good order just missing 3rd gear pinion off the output shaft if you need it ? be worth a lot more money running then it is now and for the sake of a days work (with the right parts) it has to be worth doing if you do sell it in parts what exhaust does it have i could be interested Link to comment Share on other sites More sharing options...
Fatbloke Posted December 19, 2011 Author Report Share Posted December 19, 2011 To be honest the lad doesn't have any interest in it. I asked him to come down and clean some of the bits up...............3 weeks ago. I might offer him a couple of hundred quid for it and see what he says. Thanks though Fatbloke. Link to comment Share on other sites More sharing options...
2poke Posted December 19, 2011 Report Share Posted December 19, 2011 if you do get it and rebuild it you more then welcome to the spare gear box i have (no good to me ) only missing third gear you could take that off the other one there if you want it mate Link to comment Share on other sites More sharing options...
Fatbloke Posted December 20, 2011 Author Report Share Posted December 20, 2011 Thanks for the offer matey, I'll keep you posted whats happening with it, Fatbloke. Link to comment Share on other sites More sharing options...
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