Mr OCD Posted February 3, 2008 Share Posted February 3, 2008 Hi All, I have just bought myself a 99 Yamaha Thundercat so thought would join the forum. I got the Thundercat for a tidy sum due to it needing a couple of small jobs... one is that the front brake calipers are binding... the other the downpipe has a tiny pin hole in it... Now tonight I stripped down the calipers and had problems shifting the pistons... I managed to clean them up and get the pistons back into the body but they are still very stiff so I am going to source some others but for now I need to put them back on the bike but I'm having MAJOR problems bleeding them... can anyone help? - not had issues bleeding bike brakes before but these arent having it... the Master cylinder doesnt seem to be sucking fluid down... Regarding the downpipes do they rot badly in general? I have had a look at mine and I can weld up the small hole then strip / paint but I'm thinking maybe replacing the whole lot might be an idea instead although not cheap Any help appreciated Link to comment Share on other sites More sharing options...
chrisw Posted February 3, 2008 Share Posted February 3, 2008 Hi there and welcome! Sorry if I state the obvious here but when you pushed the caliper pistons back ... you did take off the reservoir cap didn't you !! If you didn't then they would have been very hard to press back. Usually if you push them right back and give thearea a good clean (I use parrafin and a toothbrush) then they'll probably work fine. To bleed them shouldn't be a problem, are you saying when the bleed nipple is open and you squuze the lever then nothing comes out the nipple either, or that the system is emptying but not taking and fluid back in? I found the Cat downpip does corrode and swapped it for a stainless steel MOTAD on, but the bolts can easily snap in the engine .... which aint funny. Link to comment Share on other sites More sharing options...
Mr OCD Posted February 6, 2008 Author Share Posted February 6, 2008 Thanks for that... the calipers have freed off now the bike is being used daily... got some braided hoses coming this week then I'll be stripping the calipers down again with new seals, etc... Downpipe has been welded up for now so does the job but I will try and source a stainless one for sensible money... the downpipes were removed last December as it needed a new sump (cracked it overtightening the sump plug) so they shouldnt be too difficult to swap. Does anyone have a Thundercat here who can tell me if theirs starts on the starter button? - I have to give it some throttle then press starter before it spins into life - is this normal? - my old Bandit never needed throttle to start neither does my Wife's TT600 so seems odd to me... How do I find out fault codes on these bikes? - appparently the rev counter will tell me? Link to comment Share on other sites More sharing options...
chrisw Posted February 7, 2008 Share Posted February 7, 2008 for reading fault codes the Rev needles jumps bettween actual reva and either the folowing 8,000 rpm - Either the fuel light bulb has blown or .... most likely the sender unit has become faulty (usually just requires a wire soldering on but requires you to take the sender out of the tank to repair. 3,000 rpm is the Throttle Position Sensor Some people also say 7,000 is a code but this refers to the EX-up valve which isn't fitted to the Cat. Your other topic has got a reply from me about the throttle needing a bit of a twist when starting . but in general Yes you do tend to have to mine used to and a mates used to need it. Link to comment Share on other sites More sharing options...
Bluekat Posted June 17, 2009 Share Posted June 17, 2009 Chris this advice was spot on.... Checked the bulb first .... Not the fault but when I took the sender unit out of my tank ... Bingo the wire had been disconected from the solder tag. Fired up a soldering Iron and sloved the issue... Saved me a few hundred quid... for about 1 hours simple DIY. Once again thank you... So if you get a 8000 rpm fault code check the sender unit out inside the tank... Link to comment Share on other sites More sharing options...
kev1961 Posted February 9, 2012 Share Posted February 9, 2012 in reference to the sticking front brake on your thundercat,I recently purchased a 2001 model and found out three weeks later the bottom two pistons on one of the front calipers were seized solid (making it difficult to even turn the wheel) I phoned yamaha for some prices on both the pistons and the seals £330 + vat for the pistons (eight pistons.seals included) or £102 + vat for just the seals. I managed to get all the pistons out ok,apart from the seized ones which were not really servicable after removal,unwillig to pay the price for genuine ones I scoured ebay for pattern parts ( ebay code-140678427285 for four pistons and all seals for £69.95) (or 220918636002 for the seals for one caiper £19.95) I have used the piston kit which arrived very quickly and works perfect (I hope it is ok to quote pattern parts as I am new to this site,but if the main dealers didnt charge as much I would use them) just one tip I found the old seals a pig to get out,I tried cocktail sticks,small screwdrivers,a tiny ofset pair of long nose pliers with no joy due to lack of space big hands but eventually used the needle from a hyperdermic syringe (wifes a nurse) bent it into a "c" shape and with the aid of a pair of long nose pliers had all the seals out in seconds with no damage to the calipers (a bent pin would also work ok) I had a problem bleeding the brakes at first,but I think it was due to the fact that all the pistons had been pushed fully back in to the calipers,I bled each side a couple of times then making sure both bleed nipples were closed kept pumping the brake (the fluid did go down still) eventually I started to get something regarding a brake,both sides were bled once more and every thing was spot on. hope this is of some help cheers kev Link to comment Share on other sites More sharing options...
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