yamaha tmax 1st post!

[neilab28]

Welcome to the forum, I hope you get things sorted

[shottsy]

Right, listen up!
Spent the entire day and stripped every connector out, cleaned reassembled, the entire bike, fuse in starter relay keeps blowing, i disconnected the ignition, clutch, and side stand switches, one at a time and checked the switch were working with dmm. All fine, i was at the end of my tether and wondering other than scrap what i could do.... I bypassed the starter relay, by attaching a cable direct from positive side of battery direct to the side of starter relay that goes directly to starter, bike started perfectly no issues.
I unplugged the plug from the relay, and connected up battery, fuse was ok but not start obviously,then i made a short piece of canel with connectors either end, i conected one by one the plug that goes into top of starter relay, inside the plug there are four connectors. It blew the fuse on touching two,only. I traced them and they seem to go to the rectifier/ regulator. Which is all shiny and new as it was replaced by the dealer when i bought this heap. So i have presumed all along it would be fine. Mistake! So when i then unplug this gleamng new rectifier/regulator the bike fires up instantly and all is well with the world......except the battery is taking no charge.
I am now wondering whether i have a problem with this new rectifier/regulator or whether the real cause could be the magneto/alternator...??????
So anyone know where the bloody thing is, how to test it , and whetehr this is the end of my issues?

I would drown in beer if i was not trying to lose weight!
Shottsy

[michaelphillips]

hi lad, you can download a service manual here http://scootercommunity.com.au/files/fo ... fault.aspx" onclick="window.open(this.href);return false;
use the top one although this is the 2001 carb model the magneto and reg/rectifier will be the same
the magneto is in AC volts (scooters normally chucks out 50+ ac volts) Rectifier capacity is 18A and can withstand up to 200 volts

then the rectifier changes this to dc volts ( this could be cause if not working)
the Voltage regulator side then keeps the dc volts constant about 14.1 14.9 V dc so on the output side of rec/reg

can you clarify... is blowing the fuse on trying to start (turning starter over) or when you switch ignition on

you need to clarify the above first

[shottsy]

hi Michael

fuse blows when you connect the battery up , no ignition on....
the if you unplug the rectifier , the fuse stays good, engine starts on a button, revs, and the world is a beautiful place....
I have just unplugged the magneto , rear left side white plug that goes around to the rectifier on the right side rear , with engine running and my tester into the plug, I am getting 25-28 volts on tick over and up to 70 odd when revved up..............
I had te minutes to try it before customer came over, I will go back and do the check again to make absolutely sure of what I am getting. but I am slightly at a loss as the plug has three connectors in it, 2 of them gave me the results above and the 3rd one gave me nothing.......but as I say I need to check again properly...
I have found some guys saying that due to the magneto being immersed in the engine oil , chemicals created , it attacks the cables coming from it to the plug , the very same plug I am checking out...more than one these guys have said that the magneto in the bottom left has a burnt out section, been the same on a few bikes of that era with 30k on the clock......maybe something in it...
I would love to know how and if possible, to check that the magneto is working correctly by knowing how to test the plug coming from it, as getting it out and replacing it is costly and boring, I do have another rectifier on order and coming but as I said before this was replaced by the main dealer when I bought it , due to a discharge problem the week after I went home with it, I am now wondering if the magneto had started to breakdown at this point, and what I am now dealing with is the final bit of life of the magneto which has finally s**t itself........
I am on the south coast and boy we have some wind today!!!

much thank you's to all so far...........

[michaelphillips]

if you getting AC volts of 28 on tick over and 70 on revs then i cant see that being the problem, as scoots tend to be around the 55 volts , not sure on what yours is supposed to be in the manual though, i would wait till the regulator comes and fit that first, as this is suspect... the three connectors from the magneto when you look at it, then you can put an ohms reading on 1 to 2 etc to see if you get the specified ohms from the manual... yet i suspect the regulator/rectifier to be faulty... while you waiting check the earth cables on scoot are grounded properly usually one from the starter and battery area, but check the manual, you do have a workshop manual from online

[shottsy]

yep, just been talking to Roger at bbbikeshop.co.uk , that lad knows his stuff.......
I have now tested the magneto or stator, and it does exactly what it should across al three connectors in the plug.
which now points heavily at the rectifier, but I see absolutely no damage to the rectifier, no overheat bulges, or distortion, nothing...
does anyone know how to check a rectifier???
I have the new one coming but it would be agreat shame if I plugged it in and then it overheated and s**t itself again.........
so whilst I am happy it would appear that the stator/magneto is okay I am wondering what the cause of all this is.......or am I just unlucky with a brand new rectifier fitted by the dealer has gone wrong........do they go wrong often??? every bike I have ever had has never had an issue with a rectifier......
despair will set in if the new one does not fix it.....

[michaelphillips]

yep, just been talking to Roger at bbbikeshop.co.uk , that lad knows his stuff.......
I have now tested the magneto or stator, and it does exactly what it should across al three connectors in the plug.
which now points heavily at the rectifier, but I see absolutely no damage to the rectifier, no overheat bulges, or distortion, nothing...
does anyone know how to check a rectifier???
I have the new one coming but it would be agreat shame if I plugged it in and then it overheated and s**t itself again.........
so whilst I am happy it would appear that the stator/magneto is okay I am wondering what the cause of all this is.......or am I just unlucky with a brand new rectifier fitted by the dealer has gone wrong........do they go wrong often??? every bike I have ever had has never had an issue with a rectifier......
despair will set in if the new one does not fix it.....

unfortunately you normally test the rectifier in situe and test the output dc volts, which should be 14 to 14.5 dc volts when engine running.. as you cant do this and everything seems ok when out of the loop would stand to reason that the rectifier has a fault, , they are sealed units and disposable items , i had one go on the Nexus at 30,000 miles yet depends on whether the one which was put on yours was new or not you could be unlucky, most manufacturers put them in a place where they can cool, eg near the front rad on larger scoots but in recent years they have creeped up to the side of the frame area etc, and tend to get hot

[shottsy]

yep, you are right, exactly.
I am now wondering why on earth the fuse is blowing when the key is not even in the ignition, not turned on, yet I go to link up the battery and the fuse blows, but only when the rectifier is plugged in...?? if the rectifier was faulty with a short or something inside it then how is it coming live when I connect up battery yet with the ignition off??? or does it sit on an open circuit all the time???
at a loss here.............

[shottsy]

afternoon chaps;
t max has now gone , never solved the electrical problem as it seemed to sort itself out, never had another issue........now looking at a gilera gp800 , Honda silverwing, or burgman 650, all second hand up to 2008 , circa 20,000 miles, lots available .............any advice from you good people ??

[poldark]

I'm a fan of the B650 but under no circumstances buy a K3 or K4 (early) bike, they have a design defect quietly rectified on K5 onward (primary spline).