JimR

how did you know where I live ....... Regards Jim

hmm I guess the drill man must have worked in a swiss cheese factory part time... in my 15 years as a m/c mechanic i saw some snafu's but that one takes it !!!! had a good hour or so doing all 300+ posts ( and some links) what a twat regards Jim

is that with gasket removed or not regards Jim

I guess the bike has been well maintained ? if not do the normal things plug etc. Larger 4 stroke singles have a bit of a technique to starting so if the mechanics are ok you may need to change the way ur trying to start it. Regards Jim

was that for real ? regards Jim

I guess so as 2N2 is a MR50 (1978) but 2N1 is an XS400-2E(1978) could go either way regards Jim

no probs !! Regards Jim

It was my job !! I left the M/c industry in '89 which was not my doing ! my parents had a Yamaha shop & paid for me to be trained to a good standard but as I had health problems they sold it (no one to leave it too)now I'm an old git & fixed health wise I would like to help people with problems from machines I grew up with !!!! Regards Jim I'll PM the walk thro if thats ok

What relays have you got to test ? ok US modal has the annoying bit that you cannot switch the lights off (maybe a relay there) but whats left ? nowt ! if the neutral switch shorted you would not have the problem unless the US modal has a side stand switch ? to test the n/l switch disconnect the sky blue wire off the other plug from the engine (may appear nearly green with age) and see what happens ... or disconnect the starter switch (from memory royal blue wire & red with a white trace in a D plug). Ok seen new post I'll do the walk thro !!! regards Jim

You have a 'back feed' or faulty earth you need to start again do you still want the walk thro or ru ok to work it out ? regards Jim

How did you trace it to there ? I hope it was a bit more tech than just unplugging the genny and the lights went out. with regard to the 3 whites it doesnt matter regards jim

early yam's used these codes to identify the modal rather than the table shown. This would mean RD50M (1978 code 2L8) would be 2000 (M) RD200DX (1977 modal code 1E7) would be 2008 (X) XS650S (1979 modal code 3L1) would be 2004 (S) or 1986 (S) XS1100 (1978-80 modal code 2H7) would not exist XJ900S (1998 modal code 4KM) would be 2004 (S) or 1986 (S) FS1E (1973 modal type 394 ) would be 1978 (E) RD250LC (1980 modal type 4L1) would be 1976 © then you run into points of say XS250SE (1980, 4G5) and XS7502D (1977,1T5) how about the 1976 RD250 - 2 versions SP & CW (1A2) so it's not much good for older kit the 3 digit code will identify the correct modal regards Jim

how good r u at electrics ? I can give you a walk thro on testing but I would need you to know basic principles Regards Jim

The only way to set the ignition timing correctly is with a dial guage & ohm meter and the following order should be used:- L/h Cylinder first set the engine to TDC (zero the dti there) clean and gap the points to 12 thou wedge the advance/retard unit open (a cycle spoke bent into a u shape will do this, fits into the 2 holes in the unit) wind the engine clockwise 1.8mm, at this point the contacts should just break(open). Then do the r/h cylinder the same. don't forget to remove your atu wedge b4 you gap the points on the r/h cylinder. Don't use the timing marks on the advance/retard and that silly screw on datum mark, they were there to use a strobe to check if the advance/retard worked & not to set the timing. I've seen many a holed piston with timing set to those marks Regards Jim

which switch turned off ? main or kill ? regards Jim

Hi there are first three digits of the engine number 2H7 ? Regards Jim

Hi Ian, what's the air filter like ? The machine shouldn't start with no choke from cold. but 10 secs and it's time to knock it off, so I would guess it's running a little rich but a blocked silencer can cause over richness, try running the bike for a bit without the silencer run it up the road & see if you have a performance gain if so job done. With the silencer in that nick a new one would be a good idea, but to clear the old one tempory you could fill it with a caustic solution and leave it for a day or 2 but with a repair the caustic may eat thro it ! other alternative is to leave the silencer stood upright (gland nut downwards) until all the 'wet' gunge has droped out then shock the silencer (with a hammer or by bashing it on the floor, don't forget to remove the baffle) and shake out the dry carbon deposits. Had a YB once that would only do 20mph I removed double the weight of the silencer in carbon from it and performance was restored, this bike was a trade in the previous owner thought it was dead, he was a bit sick when he saw it wizzing round at 60 two days later !! Regards Jim

Hi Curly, Nice old bird you have there but remember to change the oil filter every 3k miles as the o.e unit would clog up in that time, I guess tho oil has got better and you may be able to strech the 3k limit Regards Jim

Hi Ian, forgot this bit the bike will start without choke if you leave the fuel tap in the on position as everything is a bit worn and the machine will 'flood' the disc valve so the machine will start because of excess fuel in its primary compression phase turn off the tap & you may have to use the choke Regards Jim

Hi Ian, How much did the silencer wiegh ? it should be about half a kilo if that any more than that it'll need some serious decarbonisation and I guess you checked the exhaust port, most over look that, as it's difficult to look at and work out if the port is half the size it should be ! The oil pump is dead simple to set up .... check that the marks on the grey plastic wheel( the one the cable runs thro) align at the correct point (this is dependant on modal year, some have a mark on the throttle slide which should be set to the top of the venturi and the marks should align else the lines should align at throttle shut (easy to work out which set up suits). Then you have minimum pump stroke to check do the following :- Run the engine with the carb cover removed and at idle (after cable adjustment) watch the plunger of the oil pump cycle in & out, stop the engine when the plunger is fully out (this takes a while to stop the engine at the right time, you may have a few goes at it). Then measure the gap between the grey cable wheel and the washer on the end of the pump piston with the throttle fully shut it should read between 0.10mm & 0.15 mm, if its out of spec remove the nut on the end of the plunger/piston & washer underneath will be some brass shims add or remove these to get the correct clearence, I guess you may have problems getting the correct shims because of the age of the bike but normally if the minimum stroke is set correct it well not alter over the life of the pump, some modals were set incorrect from the factory but i would think that your bikes original owner would have complained about either 1) The mess seeping from the rear of the silencer 2) The mess dripping from the gland nut between the exhuast pipe & silencer 3) If ridden hard excessive oil consumption if this makes no sense just drop the bike over & I'll test it out regards Jim

Hi There pull the plug and have a look .. if this appears to be the correct colour(light tan) and in good condition you may have problems with ignition circut, which will need read outs and a multimeter to test it out. Regards Jim

pull the battery out !

Hi Paul, take the battery out to gain access to the other terminal, its a bit of a balancing act but can be done. Regads Jim

I guess you get a wizzzzz-clunk as the motor starts is that correct ?

Should be ok depending on how it was laid up, try to get it going first, clean out carbs ,fresh fuel, charged battery etc. Once started if it doesn't sound like something wants to exit crankcase, its worth a bash. This engine has odd oil galleries in the crankcases so After u run the motor up and are satisfied that there are no major gremlins, drain the oil & re run it with a flushing oil in to clean the odd little holes out in the crankcase. If the carbs are out of sync at idle the engine will sound like a bag of poo, if you get the rattle which will then disappear when reved, continue with the project. Regards Jim