Garygazza

Thanks Merv and Drewpy for the info.The bike is a c disc model.I have seen pistons for a 750 on Yambits web site so I will try them.

My front caliper seals have started to leak brake fluid.On removal of the caliper piston it is very pitted and requires replacing.Are these calipers fitted to any other model .M and P list a kit for a 250 d and e,are they the same calipers?

Signed

About 200+ set off from the M2 services and took control of both lanes.A few dickhead car drivers decided to take the hard shoulder,but were soon boxed in

Hi,I have a question about the kick start on my 1978 xs250.Should the kick start turn over the engine at the top of the kick start stroke?My kick start does nothing until its at about the 9 o clock position leaving very little travel left to start the engine.The clutch is not pulled in when I start the bike.

Romney Marsh bike show and jumble on tomorrow.Hoping to find some spares for the old Xs .www.elkpromotions.co.uk/

I have the wrong rev counter fitted to the xs,it has a neutral light as well as a main beam light in the counter.The rev counter also red lines at 8500 and goes up to 10000 rpm.I have seen one on ebay which red lines at approx 9250 and peaks at 12000 rpm,it also only has the main beam indicater.The part number is 1L9-83540-01.Does anyone know if this would be the correct rev counter for my 1978 xs250.Many thanks Gary

pilot error my haynes manual says x-8 not x-6 as I said previously.My parts book covers xs250s type 1u5 and xs360 type1u4.It list a y-0 for the 250 and x-6 for the 360.I think adjusting the needle might be the way to go,a bit less confusing

Im now getting confused!!According to tne yamaha parts book I have the correct nozzle is a y-0.The haynes manual says x-6?

I have an 78 XS250 with Mikuni bs32 carbs fitted and have the right hand cylinder running weak.I found on strip down of the carb the left and right hand carbs have different main nozzles fitted but the needles are the same.Not sure if this is causing the issue but I would like to start with a clean slate and have the same fitted.The bike idles and revs ok and gets up to speed fairly quickly despite a 14 stone lump parked on the seat,it tends to loose speed when takling an incline.Does anybody know of anyone who sells replacement parts for the bs32 carb as the parts I require are obsolite.Is the part I require cross reference to another bike?The part numbers are 341-14941-90 Noozle main(y-0) and1m0-14116-01 Needle(4z1-4).many thanks in advance.

Thanks drewpy thats what I thought.Do you know of a good place to pick up a good replacement coil?

Hello again,I have developed further issues with the bike.Started the bike up to find it misfiring(left hand down pipe cold)Checked for spark and found no spark on left hand cylinder.I have checked the points and wiring with a multi meter and all seems in order.I have also checked the left cylinder primary circuit by connecting to the right cylinder coil and the right hand plug spark so I happy the primary side is ok.I suspect the ignition coil but when I do a resistance check as per Haynes manual the readings are ok?Could you please tell me the correct ngk plugs as the bike has B8ES fitted which are a colder running plug that is listed.

Have you checked to see if down pipes are getting warm when you run the bike?If one is warm and the other is cold then check that for a spark at the plugs

Have stripped down and rechecked and adjusted the float level again.Bike starts up and idles ok.The revs also drop ok and does not smell as rich.I think I had 2 issues because the right hand exhaust smelt of fuel?also the right hand downpipe was cold so obviously not firing.I removed the points cover to check for a gap (gap present),I started the bike and armed with a piece of cardboard and slotted between one set of points,when removed the revs went up and the bike ran better.A dirty set of points now cleaned and will give it run tomorrow.Thank you Drewpy for your help,your a diamond geezer.

Hi Drewpy thank you for your help,when it is warm it still tends to be slow returning to idle.I have sprayed wd 40 over the carbs and pipes but does not effect the running.I have read other posts and it does seem a weak mixture is the most likely problem of this issue,but it smells very rich?Im assuming if the floats were set wrong it clold flood but no fuel is leaking from the carbs.I am running the bike without the fuel tank via a petrol reservoir.Think Im going to have to strip down again.The one thing I did notice when I replaced the o rings on the main jet nozzle was that the groove where the o ring sits were different to each other.

I have completely cleaned carbs and replaced o rings on the main nozzle.I have new inlet rubbers and gaskets fitted,the pilot mixture screw set at 3 turns from rest(they were set at 1 and a half turns before strip down) and the floats set at 26mm (30mm before strip down) and the air filters are new.The bike starts on choke but there is no fast idle(it did before problems).The bike smells very rich and seems slow on throtle responce when revved up whilst stationary and slow to return to idle ,then unless the idle screw is wound up it stalls.I have screwed 1 pilot screw right in and it does not effect the running.Which way do you turn the pilot screws to weaken mixture?

Correct me if Im wrong, If your bike/car is not declared sorned then you have to have it insured(because it is assumed taxed and road use legal).If you declare it sorned,(which is only valid for 1 year then you have to re sorn it)then it has to be garaged or parked on a private driveway?

I had one of these.The day I was 16 could ot wait to get on the road.Being new years eve there was snow on the ground and nearly passed out with hypthermia.Never put me off though.My link

Just an update,took carbs apart today.Found the right hand slide jamming up and not returning to its rest position.This was due to the spring above the diaphragm not located correctly.I checked the float level and this was set at 30mm .Cleaned out all the jets and cleaned the slides with solvol autosol and set the floats at 26mm.Can you tell me the best position to set the needle valves(both are set 1 position up from the bottom position ).How many turns is a good place to start with mixture screws?

Looking at the picture the petcock is set to prime,which means fuel is gravity feed to the carbs.

I opened the fuel cap but it still made no difference.I have an inline filter which seems ok.Thank you for the infomation on the float level height.I will get in the man cave this week and have the carbs off and reclean.

Hi all,I picked up my 1978 xs250 yesterday and went out to give it a run.I noticed at the bike was surging a bit.I then opened it up to go over a large bridge and got to about 65mph when it started to die like fuel starvation.I came to a stop and it idled but would not respond to the throttle,however after leaving to idle for a few minutes I was able to carry on my merry way.With the bike still surging a bit I decided to chance overtaking a slow car and as I was alongside it died like fuel starvation again and cut out.It would not restart but after a while it did but would not rev up and now it stalls.I suspect carbs or air leak.The bike had a full carb clean ,new filters etc before I picked it up and I put fresh fuel in the tank.I have notices the rubbers between the carbs and head looked perished which I feel would not help.Ive seen some inlet rubbers from Yambits are they of good quality?

Not on insurance database either according to Ask Mid.Would say it is looking down from above.

Have you checked you have the correct spark plug?Many years ago I had a similar problem with a z250 only to find it running a spark plug with a too higher heat range,causing engine to overheat.

Very Sedden news