JimR

Yamaha did there own carb cleaner there were a batch of XJ550's bought into the U.K which were not prepared at the factory, Ok it was good enough to get the bikes going but they did suffer from problems on running and every bike had to have its carbs off to be fully cleaned out. I soaked all the brass bits in carb cleaner for about a week changing it daily and high pressure air thro them. The bodies where more difficult I was spraying carb cleaner into all the holes and hoping it would come out the other end slowly most carbs clean thro with this method & high pressure air. Don't forget the choke tube built into the float chamber as it's drilling is at the float chamber this one has had the most mess on it for ages, in one case I had to change the float bowls and in another the whole set of carbs had to be replaced. Regards Jim

Hi Spike22, Yb100 carb is simple to work on after the case is removed 1 screw & a couple of pipes and its off. In the past yb's didn't give much trouble with there carbs but if you drop off the float chamber & check that the float is ok and that the valve it shuts off is working and the jets r ok and of the right size. Do you turn fuel off when the bike is stoped? If not you may be loosing a bit of fuel thro the overflow pipes. While the cover is off its good practice to set the oil pump up. Do the following, with the carb cover off start the motor and watch the pump move in & out then stop the engine the pump at its furthest point out. Check the cable is adjusted correctly then measure the gap between the washer on the pump and the grey plastic wheel the cable lives in (you will see a high spot on the grey wheel measure there). I cannot remember the clearance so a Yam dealer will be able to suplly with that, if correct the oil pump is the set up, if not remove the washer & fit or remove shims as required. Back to the carb, while its off check the needle is in the correct clip position and that the slide is not worn. Air filter you mention its oilly, this should be so but only just so take it out and give it a good squeze just in case someone b4 you over oiled it. Regards mJim

Hi Rich, I guess you have not got the old base & foam or else you would send it for recover..... why not try ebay for a second bike & make a good un out of 2 Regards Jim

Sorted then !

Hi 2 Stroker When you take the Gen cover off the unit is connected to the end of the shaft, it's most likely to be covered in brush dust and the to weights will be stuck in the fully advanced position (those tiny springs don't take to long till they crud up). While the covers off check the brushes for wear (there is a red line scribed on their edge) and set up the ign timming don't use the timming marks use a DTI and meter. Don't forget to gap the points to 12 thou at tdc on their respective cyls. left is to the front right is to the rear. If the unit is well cruded up you may need to remove it, you may find this tool useful I have one myself and it does the trick. Regards Jim

Hi There, Have you ridden this bike out yet ? If not the box would not have had the lube it requires, I would still inspect the clutch release bearing as this motor used a strange pumped lube system which ran from the engine oil pump through the crankcase to the generator shaft then onwards to the clutch and G/Box, fine to pressure feed the lube, but as the oil gets to the generator it lubes the bearing then is forced down a 2mm hole in the crankcase. If the bike has been laid up for a while it is possible that hole is blocked and the gearbox & clutch recieve no lube. I had one block and the results were real bad (gearbox seized and exit crankcase rear, totaled the motor). If you don't want to strip the clutch out at least take the gen off, then remove the rotor undo the 2 torx headed bolts remove the lab seal and inspect the hole which is located in the case toward the rear of the bike. On reassembly clean the edges of the lab seal and check that the o ring is ok b4 refitting the seal. This will be an hour or so well spent (unless the hole is blocked then the time taken will be a lot longer but thats another long post to fix). Regards Jim

Hi There, The Mixture is wrong you have bought bad fuel or had water in the fuel. time to strip the carb out. Engine cutting when the lights r switched on is connected to weak mixture Regards Jim

Hi Davey, I guess the engine you have drops out of second ? If the rest of the motor is ok try to find a bearing housing that holds (umm cannot remeber) either the main shaft or lay shaft from the bottom of the engine. This housing has a 'hook' on it which hold the gear selector shaft in place. If the 'hook' wears the bike (oddly) drops out of second only, so replacement cures it .... but back in the 70's/80's the part was supplied with the crankcase only (bad !!!) I did 2 or 3 repairs by using the part from write offs. If this is the problem & you can find the part all you need to do is drain the oil & drop the sump plate off and replace it (no engine out carbs/exhaust off etc). But I guess over the last 20 odd years finding the part may be a problem ! Regards Jim

I guess it is a sohc XS400 ? if so I would check all engine settings, as follows :- Intake Valve clearence 0.1mm Ex Valve clearence 0.15mm Set the ignition timing statically LF on the rotor for left cyl and RF for the right cyl at those marks the points should just open but ensure you have the engine on the correct stroke i.e both valves shut on the cyl you are timming Clean out carbs (make sure no hole/jet is done also insure the rubber bungs over the jet are ok and fit snugly) Fit new plugs (in the U.K they were BP7ES but maybe different elsewhere, but make sure the plugs are projected tip type signified by the P after the . Obtain a vaccum gauge,strobe & dwell meter. attach guages,meter & strobe Start the motor and allow to warm up. Set the dwell to 22.5% then check ignition timming adjust as required then recheck the dwell. This is a bit of a fiddle you need to obtain the correct ignition timming & dwell so you will have to recheck both a few times ! When this done time to go to the carbs ! Set Idle to 1100 rpm or close to Check vaccum readings both cyls should be the same and between 20-30 Kg/Cm if not adjust with the screw located between the carbs (the idle speed may alter as you adjust the carbs, if it does reset to 1100 rpm and continue with the adjustment when have the carbs set equal (and within tolerance). If you cannot get the engine to run with the balance equal but you can with readings of say 20 on the left and 40 on the right its time to take the head off and look at the valves & bores But if all is ok move onto the last stage screw the idle mixture screws inwards until the engine starts to die then screw out until the idle rpm starts to increase (after this you may end up with an idle above 1100 rpm readjust it to 1100rpm). Let the engine idle then switch on the lights if the engine idle drops screw the mixture screws inwards a fraction, continue switching the lights on and off & adjusting the mix screws untill the idle doesn't alter. Stop the motor and restart and heypresto it fires up first or second kick. Regards Jim P.S I guess you are using the choke correctly

Ok Common faults are : Dynostart brushes wearing (charge light stays on - easy fix, very rare for the voltage reg to go down but can be adjusted if it has.) Advance/retard unit sticking (poor low end performance - replace or dowse with lube) Vibration thro footrests (footrest bolt broken and/or engine loose) Vibration when applying front brake (bad set up of the twin leading shoe and/or build up of dust inthe hub) Poor Top end performance (90% ignition timing [CRITICAL] should be set 1.8mm btdc fully advanced) There are more 'normal faults' If you have a problem fire away I'll do my utmost to help. Regards Jim

Hi There, The motor is six speed with a shift pattern of 1 down 5 up. When I was working on those bikes back in the 80's I had and FZ600 with a simular g/box fault which turned out to be two faults; they were there gear lever being bent and catching on the casing, the customer introduced the next fault by trying to adjust it ! a way to test the box would be to remove the gear lever and carfully connect a vise grip to the shaft (no to damage the splines ) rock the machine backwards & forwards and try to engage each gear in turn, no need to use the clutch come to that later). If you find all six the g/box should be ok if not you may be in for expense. If the gear change shaft is difficult to move with the vice grip remove the engine cover and see if moves easy if so clean the case where the shaft fits thro. Clutch :- Obtain clutch cover gasket, drain the oil & remove the clutch cover and clutch pressure plate. Inspect the release bearing and arm for wear, replace as required. Check the arm in the clutch cover for free movement, bends and it's teeth are intact. You should find the fault there and I am assuming you have checked the clutch lever pivot for wear and the cable for ease of movment. Regards Jim

Hi Yamahanut, Fs1 is simular but did not share too many common parts RD80's bear no resembelance to YG1's at all (YG being a disk valve engine & RD being a reed valve). Closer to the YG is perhaps the YB100. With Cycle parts you should beable to fit/modify FS1 bits in order to rebuild them try http://www.fs1shop.nl for bits the seam to have alsorts of old bits but you do need to email them as the site only shows their new stock Regards Jim

Well looking at it that is an FS1 and not an FS1E, This year I have bought 3 of them (FS1 not E) one was £2.20 (off Ebay for spare parts) another was £155 (scruffy but only needed a silencer for MOT) and another @ £200 which had been powder coated and was in tidy condition. So I guess if yours is an FS1 you may need to hang on to it for a bit longer for the price to increase. Regards Jim P.S just about to fit the 70cc conversion & electronic ignition which should make it go a bit better, if your interested I'll let you know how it performs after the conversion

Hi John, The Tool was the same across the 4 cylinder engines XJ550/750, thinking back it may have been the 750 with the o rings .. it was a long time ago, but I'm sure a head gaskit will be your only fix. Regards Jim

Hi There in the UK the bike was called the RD200A and for my sins I worked on them. Most Engine parts and cycle parts interchanged until the DX was introduced ('76) and it was revamped but in saying that some parts continued on. I can remember a lot of the settings to service the motor and can give you a list of common faults. Hope this helps Regards Jim

I worked on XJ550 in this country where they were current machines and never had problems with the head gaskit blowing from that area ... the UK model had o rings sat in the head gasket at the swill chamber entry points (yics tube), my adive would be to have the head off & fit the gaskit and o rings. While the head is off you could check the valves for leakage and seating and if the budget allows replace the valve guide oil seals and genrally service the head. Dependat on mileage it may be an idea to put a cam chain in and check the tensioner for gauling (people do tend to over tighten the tensioner bolt). Yics itself improved the fuel consumption by storing mixture in it's chamber rather than behind the valve which in turn produced better cyclinder filling. On rebuild don't forget you will need a YICS shut off tool (fits in where that odd 12mm headed bolt is on the back of the cylinder head) or you will be wasting your time trying to balance the carbs. Regards Jim

how old is the DT ?

its over full I guess it runs out of the bottom screw hole... but they alway did on the side stand !

What do you mean by Yamalube ? from my time working on yamaha bikes ('76-'89) never came across that in my country we had autolube which ment u did not have to mix oil & fuel together every DT I have seen employed that system ... even the AT2 & CT1 models but if you have no oil pump & tank then mix at somewhere between 20:1 and 30:1