JimR

I do monitor the site ... & only answer to posts that I'm sure I am correct on but saying that I could just start adding more silly comments Regards Jim

just do a restore .. I remember the first one of those I pulled out of it's crate ... looked awesome and had the nick name of 'fire on wheels' .. for the reason of a 550 (528cc) being able to clock 120 mph and steer too (in the day). Things to watch on the motor :- The oil sprayer behind the alternator .. if it blocks up the clutch release bearing will fail along with the primary chain Carb balance without the YICS tool ,,, the motor will knock at idle Classic for sure yesssssss

how big .. i can do small

hi Scott Try this :- align the exhaust cam correctly at TDC and hold it with a spanner/tool to stop it moving.then adjust the intake cam to its marks using a spanner to keep the chain in tension from the exhaust cam (you may find you get about half a tooth out. then apply the chain tensioner. spin the motor over counter clock (viewed from the right) a few times and then recheck the valve timing, you may find the you have the timing close enough. Back in the day when a motor was striped a cam chain was fitted anyway as any small wear in the chain meant difficulties !

Welcome Scott and I think you are missing loads First off I would not soft link the cam chain the XS500 has .. you are asking for problems, best result is to get a new one that has not been tampered with (endless) can you insure the slipper tensioners are in good condition ? don't forget to turn the engine towards the tensioner about 2 turns before applying the tensioner then recheck the valve timing, with a worn chain the cam where the slack is will go out of spec, perhaps you could supply photo's of the cam marks at LT (compression) to see if it is within spec or not. is your motor a split head version or single head ? when the engine was new all marks would line up this 5mm one way and a 1 mm another sort of makes a worn chain or tensioner or worst case a worn head, Plastigauge the cam to cap to insure the head , caps & cams are good. if the motor is a split head you have other things to consider (secondary head gasket etc) but lets cross that bridge if required

so we are still off topic !!!

Ok I guess the following :- the starter cranks the motor slowly and the battery discharges quickly (in 1978/9 there was an issue with the electrical system with the XS750SE). Most problems were caused by the regulator/rectifier going to earth (via the red wire in and the bolts earthing it) or in bad cases the generator also went to earth (shorted for English speaking people). To start the bike add a car battery to the bikes, this will give you the charge in order to start the engine. If the engine then stops within 5 mins you can say the regulator is at fault, but if the car battery fails to start the engine and the starter motor slows down you have a generator problem, but take into account the age of the bike you may have some bad wires and earths so insure every thing is correct before you start

with feeler gauges !!! you must really want to put a hole in the piston !!! the only accurate way of setting the timing is to set the motor at 1.8mm btdc and have the points break at that ... simply gaping the points at 12 thou at tdc will not work. in the 70's I was so glad of this advice to owners it made me loadsa cash through incorrect ignition timing, replacing pistons etc

Don't forget the OP said road bike not race/off road so King Kenny's stuff does not apply (as nice as it is) so we are now left with the RD(Z) 500 as the only two stroke road bike of the era (1980's) with more than two cylinders

Well the US had the RZ350 (twin) Have a look but as Cynic says in the USA 2 strokes got killed because of emissions and to be fair the only 2 strokes from Yamaha (road bikes) of the 70's/80's era where either singles or twins and with the exception of the V4, RD500 or RZ500 RD/Z 500 History I rode one of these bikes what a tool ... it was just a little unreliable due to the owners of the V4 riding it too slow & using poor 2 stroke oil (the YPVS seized up with oil & carbon deposits). To get an RZ500 in North America you would have had to have made the purchase in Canada or imported one from Europe or Australia, New Zealand, if you can find one well worth a ride

I don't think so Yamaha were 2 cylinder & air cooled through the 70's. I guess you are refering to the GT750 Suzuki

Hmm does the bi valve (auto choke) still work and the resultant pipe work still intact ? If it does, perhaps the fault lies within the choke circut of the float chamber. With adding fuel to the venturi and the engine starting from that then dying this bears this out best you check out everything correctly !

add stripping the carbs down, setting valve clearences, dwell angles, ignition timing and compression testing to your to do list .

Hi There, The XS250/400 alternators run in oil, I would guess the oil is running out of the small hole at the bottom of the case ? if so there are a few causes :- The engine is over full of oil the alternator cover was removed with the bike on the side stand ( the oil will lie to the l/h side of the engine). Fuel has entered the crankcase (worn bores etc) and has 'topped' up the oil level. Was the oil rather runny ? If so this would indicate fuel in the oil

Oh Ok, I have read the rest of the replies and there are some points to take on board :- You have adjusted to many things at once (or are trying too) to assume how the motor will react What you are trying to build is a 'still air box' (very popular in the 70's on grass track/speedway bikes) look here How we did that back then was to Set the ignition timing (no need today with cdi) note:- the curve on your cdi box may be wrong & may need alteration or remapping Fit one known datum ( Exhaust or air box, I suggest the exhaust and leave the airbox off) check the bikes performance adjust the carb to suit the current setup when you feel happy with the performance (no flat spots/plug chops look good, no exhaust bluing etc ) run the bike again for a good while to make sure the engine does not heat seize ( through under jetting, needle adjustments & incorrect ignition timing) If the engine does seize work out if it was an ignition failure (wrong timing) or a mixture problem & try again Fit the airbox and note the changes to the engines performance ( with what you are trying to do I would guess the airbox volume should be very close to the Honda original) when you have every thing right just filter the airbox with a piece of ladies stocking/tights ... job done. Perhaps you are trying to over complex the problem

I did n't mention that it was a retorical question some one else added that point I just replied. so as we are on the same page perhaps you could explain what the extra butterfly valve is required for ? I would guess the bike runs ok so you are trying to add some form of enhancement

Will a throttle body from a small injected car replace the orginal carbs ??? I have never done it ... does it work ? what electrics do you need ?

Why do you need to make it in the first place ?

I have had many problems ... that is another story !!! I just hope I can forget the last 2 years so maybe I'll be back. The OP mentioned ice above the slide, hence the need to defrost the bike, water on the YEIS box can run down to the top of the carb & freeze above the slide but as a matter of course I would replace the cable

Defrost it

I live there !!! the Yaris was not to bad but it woke up sleepy Malvern & of course Trowmans no have an odd entry door !

I have had a bad year but never mind .. I'm still alive !

it never had a front brake light switch ... it was not a legal requirement back in the day

Hi I doubt what ever you do to the XJ900 (Twin shock) you'll make the old girl to steer ... there is no way it will compare to the later models.. The Forks & nose fairing caused a lot of the steering problems I guess a cut down (no fairing) would handle quite well if you can handle the front end weight !!! Regards Jim

Hi "Turn in" what does this apply to ? The twin shock 900 was famed for it's tank slappers /wobbles and needed loads of work to make it steer ..... the shaft and rear end had no bearing on its steering but the bubble fairing/forks & unsprung weight were major players Regards Jim