drewpy

you will have to use european sites for 250's as they didn't have them in usa for standard rings http://www.cmsnl.com/searchparts_other.php...-01&make=YA £42.50 +vat and P+P I use Motoward as I get great service people have recommended granby's get yourself a parts book so you can give out part numbers, there have been a dearth of them on ebay at the moment £5 approx.

you need to tell us which model xs you have as there are about 4 variants

no problem

check ignition timing, valves adjustment and change your petrol (gas). if still not right do a search for carb xs400 as I have replied numerous time to this. Drewpy

Hi, thought you had the carbs sussed! 1) the petcock has one supply from the bottom outlet going to the left carb 2) the connector at the back of the petcock goes up underside of the tank and to the right intake. this is the vaccum to operate the flow of petrol (gas) 3) there is a pipe link between the two carbs at the back, just above the float bowls, it also acts like a support between the two carbs so could be misconstrued as such, but is in fact the supply to the right carb. there's lovely for you!!

your pilot system is blocked or way out of adjustment. mains take over around 4k, i had to have mine ultrasonic cleaned in the end

OEM exhausts? forget it I had to buy a 3n6 version (nearly the last one in the world!!). the only way to go is sito, there is a distributor http://www.vyxxn.co.uk/ need to email them for prices and availability. I use motoward, cmsnl, speed sport, bike bandit, pgm (really RD aircooled but the 400D shares a lot of stuff) 400 is the same as 250 except for smaller bores and carbs and associated parts. get a parts book from ebay and that will help you identify the commonality. if you do find a new right oem exhaust (1U4) let me know

why don't you ask the vendor, its that the xs400 needs 12v for the charging,it may have enough in the capacitor to start the process.

the charging system needs a 12v supply to work. here is a wiring diagram could try this http://www.zeeltronic.com/page/bat_elim.php let me know if it works

Take out the starter motor and chain (saves a few LBS) as the xs already has kick start, you don't really need to do anything else! If you're really finicky you can take off the starter solinoid from under the seat. As Merv said you coud use an rd right hand switch gear and polish up the casings as they are alloy!!

try http://www.aircooledrdclub.co.uk/forum/ and do a search

depends on what tyres you have, manufacturers recommend different psi to standard

the pilot system affects the lower rev range to 4k 'ish and the mains take over. The galleries in the carbs are very small and even after i cleaned them they were still blocked. that is why i ended up sending them away to be cleaned. the reving you encounter is a weak mixture in the pilot system, but any tweaking of the screw will not overcome the reving. BTW its 1.5 turns from the bottom. Another fault i have found is the pilot screws snapping off at the bottom due to wear of the brass and hamfisted tighteneing (an interference fit into a conical seat) you can check by completely removing the pilot screws and they should have a really fine needle on the end, if they are "dumpy" ie rounded then the end has snapped off, this has happened on both sets of carbs i have had! the float height is very important:- yamaha say 26.6 +/- 2.5mm using a venier caliper, measure the distance of float arm from the top of the float chamber gasket seat (no gasket) to the top of the float. (the float should be resting on, but not depressing the spring loaded inlet needle) bend the tang to achieve level amont both right and left floats have to read the same. Drewpy

genuine exhausts are almost unobtainable now, but sito are available as well as motad 2 in 1's and MAC in usa. Need to check out cmsl.com for parts and speed sport in usa! as I am not too sure regarding the 360 (might be able to use 400 pistons etc. best tyres are BT45's, the rd boys swear by them. drewpy

sounds like a blockage, do you use an inline petrol filter?

far as i know its to supply enough petrol for the carbs and the way the tank sits on the frame!

I don't recommend soaking in solvent as there are rubber bits in the choke mechanism. what you need to do is get them vapour blasted ( for looks) and then ultrasonic cleaned. I use jrs in Uk but you will have to do a google search if your in the USA. these will come out ultra clean and JRS even replaced the parts of the carb with my keyster kit and built it up for me! approx £100 for ultrasonic clean.

sounds like the swing arm bushes have gone, you can check by the sideways play on the swingarm 1mm max (is on my xs400) the electrics on those bike had a reputation along with the cam chain. I agree that they are great looking bikes, the 850 was the updated 750 with all the niggles sorted. have a trail through the old forum via the search system as I'm sure that someone has asked the same question. BTW check the middle gear box oil as that gets forgotten at service times!!

If the vaccum gauges do flutter, there is a knurled knob on the pipe which needs tightening up till the fluttering stops. this acts as a damper due to the engine characteristics and is normal on all bikes. checking my manual, the carbs are the same as the 400 but have different sized jets, so you need to ask them for a 360 kit. the 360 has; 135 mains, 0.6 air jet, 4FP21-3 jet needle, X-6 needle jet, needle position 3, pilot jet 17.5, starter jet 40. air screw 1 to 1.5 turns out from stop. send them an email, as they have tons of stock. if they don't have any try NRP in Manchester UK!

Those are the carb kits, in fact the exact same ones I bought. Don't forget you need two! The valves are really easy, just use your manual to set the crank to the timing marks and 10mm spanner and feeler gauge. rtv on the inlets is not a good idea, use a gasket and check rubbers for cracks/splits

WOW some text 1) Sounds like air is getting into the inlet side of the bike. Spray some wd40 around inlets and listen for any engine revs which would iindicate a leak there 2) you need to get a keyster carb kit and replace everything with the kit 3) tune the bike by setting the valves, points gap, timing and finally balance the carbs. If you get the vaccum guages there will be instructions in there. you need to find a way of supplying fuel with the tank off the bike and you use the stubs on the inlet rubbers as vaccum take-off. hope this helps

I assume your talking about the 2A2 engine, as there was a later dohc engine which won't fit. the xs400 will slot straight in and is in fact lighter than the 250 (bigger bores I assume) you can't just overbore as the valves are a lot smaller and uses a different carb 32mm-250 34mm-400. I think even getting a 400 barrel onto a 250 bottom end could cause the liner to foul the crankcase mouths (not tried it, but i'm guessing) I bought a 400 engine off ebay for £50 and carbs for £20, then you need the rubber between each side of the carbs for the bigger mouths. Well worth the hassle though as mine motors up to 85 and great on the twisties. a custom model will fit as its only got a rounded barrel as opposed to a squared off one. Be careful of the 12n model as they have "rear sets" which If yours hasn't then you need to figure this into your equation. BTW loads of stuff in germany, but be carefull with carbs and camshafts as they have restricted (27bp) engines drewpy

I'm thinking; Flying time and CAT B write off

Go for it, if you like the bike its gotta be worth it. over 15 years old is considered a classic nowerdays!!