Speedshop

The alloy used is zinc rich, so if you polish it once, you'll always be polishing it if you want to keep it looking good. Moisture in the air is enough to cause it to corrode, let alone getting rain water on it! ACF50 is good, the questions about high stressed ares are spurious. Laquering is about the worst thing you could do to polished ally

I manufacture CDi units for older Yams. I'd say its possible but unlikely you'd be able to swap units between the models. They don't like units that are interchangable and go to great lengths to make sure they aren't. That said its worth trying, some do slip through the net. What makes these 'performance' units? There isn't much you can do to an ignition box unless its digitally programmable!

The first reply is indeed an excellent appraisal What i'd like to add is avoid the cheap HID kits on flea bay. More trouble then they are worth. Poor quality balast units cause problems like failure to ignite or sudden loss of power. I'm nothing to do with them, but these people do good realiable kits, not the cheapest but you get what you pay for. www.hidcity.co.uk Also with HID there is no need to go for the brightest kits. A mid powered kit will give more then enough light (far brighter then a H4 or H7 bulb) and use half the power of a normal bulb.

The way to tell the XS400 models apart is the SE models had rubber mounted engines, with front mount that has larger holes to accomodate rubber bushes. The older 'roadster' models had solid engine mounts. Both are interchangeable but you'll need all the mounts for the FRAME you are using.

You need to get the book and look up all the inhibits IE inputs that stop the ignition working and go through them one by one. If its been hot wired something else in the system may have been diturbed

As above - sounds like the diaphragm has gone in the tap. repair kit should sort.

You'll struggle for parts in the UK, but with the internet, no problem. make sure its got an import cert with showing that the duty has been paid, or you'll have to pay again when you register it. +VAT!

Running with it off loaded won't do any harm, its if you short it out the fun begins.

Must say I've walked away from PCs, too many security issues. you need anti virus software running all the time which slows the machine down. Big fan of unix based operating systems now. Been running a MAC with no anti virus software on line for 2 months, no problems, no viruses, spyware or other invasions. Linux users report the same! I was worried out compatibility with PCs and getting software for it, but I've found MAC software for everything I need (and more!)and had no problem recieving or exporting documents and files. I'm of the opinion now that Windows is a very sloppy system punted out quickly and cheaply with no regard to the security of the end users. The MAC is the opposite. Its very security conscious.

my advise would be if the shells are Ok, leave well alone. Minor scuffs or slight marks in a shell bearing doesn't mean it needs new. Have you plasi-gauged them and found what the clearences are? Replacing shells on Japanese bike engines where the tolerences are very fine is more likely to cause more problems then not. leave well alone if the tolerenes are within the service limits. I don't ever remember the XS250/400s requiring 20/50. 10/40 was what we used to use. If you don't use the lighter oil they can destroy the cylinder head. 20/50 takes too long to get up to the head, to the plain bearing that the cam runs in. I remember the 250 was worse then the 400 and having a couple of destroyed heads that were put down to wrong oil. 10/40 can take 20-30seconds to get up there from cold start and 20/50 a minute or so depending on the temp! All that time the cam runs with no lube (or what is left on the bearing surface i should say. My 400 had a slight pick up on the cam bearing in the head, but i used a bearing scraper on it to clean it up. It ran like that for another 25,000 miles when i had the bike and was going strong for a couple of years after I sold it. Never use synthetic oil on a newly rebuilt engine. Use basic mineral for the running in procedure then switch if you feel the expense warrants it. To be honest though on such a lowely tuned engine you won't get your money's worth from synthetic, just use normal and change it early if you want the best protection. i doubt its ever had a drop of synthetic in it before now - and its still here today! And leave the engine to last, its not good to leave it standing too long newly rebuilt, the new seals can dry out and be torn when you finally start the engine and clutches can weld themselves up. Use moly grease and 10/40 mineral oil on all the plain bearings, splash the 10/40 over all the steel parts in the gearbox/clutch case and wipe the bores with the 10/40 too. You don't need 'special' or 'super' lubes. Well only if you belive all the lubricant company's BS. Look in the ads in Classic Bike or classic mechanics for platers

The SR is resitricted by the exhaust and it's cam. But the engine is a fragile one prone to destroying the rockers. For a full tune I'd replace the exhaust (the standard one doesn't lend itself to modifaction of the kind required to get the engine to breathe) the carb and the cam shaft(if you can find a warmer one). If the oiling to the head can be improved I'd do that first before tuning the engine, if not a good synthetic oil will help protect it.

Broken drive dogs are not uncommon on the XS, my '76 suffered this fault too. Yes you can turn the engine upside down and remove the lower crank case half without taking the barrels off. Make sure you get the correct parts. Yamaha changed the clearance on the gears/shaft, the wrong parts will fit but make the box impossible to select gears correctly.

I'd guess the dt50 has a CDI magneto, which means its self powering and sepearte from the rest of the bike's electrics. I'm not sure if you'd get a 'racing' cdi box, there isn't much you can change unless unless there's some sort of rev limiter that resistricts the engine's performance.

LEDs by their very nature are polorised. Do you mean ones with a wide veiwing angle? These are commonly available in the UK. I suggest a proper electronics company like Rapid on line rather then Craplins. if you google LEDs there are many UK companies specialising in replacemets for vehicles. You'll find most indicators with a 'E' mark are viewable from the side, the veiwable section is covered by construction and regs laws so if they are legal (IE marked with an E mark) they'll have the required visability standards.

The 650 is well noted for leaking oil at the clutch push rod seal!My 32 year old example seems OK at the moment but has had a few seals in the past. Wiping all the filth from the push rod helps seal life. I'd ajust the clucth when the engine is warm, as the setting seems to alter slightly as the engine heats up. This will allow you to select neutral with a hot engine. Start by getting the free play on the worm drive adjuster right, you want it on the tight side rather then a large clearance. The XS650 does well on 20/50. The XS400 however won't. Unlike the 650 it has the cam running in plain bushes formed directly in the head. Oil must get there quickly if you want to avoid the cam shaft eating into the bearings, for this you need light 10/40. The 650 has the cam supported in ball races and it can take the oil 30 seconds or more to get up to them - which is OK as ball races will run with virtually no lube (as 2 stroke cranks prove)

Sounds like a side stand switch or clutch switch sticking or not working.

Pre mix will make the mixture lean. have you rejetted the carb to account for the oil taking place of petrol. I suggest you reconnect the oil pump, it will give the engine better protection then premix can.

DOH! You mean the magneto coil! Right I don't have the DT info with me.......but the points XT500 generator i do have! This has a similiar set up as the POINTS DT with sepearte magneto and lighting/charging coils. while it will be different, 1.65 ohms seems in the ball park for a magneto coil (the XT500 is 2.25). DSM6678- if one cdi box fitted all they wouldn't sell any new CDi units at full retail price plus it would make life easy for the after market manufacturers who would produce at much lower costs then OEM, so they ensure retails orders for the next 10 years (or however long they decide to carry on manufacturing for) by making them model specific. The differences are subtle and the basic PCB will be the same for hunderds of different models. The ND 70000 series is fitted to many bikes, but one version wouldn't run on other models due to minor component swaps - making a 1,000 units with a 100 ohm resistor in slot 'A' then 1,000 with a 750 ohm resistor in slot 'B' in a continuous 2,000 unit run is no big issue on an automated assembly machine.

I manufacture ignition units for the SRs and XTs. What you find is they alter the 'front end' of the box to stop other boxes working with other generators. Its done to protect their business! They indtroduce a fudge factor to ensure the Cdi box from a SR500 won't work properly on a DT, for example. Actually the SR had 3 different CDI boxes over the years. They are all exactly the same, but have a different fudge factor applied so a 1978 model won't run a 83 box! I.65 sounds low for this type of system. Something around 20 would be average - but then again it depends on what they did to get the box specific to that model!

I doubt its electrical. If it starts and tries to rev the pick up coils are doing their bit. You can do resistance checks on them, or if they are Hall effect there's a test box you'll need to see if they are working. A rich mixture will stop the engine reving - dead. Like hitting the kill switch, if the mixture is that far out. You will need to change jets in he carb, the adjustments on the carb, needle height and idle mixture- only trim and don't have enough scope of adjustmnet for seriously out of spec mixtures. Get the exhaust sorted first and find soemone who is experienced setting up carbs

Small capacity bikes aren't good on open pipes, you have to rev them to hold respectable speed and there's nothing like a small noisy bike to get you nicked. Also expect some messing about with the carburation to get it running properly again. Just rememeber if that's the stock exhaust it will be VERY expensive to replace if the engine doesn't run well after you cut bits off it. The best option would be to buy a cheap secondhand system to play about with. I'm not against loud pipes, my XS has very little in the way of baffling. But the difference is it will waft along at 60-70 with very little throttle and hence very little noise- good when the cops are about (wind it open and its a whole different story though). You won't be able to do the same on a 125, you'll need a fair amount throttle (and therefore noise) so you might as well fix a 'nick me' sign on your lid!

Maldon Coaters in Essex use the zinc base coat system. I've had an XS650 and the frame is a good now as it was 15 years ago when I had it coated. Stone chips can simply be touched up with paint to stop water ingress. I takes a fair bit to chip the coating though. The biggest problem is masking up. Powder coating adds considerable thickness and is a complete bitch to remove. I machine up my own blanks to go into swingarm pivots and all other dimension sensitive item. I put nuts and bolts on threaded items as well. It takes a long time, but believe me it takes a hell of a lot longer to try and get the coating off threads etc. Turn up at a powder coaters and just sling the parts at them, as removed from the bike at your own peril!

Ok, bit of confusion here. A magneto is a mechanical device that makes high tension sparks at a specified point in the crank's rotation without the need of a battery or any other external power source. Its a very old term, but it does apply to any system where it is self generating, IE its just the engine rotation required to produce a spark. Normally this is applied to a system that uses a set of points to time the spark, but you can equally apply the term 'magneto' to many basic CDi systems. Where it gets a bit confusing is that CHARGING coils to provide power for the lights and battery are often included within the same generator. To use the old terms this set up would be called a magdyno (magneto +dynamo). The two systems are completely separate and on older machines they would have been two separate units bolted on the engine. You can indeed run batteryless, but you must connect a capacitor where the battery went. If you don't you risk damaging the generator/regulator/wiring loom. You'll need an electrolytic 48v , 10,000uF (or there abouts) capacitor. Look for one that has 'switched mode capability'. All this means it that it will last much longer as it is resistant to constantly changing loads or spikes in the system.

use Yamaha 3 or 3 bond, same stuff just without/the yamaha logo on it. This is the actual specified sealant. Wellseal is best used with paper gaskets - it the best stuff for eliminating misty base gaskets.

You need to know what the actual power CONSUMPTION of each amp is, not its output power. With car systems there is a tendency by the manufacturer to some what overstate the system's true performance. For what you want I wouldn't rate the power feed at 100% of the peak requirement. I'd rate it at 100% of the max continuous rating of the amp. Have a look in the spec sheet for the current draw of each amp. Then you need to work out how long the power feed run is. With the current, voltage and run length you can work out what cable you need. A 8 AWG cable is a pretty heavy duty bit of kit and I'd guess some what over rated for what you want. I can't believe for one moment you need to supply 70 amps! When working out power requirements, stay away from car audio websites - they have some very odd ideas about what's required, there's plenty of proper electronics web sites with industry standard cable calculators on them.