Fzr 250 - How To

EXUP Adjustment

Checking and fixing the exup Jarmizz style... (thanks for writing this Jarmizz):
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Checking the EXUP valve is easy peeze. Take the left hand fairing off just sitting under the sump casings you will see a strange looking thing in the exhaust thats the EXUP valve take that silver cover off ( i think they are 4mm grub screws but cant rememeber to well) and then you will see where the cables meet up with the exup valve. Turn the engine on and get someone to rev the engine and if the cables move the exup valve then its doing its job. You should also when turning the ignition switch to on before you push the start button hear the servo motor do alittle reset sound thats good to hear. If the exup valve dosnt move pull it out of the exup chamber and spray some CRC or WD40 in the moving parts areas they might be alittle sezied from the carbon build up (take off the cables to remove this obviously). Smack it back to getter give her a turn over if it still dosnt move look at the servo motor. Spray alittle WD40/CRC in the cables and if it still dosnt work take it to your local motorbike repairs.
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I would also like to suggest a few additions:
- when you take off the cables from the valve turn on/off the bike. The servo motor should move at this point. If not the servo is dead - go to a wreckers and get one is the best option (it could actually also be electrics in this case, so you may want to check there but that is a whole new can of worms so I won't bother discussing here). It is very unlikely that the servo is dead though.
- if you end up taking the exup valve out of the chamber (which can take some effort and perhaps some hammering but it will come out just so you know...) clean it with a wire brush or something else because the carbon may not all come off with crc/wd40. (the valve itself is not fragile, so you don't have to be super gentle with it). Even if it seems to move freely when you play with it by hand it may still be a little tight, so remove it and clean it anyways.
- the exup valve->servo cables should have virtually no slack in them. To tighten you 'loosen' the nuts up towards the servo motor (you will see an adjuster on each cable).
- when adjusting the valve - take an allan key and put it between the 'tooth' on the valve and the hole in the exhaust (you will see what I mean when you look). This is where the exup should be adjusted to according to yamaha specs.

Having said that - I actually have my exup valve adjusted so it is slightly open at rest (the tooth is slightly up from where yamaha states). I have done this because of the problem you have experienced AND I know my engine is running very slightly rich, and this has helped stop my stalling. (I've been busy and not gotten around to adjusting the carbies)

Other things i have found to work/help, if above doesn't solve the problem
1) I have previously unnattached the exup valve (left the cables hanging), and wired the valve so it is open 100% of the time. This stops all stalling, but really degrades bike performance so it is not a recommended solution, but it does work.
2) This is my guideline for city riding that I use (I personally ride the bike in the city between 8000-9500 and follow this guideline)... As you are riding, every once and a while (perhaps every 30 seconds or minute when you are going at a relatively constant speed) - pull the clutch in and rev to about 12-14 000 or so for a second, then let it back down. This will release the back pressure (remember under at 9000 revs the valve is only slightly open, and if your engine is running slightly rich you may not be letting out enough exhaust for how the engine is tuned). This will set you back to normal. Sometimes I will hear a slight dip in the revs, but then they come back to normal - when I hear a dip I often will do this twice in succession and never hear the dip the second time round. Since you are moving the bike actually wants to rev, so it will 'work through' the back pressure issue without stalling. I also rev it the odd time when sitting at lights (this will clear out backpressure again but usually sitting at idle won't be an issue with backpressure. But it can also check to ensure that you won't stall when the light turns green which can be an issue if you have cars ready to move behind you).

 

WIRING THE EXUP OPEN

To quickly check to see if the EXUP valve is the source of problems on your bike you can 'wire' it open. This essentially removes one potential problem source, and if your problems go away you can essentially say that something about the exup valve is causing the problems. Note: this may be an interaction with other aspects of the motor - such as running rich.

To wire the exup valve open (you can find the valve under the stand on the left side, below a metal plate). Unhook the cables - leave them dangling for now (you can find a permanent solution if required), and turn the valve clockwise until it won't go further. Wire this in place however you can (I have used some spare copper wire in the past). then try out the bike.

 

Carb Tuning

Above there is information on balancing the carbs, but this does not necessarily mean tuning. Below is some info from Jarmizz (that he posted previously) on tuning the carbs on the FZR:

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If your bikes running rich then tune the carbs. The main mix screw should be three turns out. And then balance th carbs and that should sort the fuel problems. As with Dyno runs, it is possible to dyno a bike but what would you be looking for as our bikes are carburetors and not fuel injection so you dont have any sensors to tell you whats happning. But it would be good to see what power the beasts are pumping out after 12+ years of thrashing.

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I think the BB's trick would be great, but I use the dial way. The reason why Trevor liked the BB way was because his dials moved alot while we was trying to read them and set the carbs. I didnt have this problem because the dials I used had a tap in the vac line so that you could stop that dial movement. So i would say a real perfect carb balance is always needed. Jets should all be unscrewed and with hi presser air and carb cleaner, cleaned. Set the carbs to 3 360 degree screws out from right in.

The way I do it is, take the carbs off the engine and spray them down with carb cleaner and wipe clean. Then I would check the floats and spray them with some carb cleaner and air just to make sure that all the crap has gone. Clean the jets by the method I said above and screw back into place. Put the float bowls back on and make sure screws are tight so that no fuel will leak. GOOD HOUSE CLEANING IS IMPORTANT!!!!! CLEAN HANDS AND WORKING AREA IS NEEDED!!!!!!!!!!.

Then from then on as you have said you have had a bit of expernce in carbs, just clean the rest of the carbs, make sure you are not to unbolt them into singles because that can introduce leaks that are a bitch to fix!!. Put the carbs back on the bike, do carb balance and then install air box and filter.

Like I said before BE PERFECT WHEN WORKING WITH CARBS, NOT DIRT OR GREASE OR ANY SUCH SHOULD BE NEAR THEM> CLEAN THEM TO PERFECTION

 

Flushing Coolant

Thanks to Dave (Garfield2k) for this:

coolant is easy...open radiator cap, then unscrew the drain plug.
if its a 2kr then its underneath near the gear lever. im unsure where the 3ln one is but just follow the coolant piping etc.
once u drained all the coolant i flush it with water till it runs all out then just put everything bak in n fill up. run engine for a few mins then top up.

as for brakes, i dunno...havent done it yet...lol...but check the fzr400 manual, im sure its pretty much the same

 

Bleeding the brakes

Brakes are not quite as easy. You will need to get a bleed tube first (1.5 meters is a good length) - available at any hardware or auto store. And also get some dot 4 brake fluid. And a spare bottle (an old milk jug is fine). You will need to do 1 brake caliper at a time , and 1 valve at a time (I think the front has 2 valves). If you feel comfortable with this then you can do multiple calipers at a time (though still only 1 valve per caliper at at time). The reason I say do one at a time to start wtih is you do not want to let air into the braking system - that is a very bad thing!

1) Remove cap from brake fluid reservoir.
2) Hook up the bleed tube to the valve found on the caliper (on either front or rear) and place the other end in the bottle. if there are 2 valves on the caliper I know you are supposed to either furthest from the reservoir OR closest to the reservoir... (I forget which - I have in the past done the one furthest first)
3) Open the valve and wait. Some will say pump the brakes, some say hold the brake on, others will say wait. Whatever you choose it will slowly but surely drain out. As it drains constantly top up the brake fluid reservoir - as I said before make sure that air does not get in!!!
4) Once the fluid coming out the bleed tube is bright green then it is time to re-close the valve. To do this hold the brake lever on, and then close the valve (otherwise you won't have any brakes). Then move onto the next one. (if you see any bubbles coming out in the fluid you will have to wait till they dissipate before closing the valve).

It takes time - about 10 minutes per valve. Just be patient. And before you go out riding again check your brakes to make sure they work!

And finally - don't let the brake fluid get on any fairings or paint work - it will eat away at it. So it is wise to have some spare damp rags just in case.