The part number for the 3HX1 manual supplement is 3HX-28197-05. On the cover it has a pic of the silver/black model. If you click on the image shown on my carb page it will cycle through the models. https://litetek.co/Carb_Kit_Yamaha_FZR250_2KR.html You can buy these manual supplements from Japanese auction sites. I prefer to use Zenmarket. This is what the owners here have done over time. We then use OCR software to capture the text and then translate to English. https://page.auctions.yahoo.co.jp/jp/auction/n297084345
What's the status of the fuel filter, present, absent? Just thinking that if you've had a cylinder with a wet plug even though all of the float levels are good, or at least evenly matched, a bit of grit could have blocked the needle/seat valve
Fuel filters on old bikes are a common problem, take it out and do the blow test in the right direction. Any resistance = in the bin and replace it.
What angle should the carbies be at if i do the float level on the bench? My bikes parking spot isnt very level. Speaking of level, it did flood after stopping on an incline. Wasn't huge but it was still a hill, dunno if that changes anything. I replaced the fuel filter with one I had lying around cos I could see some crap in the tank after draining it of old fuel. But taking the bowls off yesterday, there was the same red gunk so im guessing fuel pump/lines was still dirty or the goo was too small for the filter. Its a cleanable one not a paper filter one. I might just bite the bullet and rebuild the carbs, get some new seals in it. I noticed a small amount of leak from the throttle shaft (guessing that name). Gotta buy a new helmet after a crash yesterday but after that,
"What angle should the carbies be at ...?" The angle that the carbs would be at if they were on the bike. That image is too far away to make out anything, but if you have fuel leaking out of a throttle shaft then you have an issue. If the engine floods to the point that a cylinder is full of fuel then you can bend a rod if you try to start it.
New needle/seat valve needle I think is probably in order - they can look fine - the best way to check them is to feel how soft or pliable the rubber tip is, they harden over time as they age, and some micro cracks can develop which makes them leak So the physical appearance isn't a good indicator of either their age or actual physical condition
Did some more work on the carbs today. I decided to bite the bullet and just do the full rebuild, new sealing bits, valves etc. I separated and dissasembled them individually, all good there. Float levels are all in spec from the diagram in the manual. However, the fuel mix screw on 1 and 4 is stripped to hell and back. I dont have a photo but theres no way a flathead will have anything to grip. I was thinking use a left hand drill/ extractor bit and hope for the best?
Even if the left handed drill doesn't grab it it should make a small hole that you can then perhaps tap a small torx with fine sharp edges into the hole and wind it out - I've done this numerous times with damaged allen screws Not all of them are well machined, think around T6 upwards should be a good starting point and a set is from T4 - T10 is cheap, both Jaycar and Bunnings are a good source
I'd also put a couple of drop's of ATF on the mixture screw head's and leave it to soak down the thread's for a while , may be some corrosion in the thread's too ? Just wipe the mixture screw o'ring's clean once you pull them out if you're going to reuse them and use a touch of rubber grease to make them slip in easy
So good news, chucked some wd40 on them last night and they do tighten. But there so stripped there's nothing at all for the screwdriver to grip when turning it anticlockwise. I'll try and get some left hand bits this week. Might start looking at the motor while I wait
Thinking on this, if you've got a good set of drill bits already, because they're in an orifice/tube, find the largest bit that will go down there, get one of those in left hand, then you can use that one to go straight down into the top of the pilot screw and make your centre, drill down just a little bit, then when you go to the smaller one it wont bounce around amongst the mess of what used to be the screwdriver slot whiles you're trying to drill to centre Always meant to get a reasonable set of left handed drills, I might actually get around to it this week, you've inspired me
Finally got round to that nasty job with the fuel screws. I did what ruckusman reckoned by using a large bit to centre the hole and it worked pretty good. Was pretty tense work but glad it worked out. I used the frost 5 peice kit from Bunnings, if anyone's interested. Also did the valve clearance and some repairs on the wiring harness, nothing as action packed as a carb surgery though. Last question of the day, Air cleaner joint 1, the one from the airbox to the carbs, is any Yamaha part with the 14453 bit going to work? Whole part # is 1HX-14453-00-00
1HX-14453-00 is still available new from Yamaha dealer's, it's also used on the Yamaha FZX250 Zeal Think retail is around $25ea
Great to heat that suggestion worked, it was just a shot in the dark as I didn't have any carbs nearby to actually check the cavity to see if it tapered or not, but I could imagine a small bit bouncing around because of that screw driver slot Out of interest, how were your valve clearances prior to adjustment?
Happy to be a test dummy lol. Valves were mostly good, on the lower side. Highest intake was 0.14, exhaust was 0.25 from memory. 4 were out of spec by 0.01-0.02, fixed by shuffling a few shims around