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Post by fletche36 on Feb 10, 2021 16:12:08 GMT 1
Gents, what symptoms would i have if my emulsion tubes are blocked? im still chasing down my jetting / flatspot issue. ok so i have now cleaned the carbs spotless ( apart from removing the emulsions) and have put a pair of brand new 22.5 pilot jets in to ensure they are clear as can be. im on 190 mains as it should have and im running the needles on the bottom clip which is 1 clip richer than std. also i have synchronised the carbs and there are no air leaks. it starts super easy either hot or cold and ticks over (and returns to tick over) well. running it not under load it sounds absolutely perfect to my ear but on the road it runs well up to 4k revs and you could ride all day like that ( if you were a fanny 🙂 ) and then over 6k its like a race bike but that bit in between is dire and you have to coax it through to get into the power. next step is to put the std pipes on and re test it but its pecking my head a little now and i dont want to lose the swarbricks if i can help it as they just look and sound great. if i have to dyno it i will but i hate not being able to do things myself... any sensible suggestions will be listened to  |
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Post by LC_BOTT on Feb 10, 2021 16:25:02 GMT 1
Just wondered why you didn't clean the emulsion tubes?? I'd probably take the carbs apart again, remove clean emulsion tubes and use opportunity to remove and clean behind the brass balls too. Lots of threads on here about them, and 'how too'
I did mine and found they were fairly clean anyway, others have had huge improvements in the flat spot you're describing.
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Post by shaunthe2nd on Feb 10, 2021 16:26:43 GMT 1
Remove and clean the emulsions and you can eliminate that from the equation.
Its an easy job to do so why not.
And do behind the brass balls at same time if you haven't already.
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Post by fletche36 on Feb 10, 2021 16:29:03 GMT 1
Just wondered why you didn't clean the emulsion tubes?? I'd probably take the carbs apart again, remove clean emulsion tubes and use opportunity to remove and clean behind the brass balls too. Lots of threads on here about them, and 'how too' I did mine and found they were fairly clean anyway, others have had huge improvements in the flat spot you're describing. because i didnt think to . foolish with hindsight at least im getting good at carb removal. |
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Post by fletche36 on Feb 10, 2021 16:30:05 GMT 1
Remove and clean the emulsions and you can eliminate that from the equation. Its an easy job to do so why not. And do behind the brass balls at same time if you haven't already. tomorrows job pal cheers. |
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justyr
Thrash Merchant
Posts: 331
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Post by justyr on Feb 10, 2021 17:03:38 GMT 1
Sounds like needle clip to me. Too rich.
I’ve got a theory, could be wrong, but generally std clip positions become too rich on modern fuels. Try leaning the clip position and see if it improves.
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Post by midlifecrisisrd on Feb 10, 2021 17:59:09 GMT 1
Clean them properly first
Then try top clip, then bottom clip
See which improves/makes worse and go from there
Steve
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Post by marrcel on Feb 10, 2021 18:16:32 GMT 1
My advice is to begin with the clip at the bottom. Then one up.
Test at 1/4 throttle. Smaller increments can be made with a washer under the clip.
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Post by zed1015 on Feb 10, 2021 18:50:00 GMT 1
A blocked or partially blocked emulsion tube will result in a rich mixture.
They bleed air into the mix to maintain the correct ratio.
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Post by fletche36 on Feb 10, 2021 20:36:27 GMT 1
Clean them properly first Then try top clip, then bottom clip See which improves/makes worse and go from there Steve clip was 2 from top when i picked bike up and that was shocking. it would only run on choke. |
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Post by fletche36 on Feb 10, 2021 20:37:59 GMT 1
A blocked or partially blocked emulsion tube will result in a rich mixture. They bleed air into the mix to maintain the correct ratio. Thanks, well now i know it fees more lean than rich if im being honest. |
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Post by midlifecrisisrd on Feb 10, 2021 20:43:53 GMT 1
Clean them properly first Then try top clip, then bottom clip See which improves/makes worse and go from there Steve clip was 2 from top when i picked bike up and that was shocking. it would only run on choke. It may have had partially blocked pilots at that point Also needle should not affect bottom end that much Is 22.5 the correct pilot for a 250 Steve |
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Post by muttsnuts on Feb 10, 2021 21:10:02 GMT 1
pilot on a 250 is 20, sounds to me like you have some issues there, it might not be carbs at all, if its between 4k and 5.5k I can think of around 12 possible cuases of that problem and a good few aren't anything to do with the carbs
Have you tested the ignition components?, especially the high speed windings and the pickup
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Post by fletche36 on Feb 10, 2021 23:30:15 GMT 1
pilot on a 250 is 20, sounds to me like you have some issues there, it might not be carbs at all, if its between 4k and 5.5k I can think of around 12 possible cuases of that problem and a good few aren't anything to do with the carbs Have you tested the ignition components?, especially the high speed windings and the pickup no, im afraid i dont do anything electrical. im good with mechanical stuff and usually half decent with jetting but electrics are magic and best left to people who know more than me i was under the impression that the 22.5 was the jetting upgrade from Yamaha and although i put new genuine ones in the ones i replaced were also 22.5 s. from tick over to 4k it feels decent and after 6k its great too, its just the transition. as i said ill dyno it if i cant get there myself and its you that it will be coming too but i hate being beaten !!!! i kind of discounted electrics as it starts well either hot or cold and when not under load it revs well enough. i put a video up on one of the fb forums but apparently i cant put it on here as the file is too large. |
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Post by chrisg on Feb 10, 2021 23:51:51 GMT 1
Ive removed emulsion tubes on bikes in the past that were running "ok" not 100% but ok and found that there was loads of crap on the emulsion tubes, enough to make me think how the F**k did it run. Well worth eliminating from the list though.
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Post by fletche36 on Feb 11, 2021 0:03:59 GMT 1
Ive removed emulsion tubes on bikes in the past that were running "ok" not 100% but ok and found that there was loads of crap on the emulsion tubes, enough to make me think how the F**k did it run. Well worth eliminating from the list though. Tomorrows job pal unfortunately i wont be able to road test it as its just snowed again !!! |
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Post by fletche36 on Feb 11, 2021 15:18:28 GMT 1
emulsion tube out and cleaned, to be honest the emulsions were clean and it wasnt minging behind the brass balls but its done now anyway for peace of mind.so its running 190 main, 22.5 pilot, slide is a 2.0 needles are marked 230 and its on clip 4 which is std ( tested on 5 yesterday). now on the stand it does feel slightly richer so maybe something did need cleaning but im not road testing it as its bloody freezing and im not a fool 🙂 . most of that jetting looks pretty standard to me so it cant be a million miles out. oh the reeds are std too but it will be having boyesens at some stage . if it doesnt feel right after the next test ill change the pipes back to std and see how that is and at least eliminate either the pipes or the jetting 🙂  |
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Post by ianr4863 on Feb 11, 2021 16:48:45 GMT 1
Are you sure that those are genuine Mikuni needles ? If they are they should be marked 4N10 for a 250 or 5K1 for a 350 .
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Post by fletche36 on Feb 11, 2021 16:55:15 GMT 1
Are you sure that those are genuine Mikuni needles ? If they are they should be marked 4N10 for a 250 or 5K1 for a 350 . hmmm, didnt see that anywhere on them , just 230 stamped in near the top ( under the clip notches) . maybe a pair of new needles would be in order. |
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Post by shaunthe2nd on Feb 11, 2021 18:09:48 GMT 1
... and I couldn't even see the needles in the pic let alone the marking!
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Post by fletche36 on Feb 11, 2021 19:05:16 GMT 1
... and I couldn't even see the needles in the pic let alone the marking! you cant see them in the pic. i just remembered the code as i was rebuilding , i was chanting it like a mantra so i wouldnt forget it. |
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Post by muttsnuts on Feb 11, 2021 20:15:51 GMT 1
if they have 230 on them then they are either Yambits or Keyster needles, chances are they will be too thin (rich)
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Post by fletche36 on Feb 11, 2021 20:25:01 GMT 1
if they have 230 on them then they are either Yambits or Keyster needles, chances are they will be too thin (rich) thank you. |
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Post by fletche36 on Feb 11, 2021 20:36:22 GMT 1
if they have 230 on them then they are either Yambits or Keyster needles, chances are they will be too thin (rich) Mr nuts , would you know if the ones at allens performance are genuine 4 n10s ? or is this something you sell. im probably better fitting the right parts to get the bike right. |
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Post by muttsnuts on Feb 11, 2021 20:54:41 GMT 1
they are genuine from Allens, that is where I buy all my Mikuni parts from
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Post by fletche36 on Feb 11, 2021 21:02:23 GMT 1
they are genuine from Allens, that is where I buy all my Mikuni parts from cheers. |
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Post by fletche36 on Feb 12, 2021 13:23:25 GMT 1
UPDATE..... Just braved the cold and given it a 10 mile test ( my bloody knees are still freezing), anyway its better but not quite perfect. still minor hesitation just before it comes on the pipe but its perfectly rideable now and it may just be a characteristic of the swarbricks that they hold back for a fraction before letting loose , but a little clutch helps if necessary. So it may be that cleaning the emulsions and removing the balls helped even though they looked pretty clean, anyway i have just ordered some Showe dual stage carbon reeds so lets see if that dials out the last bit of hesitation. i rode it like an LC should be rode too for a couple of mins and it was great being 19 again 🙂
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Post by oldelsieboy on Feb 12, 2021 15:50:37 GMT 1
I'd be replacing the needles before changing the reeds.
OEB
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Post by fletche36 on Feb 12, 2021 16:09:40 GMT 1
I'd be replacing the needles before changing the reeds. OEB ill probably change those as well but if , as mr nuts says ,they may be a tad richer needles then maybe dropping them half a clip would have the same effect. everything i do does seem to make it that little better and its gone from being un rideable where it would only run on choke to being pretty decent. i know its sometimes impossible to find perfection but i dont mind playing to find what works and what doesnt and by the time we get decent riding weather it will be sorted. |
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Post by Tobyjugs on Feb 12, 2021 16:54:56 GMT 1
Hi Fletche just remember your jetting will need to be leaned off once the weather warms up.
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