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81
Aircooled RD Tech Help 250cc and Above / Re: What Year RD350 LC
« Last post by kawazonkey on December 03, 2022, 09:23:22 PM »
And if you can only have 1...get the original, the daddy.
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Aircooled RD Tech Help 250cc and Above / Re: 250b seems gutless
« Last post by c50 on December 03, 2022, 07:17:47 PM »
Cruzinimage needles are almost certainly 5I4. Really makes no difference if you have 522 or 360 carbs the set up with 5I4 needles is the way I said. That  carb data isn't applicable unless you have 5L3 needles and baffled air filter, it certainly didn't come from any official Yamaha data. Nobody has come up with the air screw setting or needle position for the UK 522 carbs. . AS long as you set it up using your open  filter and 5I4 needle on 2nd slot, 120 main, a 25 pilot and 2.5 slide with air screw at 1-3/4 if it doesn't run very well with that, don't change it there is something else wrong. That set up works very well I can assure you. 
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Aircooled RD Tech Help 250cc and Above / 400c master cylinder repair kit
« Last post by murp on December 03, 2022, 07:03:36 PM »
Ok.... Someone please help, will this yambits referb kit work with a asco 11 5/8 front master cylinder.

Apparently there is a asco 12 master as well, but mine is asco 11.

I've searched forum, lots of conflicting info, just need a definite

Sent from my Pixel 4a using Tapatalk
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Aircooled RD Tech Help 250cc and Above / Re: 250b seems gutless
« Last post by Gr8uncleal on December 03, 2022, 06:32:02 PM »
PM sent (but not with any technical advice!  :P).
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Hi Tractorman, thanks a lot for your input.
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Aircooled RD Tech Help 250cc and Above / Re: 250b seems gutless
« Last post by Dale on December 03, 2022, 05:18:38 PM »
Thank you c50 and 5port for your information, I had  few hours today sorting out a few teething problems , I adjusted the air screws in 1/4 of a turn leaving them at one turn out, if I'm honest I'd say it was worse, I struggled to pull away on a slight incline, I ran out of time so haven't tried going the other way with them yet!!  . As 5port asked? I do ride a modern 1000 cc suzuki but am quite realistic of what to expect from this little stroker but feel  it could be better, I have noticed from what I can see that I appear to have 360 carbs . I think I will mail cruzinimage  and ask what number needles they supply in their kits so i know I have the right match with the slides , I will need to check the pilots foe size also
Cheers Dale
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Points arcing could be an indicator of a failed or improperly connected condensor - it is their sole purpose, after all. Primary issue from this is rapid points wear.
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Aircooled RD Tech Help 250cc and Above / Re: 250b seems gutless
« Last post by 5port on December 03, 2022, 11:36:54 AM »
Dale, did you try just adjusting your Idle air screws in to 1.25 turns (standard), or just in by .25 turns from where you had them?  It is possible that is all you needed if you just have low power moving-off.  ???

5port
Atm they are set at 1.25 turns , I haven't tried adjusting them yet its a job for the weekend, however I have had a quick check and can confirm I do have 2.5 fitted.
Cheers Dale

OK, So, as I said, simple first adjustment for your description "I thought it seemed a bit gutless pulling away, are they a bit like it from the off ?" is to try going richer on the Idle air screw adjustment. Weak on that can cause poor moving-off.   However, I can't tell if your description is valid, or you are just used to more powerful bikes?

Next. 2.5 Slides are probably not original UK/EUR RD 250 B. Here is My Precious's info:

RD250B UK 1975 522 VM28SC 522-00  Baffled MJ 95,  Needle 5L3/3, NJ 1750-8, Slide 2.0, PJ 25, AJ 0.5,  AS 1 ¼. Also, the air for the AJ is through black rubber pipe from the airbox to the nipple on floatbowl.   

So, by all means, try a little adjust of your airscrews in by 1/4 turn, but something is different with your carbs with 2.5 Slides.  You probably need to go right through from the basics of the carb id and ALL the parts because there are at least Four types of early RD250 carbs , not even starting with the RD350.  Don't go buying anything till you know what carbs you have and want.

C50 is probably right about the exact "official" detail of UK/EUR RD250B carb data being poorly written-up by Yamaha but, I believe that the Carb data listed by My Precious is what he found in a
load of genuine carbs and genuine info.  There should be no problem getting a set-up that works well, it is just a matter of finding what you have/want.

Cheers   

5port
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Aircooled RD Tech Help 250cc and Above / Re: 250b seems gutless
« Last post by c50 on December 03, 2022, 09:42:21 AM »
Dale, did you try just adjusting your Idle air screws in to 1.25 turns (standard), or just in by .25 turns from where you had them?  It is possible that is all you needed if you just have low power moving-off.  ???

5port
Atm they are set at 1.25 turns , I haven't tried adjusting them yet its a job for the weekend, however I have had a quick check and can confirm I do have 2.5 fitted.
Cheers Dale

If you have the 2.5 slides with 5I4’s you effectively have most of the 360 (most markets A/B) set up as long as you have 25 pilots, 120 main jet with open filter. Only abnormality is the air box air correction the 522’s provide, shouldn’t make any difference as long as it’s not blocked. and the different 522 pipes. Air screw setting is 1- 3/4 for your current 360 A/B unbaffled set up. I have had a couple of 250A’s running your  set up (but with 360 pipes) and have to say the throttle response was excellent, I think better than the 522B throughout the whole rev range, how much of that is influenced by the 360 exhausts? I might try some 360 exhausts on my 522B next spring (got plenty) and see if it makes any difference.

I don’t think you’re saying it bogs down are you? I read its just lacking torque below 5k ? TBH that’s normal and much worse if your carrying a bit of weight! But it should have quite snappy throttle response from idle out of gear and pull from almost idle without cutting or bogging. Worth getting the Iridium plugs and none R caps. 

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Aircooled RD Tech Help 250cc and Above / Re: 250b seems gutless
« Last post by c50 on December 03, 2022, 09:24:22 AM »
The carb data post is an excellent bit of information provided by many people. However when it comes to the 521/522B it is no more accurate than what we know  or don’t know. The clip position is just taken from the 360 carb same as air screw setting, it could be correct it could be wrong. There is probably only one person who can confirm the original settings and thats rdnuts as he has brand new untouched 521/522 B’s. He was going to provide it but it seems a difference of opinions prevented that. So don’t take that document as gospel, always check for official documentation and importantly bulletin updates which are often overlooked when advise is dished out. Luckily we acquired many and have posted a number on this site.
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