Old 9th September 2019, 12:53 PM #1
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rd 350 lc running poorly

Right folks, a tough one for ye experts,

i have a 1982 rd 350lc with new motor rebuild, i have standard airbox and main jets are 240,needles are set in standard position,she has period micron exhausts

the bike runs good in first and second powerband kicks in at about 6k revs, when i hit 3rd she struggles to reach powerband, in 4th she struggles to maintain 50 to 60 mph on the flat, have not got a hope of reaching 5th or 6th,

standard jets are 220 i went to 240 because of the microns, i do have spare 250 and 260 size jets

so on rd forums they differ alot with their answers, some say rise the needle a notch, some say use 250 or 260 jets

so lets hear ur thoughts on her thanks in advance
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Old 9th September 2019, 03:23 PM #2
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Re: rd 350 lc running poorly

Up the mains some more , better having it run fat than leaning out...you can toy with needle position after that
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Old 9th September 2019, 03:58 PM #3
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Re: rd 350 lc running poorly

thanks mate i will go up the jets one or 2 sizes see how it runs then, just found out there is ebc racing reeds fitted dont know if that would make a difference, she 1 mm over bore, gramption crank and makita pistons
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Old 10th September 2019, 12:01 PM #4
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Re: rd 350 lc running poorly

the fact that speed seems to effect it suggests an air intake issue .ill mull it over today
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Old 10th September 2019, 02:52 PM #5
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Re: rd 350 lc running poorly

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Originally Posted by chopper View Post
the fact that speed seems to effect it suggests an air intake issue .ill mull it over today
Thanks T,

was informed today she has grampien crank, makits pistons, ebc racing reeds ,1mm over bore, later 4lo barrels and carbs hope this helps
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Old 12th September 2019, 01:25 PM #6
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Re: rd 350 lc running poorly

Didn't know ebc made reeds,does it start easy?could be something else goin on there,is it exactly the same since u put on the airbox?can u check the timing and the hi/lo speed source coils?are they full pipes or just end cans?
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Old 13th September 2019, 08:09 AM #7
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Re: rd 350 lc running poorly

hi mate thanks for reply,they are full system pipes,ebc took over from hitec so thats where the reeds came from, i will check the timing this week,as for starting it started first kick with standard 220 jets there is 240 in now takes 4 or 5 kicks to start her now,seems to be slower starting since original airbox went on or its the jets,i have original set of pipes i might fit and then she would be all standard but i want to run with the microns,what do u mean hi/lo speed source coils, ?
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Old 13th September 2019, 01:10 PM #8
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Re: rd 350 lc running poorly

Shud be 2 source coils on the stator,u can check the resistances of them.tbh tho it'd more to rule it out,seeing as it rev out nice in first and second.the emulsion tubes haven't been changed have they?aftermarket ones wud have a bit of a shroud coming up out of them.compression good,not overhesting no vibes from unbalanced crank etc.just getting the basics outta the way.silencers not blocked?a quick run to see if it revs without the silencers will tell ya,same with airfilter out.just to see
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Old 13th September 2019, 02:21 PM #9
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Re: rd 350 lc running poorly

You’ll probably find the mixture screws need adjusting when you up the mains. Bring it for a spin again and give it full choke before you open it up,if you notice any improvement you know it’s been starved of fuel. If it gets worse then you’re having issues with airflow. I don’t have much experience with the 350’s but I’ve done a lot of seat of the pants dyno runs on tzr 250’s ,took an absolute heap of runs to get a 3ma dialled in but they are notoriously finicky. The full system is going to want lots of fuel fucked in to keep it happy,if the motor pulls clean in the first few gears then you’re unlikely to have an ignition issue.

The key is to have your base settings logged,pilots,mixture setting,mains,needle height. Then you log how the bike was driving with them. That way you can log changes,and you’ll start to see a pattern on what will clean up the fueling .Mains will affect all of the circuits,but if done in small increments it may not cause a noticeable problem.

Keep us posted and best of luck with it

Last edited by DavyH; 13th September 2019 at 02:24 PM.
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Old 13th September 2019, 04:01 PM #10
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Re: rd 350 lc running poorly

Quote:
Originally Posted by mrdimreaper View Post
Shud be 2 source coils on the stator,u can check the resistances of them.tbh tho it'd more to rule it out,seeing as it rev out nice in first and second.the emulsion tubes haven't been changed have they?aftermarket ones wud have a bit of a shroud coming up out of them.compression good,not overhesting no vibes from unbalanced crank etc.just getting the basics outta the way.silencers not blocked?a quick run to see if it revs without the silencers will tell ya,same with airfilter out.just to see
silencers are new, i will check the emilsion tubes,no vibes,no over heating,new air filter,plugs,carb rebuilds the lot mate
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Old 14th September 2019, 11:40 AM #11
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Re: rd 350 lc running poorly

Dirty exhaust baffles? take them out and try?
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Old 19th September 2019, 12:25 PM #12
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Re: rd 350 lc running poorly

any joy on this yet??
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Old 23rd September 2019, 12:47 PM #13
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Re: rd 350 lc running poorly

hows it going mate yes got her sorted,original airbox fitted,turned back down the oil pump as she is run in now,carbs running 240 mains,done timing so all sorted now,was on the forums and i am partly to blame i was riding it like a 4stroke u have to keep her in the powerband to get her moving she is flying it now and thanks for all the help here, she not my cuppa i think i might shift her on,looks like im a 4 stroke man

also done the timing again and we noticed the woodruff key worn a little so new one ordered will be on this week, not happy with paint on tank so will get her painted and let her on

Last edited by menapia dude; 23rd September 2019 at 12:49 PM.
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Old 23rd September 2019, 12:50 PM #14
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Re: rd 350 lc running poorly

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Old 23rd September 2019, 12:51 PM #15
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Re: rd 350 lc running poorly

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Old 23rd September 2019, 12:53 PM #16
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Re: rd 350 lc running poorly











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Old 23rd September 2019, 10:14 PM #17
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Re: rd 350 lc running poorly

If you are still having trouble with this bike there is only one person I can recommend who will sort you out, his name is Teddy Murphy, lives just outside Cork City and is an absolute authority on two strokes, let me know if you want to contact him and I'll try to help.

Last edited by bogman; 23rd September 2019 at 11:44 PM.
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Old 23rd September 2019, 10:23 PM #18
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Re: rd 350 lc running poorly

second that Teddy is a genius
but sounds like its sorted
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