OK so as some of you maybe aware I have done the 250/350 conversion to my RD and I ran this bike approximately three times. The first time I ran the bike was a 10 minute heat cycle in neutral and it seemed to run ok.
The second time I ran the bike I actually rode it for about 6 miles and it ran ok with some throttle, if I let up on the throttle in any given gear it bucked and surged badly.So I put the bike away and searched the forum for answers regarding jetting.Found that the pilot adj. screws were off big time over 2 turns out. So I ran the bike with the screws one turn out and noticed the surging/bucking at closed throttle partially disappeared. Turned around came back up the street to my house,parked and fully closed the adj. screws and wouldn't you know the bike liked that a lot.Surging/bucking has completely disappeared but from what I understand I am basically enriching the pilot circuit in which case I should go up a pilot size.This was about a week ago and I did order new Mikuni #30 pilot jets. I believe I am at #27.5 at present so the plan is install the 30's and back off the adj. screws 1and1/2 turns.Also the main is 140 and the needle clip position is 3rd from the top. These are the stock low top carbs. So any tips regarding that are appreciated.
Now upon that I thought I was at least clean the pipe baffles, they are currently in my woodstove :devil: :clint: I don't mind reinstalling them but I am curious is if I chose to do so minus the packing material I know the bike may sound louder but will this also lean out the running condition? I guess I am just curious as to the pros and cons regarding the jetting/performance not so much the sound.
I am thinking I should go up on the main to a 150 leave the needle clip alone in the middle position and try the 30 pilots?
P.S- not sure if this is too much info but I think I may add that another reason to clean the baffles is it seemed like the bike didn't want to rev much over 6k and of course I didn't do a proper plug chop but I did pull the plugs to look at them. They looked OK but a moderate grey color. I'll have to take a pic of one, they both looked the same.
if you still have the 250 baffles in.. you should probably swap them to 350 ones. they are different. yambits sells good reproductions that slide right in and flow better. you should def run baffles though, the bike will overall run better w them.
https://yambits.co.uk/rd350-exhaust-baffle-p-47061.html
Ok that's good to know. Boy those Yambits baffles do look nice and new and shiny. Is there any kinda mod I could do to mine to make them flow better, drill some more holes? or is there more to it than that, they look awfully similar.
Some pics of one of the plugs but the other looks the same. They were a fresh set of NGK B8HS.
Also I am running the stock air box with a K&N filter.
(https://i.postimg.cc/FdSrMdVw/IMG-0071.jpg) (https://postimg.cc/FdSrMdVw)
(https://i.postimg.cc/yghdJ33c/IMG-0066.jpg) (https://postimg.cc/yghdJ33c)
the id is bigger. the reproduction baffles actually flow better than stock 350 baffles. trust me, its worth it.
Ahh I understand. Do you think I am going in the right direction with the jetting? Stepping up from a 27.5 to a 30 pilot as well as from a 140 to a 150 main?
Only one more thing I can add to previous comments is I am running some old treated premium pump gas, I know I really need to get fresh gas. However the carbs are not gummed up. At least to the best of my knowledge.
*if* I remember correctly, stock airbox w chambers will be in the 150 to 160 ish main jet range w airbox lid on on a 350. pilot sounds ok as well.
Ok, give it all a try. :thumbs:
May take a day or two.
I'm also dealing with my KTM 1290 GT. I got it used five years ago with 9k miles and allegedly the dealer fully serviced it. Well the bike always runs great and I neglected doing pertinent 18k service stuff and she currently has about 27k on her. So she also tipped over in a tent due to severely strong winds that had the tent just nudge it I suspect onto it's side. luckily the bikes handlebar kinda landed square inside a milkcrate with a water bucket in it all setting on a pallet. So the bike never truly touched the ground. However there was a inner fairing cover that got cracked and a clever molded end of it for mounting got smashed and separated So I've been mending that and I did replace the plugs and air filter which all looked super. Always changed the oil at half the KTM's recommended 9k mile service intervals, way too long in my opinion but that's what they say. I dunno what to say about that bike, I also changed the chain and sprockets, added grip Puppies to the heated grips that are obnoxiously expensive for a wear item. Changed the front tire but had to troubleshoot and fix a pulsating brake issue, turned out to be sticky calipers. Lots of bull with that bike, beautiful powerful bike but way too high of the ground and top heavy for my liking. Kinda on the fence about keeping it but I just had too many things going on with it that if I sell it just makes sense to square em away. One thing about that bike is much like an RD it seems like there's this endless list of doodads to spice it up. Currently lusting after handguards, a rear wave rotor just to match the fronts and a company in the UK, MotoProworks makes some killer graphics sticker kits for these bikes that I can't explain it but they make the bike pop but I am stretching myself a bit thin money wise.
I know there's never enough time for all of us and our stuff.
Finally got my KTM squared away and got to play with the RD some more. Between a jetting change and ride yesterday and today she is starting to run better than ever.
Ironically I never fully sorted the jetting with the 250 size. As a 250 was how I acquired the bike and it was on a 2nd overbore with only 5500 miles, not sure if that was even the original top end or maybe there was some odd running issues.The bike ran lean when I got it and there was just so many things going on that didn't seem to make sense despite my newbie perspective. It had the original ignition system but didn't seem to be at the proper timing position. 125 mains which I guess is ok but 42.5 size pilots. The Yamaha dealership I bought it from claimed they had issues tuning it but got it to run as best they could. From there I discovered HVC Cycles and later this forum and although I have learned a lot and threw a bunch of money at the bike I am still learning. So as a 250 the bike had some noticeable piston slap and it had decent compression judging by the pressure on the kicker but I just wanted a bit more power and figured if I was going to get the jetting right why not have a fresh top end and have what I wanted as a 350. A rabbit hole that just seemed to make sense.
So this is where I am at now The bike has a nicely sorted Vape install but the timing is 2mm BTDC and that's because like I said I got that Vape setup From HVC Cycles before fully understanding how to set it up and why. They offered a machined keyway service as an option that has the rotor timed at that position. I learned later on that isn't ideal so maybe at some point I may wanna adj. the timing to 1.8mm BTDC. I dunno.
For jetting I am as sea level with the original carbs and I have the 150 mains, the needle I raised to the 4th clip position, 30 pilots with the pilot jet screws 3/4 turns out.
I did reinstall the 250 exhaust baffles with new sound reducing exhaust packing but I can also see there being an improvement if I can get those 350 baffles from Yambits. For now this is where I am and the bike runs pretty good. I am pretty impressed with the extra power and throttle response. I still have the 250 gearing and it seems like it hits a switch and revs a bit too quick at around 5k to 6k almost like the clutch is slipping momentarily at that point of rev range or I guess it gets into the powerband. I don't rev it much past 7k. But this is only the fourth time I rode it with the 350 top end.
My RD is a running work in progress :vroom:
yup sounds about right. if the clutch is original you can stick some fz600 fractions in there on the cheap and massive improvement. but Check freely adjustment at motor 1st. as far as it being 2.0, do t sweat it it'll be fine especially w stock pipes
OK that's good to know. A while back I did have some issues with the clutch slipping and I tried lightly sanding the steel plates thinking they were glazed. It helped but I know when I replaced the friction plates a whole longer ago I didn't use anything special, I think they were EBC brand. I also stuck with the original springs.
Just got to take a test ride this morning and the clutch is fixed, no more slipping :vroom:
What did I do to fix it?...I replaced the friction plates with those cheap Caltric FZ600 plates. Also got a cheap deal on some decent used clutch plates from Ebay, they came out of a raptor 660 but shared the same part number as the 75 RD350. Got another decent deal on EBC clutch springs. The old springs according to my Clymer service manual were out of tolerance measuring at 34/34.6mm I believe the spec is 36mm with a tolerance of 1mm, the new springs were measuring at 36mm. Also of course I scrapped the old rubber dampening rings.
Thank you all for help and guidance. Especially M in sc and SoCal250 and Chuck Supertune. I really appreciate all the archived posts relating to clutch servicing and the tech notes. A little bit of homework to locate and order the correct, best value parts. I initially ordered the wrong friction plates for an FZR600 so I had to fix that and I just shopped around. All in this cost me about 76$. 35$ for the friction plates, about 15 for the used steel plates, 18 for the springs and 8$ for a quart of oil.