In 2024 this is my saving grace, you described my exact problem when switching to a y boot with k&n filter on my rd350. I'm ordering a new needle jet asap! Thanks!
@@TurbodanNMI ordered a 169-P0 along with that 5DP7 needle. Here's to hoping 🤞. It's hard to find jetting advice\specs for stock pipes. Thanks again. I'd love to see more about how you cleaned up those ports
@ksneth i might make a video on that. Short answer: modified dremel right angle tool with a shortened carbide bit. Not pretty but it worked for my R5 cylinders and these 400 jugs too.
@ksneth I found a few more tricks, if your 350 requires them. It may not. First thing to try would be the RD400 reeds, specifically the upper petal. The 400 uses a slightly thicker top reed. I tried using the thin reeds top and bottom, which is the stock 350 setup, and it created a problem in the 4000-4500 RPM range. I alleviate this, I cut the shroud around the top end of the 169 type needle jet down to 5.9mm. This helped but the rich condition just past 4k was still present. Today I reinstalled the stock RD400 top reed and it once again revs out cleanly at part throttle. The cut down needle jets remained, which reduce the overlap between the needle and pilot circuit at low throttle. This is good as it helps the circuits operate more independently. I was able to lean out the airscrew and richen the clip position. The 169 series needle jets bring the pilot and airscrew into play to a greater extent than the stock 175 needle jets. I have been trying to optimize fueling at idle as well as low throttle cruising, and for me, cutting down the shroud on the needle jet seems to have done the trick.
@ballockybill2277 the airbox was removed long ago. Since this is a 350 frame with a 400 motor I would probably have to make something anyway. The carbs are higher up on the 400 cylinders so I would have problems even with the 350 airbox that fits the chassis.
In 2024 this is my saving grace, you described my exact problem when switching to a y boot with k&n filter on my rd350. I'm ordering a new needle jet asap! Thanks!
@ksneth glad to hear it. I never did any testing with the 350 but I would try a 169-O4. Maybe a 169-P0.
@@TurbodanNMI ordered a 169-P0 along with that 5DP7 needle. Here's to hoping 🤞. It's hard to find jetting advice\specs for stock pipes. Thanks again. I'd love to see more about how you cleaned up those ports
@ksneth i might make a video on that. Short answer: modified dremel right angle tool with a shortened carbide bit. Not pretty but it worked for my R5 cylinders and these 400 jugs too.
@ksneth I found a few more tricks, if your 350 requires them. It may not. First thing to try would be the RD400 reeds, specifically the upper petal. The 400 uses a slightly thicker top reed. I tried using the thin reeds top and bottom, which is the stock 350 setup, and it created a problem in the 4000-4500 RPM range. I alleviate this, I cut the shroud around the top end of the 169 type needle jet down to 5.9mm. This helped but the rich condition just past 4k was still present. Today I reinstalled the stock RD400 top reed and it once again revs out cleanly at part throttle. The cut down needle jets remained, which reduce the overlap between the needle and pilot circuit at low throttle. This is good as it helps the circuits operate more independently. I was able to lean out the airscrew and richen the clip position. The 169 series needle jets bring the pilot and airscrew into play to a greater extent than the stock 175 needle jets. I have been trying to optimize fueling at idle as well as low throttle cruising, and for me, cutting down the shroud on the needle jet seems to have done the trick.
Keep the airbox if you have it. Get a lightened flywheel, really helps em spin up.
@ballockybill2277 the airbox was removed long ago. Since this is a 350 frame with a 400 motor I would probably have to make something anyway. The carbs are higher up on the 400 cylinders so I would have problems even with the 350 airbox that fits the chassis.
And you have the Pirelli tires from the 80’s