I have a 75 350 with Dave F Mod ((with 200 mains, 5DP7 jet needle, 169P0 primary needle jet, 27.5 pilot, air screw 1 turn out and needle clip in center position), DG chambers, Y boot with K&N, stock ignition timed currently at 2.0 (will change soon to 1.8), everything else is stock. My question is I have the mid range bog that I hear about often (right around 5.5 to 6 K) and wanted to know if a Banshee intake with crossover tube would help with this. I have not performed a plug chop test yet, just had it running and am on vacation relaxing thinking what I could do when I return. I have a long hill near my house which will put the bike under a load, was thinking I should pull up on the choke at the mid range bog to see if additional gas helps (which would tell me to jet up a little bit). Just trying to get my plan in place for when I return next week. Looking for any constructive input.
Thanks, Brian
its a reversion thing, more fuel will actually make it worse typically. the crossover tube will help, banshee bottles are too big so use the small tube. reed spacers sometimes help as well.
Would filing down the spray bar shield help with this?
Have you moved the needles up and down yet? Is it a rich or lean bog?
cutting the sprays shields wont help. been there tried it. try it one richer, i bet it gets worse on the stumble. then go one leaner from the start point, see if it gets better. the only real cure aside from some porting techniques i have ever found that works 99% of it out is a programmable ignition. and to that point, doesnt always work either. hell. by tzr even has a dull sport in the same area, just a harmonics/acoustics thing. just rev past it.
Quick question regarding previous reply "banshee bottles are too big so use the small tube. reed spacers sometimes help as well", Who is the best supplier of the reed spacers? I did a quick search and have seen carbon fiber and aluminum, and these come in varying thicknesses, is there an optimum thickness? Thinking both do the same and aluminum is most likely more cost effective? Additionally, is there banshee intakes to definitely avoid (i.e. Amazon)? I bought some before for my 73 few years back (that were UPP or IPP - Chuck Q mentioned the name), seemed to work and didn't break the bank. Just don't want to introduce additional issues with suspect parts.
i like the upps, they arent cheap but they are about a 5-7 year life span. honestly, economy cycle sells spacers and a crossover pretty reasonably.
https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/fuel-and-airintake/reeds-spacers/yamaha-rd250350400-reed-block-spacers-billet-pair-plain/
john also sells new oem intakes w the oem crossover tube and gaskets, you'll need a second set of gaskets for the reed spacers.
that whole thing will be like 250 for everything. not cheap but top quality.
I found that the cross over tube helped
Smooth out the burble you talk about at 5500-6000k rpm. I then made a boost bottle out of copper copper plumbing materials to see if it would help without having to spend a small fortune on a moose racing bottle. Which it did, I then fitted 6mm Reed spacers and found that it practically ironed out all of that 5.5-6k burble.
I did see your comment regarding cutting the spray bar down, it may or may not help. But if you've followed the Dave F mod and left that bit out. It's certainly worth doing the job correctly to rule out any teething problems.
Hope this helps.
ira funny, Dave and i used to talk pretty regular, even he eventually figured out the spray tube cutting wasn't really nec. just fyi.. either way won't hurt.
I have the EC spacers, modified stock reed cages with TDR Stage 2 reeds. Banshee intake boots with the stuffers cut off and jus the regular crossover tube. No mid-range bogginess that I truly notice. The top end was ported to between stage 1 and 2 by John Ritter. She rips!
Another question. Do the banshee reed cages fit within the RD350? I have a line on a complete Banshee intake set with reed cages. If so are their pros/cons to the banshee reeds verses stock RD350 OEM?
They fit but require more machining/grinding away of inside of the cylinders where the reed cages sit. I used yz85 reeds with banshee intakes and spacers. You still need to enlarge the area were the yz85 reed cages sit. However, I am still trying to get my RD squared away through.
not worth all the machine work for the reeds, at all. however the intake can be used w out the banshee specific reeds.
YZ85 cages fit with just a little work, and the RZ cages will find daylight very easily. Ask me how I know!
rm100 v force reeds fit with zero cutting. :whistle:
if you are looking to increase tip area, fit some single petal reeds, tdrs etc. on stock cages (not boyesen) & cut the bridge out. Me, I don't bother with bigger reeds until im at 32mm + ont he carbs, theres no real gains overall on a mild motor.
I found new old stock (Yamaha OEM banshee intakes- 31K-13565-01-00) online from a bunch of different suppliers. Are these a direct bolt on to my factory carbs (i.e. bore size) ?
you have to cut the stuffers off. why old stock? get new ones. but yes, they will fit after you trim the ears.
John basically cleaned my stock cages up. Sharpened the rough spots for better flow, widened them just a touch and called it good. My TDR reeds are separate pedals and work well.
Oh and just order the banshee intake boots new from Yamaha as Mark said. They still stock them.