Blackout '74 RD350 Motor

[mlakritz]

Just finished the motor for a restomod 1974 RD250.

Kveldwulf 350 cylinders and pistons
Vito's crank
Vape ignition
oversize intake boots
reed block spacers
30mm Legacy Evo flat slide Lectrons
performance mod heads
K&N pod filters
EBC carbon clutch
some other minor bits to round it out into a reliable beast


I had to remove a couple mm of material for left carb bowl clearance and also put a tiny 90 degree hose barb to clear the case on the right carb.

[RDryan]

Wow, that looks bitch'in.

I hope it runs well for you, I know folks say with those individual pod filters it can be harder to tune, just what I've read and you gotta see what happens with that anyways.

[85RZwade]

 

[Kawtriplefreak]

Very nice  

[m in sc]

its the reversion off the back plate of the filter thats the issue. either run really long ones, use extention runners, angled ones or all foam ones.

[rodneya]

Not a fan of the filters or clamps, but those lectrons look sweet.
Edit - have you checked clearance for the filters when fitted i the frame yet. Not a lot of room back there.

[RDryan]

In regards to the EBC carbon clutch plates, I'm not sure about those but per recommendation here on the forum I went with the Caltric FZ600 fiber plates(more surface area and loses the stock rubber damper rings) that are very cheap $$ on Ebay along with heavy duty EBC clutch springs specific to RD350's. Also mix and matching some used Raptor 660 steel plates with my original ones that were in the best shape as I had issues with the clutch slipping and my bike is pretty much stock in terms of power. Yeah my clutch works great now with that setup. Anyways again you'll just have to see how yours is. Looking back on it maybe all I needed was the springs but all those parts were very affordable.

[mlakritz]

Not a fan of the filters or clamps, but those lectrons look sweet.
Edit - have you checked clearance for the filters when fitted i the frame yet. Not a lot of room back there.

yeah, it's tight and i do have a slightly shorter set of pods if needed.  Why don't you like the clamps? I like a little extra bling and initially I thought the double bead would make a better seal but the flange on the intakes are just a little too short and the 2nd bead keeps the clamps from seating flush so I removed the inner double bead sleeve and now they are just regular clamps but with a little branding. :-)

and yeah, the black creosote Lectron's do look really good and are pretty much a necessity as I live at about 5300' in Boulder and any ride could take me up past 9000'. Lectron tuned the fuel rods and everything to work at those altitudes but we'll see what happens in the real world.

[mlakritz]

its the reversion off the back plate of the filter thats the issue. either run really long ones, use extention runners, angled ones or all foam ones.

MinSC, can you speak a bit more to that? I am not sure I understand all your suggestions/options since space is already so tight. Is the issue with reversion because of the solid back plate on the pods? Could that be modified with a permeable back plate and eliminate the issue? Not familiar with extension runners and also how do angled pods address the potential reversion issue?

[mlakritz]

In regards to the EBC carbon clutch plates, I'm not sure about those but per recommendation here on the forum I went with the Caltric FZ600 fiber plates(more surface area and loses the stock rubber damper rings) that are very cheap $$ on Ebay along with heavy duty EBC clutch springs specific to RD350's. Also mix and matching some used Raptor 660 steel plates with my original ones that were in the best shape as I had issues with the clutch slipping and my bike is pretty much stock in terms of power. Yeah my clutch works great now with that setup. Anyways again you'll just have to see how yours is. Looking back on it maybe all I needed was the springs but all those parts were very affordable.

Thanks for the tips, the clutch is fitted with the heavier Barnett springs and hoping that is enough. But yes, this thing will make some good power and slippage could be an issue. Everything on this project will be sort of "well let's see if this works" so I am ok with some wrong turns.

[m in sc]

exactly.  it actually creates weird harmonics,  it can almost cancel the signal in the carb causing the 'flat spot' . angled all foam unis are your friend here. also a big reason i printed oversized y boots for a few bikes of mine. the reed closing creates that blowback wave. piston ports do this to  degree as ell but it can usually be tuned out a bit more, but the same problems can happen.

[mlakritz]

So the k&n pods are part of the "look" so i came up with what i think will be a pretty elegant solution to the reversion issue. The back plate/cap is rubber so I cut out the center flush with the inner mesh then cut a disc of foam filter material and siliconed it in. Functionally this removes almost all of the previously impermeable flat surface area on the inside of the cap. Oil it up like the rest of the filter and this should eliminate the reversion issue since any blowback will just pass through now, while preserving the aesthetic I'm going for.

[m in sc]

actually a 30 degree cone is the best fix if you insist on using them... and a lot longer than your filters. i actually did my final engineering thesis on this exact phenomenon many years ago. would ne better to space them back 1~1.5 inches as well.

[mlakritz]

I can splice in a printed 30 degree section that also lengthens the whole operation. It's a custom from top to bottom so I want to be true to my design vision as I mock it all up and then I'll can deal with whatever engineering issues arise. I Really do appreciate the tips and knowledge.

[m in sc]

use 90a tpu for a runner

i get 'vision' but form should def follow function. it can be done well though.