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Dumb idea. I'm doing it anyway.

Started by DaytonaCafe, August 02, 2022, 11:49:49 PM

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DaytonaCafe

Apparently I have brain damage because I've decided to embark on yet another trip down the rabbit hole. This plan is an RD350 engine in an FZR400. This is a different FZR400 frame my buddy has as I'm keeping my current FZR400/600 as is. Engine pics below show a basic paper weight that I'm going to be throwing money at (that I DO NOT have) until I'm satisfied with the power.  Then we'll put it together & make a 50 foot scroll list of all of the obstacles that will make this a complete pain in the tail to make happen & cross each off as we adapt and overcome. I say "we" because I have basically no skills & no appropriate place to do anything like this so my buddy will be doing most of the adapting, overcoming, & ALL of the machine, welding, and powdercoating work. I do need someone that can help me with this engine, though. The jugs need help, the pistons need replacing along with most of the other parts I'm guessing in the bottom end because it looks like it's been in some weather for some long amount of time. Please, weigh in here with jeers, cheers, & mostly (please) with helpful information because I've found jack all pertaining to anything like this. Also, again, anyone that can help build this engine, I need ya. Lyn Garland restored the crank in my Daytona and Mark Storey built the engine after that. Not sure that either of them could help. Haven't been in touch in many, many years as life has gotten in the way of my favorite hobby. Also need heads and carbs for this engine so building parameter suggestions are wide open. I am thinking of working many, many extra shifts to spring for the SCR Gold DG Sunburst reps simply because I just love them. Man, they're expensive!

elliottles1

#1
DatonaCafe,

done it, here is a build vid which may help maybe, bottom end is rd250, because solid mounts let you stress the engine, as the fzr was.
there are other vids that link from this one.

cheers and good luck, i had few skills but it was not the end of the world to do and i had great fun.. plus, it handled like an absolute dream, over here they call the small fzrs "chicken chasers"!

Les.

https://www.youtube.com/watch?v=7g6CaQFdt3g


The Red Scourge

Awesome!  I have a basket case FZR400 that I'm planning to do a similar thing with, so I'll be following along!
'76 Yamaha RD400C
'71 Kawasaki G3SS
'88 Honda CBR400RR
'90 Yamaha FZR400/600 hybrid

m in sc


Clem710

+1, get after it and I'm pretty sure that drain bamage is standard around here:)

msr

#5
Honestly m in sc could rename this whole site "Dumb idea. I'm doing it anyway."  :dawg:

Maybe we can get that on the next group of t-shirts.

m in sc


dgorms

Quote from: Clem710 on August 03, 2022, 02:34:48 PM
+1, get after it and I'm pretty sure that drain bamage is standard around here:)
So that's what my problem is!
rz,r5,ds7,srx,fzr400rr,vfr,cl77,s90, F-7,CL 77, CA-77,ad infinitum

2steve

Being delighted by the smell of a 2 stroke running, thinking it takes you to a happy place, is a sign of this drain bamage.

teazer

Did I miss something here.  Aren't all two stroke projects a dumb idea by definition?  :umm: :whistle:

DaytonaCafe

Yes, they are! It's difficult enough to keep a stock one running properly but to think that making a one off Frankenstroke work properly...we all have major issues.

DaytonaCafe

So, in the spirit of actually making a tiny bit of progress on the actual manifestation of this...uh...thing. I am going to focus on engine build first. Let's face it, the FZR400 was only blessed with 50 high revving hp. I would personally like around 80 but I'm not a very smart 2 stroke dude so, that may either be impossible with an air cooled RD350 motor or not impossible but extremely expensive. I'm NOT stuck on a freaking number, however.  My hope is to get good power that is not on the ragged edge so that it'll run when I want to ride it. So, you all are way smarter than I am with this. Pics of the starting point with the motor are above and I'll have those engine parts in my hands at the end of this month, so game on! Help me decide what direction to point this power plant to get some good, reliable ponies!

rodneya

I dont think you are getting anywhere near 80hp out of an AC motor. Even mid 60's will need a lot of $, maintenance and be less than street riding friendly.

I thought about modifying my 350 motor a while back, but in the end I put together a mishmash of RZ and banshee parts that should be making mid 80's HP. best think is if something in the motor grenades, I can easily get replacement parts. Well, maybe not the RZ trans so much.

DaytonaCafe

Further investigation says you're 100% correct. Looks like 50hp-ish is where it'll end up to be reliable enough to enjoy. Now I will have to figure out who will build this thing bc I'll likely just muck it up.

m in sc

few suggestions: 2 biggest things re chain alignment and how the exhaust will exit. Ive done a bunch of motor swap projects over the years and it can get.. frustrating. one thing you HAVE to work around 1st is the sprocket alignment. consider offset sprockets for the front. try to avoid chain rollers.

also.. as far as power, 50 is plenty good, remember, the aircooled rd motor is ~100 lbs vs whatever the fzr400 motor weights (probably a lot more) AND the center of gravity is a lot lower on an rd motor.