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It just keeps happening! - Yamaha FZR400/600 hybrid

Started by The Red Scourge, May 10, 2022, 01:19:47 PM

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The Red Scourge

They just keep following me home!  I found a totally sketchy looking frankenbike on Facebook marketplace at least a month ago.  It had 3 pictures in the listing, but could tell it was an FZR400 aluminum Deltabox frame.  After a long, pretty strange correspondence with the seller I was able to go pick it up last week.  It's a 1990 FZR400 with an FZR600 3HH engine and '92 GSX-R front end on it.  It's absolutely clapped as you can see.  I really wanted it for the frame.  They're pretty uncommon these days.  I was planning (and maybe still am) putting a 2 stroke engine in the frame down the road.  Was thinking Rotax 257.  That engine is right side drive, so I'd need something like an Aprilia RS125 swingarm or modify the current one.  I'm getting ahead of myself lol.  Since apparently the engine is still good, I plan to get it fully roadworthy after my CBR400rr is finished and worry about crazy swaps later.  It's more of a complete bike than I thought, but is still missing front brakes, controls, and probably a bunch of other stuff.  I haven't dug into it yet.  I was pretty jazzed to see that ubiquitous gold gas cylinder from the rear shock when I got out of the truck though!  It'll be a bit until I get to it, but wanted to post this properly knackered FZR here.  Oh, and it was definitely raced at some point.  It has safety wire all over it.
'76 Yamaha RD400C
'71 Kawasaki G3SS
'88 Honda CBR400RR
'90 Yamaha FZR400/600 hybrid

The Red Scourge

.
'76 Yamaha RD400C
'71 Kawasaki G3SS
'88 Honda CBR400RR
'90 Yamaha FZR400/600 hybrid

dgorms

rz,r5,ds7,srx,fzr400rr,vfr,cl77,s90, F-7,CL 77, CA-77,ad infinitum

The Red Scourge

'76 Yamaha RD400C
'71 Kawasaki G3SS
'88 Honda CBR400RR
'90 Yamaha FZR400/600 hybrid

The Red Scourge

So I'm looking for some input/experience.  I've gone back and forth on what I want to do engine-wise for this thing.  When I pulled the carbs there was significant rust and corrosion as well as rust running down the carb boots into the engine.  It clearly has sat outside in the elements for quite a while.  I'll pull the engine and see how bad it is.  I don't know if I want to rebuild an FZR600 engine at this point. 

So, with an eye on putting a 2 stroke engine into this frame, I'm running into some roadblocks.  Of course with unlimited funds, anything can be done, but budget is definitely a consideration for me.  When I get a new project like this I get super excited about it and admittedly waaaaay ahead of myself when thinking about the build.  The reality is I probably should sort out the suspension and brakes before engine.  That being said, I'm still looking at 2 stroke engines online!  So here are some of the ideas I have for it based on what's available.  I'd like to go liquid cooled if possible.  It'll be fully faired for the final build.

-Rotax 257: Would be a crazy cool bike.  It's a right side drive engine (why Rotax?!), so swapping an Aprilia RS125 swingarm would make the most financial sense.  I could modify (I believe) the stock Deltabox swingarm, but I'm rather not butcher it.  I can get the engine from Frinken Racing in Germany for about $1,000, then there's shipping and I'd still need to work out the ignition system and carb.  This option would be my ideal build if I can afford it, but that'd probably be a few years down the road.  The kids are pretty young and my wife isn't working right now.  Could be an okay timeline as I'm almost done with my CBR400, and still need to finish the RD400 and G3SS. 

-Kawi H1 500: This seems to fairly cost effective.  There's a local guy that has a few 500 engines.  I've never ridden an H1, but the numbers seem more than adequate for what I want out of this bike.  This may be a stupid question, but would full fairings have a significant effect on the engine's ability to shed heat? 

-RZ350/Banshee: Great option if I could find one lol!  It seems like there's a better chance of finding a Banshee engine out of the quad.

-Rando dirtbike engine: With Mark very successfully building his CR powered G3SS, it gives me a lot of hope for this sort of thing.  This would probably be fairly cost effective as well.  My only thought here is that those MX 2 strokes weren't designed to be ran high in the rev range for long periods.  Are there any considerations for putting that in a road bike?  I wouldn't be planning on taking it on the freeway much if at all.

I should probably stop rambling, but these are the options that have been rattling around in my head since picking this up.  Thanks in advance!
'76 Yamaha RD400C
'71 Kawasaki G3SS
'88 Honda CBR400RR
'90 Yamaha FZR400/600 hybrid

~JM~

I began attempting to swap an RD400 engine into the FZR400 frame. It can be done, but the frame is a bit wide. The countershaft sprocket alignment will require an offset sprocket if you center the engine. Shifter linkage might be challenging also. I've seen some pics of RD powered FZR400, but not detailed views.

The Red Scourge

#6
Ok, I appreciate that insight.  I'm glad you mentioned final drive alignment.  I hadn't thought of it being my first potential motorcycle engine swap.  The Rotax would likely cause some real problems as it's a single cylinder.  Maybe I'll hit up that local guy for some measurements on the H1 engine.  So you didn't go ahead with the build?
'76 Yamaha RD400C
'71 Kawasaki G3SS
'88 Honda CBR400RR
'90 Yamaha FZR400/600 hybrid

busa1300

RZ350-RZV500R-TZR250RSP 3XV2
RGV250 VJ21 SP/VJ22 SP/VJ23 SP
RS250 for track - KD80 - JR50 for kids
https://youtube.com/@wedgehorsepower9869?feature=shared

The Red Scourge

Quote from: busa1300 on May 15, 2022, 08:40:35 AM
Yamaha two stroke snowmobile engine....

I had that thought once years ago, but don't they use a CVT transmission?  Some dude on YouTube slapped one one a motorcycle frame, but it had the big ol' belt on the side.
'76 Yamaha RD400C
'71 Kawasaki G3SS
'88 Honda CBR400RR
'90 Yamaha FZR400/600 hybrid

2 Stroke Jamoke

I built a gs500 with an h1 engine. It was cool but I would vote against the h1. It's a hard engine to tame and it just didn't gel with the other frame. Felt like 2 bikes fighting to see who is in charge. The yamaha engines are far better, just my .02

The Red Scourge

Quote from: 2 Stroke Jamoke on May 15, 2022, 10:22:18 AM
I built a gs500 with an h1 engine. It was cool but I would vote against the h1. It's a hard engine to tame and it just didn't gel with the other frame. Felt like 2 bikes fighting to see who is in charge. The yamaha engines are far better, just my .02

Yeah, I bet that's kinda unexpected once you finally get it on the road.  Frinken Racing also sells 2 different generations of the tzr250 engine.  I'll need to get the engine out of the frame and take a bunch of measurements before I make any decision on the engine.  The TZR is a twin so I feel like that may fit better, but who knows at this point.
'76 Yamaha RD400C
'71 Kawasaki G3SS
'88 Honda CBR400RR
'90 Yamaha FZR400/600 hybrid

85RZwade

Looks like a GREAT project to me, and I might consider a big-bore off-road single, like a KTM 380. Lots of power, exhaust valve, PWK Air Striker and wide-ratio 'box might be very satisfying.
I post waayyy too much

~JM~

Quote from: The Red Scourge on May 14, 2022, 10:22:07 PM
Ok, I appreciate that insight.  I'm glad you mentioned final drive alignment.  I hadn't thought of it being my first potential motorcycle engine swap.  The Rotax would likely cause some real problems as it's a single cylinder.  Maybe I'll hit up that local guy for some measurements on the H1 engine.  So you didn't go ahead with the build?

I did not.


m in sc

id aim for rz or banshee. while the H1 may be cheaper up front, it will cost later. especially a crank rebuild.   :twocents:

The Red Scourge

Quote from: m in sc on May 23, 2022, 10:29:45 AM
id aim for rz or banshee. while the H1 may be cheaper up front, it will cost later. especially a crank rebuild.   :twocents:

I hadn't even thought about the crank rebuild.  There seems to be a good number of Banshee stuff out there.  What's kinda wild is everyone is selling engine parts, like down to the engine cases, transmission gears/shift forks.  Like, did you fully grenade it?  I've never seen engines so consistently broken all the way down to sell. 
'76 Yamaha RD400C
'71 Kawasaki G3SS
'88 Honda CBR400RR
'90 Yamaha FZR400/600 hybrid