BUMP! Bump & a HUMP!
These Kaz Yoshima NOS PARTS-PORN pics are yummy. I figure any CB350F/CB400F nerds out there should get to see 'em, if they haven't already. There really ought to be a STICKY up about this stuff, containing all of the pictures in this thread. I worry that stuff too far back in the archives is gonna be lost & forgotten. AND I suppose, I've got some pics of later era exhaust stuff that's pretty dang similar to the Kaz Yoshima OMT product, which I might as well share with whomsoever else might wanna look at these sexy old bike-porn pics. THAT'S why I feel it's worth bumping!
Heck I'm sure ya'll might agree, despite it being a yucky DOHC bike, that it's lusty stuff just contemplating what MY pipe's gonna do for my bike, once it's tuned properly and the CV carbs come off - I've heard about DOHC 750's being able to use the SOHC headers, and that they've got the correct spacing and overall 'ergonomics' if you will, but that they're somehow too small of a diameter to work with the 900cc+ engines - No doubt due to the "D-shaped" ports of the bigger stuff? Well you've gotta wonder then, whether it's feasible to use the 900cc+ exhausts on the SOHC 750's - Well, I'd guess you'd have to do some extensive port matching, and matching the exhaust runners to the ports while you're at that, and heck maybe matching the exhaust valve diameter to the runners, and then the combustion chambers and overall displacement to new exhaust valves, then the intake valves to that, the intake runners and ports and carbs and filters and.... Might as well get yourself a DOHC valve-train to make the best use for it all. HA-HA. SOHC-ers! No really though, maybe there IS some possible way of fitting these DOHC 900-spec pipes on a SOHC 750 engine?
ANYWAY, THIS one is a WOLF pipe, completely original, for the DOHC-4, on an '82 CB900F, ostensibly with a 985cc kit in it, plus the "good" pods from K&N - Thus far I've added a DIMO air-box, though I think I might use it to try & construct some kind of over-sized air-box with a nice huge free-flowing filter in it. Got a bunch of ABS sheet for this expressed purpose. But with this pipe and engine now it's got me thinking none of this will be worthwhile without the Keihin CR carbs in the mix. I wonder whether anybody's ever put an air-box on the racing carbs. Could be really interesting IMHO.
Even as tight as it looks in the "as bought" shot, my bike ran kinda sketchy with the pipe & pods - I mean, it still ran HARD but I could detect a palpable flat-spot in the mid-range, which felt weak compared to what I'd come to expect with previously experienced '82 CB750F's in bone-stock OEM tune (well, with the K&N air-box type filter and some jetting, I suppose) But while it COULD be chalked up to the pods on CV carbs thing, I also found a lot of #$%* up inside the pipe when I popped it off for the first time - It was all clotted up with grotty sooty fiberglass wrap that had been blasted apart in places. So whatever I use for a wrap when it's back on the road, I wanna get a big supply of it so I can change it out, keep it good and clean. So it would be nice to go the budget route - Gonna see if I can buy the pro-grade crap by the ROLL - perhaps a kit for some type of American Muscle-Car Detroit #$%*-box CAGE's upgrade exhaust, might just include two patches of cloth for a decent price? It's like they're selling the crap one sheet of loose-leaf at a time, when you SHOULD theoretically be able to buy it in bulk. Obviously THEY'RE doing the same damn thing! 'Cause yeah, like I say, I don't intend to let it get all sooty & grotty like that ever again!
Dunno about this here DIMO air-box though -
I had expected it to fit the OEM frame more perfectly, but I guess it's actually made to fit the EGLI or MOKO type of spine frames, hence the little divot in the center presumably meant to clear a mono-shock element. It's also meant to fit a bunch of other models for that matter. So the PLAN is to add on more volume. Originally I'd thought I'd be able to stuff a filter into the bell mouth opening at the bottom, but the clearance THERE is too tight! So now I've got to figure out a way to block off the bottom and go through the back, or better still add a plenum space along the bottom and connect to IT for the additional volume, using the existing back wall as a separator for the plenum & filter area, etc. Not exactly the way I'd like to have done it. SO, perhaps it's a good thing it's all made from Fiberglass, as I might be looking at using just the front plate and sides with the curved corners, just build a huge box onto the back end and cut it off to where it'll fit the frame, then extend THAT with an add-on box under the seat in the sub-frame section etc. IMHO that'll still be worth the purchase, 'cause this is the area where aesthetics would matter, and it could save me from building some thing that REALLY looks like #$%*!
I'm sure it's gonna add some power, just as it is - it's completely free-flowing, it's basically a fix so you can run the open inlet on the OEM constant-velocity carbs. Ya'll SOHC folks should be happy knowing you've got the direct-pull carbs. Heck, I'm gathering parts for a "featherweight" version of the DOHC 750, for my Kid, and when I think about budgetary constraints vs seeking better power, I'm tempted to try & run some early SOHC carbs on the DOHC, or something off a KZ even. When shopping for an air-box, I was hopeful I'd get to run a SOHC air-box, the replica Sand-Cast version with the paint etc. Well the carb spacing just won't do it, the DOHC bank & it's boots are just too wide for the SOHC box. So maybe a bank of SOHC carbs could be a fix for that as well. Still ... probably cheaper to hunt for a deal on TWO banks of the Keihins, and the SOHC box has a pretty small internal volume and plenum compared to the DOHC version - and I'd wanted to go even bigger than that. The plan for the "Featherweight" is the Cycle-Exchange 4-into-4 straight pipes, maybe with some mufflers maybe even without. Preferably something removable, "Snuff-R-Not" style perhaps. But yeah, lighter weight or not, it's still gotta be hopped-up a little bit.
The only thing about these 4-into-1 headers, OMT style stuff, hand-bent headers like my WOLF - Is that they're so tight, I can't do the "Sandwich Style Deep Sump" mods (which I'VE invented, borrowing heavily from Motoren-Israel BMW products) AND more to the point - I can't even access the oil filter without having to take the whole damn pipe off. And this time 'round I've gotta be dilligent about the oil changes here. Not like the first '82 CB750F that I murdered as a younger guy. That thing was CHERRY, with respect to the engine - when I got it the oil was clean enough to cook with, to clean with for that matter. And some very neat fresh silicone on clean new gaskets. Got it from the impound auction in Calgary but with an Ontario plate on it. So the impression I get is that whomsoever lost the bike to the cops, must've been giving it the shake-down run after a rebuild. And it must've been FAST if they lost the bike over some tickets etc. Horrible that somebody lost the bike that way, but nobody else was bidding on it - $375 Y2K Canucks! And nobody came to say "lemme buy it back" so presumably they were either in jail or back in Ontario. Well THESE days I might feel tempted to try & help a former owner get their valuable ride back. Tough to say - Back THEN I was in pretty dire straights. If it weren't for that bike, I wouldn't have had wheels on the road! And I needed it BAD. Used it for last minute emergency transport for a follow-up appointment for back surgery. And a failed back surgery at that, the one-in-three type which made things worse. Fearing having to pay for the missed appointment, unable to travel by auto due to horrible pain with all of the bumping & side-to-side motion, and having no time to arrange a HELICOPTER, I had no choice. 250kph cut the travel time down by more than half, and I barely made it to the appointment 250km away, having already wasted half of the day attempting the trip by auto. Laid down flat on the tank with low bars & passenger pegs, like a hospital gurney. THAT'S how badly I needed the bike and how well it filled the position! Ha-ha. A miracle to have survived it. Anyway my point being that I STILL wound up failing that bike, not living up to what I owed it, 'cause it was so #$%*ing painful doing the oil & filter changes and I couldn't afford to pay to have 'em done. THESE days, the type of women I've dated after that time, my GF would've done the oil changes for me, rather than me working on HER vehicles with the stitches in my back, on a gravel driveway under her car in a -40 Celcius Alberta winter, so she could save a couple of bucks. And more to the point THESE days, I'll do whatever it takes not to miss those oil and filter changes! THIS engine's gonna be treated kindly ... while it's not being whipped like a horse in a stage-coach robbery.
The only pain in the ass about THAT being, the damned WOLF PIPE is gonna have to pop on & off of the bike all of the damn time. Which leads me to the conclusion that IF you're gonna run this type of tight-fitting hand-bent pipe on a bike, then you should adopt some of the OTHER aspects of the race tech which bred these exhaust systems. Such as SPRING HOOKS.
And that's the catch here, is that the fix to a "problem" like this (Yeah, I know, I shouldn't #$%*!) would permanently modify the thing, perhaps ruining any real value - not resale value mind you, 'cause I'm not gonna sell it, I mean it's "historical value", it's "TIME MACHINE factor" - Unless of course, the spring hooks themselves are done in such a way that the themselves are even more historically correct than the rest of the pipe! From what I gather, some of the Yamaha TZ parts suppliers deal in parts such as these, kits for weld-on spring-hook exhaust retainer systems. The trick would be in finding somebody who could modify the thing for me! Ugh.
And if it's gonna go as far as all of THAT, if I'm gonna ship it far away and sink some serious $$$ into it, well then I'd have to get it ceramic coated, possibly even chromed for the best look with all of the other "Retro-Fried" OEM-style mods I'm doing to the bike. AT which point, I really ought to look at just buying another header! So yeah, for the time being I guess I'm gonna have to suffer along with this pipe just as it is. And perhaps look into a bulk pack of exhaust gaskets plus some really good studs & stud-nuts like maybe some high-temp nyloc nuts or some such, so the pipe coming off & on repeatedly doesn't mess up the head etc.
JUST SAYIN' - If you think a pipe like this is gonna be a dream come true? Think about all you're gonna have to put up with!
Yeah, them 4-into-4 headers from Cycle-Exchange are looking awful decent right about now. All tucked in tight, & perhaps the straight sections could be made up from Titanium pipe to off-set the weight gains? I'm aware of what all it costs to create a BENT Titanium pipe, however it's gotta be substantially less just for some straight tube stock? Might be feasible, you never know. That, or buy a crap load of really flimsy thin-walled tubing that would wear out a lot quicker than a standard exhaust, yet sufficient to last half a season's riding? Just sayin', IF there are gonna be long straight sections in a header like that, perhaps there are some cheap fixes that otherwise wouldn't present themselves? But the MAIN thing about the 4-into-4 header, is I'm really excited about building a really huge DEEP SUMP, whether that's just a sandwich-style thing, or adapting another type of pan from another model, or a huge convoluted weld-up structure. EITHER way, it's gonna be the full extreme manifestation of my long sought deep-sump mods. Did some on my last '82 CB750F, but lost it all to a fire. So call it a "burning desire" if you will. A long time waiting to bring it to fruition. Plus there's the over-sized spin-on filter, sans adapter just a threaded pipe nipple instead of the filter bolt, and a spin-on canister filter that's broad enough to seal directly to the crank-case, with the same size of O-ring as the OEM filter housing uses. Finally rounded up the correct type of filter, but lost it and all info in the fire, so never got to bring THAT one to fruition either - and likely won't, either - not until the pipe's replaced or modified. THAT'S what all this PIPE is holding back!
And yet I don't wish to be parted from it, 'cause it's SOOOOO DAMNNNN SEXXXYYYY!!!
-Sigh.
