1969 CL350
Veteran Member
Where did you find them so cheap?!?
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(Not so) Budget drag bike project - DOHC 450, of course
- Thread starter ancientdad
- Start date
Amazon - and Keihin is molded right into the side of them, they're amazing for the price. And they even have a Sudco sticker on each float bowl
Paul F
Veteran Member
whoa! 71 bucks, would this be considered a (no brainer) replacement for the VM carbs?
briandel
Veteran Member
I *really* hope you're going to use the Amazon pics for fuel line routing ideas 
Sorry, no blue fuel lines on the drag bike... just plain old black 5.5 Honda fuel line already on its way from 4into1.
As to the thought about VM replacements for the 350 and 450, I'm guessing these would work well and they use Keihin jets readily available from JetsRUs. You'd still have plug chops/jetting to do and unfortunately these carbs do not have the slick hex cap on the bowl to easily facilitate it (standard 4 screw bowl), but the price sure is right compared to new Mikunis.
As to the thought about VM replacements for the 350 and 450, I'm guessing these would work well and they use Keihin jets readily available from JetsRUs. You'd still have plug chops/jetting to do and unfortunately these carbs do not have the slick hex cap on the bowl to easily facilitate it (standard 4 screw bowl), but the price sure is right compared to new Mikunis.
tomeben
Veteran Member
Nice! Those sure are purty... a set of VM Mikuni’s $$$ sparked my interest before I got up the nerve to rebuild the ‘ol VB Keihin’s. Gotta love the clear bowls!
Tom - 1982 CM450E
(“Noob”, but learning fast!)
Someone should make clear float bowls for "other vintage Hondas" cool stuff that.
Edit: especially with the graduations on them for float height, so nice!
Thanks for pointing us to 4into1 (a good seller they are) for the 5.5mm fuel lines too, can't find the real stuff just anywhere, 1/4" = 6.34mm (corrected, thank you) and I'm not sure there's a benefit to running that, what's your experience?
Edit: especially with the graduations on them for float height, so nice!
Thanks for pointing us to 4into1 (a good seller they are) for the 5.5mm fuel lines too, can't find the real stuff just anywhere, 1/4" = 6.34mm (corrected, thank you) and I'm not sure there's a benefit to running that, what's your experience?
Assuming you meant 6.34mm and yeah, I've used 1/4" fuel line in the past but it requires clamps and still doesn't really fit right and really, spring clamps are the only way to go on small line like that because worm drive hose clamps aren't really made small enough to work properly on 1/4" line. I didn't realize some weren't aware of 4into1 selling OEM Honda 5.5mm line, I've known it for almost 5 years and mentioned it a few times on both forums. It's a little pricey but worth it. The best part about the Honda fuel line is it stays soft unlike some fuel line that gets hard after a few years. The line on my red 450 is just as soft now as it was when I put in on over 4 years ago, and I used the 5.5 on the Mikunis which really have what seems to be a 1/4" inlet, just stretched over it so I plan to do the same with these PWK carbs
Decided to spend a little time on the flat aluminum cover plate Russ made for the alternator area of the engine. He punched the center of the crankshaft opening based on measurements and you can tell why the guy made a living doing precision work. I got out the biggest drill bit I had and clamped the plate to a couple of wood blocks and drilled the initial hole, then with nothing more professional to work with to get to the 22mm crankshaft diameter than a reamer, set to work with that. Had to stop to clean the aluminum accumulation off it many times and flip the plate a couple times as well, and it took me about an hour to get there but now I can finish cleaning up the hole and start looking for a seal and cover (or use a labyrinth seal as suggested by Jay the engineer). Either way, it's gonna be unusual and different (and that's pretty much me already). There is no weight savings in this deal, Russ used a thick piece of aluminum plate that roughly equates to the weight of the cover and sub-cover so only a width savings, and the crank stub sticking out spinning while it's running.
briandel
Veteran Member
Maybe a stupid question but could you maybe have shortened the crankshaft instead, keeping it inside the plane of the cover, since you no longer need that end of it?
I can't imagine what it would take to do though...
I can't imagine what it would take to do though...
briandel
Veteran Member
Also, maybe you can find someone to hollow out the inside of the plate with a CNC mill, leaving gasket surfaces full thickness. Probably not worth it though.
You do need a good wizard mural on the outside or something...
You do need a good wizard mural on the outside or something...
Yeah, cutting the crankshaft would take a lot more than a hacksaw... and reduce it to a crankshaft only good for this project as well. One day I'll be gone and this bike will likely end up being disassembled for parts by someone (not much of a market for a drag bike with no title). And, as far as weight savings goes, the little gain made by reducing the thickness of the inside of the plate would easily be offset by whatever I had for dinner before making some runs down the track :neutral: or a couple of beers
briandel
Veteran Member
I can easily drink more beer than the inside of that cover
I can easily drink more beer than the inside of that cover
Yeah, I think that's a given! (for both of us)
Jays100
Veteran Member
It’s a beautiful thing!
I’d almost bet money (at least $1) that a simple “felt washer” would be enough to seal.
I’d almost bet money (at least $1) that a simple “felt washer” would be enough to seal.
But wouldn't it then become another crankcase vent filtered by a felt seal? I mean, it would have to leak at least a little pressure at high rpm despite the seemingly adequate vent hose it has already, wouldn't it?
Jays100
Veteran Member
Oil pressure
I just think there isn’t much pressure there/in that area. That is, there might be splash oiling on startup but the drag of a spring loaded seal may be overkill. Have to control frictions don’t cha know. Frictions eat up horsepower!
I just think there isn’t much pressure there/in that area. That is, there might be splash oiling on startup but the drag of a spring loaded seal may be overkill. Have to control frictions don’t cha know. Frictions eat up horsepower!
You're right of course, but I have much larger worries (rotund-ness) that is a significantly greater contributor to horsepower loss...
Hey Tom, as far as cutting the crank stub, an abrasives cutoff wheel in a 4" angle grinder would make quick work of it. I personally think that a dedicated drag bike is a pretty cool thing to leave behind and may be more desirable to some guys than just a pile of 450 parts.
I'm sure I could do it with what I have, but the truth is 4 speed cranks are hard to come by and if this bike ends up going to my buddy Chris or someone else who is a 450 owner/collector, the crank could still be used in a stock bike if I leave it alone (provided it survives what runs at the strip it will make).
Thanks, it's taking a lot of time but I hope to build my strongest 450 engine yet with the parts I've been able to assemble and the head being done by one of the best in the business. Chris locating the 4 speed bottom end for me is the primary reason for the effort and having a top flight machinist to work with has been a big advantage so far as well. Hopefully it will be running this fall.
I just realized I hadn't posted any pictures of the pistons and cams I'll be using (though the exhaust cam is pictured with Russ working on the bearing surface). I bought Todd Henning Racing 74mm 12:1 pistons (which may be Wiseco) and one of the last sets of cams from Terry Naughtin before he retired, the biggest cams he ran with stock torsion bars at .414" lift and 280° duration (and though generally not recommended for torsion bars, he ran a set of these for a year with no issues which is the only reason I bought them). I bought a set of NOS torsion bars to go with them so hopefully I'll get some good results combined with Chris Schumann's porting and hand-made titanium valves I've invested in. There's almost $1000 sitting there in just two pieces of the puzzle, there goes the "budget"
tomeben
Veteran Member
You can’t take it with you, or so I’ve heard. Just keep spreading it around so it has a path to come back to you. The engine internals are Greek to me beyond their basic functions, but who doesn’t love new parts - they sure look fast!
Tom - 1982 CM450E
(“Noob”, but learning fast!)
They better look fast considering a stock set of pistons can be had for $100 and used cams are out there for $50 or so each, sometimes less. It's crazy how small the increase in lift is with the cams, you'd think it wouldn't make as much difference as it does but the stock cams have about .300" lift or so, the cams in my red bike are low lift at .350"/.365" but the same long duration at 280° so the .414" lift combined with the same long duration is significant. Here are comparison pics to show you how easy it is to see the longer valve opening duration. The Megacycle cams mentioned in this website thread are the exact set I now have, in a long and convoluted journey from the US to Australia to VHT member LiamG6 for his 500T project after he bought them from Ed, then back to the US when Liam and I swapped cams as I liked the 120-40 set better than the more recent purchase of the 120-x11/x12 set I originally bought for the red 450. After getting them from Liam they had some rust pits on the bearing surfaces and Russ cleaned up the exhaust cam and did the first of two bronze bushings in the left exhaust bearing cap for me, then they went in the red 450 because I'd owned the exact same grind back with my first drag bike and liked the way they ran. Check out the comments at the bottom of the page
stock cam
Megacycle 120-40 grind
stl360+450
Veteran Member
The fabrication on display in this thread is really impressive, especially the steering stem pieces, the aluminum welding with the tank, the frame modifications, etc.
The price point on the PWK carbs is insane compared with Mikuni's. I'll be curious to follow the jetting work at a later point in the build. Is there a special throttle cable for PWK carbs and is there a 1-to-2 cable that would work with a standard Honda throttle housing? (I'm assuming you will have a non-OEM throttle on this build.)
I saw that you mentioned the flat aluminum side cover provides a width savings, but not a weight savings. Why is the width savings important? And does the exposed crankshaft mean that a drop on the left side could be catastrophic? Exposed primaries make me nervous.
I guess those pistons put you around 497cc?
Russ is amazingly talented, when you go to his shop and see all the stuff he has to work with and look at the many things he's created it gives you a feeling of complete confidence that anything you need can be done, and done well.
Yeah, the flat left cover was as much for the visual and the curiosity of it as it was for functionality. It may or may not make the cut. The lack of weight savings is in part because he chose such a thick piece of stock to make it from, it could have been half that thick and would have sealed the crankcase as well. I ran the empty entire left crankcase cover on my old drag bike, it's just odd to have the large, deep cover on there with only the stub of the crankshaft spinning inside it. Unless the fall on the left side with the flat cover was pretty hard I'd imagine the end of the crankshaft could handle it without getting bent though, and something like that could happen in the pits but it would only be at low speed. Either way I'd still have to fit a seal for the crank stub and that hasn't been worked out completely yet anyway.
Though I haven't tried them yet, I assume the stock Honda throttle cable will work with the PWK carbs. I may need to shorten the outer cable to create more inner length but it's doable, I did it on the red 450 for the Mikunis so I could use a stock gray cable. Actually, I plan to use an OEM Honda throttle assembly if possible because of the incorporated starter button which will be used as an ignition kill for clutchless shifting. I bought a cheap right switch from a later 4 cylinder model (push/pull cable style) because the price was right and it has the later version (really large) starter button, but it might cause single cable adaptation issues. It's a minor thing if it turns out to be a problem and I'll deal with it later on. There will be a lot of little stuff to sort out as the big parts of the build come together. And yes, the 74mm bore makes it the same size as my red bike, 497cc.
Jays100
Veteran Member
Here is a link to my earlier work on PWK33’s: https://www.vintagehondatwins.com/forums/showthread.php?818-PWK33-450-Project. Do the 33 and 36 use the same cable?
I will share jetting and cable specs, send a PM with the understanding of no publish.
I had thought to offer the knockoff PWK’s as a kit but just don’t have the bandwidth to get it all done. PM me if you’re going to go that route rather than Mikuni. I for one am very satisfied with my PWK’s on a stock 450: equivalent fuel economy and superior performance to the stock CV carbys, and for the cost of a rebuild kit, you get a whole new unit!
I will share jetting and cable specs, send a PM with the understanding of no publish.
I had thought to offer the knockoff PWK’s as a kit but just don’t have the bandwidth to get it all done. PM me if you’re going to go that route rather than Mikuni. I for one am very satisfied with my PWK’s on a stock 450: equivalent fuel economy and superior performance to the stock CV carbys, and for the cost of a rebuild kit, you get a whole new unit!
I don't know if the 33s and 36s have the same cable requirements but I'd suspect they do. I'll find out eventually and I'm confident I can adapt something
ballbearian
Veteran Member
I just found and read this whole thread. It's great! So many ideas materializing. Quite inspiring!
Yeah, it's been buried for a while since there hasn't been any activity. The wait for the cylinder head to be finished is almost over, Schumann emailed me last night and asked for the torsion bar retention bolts and dowels that I did not realize he would want when I sent the head. I never expected him to finish-assemble the head for me so it didn't occur that I should send them with the torsion bars, but this way the head will be ready to install the cams when it comes back. This will be the most professional head work ever done on any engine I've built for track use, so unless I completely screw up everything else it should run better than any other 450 engine I've ever put together. Caveat to that would be the first drag bike in the '70s when I sent a spare head to Jerry Branch (Branch Flowmetrics) and had it ported and bench-flowed, but I went broke and never got to use the head. The bike and spares were sold not long after so I never got to find out how well it might have run. Yet another thing that has bugged me over the years, leading to what I've done with both the red 450 and this project...
stl360+450
Veteran Member
That's a shame. Hopefully this build will more than make up for that. If you get paired up with a modern bike at the track again, I'm hoping you'll cross the line first.
Do you have a sense of what you can get out of your build in terms of max engine speed, 4-speed transmission, sprockets, etc.? Is that 650 wheel larger than stock? And in a drag situation, I'm assuming you would end up in fourth gear, but I have no racing experience so I don't really know.
Yeah, that was a sad moment when I chose to let all the spares go with the bike back then, but I was in a really difficult situation - out of work, broke, and trying to sell a bike that was purpose-built, no title, and with me in a bind... I had to sweeten the deal with all the spares just to make the sale. Even sadder is what happened next... the idiots I sold it to were the new owners of the small bike salvage yard I'd only worked for a couple months and they let me go when they took over, so they knew I was out of work and of course there was no internet and other easy resources to reach a wider audience back then, so since I needed the cash in a hurry I took the offer in front of me. Making things even worse after that, they took it to the drag strip themselves and told me later how they were turning some ridiculously high rpm with it (13,000 or so) and blew it up... a bike I'd thrashed for almost 3 years with zero engine issues and in the hands of morons only lasted one day.
As for gearing and rpm range on this build, I'm still working with the possibilities for ratios for the track. I'll probably be running mostly 1/8 mile so it won't be going through the traps in 4th gear. And, I learned while test-fitting the front sprocket and chain (with lower case and countershaft sitting in it for chain alignment) that the shape of the 4 speed crankcases near the countershaft for front sprocket and chain clearance is different than the 5 speed (something I do not recall from almost 50 years ago) and it looks like I might not be able to run a 14 tooth front sprocket (1 tooth smaller) like I can on the red 450. If that turns out to be true I might end up going a fair amount larger on the rear sprocket and compensating with a 16 tooth front if/when I take it to Gainesville for the 1/4 mile. Optimally, you'd want it pulling whatever rpm turns out to be the power peak right as you go through the traps, which is 10,500 on the cams in the red 450, but these cams are more radical and it should breathe a lot better as well so I really don't know yet what to expect. Hopefully I can go through at the top of 3rd gear at the 1/8 mile but the real advantage of the closer-ratio 3rd and 4th gears on the 4 speed is for the far end of the 1/4 mile so it will have to go to Gainesville at least once. It all remains to be seen.
stl360+450
Veteran Member
You'd almost rather you never heard from them again. What a waste...
Yeah, it was sickening for sure... but it was one of many reasons I wanted to eventually do the project over in street-legal fashion. I'd go years without thinking about it too much, and then I'd go to the drag strip with someone and it would all come back to me. I was a slimmer young man then (about 170 lbs) which allowed quicker times and better performance but that bike ran so strong that by just rolling on the throttle in first gear, it would lift the front end when it came on the cams around 6000 rpm. Obviously that made it harder to ride and the stock wheelbase didn't help either, but this version is 4" longer with the 650 swingarm and sits lower than the old bike did so it should be easier to ride.
I do need to measure the circumference of the 650 rear wheel/tire to see how it compares to the stock wheel/tire, for Gearing Commander purposes.
Jays100
Veteran Member
I put together a gearing calculator, gear v. rpm = speed/gear...have I sent that to you? Anyway, just measure the diameter and multiply by pi to get circumference.
J
J
Don't you mean pie...? In fact, I could go for some for dessert after my wife's marvelous cooking for supper.
I think you may have sent me a calculator a while back but it's probably buried in months of accumulation. So many emails when you sit in this chair... so few hours in the day. And I'm still working on my wife's greenhouse project, it seems to never end.
Jays100
Veteran Member
No worries, I’ll just resend. If anyone else wants a copy, send me a PM.
Jay
Jay
stl360+450
Veteran Member
Do you have any kind of ETA on the head? I would imagine less than two weeks if your machinist is already working on it, but I don't know how busy he is. I know you're going total loss on the electrics, what about gauges? Tach only?
Are there any other bits and pieces that you still need to track down for the build?
The head has been with Schumann Motorworks in Oregon almost a year to the day at this point, and it's finally ready except for buttoning up the torsion bars so he can check the torsion bars/valve seat pressures. I didn't realize he would completely assemble the new titanium valves and NOS torsion bars for me after the porting and other work was complete, so I failed to send the torsion bar retention bolts and dowel pins. Schumann is well-known for his cylinder head work for AHRMA racers so I asked him to port the head for max flow with the specs of the cams from Terry Naughtin. Chris should be receiving the bolts and dowels today if he didn't get them yesterday, and he said the head would be shipped out on Monday.
I plan to run a stock tach with a single LED for illumination from a roughly 20-22 amp LiFePO battery. I have waited to buy the battery so it doesn't sit idle for more months leading up to when the bike will be functional. I still need a drive chain, some or all parts for the exhaust and a few other little items, and I know as I begin engine assembly some little stuff will come up but I have most of the parts to get started on the bottom end soon. I do need to get the previously-bored cylinders checked since they were done by someone I've learned a lot more about in the year+ since it was done and I need to be sure they're truly usable.
I'm building this engine with an assemblage of 4 speed parts for the bottom end and 5 speed parts for the top end, all of which have been gathered together separately along the way so I'm sure I'll be missing something that I hadn't thought of. Since the summer heat is right around the corner here, I'll have all summer to build the engine to get it track-ready for the fall (probably after we return from SC again this coming October).
stl360+450
Veteran Member
It will feel good I'm sure to lay your hands on the completed head. Just a few more days...
I know I sort of asked about this already, but does the sprocket on the 650 rear wheel use the same chain as the front sprocket on the 450? As I recall you haven't completely decided on the sprocket sizes you want to run.
Yeah, I am certainly anxious to see Schumann's efforts. He had a few setbacks during the effort, some of which were avoidable (he made the first set of valves without checking the seat depth and the head had the seats cut prior to me acquiring it) so he had to make another set of valves, during which a bearing in the motor on his '60s Atlas lathe came apart and allowed the brushes to short on the shaft and cause a small electrical fire. After he got those repairs made he turned out a new set of valves the correct length for the previously-done valve job, then this description from his email:
"...because the intake seats were cut so deep there is a step that shrouds the valve and will disrupt flow. I'm reworking the chambers along with the porting which will take care of that."
So it has been an adventure for both of us.
Oh, and the 650 rear sprocket on the wheel I have uses the same 530 chain the 450 uses.
Tom very interesting thread and build for sure with some pretty radical mods to the engine. How do you time the engine for that cam and do you run an electronic ignition that can be tuned too? New area for me so is everything still set at TDC, or do you need to use a degree wheel to adjust for the cam lift and overlap changes?
If the cam sprockets were adjustable I could use a degree wheel, but they are not. I'll obviously be putting the alternator rotor on it for setting the timing marks on the cams but they'll be set just like a stock engine. Might be a degree or two off from perfect but I've spent enough on the top end as it is, getting adjustable sprockets on the cams would have added even more to the (not so) budget budget. I'm going to be running total loss points ignition, straight battery with no alternator rotor or stator to recharge to reduce the rotating mass on the end of the crankshaft. On my drag bike back in the '70s I used the original 12 amp battery and it lasted the entire evening of runs (often as many as 12 to 15) and this time I'll be using a much larger 20 to 22 amp LiFePO battery because it's so much lighter than a lead acid, allowing me to use a larger battery for more reserve capacity yet still no more weight than original (possibly a little less). I'll also be using a modified advancer with the breaker cam lobe trimmed down to less than half the points-open duration to ensure it will get plenty of dwell and rev cleanly to well past the rpm range the engine will turn, probably around 10,500 to 11,000.
stl360+450
Veteran Member
There was some discussion about shortening the crankshaft earlier in the thread and when I read Flying900's post I immediately thought about the fact that you'd have a much harder time setting the ignition timing without being about to mount the rotor.
Yeah, that and it would also render the somewhat rare 4 speed crankshaft useless for anything but my project too. Which reminds me (since it's been almost 50 years since I last set the timing on my old drag bike), I'll need to make a pointer for the timing mark inside the stock left crankcase cover for when the rotor is on the crank and checking/setting the timing. Or on the outside of the flat cover if I decide to use it.
ballbearian
Veteran Member
I guess you could run a lightened rotor, sans magnets.
Just mount up an old AOL CD, they're good for 15,000 rpm before they scatter.