(Not so) Budget drag bike project - DOHC 450, of course

When I bead blasted my engine I used worn out screws and bolts to attach the outer cases and taped off the cylinder holes and then blasted the lower end as a unit to keep most of the media out of the engine. The same for the head, I had the cam bearings and valve covers in place on the head when I bead blasted it. The place I went to was a self serve place that charged you by the hour. I was able to be careful where I blasted but even so, I still found media inside the bottom end and in a couple of blind holes. Run a tap through every threaded hole to make sure they are clean - ask me how I know :eek:
 
boddy said:
When I bead blasted my engine I used worn out screws and bolts to attach the outer cases and taped off the cylinder holes and then blasted the lower end as a unit to keep most of the media out of the engine. The same for the head, I had the cam bearings and valve covers in place on the head when I bead blasted it. The place I went to was a self serve place that charged you by the hour. I was able to be careful where I blasted but even so, I still found media inside the bottom end and in a couple of blind holes. Run a tap through every threaded hole to make sure they are clean - ask me how I know :eek:
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Yep, I have already run screws into every threaded hole and those are okay after being blown out with good air pressure, I fully expected that from this hack. Fortunately most of the hackery is now behind me and if the cylinders are okay I'm happy-ish. Still pisses me off that he got my bike for at least $300 or more under the deal we priced out based on good quality used parts. Grrrr
 
Last thing done today was removing the oil pump from the test rig, taking it back apart and washing everything clean to put a tiny bit of Hondabond on the housing mating surface, then reassemble and let it sit overnight (according to the Engineer overseeing this part of the effort :giggle: ). Have to put it back on the test rig tomorrow and run it in a little more (5 to 10 minutes), then bolt it into the engine so the clutch and oil filter cup can follow. Then I can close up the bottom end and put full focus on the top end... unless (until) the next bit of hackery is discovered.
 
ancientdad said:
Last thing done today was removing the oil pump from the test rig, taking it back apart and washing everything clean to put a tiny bit of Hondabond on the housing mating surface, then reassemble and let it sit overnight (according to the Engineer overseeing this part of the effort :giggle: ). Have to put it back on the test rig tomorrow and run it in a little more (5 to 10 minutes), then bolt it into the engine so the clutch and oil filter cup can follow. Then I can close up the bottom end and put full focus on the top end... unless (until) the next bit of hackery is discovered.
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Interesting no gasket assembly, just Hondabond.
Hope the next phase is as interesting but in a good way.
 
ballbearian said:
Interesting no gasket assembly, just Hondabond.
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The surfaces are nicely machined, it would probably do just fine without sealant honestly. And mine is the early version that has open shaft holes, one of which seeps a tiny little bit of oil as it runs. Still, the flow coming out of it is strong and steady.
 
ancientdad said:
The surfaces are nicely machined, it would probably do just fine without sealant honestly. And mine is the early version that has open shaft holes, one of which seeps a tiny little bit of oil as it runs. Still, the flow coming out of it is strong and steady.
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Open sounds good, it will stay flushed out.
 
Well, when you believe you're sure of everything you know and have seen, that's obviously when you get tripped up.

I've been working for days now to get this oil pump working right (rust deposits in the bottom of the gear teeth from sitting in my garage in a plastic bag waiting to be used), then get a new set of gears from Jay, reassemble the pump and put more run-in time on it, then try to fit it only to discover that it binds up when mounted. I looked at everything, or at least I thought I did. Turns out the problem was right in front of me, something I would NEVER have suspected, nor have I ever knowingly seen, but it's true.

The mounting bosses for the pump in the better (read: actually usable) lower case I have are the problem. After trying anything and everything I could think of to ensure the pump fit correctly in my now nearly complete bottom end, I checked the other lower case for the fit of the pump. And it fits perfectly.

So now I have the dilemma of how to extract the totally-wrong and likely cross-threaded drain plug from the only other lower case I have, or buy another lower case and hope it gets shipped undamaged. And take 4 steps backward while I undo half the progress I've made.

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At this point you have nothing to lose in trying to remove that wrong drain plug and salvage the case. If you can get it out, you might be able to salvage the threads in the case. If the threads are questionable, maybe JB weld the proper plug in there and then cut the head off and drill and tap for the smaller size drain plug found on the smaller Hondas.
 
boddy said:
At this point you have nothing to lose in trying to remove that wrong drain plug and salvage the case. If you can get it out, you might be able to salvage the threads in the case. If the threads are questionable, maybe JB weld the proper plug in there and then cut the head off and drill and tap for the smaller size drain plug found on the smaller Hondas.
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You have no idea how tight that plug is in the lower case. A pipe wrench and massive vise grips have already been employed along with other methods, never once moved. But of course I have to try. It just pisses me off that I'm going backwards at this point, and no one would even have suspected the "bad" lower case based on visuals.
 
ancientdad said:
You have no idea how tight that plug is in the lower case. A pipe wrench and massive vise grips have already been employed along with other methods, never once moved. But of course I have to try. It just pisses me off that I'm going backwards at this point, and no one would even have suspected the "bad" lower case based on visuals.
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Any chance of repairing the case that you are trying to use but the pump won't fit?
 
boddy said:
Any chance of repairing the case that you are trying to use but the pump won't fit?
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It seems the right mounting boss is a bit low, causing the pump body to twist slightly when bolted down tight. Then the shafts won't turn. The challenge is, it's the same location where the oil feed comes from and I don't want to chance causing a less than perfect seal around the dowel and o-ring sealing off the pump flow to the engine. I'm not sure how much thickness is missing and there's no obvious signs of damage or (of course not) wear, and it feels like it's only maybe ..010" to .020" movement though I have not tried to put a feeler gauge under it to check.

I'm just frustrated, that's all. Never in a million years would I have thought to check that area for fitment first, nor would I have ever even suspected that area to be a problem.
 
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Yeah that sucks.

Just a thought, if the old plug is in that tight and is not leaking, why not cut the head off that and re-tap for a new smaller drain plug.
 
boddy said:
Yeah that sucks.

Just a thought, if the old plug is in that tight and is not leaking, why not cut the head off that and re-tap for a new smaller drain plug.
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Problem is, I have no way of knowing it sealed, note that it's completely inside the hole and has no lip area to seal on the outside at the machined spot for the o-ring to seal.
 
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crazypj said:
I would drill through that drain bolt then open up hole with die grinder.
May even go so far as to put it on mill as it's easier to centre ( although I broke several carbide mills last few weeks 'drilling out' a broken tap, stainless is a PITA to tap)
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The nearest mill to me is 70 miles away and I have to make an appointment with him if he'll even take it in now, roughly 5 years after the last help he gave me.
 
You could maybe test for whether the drain plug leaks by cleaning up the case, setting it up somewhere out of the way of getting knocked around and pour some drain oil or whatever you have into the bottom of the case, then wait and see if it leaks.
 
crazypj said:
I would drill through that drain bolt then open up hole with die grinder.
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Funny you mention it, one of my previous attempts was to drill the center of the plug and then use a hole saw to try to carve out 95% of the inner part so I could crumble away the rest out of the threads. But then it got stuck and the hole saw wouldn't go any deeper, so I gave up and used the other one. Which unbeknownst to me, had an irregular oil pump mounting area.

I guess the 4th time is the charm, I decided I had nothing to lose so I went gorilla on it with my big Wilton vise. I first tried to clamp the mangled nut area in the vise but the sides aren't at all square, so it turned right out of the vise when I gloved up and rotated the entire lower case. I was attempting to stay away from the surface of the case to avoid scratching the o-ring sealing surface. So I threw caution to the wind and clamped it right next to the case on the less than 1/8" wide portion of the plug right above the mangled nut area (I had gotten it to turn some previously but then it bound up and I thought it would never go any further). I guess previous attempts with something clamped to it, and done without really any way to actually hold the case other than the front motor mount, weren't clamped tightly enough to the plug so it slipped off. Well this time I was so pissed I practically yanked my worn right shoulder out tightening the vise, and finally the case turned on it and within 3 thread rotations it was out.

While wondering what the hell I was going to do for a plug afterward, I noticed that the POS plug someone used didn't actually go in far enough to ruin ALL of the threads, it left me 3 or 4 threads in the bottom of the hole and amazingly, it feels like they'll be strong enough to use with a test fit on a good drain plug. I guess I'm fortunate to avoid having to find another one, but this situation makes me want to safety wire that plug just in case. No pictures tonight, I was too busy dragging out the pressure washer to clean up this poor, abused and hideously dirty lower case while keeping an eye on some salmon in the smoker. And just like the other lower case, this one has some seriously deep-seated crud on it, don't think it's going to come as clean as the other one did. And I wasted a new shift shaft seal on the other one, pretty sure I have another spare.

And if there's one piece of good luck in all this, it's that both lower cases had good kickstart shafts and the splines on this one (from the low mileage engine again) are actually in great shape, which is counter to pretty much everything else about that poor motor aside from the crankshaft and transmission gears (which is also amazing considering how badly that bike must have been beaten).
 
stl360+450 said:
What do you think about the idea of repairing the lost threads using TechSteel or JB Steelstik? How many threads would you guess were lost?

I'd be curious to hear @Flyin900's thoughts.
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The Tech Steel would not be strong enough to withstand the removal of the plug on a semi regular basis. It is not a stress area product per se. I have reinforced it with wire scaffolding when rebuilding cooling fins etc.
 
I would bore the plug out, and if the thread in the case is damaged, think of a strategy to tackle it. But first get that plug out. Chamfering with a chamfering tool would be the best solution, and when the walls are straight and round, press a plug into the hole with a smaller thread and a "normal" plug. But that's easier said then done when you have no acces to such machines
 
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jensen said:
But that's easier said then done when you have no acces to such machines
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And that is the key for me here in Floral City where precision equipment is in short supply, especially in my garage. The lower threads in the case are gone, I'll get a picture of the results later so you can see how ugly it is. I wish I had another lower case to use, but the nearest place that has one is the outdoor junkyard a few miles from me where all the 450 engines are still in the frames, sitting half buried in weeds under no cover at all and most of the engines have a bottom end full of water. And the seller would not pull an engine to be disassembled, he would expect me to pull the engine where it sits and then sell me the whole engine, not any single part from it, and his price would be hundreds of dollars for mostly rusty unusable junk. I know Chris (12ozPBR) would have a good one but he's 600 miles away from me and shipping would be expensive and risky.
 
Just reading all this on Sunday morning. Sounds like you may have solved the problem. I hope that is the case. If not I’m sure I can scrounge up a bottom case for you if needed. Hell, if I’m in the right mood I may even clean and blast it for you! With the holiday coming up this week I might actually get it out the door to you in a relatively soonish fashion as compared to the ways my choppy, intermittent schedule normally allows.
 
12ozPBR said:
Just reading all this on Sunday morning. Sounds like you may have solved the problem. I hope that is the case. If not I’m sure I can scrounge up a bottom case for you if needed. Hell, if I’m in the right mood I may even clean and blast it for you! With the holiday coming up this week I might actually get it out the door to you in a relatively soonish fashion as compared to the ways my choppy, intermittent schedule normally allows.
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Well, that would be awesome but shipping it wouldn't be cheap and it would have to be super-well-packed to avoid damage with the way they handle stuff today, but I know you're aware of that. I'm not thrilled with the idea of using a partially compromised lower case on this engine, or any really, but if need be I think the one I have is reasonably serviceable.
 
ancientdad said:
Well, that would be awesome but shipping it wouldn't be cheap and it would have to be super-well-packed to avoid damage with the way they handle stuff today, but I know you're aware of that. I'm not thrilled with the idea of using a partially compromised lower case on this engine, or any really, but if need be I think the one I have is reasonably serviceable.
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I am undaunted by any shipping challenges. All you have to do is give me the go ahead. I’ll be home and rummaging through parts later this afternoon.
 
12ozPBR said:
I am undaunted by any shipping challenges. All you have to do is give me the go ahead. I’ll be home and rummaging through parts later this afternoon.
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Well in that "case"... :ROFLMAO: by all means, if you're up to it and have time for it, please do. I'm thinking you probably don't have one disassembled though, but maybe you do among that metric ton of spares you have LOL
 
ancientdad said:
Well in that "case"... :ROFLMAO: by all means, if you're up to it and have time for it, please do. I'm thinking you probably don't have one disassembled though, but maybe you do among that metric ton of spares you have LOL
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With any luck I can update you on what I can offer by sometime tonight
 
jensen said:
Ouch, that's ugly, but can be saved with the right tools.
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That's the problem, I don't have the right tools for this. I'm not sure a tap that size is even available anywhere near me, and it would get used probably once and then rust away in the toolbox. The remaining threads snug up pretty well with a wrench, so it could be used if necessary since the rest of it *seems to be* okay. Of course, I thought the same thing about the lower case I just installed...
 
Well, the delay will be minimal, Chris found a good K6 lower case in his inventory and got it boxed up and shipped to me today, should have it Wednesday. Time to get started going backwards so I can go forward again LOL

In the meantime, I checked one of the PWK carbs in a stock replacement manifold and they fit much like the Mikunis do, so very little resizing will be needed. Gotta pick up some quality clamps though, note to self.


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Did some prep today while I wait for (hopefully) the delivery of the lower case tomorrow. Pulled the unusable (with Jay's pump) lower case from the bottom end, pulled the better of the two kickstart shafts from one of the 2 spare lower cases and reassembled Jay's pump with Hondabond on the gear housing, then made a short video of the movement in the stock oil pump on the lower case that is unusable. You really can't see it easily, but you can hear it when I hold the left bolt hole down with my thumb and push on the right bolt hole. A stock pump might get slightly tweaked when bolted down but it probably wouldn't affect it because the piston fit is not overly snug in the pump bore and the pushrod on the stock pump has a lot of side movement so I can't imagine the pushrod binding on the pin in the piston.

 
boddy said:
Definitely some play there, wonder how it got to that state.
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That's the same thing I wondered since realizing that was the problem. Again, I've never seen it before, or maybe just never noticed because of using the stock oil pump, but since there is no visible damage or excess wear in the area, it just doesn't make sense aside from a manufacturing tolerance inaccuracy.
 
The lower case arrived Wednesday before turkey day, right on schedule and as always from Chris, packed really well and unscathed. (y)

I should have taken a before picture as it was as gnarly as any lower case I've seen from the time under his house. I was mostly concerned with the rusty windage tray and used all the rest of the free sample packets of some rust remover I got at Barber in 2018 (and yes, it still worked) so I wouldn't have to try using what is left of my gallon of Evaporust, not enough to submerge it anyway. It did a nice job on the top but of course I was concerned with the underside and the rusty debris that could soak loose and get in the oil over time, so I tried to get some of it underneath with a flexible brush.

After letting it soak in a tub of about 3 gallons of old dirty solvent (saved from refreshing my parts washer a couple months ago) for most of the 3 days since then, along with the occasional brushing of various outer areas to get some of the caked on goo soaked loose, I pressure washed it today. It came quite clean in most areas but still had this odd layer of brown on the outside, along with some rust that could be felt under the edges of the windage tray, so I dragged out the last resort - the gallon of phosphoric acid I bought to clean up my newly-chromed tank inside after they sent it back to me still wet. And after some research it seems, much like Evaporust, it can be re-used. I've never used it before this but it is said to do a good job. Well, it damn sure cleaned up the bottom of the old rusty metal pail I found in my wife's garden shed that was small enough to make good use of the single gallon. I rotated it multiple times to get good coverage on all side and wow, what a difference. I could have left it longer but in about 30 to 40 minutes of exposure it did the job more than well enough. Still a little crusty looking but fortunately only the lower outer areas.

AND, test fitted the pump. Feels like a solid, flat fit that should not cause any trouble, fingers crossed.

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12ozPBR said:
I’m glad you received the case and agreed to clean it yourself. Had you enlisted my cleaning services you would definitely still be waiting for it. Good luck getting the project back on track 👍
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Yeah, I'm going to test fit the pump with bolts today to be completely sure of the proper fit before I go any further but if all goes as well as I hope it will, I'll take a wire brush to the remaining corrosion and it will look plenty good enough for the job required. Thanks again Chris, this saved me from having to use that other lower case with limited quality drain plug threads.
 
Well, life and a couple of appointments got in the way, and it took this long to finally get things together for a real test fit on the replacement lower case, and then tested with 2+ quarts of oil in the lower case. The right crankcase cover from the badly abused engine had 2 of the 3 oil filter cover screws broken off in the cover, so it was a good candidate for cutting the upper part off to more easily watch the process while containing the oil. Had to prep the pieces necessary and rig up another drive arrangement. Opened up the outgoing oil port in the cover and JB Welded a piece of copper tubing in place for an oil return.

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The hole required for the shaft to drive the pump is about 1/4" or so above the oil level.

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Adjust the video settings to 1080p and you can see the bubbles in the oil moving in the back of the sump.

 
wentwest said:
I'm impressed with your video skills! This is really fascinating.
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Thanks Bob, but it's just a few moments of steady hands and the camera on my economy Samsung A42 phone ($350 new), no big deal really. The fit of the gears in the pump body is snug to provide maximum oil movement and I was surprised it didn't need to be primed after sitting out of the crankcase for well over a week. I also discovered that using only about 1.5 quarts of oil allowed it to reach the pump, but not enough to sustain continuous pumping at high drill speed. It took at least 2 full quarts to allow continuous flow without interruptions, even with the three 1/4" holes drilled in the inner wall that separates the area under the windage tray from the pump feed area. At least I now know this lower case can be used safely, unlike the previous one with the (seemingly unlikely) uneven mounting surfaces.
 
boddy said:
Nice setup to test and demo the output of Jay's pump. Really good flow from that pump.
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Thanks, I should have taken a short clip of the pumping volume with the drill wide open. I had to put a cardboard "cover" over the hole in the lower case on the alternator side because the flow almost reached the left outer edge of the windage tray at max drill speed.

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Seems like a month ago (but actually 8 weeks!) I was here...

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Well, after exhaustive checks for fit between 3 different lower cases (one I COULD have used but with few threads left for the drain plug) and lots of immersive testing of the pump, I'm back at the same place again. The donor lower case I got from Chris cleaned up decently and since the pump was run while mounted in that lower case and rotated freely when mounted, I can now confidently reassemble the bottom end. And here I am again. :giggle: Oh, and because the lower case from Chris was completely empty, I took advantage of the like-new kickstart shaft from the low mileage engine too... the other one was fine but if you're going to remove one, all things considered the shiniest one makes sense.

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Learned a few more things today about the 6 spring clutch in the K0. The only other time I've used one was on the 4 speed bottom end in my first drag bike in the early '70s and it was part of the used bottom end when I got it, of course, since it was literally only 6 or 7 years old then. And maybe this isn't something consistent across all K0 clutches, but it sure is with this one.

But first, oil pump mounted, torqued and rechecked, still spins freely.

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So this was next. That's when the fun started.

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All looks just fine, but then you put the inner hub on the mainshaft and... can't put the circlip in place. Somehow there's a depth difference between the 4 speed and 5 speed baskets, which I'd never noticed previously. It isn't much, but just enough to hide the circlip groove. Shaft sticks out, looks normal but then when the hub is in place the circlip won't seat. But my first thought was the 500T mainshaft (for the slightly higher 1st gear) might be just a tad shorter (but why?). So I dug both leftover mainshafts out of the box of spare transmission stuff and slipped the basket and hub over both of them - still the same. So I dug out one of the 5 speed clutch baskets and that was the solution. So apparently, though I've never heard anyone say it about the 6 spring conversion, you need the 4 spring basket with the 6 spring hub to make things fit. And they did. A little extra cleanup to do but otherwise, a good mix of parts. And to be completely sure everything else jived, I put the clutch rod in place and bolted (screwed, actually) the front sprocket cover on, then slipped a spare clutch cable into the lifter and test-"pulled" the clutch while I watched the plates.

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Then I decided to recheck the transmission so I slipped the shift lever on and went to work through the gears. Seemed fine except it wouldn't go into first, felt like it was hitting a brick wall. Second-guessing myself again, I pulled the entire clutch back off to make sure the shift detent setup was correct and it shifted just fine while being watched, so back together it went. Oh yeah, found out my genius idea to use 2 of the beefier 5 speed springs opposite each other with the rest of the 4 speed springs no worky, the openings in the pressure plate are a tad too small for them to fit, fatter coils rub the sides halfway in. :rolleyes:
 
ancientdad said:
So apparently, though I've never heard anyone say it about the 6 spring conversion, you need the 4 spring basket with the 6 spring hub to make things fit. And they did.
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I guess this is part of the fun with such a unique build.

ancientdad said:
But first, oil pump mounted, torqued and rechecked, still spins freely.
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It's nice to see that the replacement case is working nicely with the gear pump. Onward and upward to the top end!
 
stl360+450 said:
I guess this is part of the fun with such a unique build.
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It is, and I guess I should have expected more of these little things to come up, but with so many interchangeable parts between all the 450s and 500T I didn't expect the clutch to offer a surprise. I find myself going over all the things I've done with the transmission and clutch in my head while lying in bed at night before I go to sleep, double-checking all the little differences and possibilities that I might have missed. I used to just slap the parts together without thinking about it too much because all the standard parts of a 450 fit nearly all of them the same aside from the K0, but this bottom end is a menagerie. If it weren't so much work to swap transmission gears, this would be something I might want to do to the red bike. But I'm not that ambitious at this point, LOL
stl360+450 said:
It's nice to see that the replacement case is working nicely with the gear pump. Onward and upward to the top end!
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Well, we're not going there quite yet, I want to prep the right crankcase cover for an oil pressure gauge but the small scale gauge I want to use isn't available until after the holidays, and obviously I have to install it in the right crankcase cover before closing up the bottom end. I might look for one locally, hopefully the markup won't be a lot more.

 
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