Clutch Basket and Crank Gear Clearance Issues
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Thread: Clutch Basket and Crank Gear Clearance Issues

  1. #1
    Member Emerikol's Avatar
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    Clutch Basket and Crank Gear Clearance Issues

    I finally had some time to dig into the CB450 engine. The failure was in the right-hand connecting rod crank bearings. Looks like the entire inner bearing set detonated and left the big-end flopping around like a fish out of water. I'm going to look into ordering a new bearing set and finding a machine shop capable of overhauling the entire crankshaft assembly. I have a couple of spare engines floating around, so I grabbed the rotating assembly out of one that's already been broken down and after a good cleaning and lube, I slapped it into the case. So far so good. I started assembling the case halves, and everything lined up and went together amazingly well, until I got to the clutch basket and crankshaft gear. The small output gear is rubbing on the back of the clutch basket, and the inner clutch basket doesn't slide onto the shaft far enough to get the retaining ring installed. I'm not terribly worried about the gear making slight contact with the back of the clutch basket, it really is very light contact, and will self-clearance after the first run. The oil will get changed out at least twice in the first couple of miles, so I'm not even concerned about loading up the oil with the metal filings. Another option would be to mill the back of the clutch basket a couple thousandths and eliminate the issue right from the start. Since I put a different rotating assembly into the motor, I can understand where that clearance issue comes from, but I'm really scratching my head on the inner clutch basket issue. It's the same transmission set that came out of the engine, why isn't it going back together the same way? Any advice or guidance on the entire issue would be greatly appreciated, I'd like to get this bike back together and back on the road by the end of the year. -E

    Clutch Basket and Crank Gear Clearance Issues-img_0846.jpgClutch Basket and Crank Gear Clearance Issues-img_0847.jpgClutch Basket and Crank Gear Clearance Issues-img_0849.jpgClutch Basket and Crank Gear Clearance Issues-img_0850.jpgClutch Basket and Crank Gear Clearance Issues-img_0851.jpg
    First Rule of Aviation: Never Pass Up the Opportunity to Pee

    2004 Yamaha V-Star
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    1973 Honda CL450 (The Basket case)
    1974 Honda CB450

  2. #2
    Supporting Member 12ozPBR's Avatar
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    Two thoughts.
    Which K model was the original crank and which K model did your donor crank come from? The reason I ask is the thrust washer behind the crank primary drive gear changed from the early models to the later ones and the later ones were a bit thinner. It looks like you have the early (brass?) thrust washer on there in the first photo. Not sure if this would make a difference but it’s worth asking.
    Also check the arm for the oil pump piston on the rear of the clutch basket. I believe it has an offset and there is a certain orientation for it. If installed incorrectly it can make the piston bind in the pump. Perhaps this is what is keeping you from sliding the clutch in far enough to get the retaining ring installed.
    Last edited by 12ozPBR; 12-02-2019 at 07:37 AM.
    Runners
    1971 Triumph Tiger
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  3. #3
    Super Moderator ancientdad's Avatar
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    ^^^agree with above - and no, you shouldn't let it go that way. When the correct parts are put together for the proper year engine, these things fit correctly. Honda wasn't that sloppy. Compare the thrust washers and you may find the difference. As for the trans shaft, are you certain you have the small end bearing located on the pin in the upper case correctly? If not, and if you've already tightened the lower case bolts, you may have pushed the locating pin through the upper case. Look at the left side of the bottom end where the clutch rod goes into the mainshaft to see if the pin has punched through the upper case
    Tom

    CL450 project reboot, street legal this time
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  5. #4
    Member Emerikol's Avatar
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    I have the brass thrust washer on the oil rotor assembly now. The thinner washer is too thin and goes so far back on the shaft that it falls off the splined area, if that makes sense. The brass thrust washer keeps everything located properly for reassembly. The pins and keepers for the transmission set were all located properly, and the engine cases went together like butter. It seriously just fell together and I didn’t have to do anything but run the bolts down. No issues there. The original engine number is CB450E-7003673. That’s the one with the trashed crank and con rod. The engine I pulled the rotating assembly from is CL450E-5018372. If I’m reading these numbers right, that would be a much earlier engine (and obviously from a scrambler, not a CB). I have the option to either turn the brass thrust washer down a few thousandths, and keep the brass in place to help locate everything. Right now I have no crankshaft end-play between the washer and circlip on the stator side. Everything feels good, just have that interference issue with the clutch basket. As for the inner basket circlip, I’m really drawing a blank. Like I said, everything is located and pinned in properly, and the case halves went together without any issue.
    First Rule of Aviation: Never Pass Up the Opportunity to Pee

    2004 Yamaha V-Star
    2015 Haosen Hawk
    2015 Suzuki DR560
    2016 Ural Gear Up
    1973 Honda CL450 (The Basket case)
    1974 Honda CB450

  6. #5
    Super Moderator ancientdad's Avatar
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    I just compared the part numbers for the CL450K5 and the CB450K7 thrust washers and they are the same except for the last 3 digits, which usually means a different supplier IIRC or in some cases, different cosmetically, so I don't think it's that. BTW, the CL450K5 and CB450K7 use virtually all (if not exactly) the same engine parts and the CL is only 2 years older, not a significant difference. There has to be something introduced that wasn't there before or is different in some way for that much difference when assembled. Steve or Bill will need to weigh in on this one
    Last edited by ancientdad; 12-02-2019 at 09:56 AM.
    Tom

    CL450 project reboot, street legal this time
    Budget drag bike project
    CB350K1 full patina project
    Ride along at the drag strip


    running points... because I'm too old for mysteries that begin with pushing

  7. #6
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    The entire rotating assembly wasn’t there before. Seriously though, I wonder if there was a difference with the crankshafts, and the dimensions are just different enough that the new (or in this case, older but not destroyed) crankshaft is keeping the drive gear farther out. The gear actually rides in the middle now, instead of off to one side like it did when it all came apart. You can kind of see the shiny wear marks on the pictures. It would be great if it wasn’t just barely touching the clutch basket. I’m really scratching my head on the clutch basket circlip issue, though. I really hope I don’t have to break the cases apart again, but I’m wondering if that’s going to have to be what happens next.
    First Rule of Aviation: Never Pass Up the Opportunity to Pee

    2004 Yamaha V-Star
    2015 Haosen Hawk
    2015 Suzuki DR560
    2016 Ural Gear Up
    1973 Honda CL450 (The Basket case)
    1974 Honda CB450

  8. #7
    Super Moderator ancientdad's Avatar
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    I understand what you mean about the "rotating assembly", more of a car term than vintage Honda term - the crankshafts on the 5 speeds are pretty much all the same AFAIK, so it's a mystery to me as to why you're encountering this situation - but then, I certainly haven't seen it all with these engines either, which is why I suggested that either Steve or Bill might have more insight.
    Tom

    CL450 project reboot, street legal this time
    Budget drag bike project
    CB350K1 full patina project
    Ride along at the drag strip


    running points... because I'm too old for mysteries that begin with pushing

  9. #8
    Supporting Member 12ozPBR's Avatar
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    I think I understand and experienced what you describe with the wear on the primary gear and it riding off to one side and now you have it centered up using the brass washer. I can tell you that my K7 CB450 had the thin washer (not brass) that you mention falls off the splined area of the shaft and fits loosely until the centrifugal filter is bolted on.
    In my K7 bottom end I replaced the original crank with a K2 CL450 crank and I used the brass thrust washer that came in the K2 bottom end. I can’t remember which gear I used or if I noticed any difference in thickness between the K7 or K2 gear. I do remember comparing the differences in the washers and how things fit to come up with a combination that seemed to fit best. I’ll look back through any pictures I may have for comparisons sake.
    Runners
    1971 Triumph Tiger
    1972 CL350
    1974 XL350
    1974 CB450

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    1966 CB450 Black Bomber

  10. #9
    Super Moderator ancientdad's Avatar
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    I just looked to compare primary gears and other than the last 3 digits (020 vs 010), they are the same, so there shouldn't be a structural difference there
    Tom

    CL450 project reboot, street legal this time
    Budget drag bike project
    CB350K1 full patina project
    Ride along at the drag strip


    running points... because I'm too old for mysteries that begin with pushing

  11. #10
    Supporting Member 12ozPBR's Avatar
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    I was able to go out and check my parts stash and I found this. The upper gear and (thin) washer came out of a bag labeled K6. The lower gear and (brass) washer came out of a bag labeled K3. Also of note is the part of the K6 gear where you can see the difference in color from the meshing of gears and where it was not in contact with the clutch gear.
    Clutch Basket and Crank Gear Clearance Issues-img_7539.jpg
    Runners
    1971 Triumph Tiger
    1972 CL350
    1974 XL350
    1974 CB450

    Current Project
    1966 CB450 Black Bomber

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