Non Running CB450 questions
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  1. #1
    Junior Member smcparland's Avatar
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    Non Running CB450 questions

    Hey Folks. Some quick background which you can skip if you would like. I grew up wrenching on cars and have done everything myself for the last 16 years from small maintenance, to axles swaps, to tranny replacements on older vehicles etc. i'm comfortable taking anything apart, but i certainly wouldn't say i am an expert in all things mechanical. However i greatly believe in research, research, research first . . . and the information and answers are out there. I have been researching on this forum as well as a few other places (and the Honda service and repair guide) for the last 4 days straight. I have learned a lot, but also recognize that many of you have incredible experience and in short would like to run this scenario past members to see if the diagnosis makes sense.

    I'm looking to buy a bike, its a '72 CB450. According to the owner it has been sitting for the last 2 years because the valve guides went bad and according to his original post, burns oil when letting off at high RPM's. He is selling because he has too many projects and doesn't have the time. I have researched this issue, I have learned a lot, and i understand that for this to be fixed correctly i would have to remove the head and really send it out to make sure the new valve guides are put in properly. I think where i am a little wary is this:

    Should this failure have really rendered it NOT running and un-ridable for the last 2 years? I could see it not running well, losing compression, and not something you would want to ride to prevent damage, but i'm suprised that it won't even start. When i ask if it started his response was that he could "probably get it to run with starter fluid".

    He assures me he knows exactly what is needed, did a compression test and put a scope on it, and that the motor still turns over when he kicks it so its not locked up. I'm basically asking the brains and "gods" of this forum their opinion on if this smells fishy or seems reasonable before i go back and setup a meeting in person with a lot of questions.

    To conclude, i'm not shy of any amount of work, but this will be my first bike (visually in great shape) and definitely a learning experience/winter project. I'm assuming in addition to the valve guide issue that after sitting for 2 years i will have to do a full tune up, fluid change, and replace any valve/piston/etc seals that may have gotten dry and cracked in the meantime.

    I'm open to any and all feedback here, but my main focus is, DOES this sound realistic?

    THANKS ALL!

  2. #2
    Senior Member tbpmusic's Avatar
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    Smoke when decelerating is a classic symptom of valve guides.
    It's not surprising at all that it won't start after sitting for two years, but that probably isn't due to valve guides - more likely gummed up carbs or timing.
    Valve guides will require complete disassembly of the top end - they're fairly cheap to have a machine shop do them (recommended).
    While it's apart you might as well have the machinist examine the cylinders and pistons.
    Bill Lane
    Honda Twins Founding Member

    No advice, just info

    '75 CB200T, '71 CB450 K4 Half-Breed, '72 CL350 (Sold), '81 CM200T, '72 C70M
    and a little red Chineeze scooter

    http://www.bikeexif.com/honda-cb450-restoration

  3. #3
    Junior Member smcparland's Avatar
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    Thank you Bill. Obviously you are a great resource on this (and potential candidate for the service work should i move forward and want to ship the head to you? i believe i found your name a few times during my research)

    i think that is my main questions too which I'm working on clarifying . . . will it not start because of supposed valve guide issue . . . or because its been sitting. Thanks again!

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  5. #4
    Super Moderator ancientdad's Avatar
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    Sounds like a nice introduction - moved to Member Introductions section
    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

  6. #5
    Super Moderator ancientdad's Avatar
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    Quote Originally Posted by smcparland View Post
    Thank you Bill. Obviously you are a great resource on this (and potential candidate for the service work should i move forward and want to ship the head to you? i believe i found your name a few times during my research)

    i think that is my main questions too which I'm working on clarifying . . . will it not start because of supposed valve guide issue . . . or because its been sitting. Thanks again!
    The bike will not be kept from starting by worn valve guides as mentioned above, it's most likely carbs are dirty which is why the seller referred to using starting fluid to show that the engine will run. If you can post some pictures of the bike you'd like to buy, or the ad if it is advertised, that would help us give you a little more info and opinion
    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
    Member doctorruckus's Avatar
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    Sounds like a $1/cc buy to me

  8. #7
    Junior Member smcparland's Avatar
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    Sounds reasonable. And yea after 2 years I assumed i would have to run through a carb cleaning, fluid change, maybe pull the plugs and put a few drops of oil in for the piston rings. I have been scanning for a potential light restore candidate for about 6 months now . . . this bike aesthetically is certainly above what i was originally planning on to purchase, but its a beautiful build (IMHO, probably not everybody's cup of tea) and i'd rather focus on the mechanical components then the "dress up" part of the build anyways!

    Pictures below at the request of @ancientdad

    Non Running CB450 questions-72593316_10157680017954721_575839218996084736_n.jpg
    Non Running CB450 questions-72831704_10157679997499721_2594734660005134336_n.jpg
    Non Running CB450 questions-72410205_10157679997804721_3716793654904356864_n.jpg
    Non Running CB450 questions-72461521_10157679998129721_5511399761913053184_n.jpg

  9. #8
    Super Moderator ancientdad's Avatar
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    Quote Originally Posted by smcparland View Post
    Sounds reasonable. And yea after 2 years I assumed i would have to run through a carb cleaning, fluid change, maybe pull the plugs and put a few drops of oil in for the piston rings. I have been scanning for a potential light restore candidate for about 6 months now . . . this bike aesthetically is certainly above what i was originally planning on to purchase, but its a beautiful build (IMHO, probably not everybody's cup of tea) and i'd rather focus on the mechanical components then the "dress up" part of the build anyways!
    Mechanically, I'd go over all the necessary adjustments to the engine, change the oil and clean the centrifugal filter and look into the interesting approach to rear brake actuation first. As for oiling, you have bigger concerns than the rings on this engine... the DOHC 450 is unique in that it holds no residual oil beneath the cams and followers to help with lubrication until the oil flow reaches the top end on a cold start. Oil flow takes a full 1 to 2 minutes to properly travel up the 2 right hand cylinders studs from the oil pump and filter area, then into the right side cam bearings and fill the camshafts to lube the cam bearings on both ends and out the orifices in the lobes to lube the followers, so keeping the revs low on cold starts for the first couple minutes is important to avoid excess cam lobe and follower wear. I see the petcock is off in the 3rd picture, and you should make sure it's always turned off when you turn off the key as these carbs are known to seep fuel past the float needles and past an open intake valve down into the crankcase if the fuel is left on, diluting the oil and causing top end damage. You can download a FSM (factory shop manual) here
    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

  10. #9
    Senior Member tbpmusic's Avatar
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    Quote Originally Posted by smcparland View Post
    Thank you Bill. Obviously you are a great resource on this (and potential candidate for the service work should i move forward and want to ship the head to you? i believe i found your name a few times during my research)

    i think that is my main questions too which I'm working on clarifying . . . will it not start because of supposed valve guide issue . . . or because its been sitting. Thanks again!
    You should also perform the "acetone test" on the valves to make sure there's no leakage.
    Bill Lane
    Honda Twins Founding Member

    No advice, just info

    '75 CB200T, '71 CB450 K4 Half-Breed, '72 CL350 (Sold), '81 CM200T, '72 C70M
    and a little red Chineeze scooter

    http://www.bikeexif.com/honda-cb450-restoration

  11. #10
    Supporting Member fxray's Avatar
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    Quote Originally Posted by smcparland View Post
    . . . I'm looking to buy a bike, its a '72 CB450. According to the owner it has been sitting for the last 2 years because the valve guides went bad and according to his original post, burns oil when letting off at high RPM's. He is selling because he has too many projects and doesn't have the time.
    I seriously doubt that the valve guides are the reason this thing is parked. It looks like he has done the maximum possible damage to that poor old CB450 and wants to move on to his next victim.

    Quote Originally Posted by smcparland View Post
    I have researched this issue, I have learned a lot, and i understand that for this to be fixed correctly i would have to remove the head and really send it out to make sure the new valve guides are put in properly. I think where i am a little wary is this:

    Should this failure have really rendered it NOT running and un-ridable for the last 2 years? I could see it not running well, losing compression, and not something you would want to ride to prevent damage, but i'm suprised that it won't even start. When i ask if it started his response was that he could "probably get it to run with starter fluid".
    While you could physically remove the head and send it to someone to replace valve guides, the head would then be worth way more than the rest of the bike. The pictures show one of the most horribly mutilated and debauched Hondas I have ever seen. You are correct to be surprised that it won't even start. It could be entertaining to accept his offer of getting it started with starter fluid. If you make that challenge, and he agrees, stand back when he tries it. Stand way back.

    Quote Originally Posted by smcparland View Post
    He assures me he knows exactly what is needed, did a compression test and put a scope on it, and that the motor still turns over when he kicks it so its not locked up. I'm basically asking the brains and "gods" of this forum their opinion on if this smells fishy or seems reasonable before i go back and setup a meeting in person with a lot of questions.
    I am neither a "brain" nor a "god" of this forum, but yes-- it smells as fishy as a perch left in the direct sun for five or six days.

    Quote Originally Posted by smcparland View Post
    To conclude, i'm not shy of any amount of work, but this will be my first bike (visually in great shape) and definitely a learning experience/winter project. I'm assuming in addition to the valve guide issue that after sitting for 2 years i will have to do a full tune up, fluid change, and replace any valve/piston/etc seals that may have gotten dry and cracked in the meantime.

    I'm open to any and all feedback here, but my main focus is, DOES this sound realistic?
    This bike has absolutely no socially redeeming value left. He has gutted its very soul. It is not worth a dollar per cc, it is not worth a nickel per cc. There is nothing you could even learn by buying it and taking it to pieces as exploratory surgery. It is so messed up already that there is nothing you can learn from it. In fact, studying the remains of this machine could give you a perverted perception of motorcycles for the rest of your life. In the future, if you see a bike with a brown seat, missing fenders, missing chain guard, clip-on handlebars, loosely assembled rear-sets, a home made, barely attached exhaust system wrapped up in pipe bandages, velocity stacks on the carburetors, melted yellow plastic used as visual highlights, rattle can paint peeling from the remaining chrome on the wheel rims, foam insulation plugging holes in the oil filter cover, etc., etc., etc., run -- don't walk away from it. It has been put together by some poor soul hooked on meth.

    This is, of course, only my opinion, and you did ask for our opinions. I don't mean to be unkind. I am trying to help you avoid a sad experience.
    FrisianWheel likes this.
    It's hard to have too many motorcycles, but easy to have too many batteries and tires.

    1971 CL350K3
    1970 CB450K3
    Plus a few non-Hondas

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