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CB400T Shitbox Build - Daily Driver

This is a discussion on CB400T Shitbox Build - Daily Driver within the Project Builds forums, part of the Caferacer.net Forums category; Those rocker arms would make it sound like a bag of hammers. But now you are in there keep looking....

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Thread: CB400T Shitbox Build - Daily Driver

  1. #221
    Senior Member TrialsRider's Avatar
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    Those rocker arms would make it sound like a bag of hammers. But now you are in there keep looking.

  2. #222
    Senior Member jakejensen's Avatar
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    Quote Originally Posted by TrialsRider View Post
    Those rocker arms would make it sound like a bag of hammers. But now you are in there keep looking.
    Holy shit the bearings on this thing are spendy! I am going to get some plastigage and check clearances, just to see whats going on. Hopefully they are within spec and I can put it back together.

    I seem to have sorted out the camshaft issue, which makes sense. I was suspicous when I mic'd them initially, having lost 2mm of diameter would basically make them round and they still look very egg shaped. According to several of the German forums I follow, the camshaft I have was made for city use, and lots of guys have done the swap only to notice no difference unless they are on the track or on the BAHN. I won't be taking this thing anywhere outside of town, at least not often. For now, I won't worry too much about converting it over, especially since I can pick up a very nice, used VFR750 for under 800 bucks any day of the week here.

    So with the knocking sound.... Here is where I'm at.
    - No play or excessive wear with conrod bearings (before plastigage)
    - No play or excessive wear with Main bearings (before plastigage)
    - Balancer chain was less than halfway stretched (according to teh detent in the adjustment shaft)
    - Balancers are newer version which do not use cush drives for the sprocket.
    - No excessive wear or chipping on either the balancers or their respective bajillion different chain/tensioning matrix structure components.
    - Lower end looks good for now, just gotta check clearances on journals to be sure.
    - Top end was worn as fuck, and now I have the replacement rocker arms. Camshaft isn't out of spec, so it will likely be re-used.


    What am I missing here?
    Last edited by jakejensen; 09-23-2019 at 07:46 AM.

  3. #223
    Senior Member TrialsRider's Avatar
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    Quote Originally Posted by jakejensen View Post
    ...
    What am I missing here?
    Buying that VFR750 for under 800 bucks.


    You know how to measure a chain for stretch? <- lay it along side a new chain.
    + I am trying to imagine what would cause so much wear on your rocker arms unless they were starved for lubrication and that should result in lots of damage throughout


    "the camshaft I have was made for city use, and lots of guys have done the swap only to notice no difference unless they are on the track or on the BAHN."
    In their dreams maybe. The whole bike was made for casual use, it was built to compete at the price tag, not at the track.

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  5. #224
    Senior Member Cyorg's Avatar
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    [QUOTE=jakejensen;639111]
    - Top end was worn as fuck, and now I have the replacement rocker arms. Camshaft isn't out of spec, so it will likely be re-used.

    What am I missing here?[/QUOTE

    “Usually” when rocker/followers are that knackered, there is a least some corresponding wear on the cam. Are you sure that cam is reusable? Might be an idea to post a photo here or on one of the others forums. Installing new rockers on a cam with any scoring isn’t money well spent. When ordering those shell bearings, quantity 1 normally gets you one half shell. Read up on bearing selection if you do end up needing them. They are a select fit.
    Last edited by Cyorg; 09-23-2019 at 11:26 AM.
    "Non urinat in ventum"

  6. #225
    Senior Member jakejensen's Avatar
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    So, heres bearings. I did the trigonometry to figure out which ones are in my shitbox. Hopefully I'm correct? Looks like itll be about 100 euros for all 10 halves, from threedifferent sellers. I have the math done for the Conrod bearings as well.

    Might have to pull the trigger on the VFR.
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  7. #226
    Senior Member TrialsRider's Avatar
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    That' your crankshaft, what do the soft bearing surfaces look like where the hardened crankshaft has been banging into them, (after you wipe the oil off)
    if they are perfect your crank is probably dandy and the bearing tolerance codes still apply,
    if the old bearings are hammered then the crank is in question.

    Considering the supply chain, so much to replace, so much to go wrong.
    ... and if you are in that far and don't replace the crappy primary chain it is a bit of a waste. (make sure your next bike has a gear primary drive)
    Last edited by TrialsRider; 09-23-2019 at 12:42 PM. Reason: all bearing surfaces

  8. #227
    Senior Member jakejensen's Avatar
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    Noted. Here is a pic of the bearings from the case half. Bearings from the cap half are similar in wear pattern.
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  9. #228
    Senior Member TrialsRider's Avatar
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    IF a picture can tell their condition I'd say they are done but not horribly damaged looking.
    Here is the thing, there is nothing except an ultra thin layer of oil those bearings are suppose to be running on and that layer of oil is dependent on oil pressure feed. As the oil bearing clearances increase due to wear, your oil pressure drops throughout the system, engine clatters, some parts (like cam followers) can wear very quickly if they become starved for oil. In the battle of metal the steel parts will always survive the softer metal bits. imho you just need to replace a lot of soft metal bits. (it just sucks for you that those parts are now old rare and expensive)

  10. #229
    Senior Member jakejensen's Avatar
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    Quote Originally Posted by TrialsRider View Post
    IF a picture can tell their condition I'd say they are done but not horribly damaged looking.
    Here is the thing, there is nothing except an ultra thin layer of oil those bearings are suppose to be running on and that layer of oil is dependent on oil pressure feed. As the oil bearing clearances increase due to wear, your oil pressure drops throughout the system, engine clatters, some parts (like cam followers) can wear very quickly if they become starved for oil. In the battle of metal the steel parts will always survive the softer metal bits. imho you just need to replace a lot of soft metal bits. (it just sucks for you that those parts are now old rare and expensive)
    That's good looking out. I ordered the plastigage and have located the bearings online. I will get them coming in here.

    I want to plastigage the journals with these old bearings to see if they could possibly have been the cause of my clanking sound. It would probably be foolish to not replace the bearings after going to the trouble to split the cases. But I still need to find a better explanation for the clanking sound than just worn out rocker arms.

  11. #230
    Senior Member TrialsRider's Avatar
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    If you find anything that would induce low oil pressure you likely found the culprit.

    How are the cylinder walls, rings and pistons looking? On an air cooled motor you can really hear the pistons rattle if everything is not perfect in there.

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