1967/1969 Bonnie Rebuild Desert Sled Project - Any Advice

Discussion in 'Vintage Classics' started by Sundance, Sep 15, 2021.

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  1. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
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    maybe nothing. the tappets have worn into the cam lobes in a certain orientation. if theyre replaced backwards then the surfaces of the tappets and cam lobes will wear into each other a bit until they settle in.

    but as i said earlier, people mix and match all the time so it is more a fussy thing than a critical issue.
     
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  2. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Hydro blasting advice. I am going to take my engine parts to be hydro blasted. I am curious as to which parts can withstand this process. Obviously the cast engine cases - but does anyone also have the covers blasted? Or is this something that ruins them? Thanks for any advice.
     
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  3. darkman

    darkman Crème de la Crème

    Oct 26, 2015
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    I only blast the cast parts that are staying a cast finish as i polish the outer covers, i have seen outer covers blasted and then polished by others though.
     
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  4. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    darkman, got it - thanks. By the way, my head is painted black. My hydroblaster wants all oil, gaskets, paint and crap off the pieces before he will blast them. Do you have any advice about removing paint, as well as carbon from the combustion chambers? I am planning to get the head blasted before sending it out to get rebuilt.
     
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  5. darkman

    darkman Crème de la Crème

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    I have never had to remove paint from an engine but i wash all my parts with a steam pressure washer before blasting and i use small glass beads to do my own blasting so you could buy a 25 kilo bag of small glass beads and use it outside with a small media gun to remove the paint etc.
     
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  6. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Thanks for the advice. Seems like a good solution.
     
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  7. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Tappet oil drillway advice needed.

    So I purchased an AERCO big bore kit to replace my aged Routt. On the old Routt there was no exhaust tappet oil feed driveway, and the right side engine case had the oil driveway plugged. Additionally the exhaust tappets in the engine had no machined cut out or oil hole.

    The AERCO cylinder has an open, exhaust tappet oil feed drillway. So what is a good way to proceed? Should I open up the right side case driveway, and buy new exhaust tappets with the machined part and oil hole? Has anyone had experience with this kind of situation?

    Thanks!

    IMG_1586.jpeg
     
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  8. darkman

    darkman Crème de la Crème

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    R lifters are primarily for inlet so do not have the oil holes fitted as in non R, as your cam maker stipulated R lifters for exh as well i would go with the set up you had previously as in no oil feed, this also has the benefit of increased oiling to the crank.
     
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  9. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    OK, thanks. So the oil drillway in the case is already plugged. Do you have a suggestion on how to plug the drillway in the cylinder?
     
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  10. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
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    just leave it. all the pressure is behind that plug in the right side crankcase.
     
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  11. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Speedrattle - forgot to answer this earlier - yes, tight in the piston, not the rod.
     
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  12. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Cams and Bushings.

    I ordered from Classic British Spares a set of sintered bronze bushings for my 1969 T120R. 3 of the bushings seemed to be right on as to size, etc. 1 of the bushings, the drive side intake bushing, was longer than necessary. I contact CBS and they said longer would provide more support and didn’t need to be cut down. However this length would interfere with the breather system. I revealed this to CBS again and they said to switch this bushing out with the exhaust drive side bushing, since it was shorter. Of course the exhaust drive side bushing did not have an oil hole drilled. So CBS said I should drill an oil hole and then debur and ream. I have not checked out if using the much longer bushing on the drive side exhaust cam would interfere with anything else. Has anyone had a similar experience with new cam bushings on this kind of motor?

    Also, upon further examination of my cams I found some pitting. On the exhaust is a large pit on the lobe, and a smaller pit on the intake lobe. I’d be interested in knowing if these pits are a serious concern?

    Thanks to all!

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  13. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Is this a problem?!

    So I finally got all my engine cases clean enough to send to the hydro blaster (perhaps they look good enough without this blasting?) Anyway, when finally getting the head clean I noticed this breach in the right side exhaust portion of the head/chamber. So you can see there is an insert in this space (which the head bold goes through), so I’m not sure if this is OK to use or what. It looks as though this may have been there a long time. Any comments are appreciated.

    Also, I live in the Northern Virginia area and am wondering if any members know of someone who could rebuild my head (if it is indeed ok to use). I know of a place in California to send it with a long wait list, and also have someone in Ohio who was given as a reference. I’m wondering who may be more local to me.

    Thank you.

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  14. darkman

    darkman Crème de la Crème

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    I have seen the ports like that before on a few bikes, could be why Triumph fitted the steel inserts.
     
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  15. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Thanks for the comment. I imagine that this has been run with it like it is. It does not seem like damage or wear. So it doesn't seem like there would be a safety or longevity issue with the way it is, perhaps a performance issue since it might impact exhaust flow a bit. I'm considering leaving it as it is if this is the case. I've got to think others have seen this exact defect.
     
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  16. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
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    i thought they all had the sleeves.

    when did they start putting them in?

    maybe this head has been ported.
     
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  17. darkman

    darkman Crème de la Crème

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    Yes as far as i know they all have the inserts but i will check it out as ports are smaller on earlier heads.
     
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  18. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    There is another sleeve in the adjacent exhaust port head bolt hole. But it does not break through the casting.
     
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  19. Sundance

    Sundance Well-Known Member

    Aug 2, 2021
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    Soon, hopefully, I will be installing my new cam bushings, as well as new bearings in my cases. I suppose this will sound like I am a true novice at this (I am), but can anyone explain camshaft and crankshaft float? I’m most interested in making sure that I understand this before installing and reaming my cam bushings. Thanks for any helpful comments.
     
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  20. darkman

    darkman Crème de la Crème

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    Float normally applies to the lateral movement of the crank or cam, your bike has none as such as the right hand main fixes the crank and end float of the cams is controlled by the timing gears and bushes as S R explained the other day.
     
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