Featured Back To The Forum...with A New Mountain Cub

Discussion in 'Vintage Classics' started by HMC_MT, Mar 28, 2022.

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  1. Iron

    Iron First Class Member

    Dec 29, 2021
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  2. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
    93
    Billings MT
    Quick question while I'm waiting on my piston rings and gaskets. When I took the advance unit off and inspected I noticed that it's just being held on by the long bolt/washer but on the inside I see a groove that I'm used to an advance unit locating itself with say, on the end of a cam. Is it correct that it basically just goes in that hole and then is fixed with just that bolt?
    IMG_20220328_094203881.jpg
    IMG_20220328_094156245_HDR.jpg
     
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  3. Iron

    Iron First Class Member

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    They are a tapered fit. On some of them there's a locating peg at the end of the camshaft that fits into a slot on the advance retard unit, on others there isn't and you will need to time appropriately.
    So, in either case, the bolt pushes the advance retard unit onto the camshaft where it will stay in the position you set.
     
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  4. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
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    So in the first pic the fact that that hole is empty, i.e. nothing there for the unit to locate one is normal
     
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  5. Iron

    Iron First Class Member

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    Yep, it's an arse aint it. A bit more fiddling about during rebuild. But look at it as an opportunity to learn more about your ignition timing. o_O
     
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  6. Iron

    Iron First Class Member

    Dec 29, 2021
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    Have a watch of Dave sorting his out and removing/replacing the advance retard

     
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  7. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
    93
    Billings MT
    Hey all, just wanted to update. Took me a while to source rings, hard buggers to find. Got those now and a full gasket kit. Everything is ready to be put back together but I'm trying to be patient enough to have the broken fins repaired. Super excited to get back into it. I'm contemplating putting a Boyer ignition in it while I'm rebuilding. I put one on my 69' T120 and have loved it.

    Speaking of T120, while I've been waiting on parts I started in on my 71' T120r. Had been sitting for quite awhile. Did fluids and some odds n ends, fired up 2 kicks! But smoked like a whore lol.

    Pretty bad on startup and you can see some coming from the crossover pipe at header. It clears out and I even rode the damn thing a bit, couldn't believe it. If you shut it down then start it a few minutes later no smoke. So only cold start smoking. I expected a rebuild on this one but am still pretty new to Triumphs. What could I look at to avoid a full engine rebuild?
     
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  8. darkman

    darkman Crème de la Crème

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    If you don't know the history of the T120 then its best to strip the comp engine and check the sludge trap, oil smoke on cold start that then clears would indicate oil running down possibly worn valve guides.
     
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  9. Iron

    Iron First Class Member

    Dec 29, 2021
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    I agree with @darkman, unless you know the history, an engine rebuild is the only way to check that the sludge trap isn't full.
    There's no inspection hole, no way of checking that the oil is about to stop flowing to the big ends and no way of "flushing it out" using modern oils.
    Of course, the sludge trap could be clean from a previous recent rebuild.
    Smoking on start up would lend me to think it's an engine that hasn't been worked on any time recently........
     
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  10. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
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    Billings MT
    I agree that it's best to do a motor overhaul on it. Good time to learn as well since I've never had a Triumph engine apart! The plate on the bike says 1974 and the guy I got it from said he had it running once but "it smoked like a whore" lol. I'll keep my Cub the priority and then start in on the OIF and start a thread on that one. Good fellas here to help me through it!
     
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  11. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
    93
    Billings MT
    I'm back. With everything needed to reassemble the motor, gasket kit, rings and I had my broken fins welded. I must say I wasn't super happy with the repair but considering this is a cast cyl and most of the repair will be hidden by the head, it's fine. At least all the fins are intact now. Done by an 85 year old master welder so it's as good as I can ask for.

    I have the rings installed on the piston, just need to research proper ring orientation. Ring gap is perfect. After a light skim of the skirt the jug fits perfectly. Recommended to install the piston on the rod first or put in cyl first then place cyl/piston on the rod?

    Here we go...
     
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  12. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
    93
    Billings MT
    I'm back. With everything needed to reassemble the motor, gasket kit, rings and I had my broken fins welded. I must say I wasn't super happy with the repair but considering this is a cast cyl and most of the repair will be hidden by the head, it's fine. At least all the fins are intact now. Done by an 85 year old master welder so it's as good as I can ask for.

    I have the rings installed on the piston, just need to research proper ring orientation. Ring gap is perfect. After a light skim of the skirt the jug fits perfectly. Recommended to install the piston on the rod first or put in cyl first then place cyl/piston on the rod?

    Here we go...
     
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  13. Sandi T

    Sandi T It's ride o'clock somewhere!
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    Good luck and here you go, @HMC_MT! Keep us posted and we always like photos. :)
     
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  14. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
    93
    Billings MT
    Got the piston installed. Thought the clips would fight me but they went in fine. Fit base gasket and successfully got the cylinder installed without any broken rings. I was nervous as they are EXTREMELY hard to source. Jug slid down like butter. Here's some pics. You can see why I didn't like the fin repair but keep in mind it's cast and at least they're all there!

    Should I anneal the new copper head gasket?

    IMG_20220512_164216386.jpg

    IMG_20220512_165331224.jpg

    IMG_20220512_170517899_HDR.jpg

    IMG_20220512_170703952_HDR.jpg
     
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  15. Sandi T

    Sandi T It's ride o'clock somewhere!
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  16. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
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    Holy pushrods batman! That was one of the most frustrating things I've ever done. Since I beat anyone except Sandi to a post, the engine is back together. After SEVERAL attempts I got the pushrods and head installed. What a nightmare. Inlet & exhaust valves opening and closing, finally. If there's a trick to that, I'd love to know it.

    Going back to what started all this, no compression, as much as I hate to admit it I think the valves were just being held open due to improper clearance. I guess I learned that the hard way but am also on my way to knowing this engine very well. It's very possible that the pushrods were backwards but wouldn't that just open the inlet/exhaust valves wrong but still show compression?

    Taking a break for now.
     
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  17. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
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    Billings MT
    IMG_20220512_210127617_HDR.jpg
     
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  18. Sandi T

    Sandi T It's ride o'clock somewhere!
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  19. HMC_MT

    HMC_MT Well-Known Member

    Nov 30, 2020
    174
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    I don't know what I'm doing either. Haha,.I guess we WILL see.

    And that...is a creepy doll in an old Rum box I found at an antique store. She scares away all the moto goblins attempting to haunt my engines.
     
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  20. darkman

    darkman Crème de la Crème

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    Great to see it all going back together :)
     
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