Triumph 750 engine tear down question.

Discussion in 'Old's Cool' started by marksbonneville, Dec 18, 2011.

  1. Rathlindri

    Rathlindri Guinness fan

    Joined:
    Oct 22, 2007
    Oddometer:
    351
    Location:
    Ireland

    Love it!! Just wonderful!!! :freakymen at work!!
    #61
  2. bmwrench

    bmwrench Long timer

    Joined:
    Nov 10, 2006
    Oddometer:
    2,432
    The oven trick reminds me of the time a friend thought it a good idea to abrasive blast his heads with them still assembled, in preparation to me putting his top end back together. When I saw what he had done-and had no way to take the heads apart-I asked if his wife was home. "Nope, she's out for the day". "Good. Let's put 'em in the dishwasher" Twenty years later, that motor is still running fine. But their dishes smelled funny for a few days.
    #62
  3. concours

    concours WFO for 41 years

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    Kensington, NH USA
    NICE:1drink
    #63
  4. bagpiper22

    bagpiper22 Adventurer

    Joined:
    Jun 27, 2012
    Oddometer:
    18
    Location:
    Norwalk, CT
    Ok, the crank is out! I braced the case on some wood and tapped a deep impact socket (21mm) around it until it popped out. The socket clears the end and threads nicely but still fits through the bearing. I believe in the philsophy of 100 small taps vs 10 smacks, and it worked.

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    So here's my next question. The sludge trap screw does not appear to have ever been touched, but I thought the dimple to hold it in place is supposed to be by the groove. Maybe it doesn't matter? It will make it harder to tap out I suppose.

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    At this stage, I figure it makes sense to check the rod bearings, true? I'm assuming I should remove them before going after the trap? Other than making sure I keep each piece in order so they can go back the same way, is there any trick to the rods? I know there are these markings to make sure I get the ends back on the right way. Anything else I need to know before proceeding?

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    Thanks!
    #64
  5. bagpiper22

    bagpiper22 Adventurer

    Joined:
    Jun 27, 2012
    Oddometer:
    18
    Location:
    Norwalk, CT
    Onward and inward! Rods are off. Bearings and crank look good to me, but what do I know. No harsh scoring anyway.

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    I filed down a drag link tip to get the plug out.

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    Impact gun on low, and the plug came out, very slowly, but without too much cursing! And I found...(drumroll) Almost nothing!

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    A few soft oily lumps, but basically nothing. Some PB Blaster and compressed air and it looks like new in there. Air and oil comes out the bearing holes in full force, so here's a question: given the clean state of the trap, do I really need to tap and remove the tube? I imagine it will come out easily enough, given how clean it is, but I don't have the tap or proper bolt. I tried using a bent wire to catch the hole in the center, but no luck yet. any other ideas?

    thanks!
    #65
  6. marksbonneville

    marksbonneville Been here awhile

    Joined:
    May 12, 2008
    Oddometer:
    966
    Location:
    Arizona, Prescott more less.
    Did you pull the trap? use a tap and vice grips and tap it out, go buy a cheap tap. I drilled out the dimple before removing the cover (makes it easier to re install ) yours may not be an issue.
    #66
  7. bagpiper22

    bagpiper22 Adventurer

    Joined:
    Jun 27, 2012
    Oddometer:
    18
    Location:
    Norwalk, CT
    Yes, I got the trap out. I used the ChopCult method: http://www.chopcult.com/forum/showthread.php?t=3063. Worked like a charm. The 3/8-18 tap cost $10, but it's worth it. There was more gunk inside there, so I'm glad I got it all out. Looks pretty good now!

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    Now I can start putting this whole thing back together. Hope I remember where the parts go. :rofl

    I've spent about $100 on special tools to disassemble the engine, so if there's anybody in the SW Connecticut area who needs some help, I hope you'll reach out. I'll be happy to help.

    Once the engine is rebuilt, I can tackle the rest of the bike. I haven't done a thing with brakes, front forks, electrical, oil, etc. I figured unless I got the motor moving, no sense having brakes!

    Thanks!
    #67
  8. bagpiper22

    bagpiper22 Adventurer

    Joined:
    Jun 27, 2012
    Oddometer:
    18
    Location:
    Norwalk, CT
    Quick question about reassembling and the transmission: I'm fairly certain I got the gear shifter back in the correct spot as i put back the inner cover. Is there a way to test at this point? Should I be able to shift gears by moving the selector up or down (it's pretty hard to move)?

    Thanks.
    #68
  9. concours

    concours WFO for 41 years

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    5,441
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    Yeah, I temp assembled the cover, went through all the gears to verify. Remember to turn the input (or output) shaft as you go to allow meshing.
    #69
  10. bagpiper22

    bagpiper22 Adventurer

    Joined:
    Jun 27, 2012
    Oddometer:
    18
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    Norwalk, CT
    Ok, the transmission is set. It took a few tries, but I had photos of the engine from before I took it apart, and that helped me get the shifter in the right spot. I was able to go though all the gears. It was hard to move the shifter by hand, but I'm sure once there's oil in there it will move smoothly. The cases are all clean and ready to go back together. I just need to replace a few oil seals.

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    I'll search the boards for opinions, but what grease is generally used when reassembling? Cam shafts, main bearings, Etc. all need something. Shop manual just says "lubricate" but not sure what's best.

    Thanks!
    #70
  11. YOUNZ

    YOUNZ Been here awhile

    Joined:
    Jul 8, 2011
    Oddometer:
    329
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    Around Pittsburgh
    In my time, I have always used regular 20W50 motor oil in rebuilds as assembly lube, but most important is to spin the engine with out spark plugs to attain oil pressure before the first start up. I use regular 10W30 as break in oil for about the first 500 miles. Never had a problem.
    #71
  12. t.read

    t.read Adventurer

    Joined:
    Nov 19, 2012
    Oddometer:
    10
    Location:
    Nashville, TN
    Here's a trick for the next time you need to stick the gearbox together.

    Those teeth on the shifter quadrant...there are 5 of them. 5 speed transmission.
    Bottom is first gear and so on. When you're putting the inner cover back on, line up the slot between tooth 1 and 2 with the centerline of the shifter shaft hole to index it. As long as you have the gearbox in neutral when you put it together, it slots right in.

    Putting together and taking apart these 5 speeds is a piece of cake really. Just have to look at it and think about it a bit logically. The mainshaft gears are 5 to 1 from the inside out(big gears to smaller gears), the lay shaft is the opposite. The gears can only go on the shafts one way really, or it won't all fit in. The tricky part, which took me a few times putting in and taking it out, is figuring out which shifter fork went where and which order. But those can only go one direction if you look closely.

    High gear mainshaft will already be in because it's holding the counter shaft sprocket. Next is the lay shaft with it's high gear on it. From there you just alternate gears with their forks one at a time. The indentations on the shifter cam plate are for each gear with neutral. Put the plate to neutral with the plunger and it will come to you. It's like putting a puzzle together.

    Early 5 speed cam plates were round so you had to take high gear out to get the cam plate out. Later models had a flat area machined off so you turn it to remove it from the case without taking high gear out.

    I've got A LOT of experience with this motor. Road race a '73 T140 with AHRMA and I have another TR7 for a street bike. I've rebuilt these motors many times. I love these bikes.

    I prefer to break them in with either break in oil (Brad Penn SAE30 break in oil). Or at most auto parts stores in the motorcycle oils section you can find the Valvoline 20W-50 4 stk motorcycle oil. It doesn't have all the friction modifiers that regular motor oil usually has. Seems to work a treat as with the break in process, I can get my rings seated pretty quick.

    The break in process is crucial with these because it's not all that easy to get the rings seated sometimes. Make sure you put the pistons in dry, no oil on the walls. I know a lot of people probably know that, but I've come across several that wanted to coat the walls down before sticking the pistons on.

    After mine is broke in, I use 15-50 Mobil One synthetic. Never a problem. And that's coming from an engine that's been worked hard revving to 7500 for extended periods of time. I use 75-90 Mobil 1 synth in the gearbox as well.
    #72