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Return of the Nitrous Norton (2016)

Discussion in 'Other Norton Motorcycles' started by lcrken, Jul 27, 2016.

  1. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    It's been a while, but I finally have the engine finished and almost ready to install. I do have to make some new manifold spacers to take the nitrous injectors, but that shouldn't take long, and I should be fitting the engine into the frame in the next few days.

    Drive Side 1200.jpg

    Timing Side 1200.jpg

    Ken
     
  2. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Looking more like a bike every day. I only have two weeks left to get it ready for El Mirage, but that should be enough.

    Right Side 1200.jpg

    Left Side 1200.jpg

    Ken
     
    Fast Eddie likes this.
  3. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    We’re cheering you on Ken !!
     
  4. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Ken, when things have settled down after your El Mirage push, I’d be grateful if you could share some details of your N2O set up...
     
  5. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Well, not such a great end to this years efforts. I finished the bike in time for the El Mirage event, but we didn't make it there because of the local wildfires. We were packed and waiting, with the motorhome in the driveway, ready to evacuate, for several days. No way I could run off to the dry lake for three days of fun. New plan is to run at the first 2019 event in May, hoping to set new record in the gas class, then fit the nitrous and work on the fuel class. This is the bike pretty much ready to go.

    Right Side 1200.jpg

    Left Rear 1200.jpg

    Right Front 1200.jpg

    Ken
     
  6. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Ken, we’re all glad to here the wildfire didn’t come along and got your home, or your workshop!

    Forgive me if I skipped it somehow, but who did the head job Ken? The ports look very nice...
     
  7. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Steve Maney stage 3.

    Ken
     
  8. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    That explains why the ports look so nice !
     
  9. Dutch

    Dutch

    Joined:
    Sep 21, 2015
    That is one bad dude - I'd love to hear it in top gear, on the juice, fighting for traction.
    I'm sure you would more than me ---- hope your home situation settles down soon.
     
  10. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Ken, what did you do for the external oil drain connector into the back of the timing case?
     
  11. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    I drilled and tapped the back fo the timing side for a 1/4" NPT to 3/8" hose fitting.

    The fitting on top of the timing side is the breather return to the oil tank. It was just temporary to get me to the lake. Now that I have more time, I'll be fitting the Comstock sump plug breather that just arrived.

    You might also note the new stainless steel nitrous injectors. Hopefully they will be stronger than the aluminum ones that broke at Bonneville.

    Ken

    IMG_3508 1200.jpg

    Ken
     
    elefantrider likes this.
  12. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Me too, Dutch. I really expected to manage that this year, but at least I'm ready for 2019 well ahead of time now:)

    Ken
     
  13. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Well, it certainly looks the business Ken!

    Try not to strip it down before the next events eh?!
     
  14. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Well, time for another update. When I first fired up the bike it seemed to run OK, but had a ticking noise. I was going to run it at El Mirage anyway, but couldn't because of the fire threat. After the race weekend had passed, I took another look at the engine, and discovered that the set screws holding the lifter blocks in were loose, so I got worried about the ticking noise. I pulled the top end, and found the problem. As Jim Schmidt has pointed out a couple of times, the BSA lifter setup is pretty touchy to get right with the N480 cam. I had measured all that pretty carefully when I assembled the engine, but apparently not carefully enough. The ticking noise was from the lifters almost falling out of the blocks on the base circle of the cam. My measurements and calculations told me that I was pretty close to that, but I thought I had enough safety margin. Apparently not:(. I could see the wear marks on the lifter block edges where the lifters had almost come out of the blocks, and apparently rotated a tiny amount, then hit the edge of the blocks as they dropped back in. I measured the height of the base circle and of the top of the lobe below the cylinder base, and compared that to the height of the lifter below the base. It looks like I have enough room to shim the lifter blocks about .060" further out. That should prevent the lifters from coming out of the blocks, but still leave a little (very little) clearance between the lifter blocks and the cam lobe at full lift. I made a couple of .065" shims to raise the lifter blocks, shown in this picture. I'm hoping that works, but I still have to assemble the engine again to find out. If that doesn't work, I'll have to do something more involved.

    IMG_3601.JPG

    Ken
     
  15. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Another clever idea shot down. With the .065" shims, the cam just barely rubs against the bronze lifter blocks. I could make up some thinner shims, but that wouldn't give me as much overlap as I'd like when the lifter is on the base circle of the cam. I need some safety margin when the engine is running at 8,000 rpm and the cam is flexing. Instead, I'm trying to copy what Herb Becker did in a similar case, where he extended the lifter body by combining two BSA lifters to make one with a longer body. I'm doing it a little different, by welding a couple of 1/8" spacers to the top of the lifter base. I cut two junk lifters into pieces to make the four spacers I needed, and then tig welded them onto the top of the body. The welds don't look that great, because I was being very careful to not get the lifters so hot that the braze joint melted and the carbide base came off. I welded one side at a time, with the lifter sitting in a wet rag, and used a high current to keep the welding time as short as possible, cooling it immediately after with another wet rag. I didn't try to get a beautiful bead all the way across, just enough to keep the spacer on. Next step is to re-assemble the engine and verify that I still have enough travel for the lifter. If that doesn't work, I'll have to go to plan B, whatever that is.

    Extended Lifters 1200.jpg

    Ken
     
  16. Fast Eddie

    Fast Eddie VIP MEMBER

    Joined:
    Oct 4, 2013
    Ken, very smart idea there sir! You’ve added depth without compromising any structural integrity.

    Actually, perhaps you could have glued them in place?

    I think you’ll have enough clearence for lifter travel. But if not, surely it’s easy to mill (or file) a slightly deeper slot in the lifter block?
     
  17. Bernhard

    Bernhard

    Joined:
    Apr 20, 2011
    Re;”Another clever idea shot down. With the .065" shims, the cam just barely rubs against the bronze lifter blocks. I could make up some thinner shims, but that wouldn't give me as much overlap as I'd like when the lifter is on the base circle of the cam. I need some safety margin when the engine is running at 8,000 rpm and the cam is flexing. Instead, I'm trying to copy what Herb Becker did in a similar case, where he extended the lifter body by combining two BSA lifters to make one with a longer body. I'm doing it a little different, by welding a couple of 1/8" spacers to the top of the lifter base. I cut two junk lifters into pieces to make the four spacers I needed, and then tig welded them onto the top of the body. The welds don't look that great, because I was being very careful to not get the lifters so hot that the braze joint melted and the carbide base came off. I welded one side at a time, with the lifter sitting in a wet rag, and used a high current to keep the welding time as short as possible, cooling it immediately after with another wet rag. I didn't try to get a beautiful bead all the way across, just enough to keep the spacer on. Next step is to re-assemble the engine and verify that I still have enough travel for the lifter. If that doesn't work, I'll have to go to plan B, whatever that is.”

    IMO welding would be better when joining two parts with butt weld if you grind 45 degree on each of the side to be welded. You would get a much stronger weld.
     
  18. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Quite right. That probably would have been a better way to do it. The only benefit of doing it this way was that I didn't need to use any filler rod, and that let me get the welds done a little more quickly. It was a bit of a learning experience, and if I ever have to do it again, I might do it a little differently, and the result might look a little better. I'm also considering a couple of alternative designs for next time, if I do any more builds with a N480 cam.

    Ken
     
  19. lcrken

    lcrken VIP MEMBER

    Joined:
    Mar 15, 2009
    Correct. If I don't have enough clearance at the top of travel, I can mill the slot deeper. But I hope not. I'm getting tired of repeated assembly and disassembly:(.

    Ken
     

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