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Vintage Cafe project "Thumper"

Discussion in 'Racing' started by Jackjr, Jun 19, 2012.

  1. Here is my toy, almost ready for the track. Lots of upgrades, will be doing engine build this winter I hope. 1978 SR500 290lbs I made my seat fiberglass/composite 2.3 lbs. In the build stage of a carbonfiber belly pan.
    The header is a 1.75 mild steel from G Hoos Racing, several coats VHT, the muffler is from "Cone Eng" good thump and aggressive. Looking to track her here in PDX and Eastern Ore. The best part about this bike was the price, the seller had NO knowledge about bikes, $350.00. He was not happy afterwards. project/

    Last edited: Jun 22, 2012

  2. Sweet bike!

    Looks like fun :)
  3. sweet more build pics?

    Where did you start?
  4. RedKat600

    RedKat600 Vintage Screwball Staff Member

    Can you expand a bit more on that muffler? I will probably need something like that for my Dad's 250 I just restored.

    COOL BIKE! Looks kinda
  5. Thanks, it has been fun. Where I lack information is in the racing class, cannot place mine in the class section with any certainty, at this time stock motor, intake/exhaust upgrade.
    I felt that if I were to show a pic someone might be able to pinpoint a class if there is one for my ride. I had one fellow tell me I could be a hazard to the other riders. I am not that old either is my bike... So what gives......

    Any help is always read and heard, Thanks Jackjr

  6. Cone Eng, in California. 1.75 in dia, SS, mild steel baffle with SS wire. $77 $15 shipping if I remember correctly. all different size's and choices. Very happy with there product.
  7. RedKat600

    RedKat600 Vintage Screwball Staff Member

    For class info, hit up the OMRRA website and shoot an email to the Vintage Class Representative. They'd be happy to talk with you. I just did the same thing for WMRRA and sent in all the info I had and a couple of pictures. They placed me in a class no issues at all. Here is their contact list:

    I assume by Cone Eng, the Eng stands for Engineering?
  8. Yes that is correct. I really like these pipes....

    Thank you for the lead to classification.
    Last edited: Jun 19, 2012
  9. The bike was almost new, it only had 1650 orig miles, all orig even had the OEM tires from factory, zero rust. It had been parked in a garage in AZ for at least 30 years. I picked her up, tear down to frame and engine then wiped polished and got her running. Cleaned carb , oil etc. Was never happy with the power of the 500, the stock intake and exhaust really puts a restriction on power. Once the intake and exhaust were changed I knew I wanted her on the track. A very good friend of mine from high school for years and he turned me on to this site, and my love for the older class bikes made me choose to race her. This winter I am planning on a high comp piston, work the valves a bit and med high lift cam. Keeping stock 500 cc. About 50% of the nuts bolts and washers have been replaced with SS, I have left the critical areas alone sometimes SS can break or snap.


    The before pics, Red orig color.


    Last edited: Jun 22, 2012
  10. RedKat600

    RedKat600 Vintage Screwball Staff Member

  11. Looks great Doug!!! Congrats on the build. 8) Hope you get to race her soon.

  12. Thank You Mr Greg. oh and you are to drive the Ferrari not push it :} grin..
    It has been a a learning experience, here is the most current shot, just a few min ago, I just finished putting on my new master brake, found a crack in the OEM master. Cheaper new than OEM.


  13. Since you want to race it, keep it at 500cc. I've seen my share of big bore kitted SR/TT/XT motors that crack at the cylinder base, and heard of even more.

    I can't tell for sure if I see dual oil lines to the cam/rockers. That's a must-have, along with a good oil cooler.
  14. Hi DM47, I have heard the same about the SR's that is one reason I am staying stock cc's
    I have found this bike after changing the intake and exhaust will go past redline very easy now, so I have to watch the tach a bit more. Yes I have the duel hivol oil line, picked it up from Mark at Thumperstuff. Already have my eye on a heat sink from Derale, I am planning on placing it where the batt box used to be, should be a good location. The one suggestion I could use help with is the cooler or heat sink, should I do an inline for the lifters or a mainline oil. That is a the one choice I have not made yet...
    Thanks for the input. :}
  15. SaWeeeeeeeeeeet. I love that thing. It is so wonderful, I want one.
  16. I'm not sure I understand the question. Are you asking about using a separate inline cooler/"heatsink" for just the external oil lines to the rockers? Or, ...... ???? :scratchea:scratchea:
  17. OK, I have a main return line, there is also the oil lifter line, I have seen fellows put a oil cooler on the main return line and some put the cooler on the lifter oil line. In other words
    should the cooler be setup for extra cooling for the lifters or the main oil system.
    Hope that helps :} best to cool main oil base or one hot area.
    Would be defeating the wt reduction by having two systems, so I am only placing one on the bike. Thanks... :}
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