Crankshaft Rebuilding at BDT Motorsports
Page 1 of 4 123 ... LastLast
Results 1 to 10 of 33
Like Tree12Likes

Thread: Crankshaft Rebuilding at BDT Motorsports

  1. #1
    Senior Member acecarlos's Avatar
    Join Date
    May 2010
    Location
    Alta Loma, California
    Posts
    12,444

    Crankshaft Rebuilding at BDT Motorsports

    We rebuild all our own crankshafts in house at BDTM. Here is a sample of a customers crankshaft, before and after. We first measure the crankshaft for run out, twist, and measure the shaft bearing diameters for wear. We also inspect the Tins for any signs of shifting & damage. We then disassemble, clean, and partially reassemble with a new rod, needle bearings, and spacers.

    Then it is mfixtured in a press die and the assembly begins, during assembly it in mounted between centers and inspected, as the assembly progresses. Final assembly and inspection between centers to Honda OEM specifications of .001" total T.I.R.

    Click image for larger version. 

Name:	20130713_113519.jpg 
Views:	109 
Size:	88.9 KB 
ID:	19954Click image for larger version. 

Name:	20130713_131534.jpg 
Views:	91 
Size:	95.0 KB 
ID:	19955Click image for larger version. 

Name:	20130713_135126.jpg 
Views:	109 
Size:	90.5 KB 
ID:	19956Click image for larger version. 

Name:	20130713_135137.jpg 
Views:	104 
Size:	89.1 KB 
ID:	19957
    SELVYSATC and american opel like this.

  2. #2
    Senior Member acecarlos's Avatar
    Join Date
    May 2010
    Location
    Alta Loma, California
    Posts
    12,444
    Here are some pictures, showing assembly and final inspection....

    Click image for larger version. 

Name:	20130713_135154.jpg 
Views:	90 
Size:	86.6 KB 
ID:	19958Click image for larger version. 

Name:	20130713_150357.jpg 
Views:	110 
Size:	89.0 KB 
ID:	19959Click image for larger version. 

Name:	20130713_150413.jpg 
Views:	101 
Size:	86.2 KB 
ID:	19960Click image for larger version. 

Name:	20130713_150337.jpg 
Views:	125 
Size:	89.0 KB 
ID:	19961

  3. #3
    Senior Member acecarlos's Avatar
    Join Date
    May 2010
    Location
    Alta Loma, California
    Posts
    12,444
    Final inspection to .001" T.I.R. This crank actually measures a Total Inch Runout of .0005" or half the Honda specification. It also looks and runs like a new crankshaft.

    On our Big Bore builds we weld the tins, crankpins, and Static balance to match the heavier pistons used in BB engines like the Sphynx, Puma and Saber. performing all of our own crankshaft builds and having the best assembly and inspection equipment allows us complete control over our builds.

    The pictures below show the finished crankshaft ready to ship to our customer....

    Carlos
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	20130719_174733.jpg 
Views:	78 
Size:	83.9 KB 
ID:	19962   Click image for larger version. 

Name:	20130719_174801.jpg 
Views:	74 
Size:	90.9 KB 
ID:	19963   Click image for larger version. 

Name:	20130719_174812.jpg 
Views:	102 
Size:	86.6 KB 
ID:	19964   Click image for larger version. 

Name:	20130719_174828.jpg 
Views:	83 
Size:	87.8 KB 
ID:	19965  
    Last edited by acecarlos; 07-19-2013 at 06:54 PM.

  4. Remove Advertisements
    TRX250R.net
    Advertisements
     

  5. #4
    Senior Member rlover's Avatar
    Join Date
    May 2013
    Location
    spanish fork, utah
    Posts
    235
    hell yeeeeha. very cool . keeping them tolerances tight

  6. #5
    Senior Member t_shee's Avatar
    Join Date
    Nov 2011
    Posts
    604
    Awesome. How do u clean them? If i dont mind me asking how much is this service

  7. #6
    Senior Member acecarlos's Avatar
    Join Date
    May 2010
    Location
    Alta Loma, California
    Posts
    12,444
    Solvent tank cleaning first, then Ultrasonic cleaning, wire wheel brushing, and bead blasted after disassembly, and final Ultrasonic clean. This complete service is $185....

    IMO only makes sense to rebuild if the Tins are not damaged or molested, and the crakshaft bearing shafts are not worn out. Most Honda OEM cranks are worth rebuilding, if not, purchase a new HotRod.

    Carlos

  8. #7
    Senior Member Dirt man's Avatar
    Join Date
    Dec 2012
    Location
    Grand Rapids MI
    Posts
    182
    I was of the understanding that rebuilding a 250r crank puts to much stress on the tins when separating and pressing the crank back together. I had two rebuilt crankshafts fail because of the tin cracking and catching the rod and dynamite. What is your opinion?
    It goes fast over bumps too

  9. #8
    Senior Member acecarlos's Avatar
    Join Date
    May 2010
    Location
    Alta Loma, California
    Posts
    12,444
    You are correct Dirt Man....if the Tins are not respected like a Babies bottom (LOL) during the rebuild, or if they have been damaged or molested, they are a lot more likely to fail.

    We use jigs, and dies that support the crankshafts on the heavy metal outer surfaces, never touch the Tins. We also support and center of the main shafts and never off the Tins. We also don't pound on the Tins to align the halfs, we use a dedicated die with guide pins to align the crankshaft halfs to specifications.

    IMO if you pound on the Tins to twist the halfs into alignment during assembly like a lot of other crank builders do, that is a Big No-No, and one that will result in Tin failure. The Honda cranks with Tins are the most sensitive, and need to be handled with a lot of care because of the Tins.

    Carlos
    Last edited by acecarlos; 07-19-2013 at 07:38 PM.
    DnB_racing likes this.

  10. #9
    Banned jcs003's Avatar
    Join Date
    Mar 2009
    Location
    pittsburgh, PA
    Posts
    1,000
    The Phantom likes this.

  11. #10
    Senior Member acecarlos's Avatar
    Join Date
    May 2010
    Location
    Alta Loma, California
    Posts
    12,444
    Yup, that is one method jcs003, not the way we really do it.

    First we don't use a cut-off wheel to cut the rod off and seperate the halfs, we use press the in pin out of the crankshaft by induction heating around the crankpin area, and lightly pressing. The localized heat expands the crank more than the pin....

    Second we inspect per Honda specifications using 3 indicators to see true run out and twist. The way they inspect the crankshaft does not meet specifications and never willwithout the 3 rd indicator all the way down the taper end of the shaft, next to the key way slot....the .001" run-out Honda tolerance is at the tail end of the taper, and much harder to obtain or assemble a crank to that spec.

    Getting .001" T.I.R. at the 2 main jornals is easy, almost all cranks fall in, close or within a few thousands, getting the twist out and holding less than .001" on the 2 main bearing jornals, and less than .001" at the taper end of the shaft is not. This should also be done with 3 indicators and between an accurate bench center such as the one shown at BDTM.

    Thanks for sharing the video.

    Carlos


 
Page 1 of 4 123 ... LastLast

Remove Ads

Sponsored Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Search tags for this page

atc 250r crankshaft run out
,

bdt motorsports from alta loma california

,
best crank to rebuild a trx250r
,
crankshaft between live centers runout
,
rebuilding 86 trx250r crankshaft to 88 trx250r crankshaft
,

rebuilding trx250r crankshaft

,
recommended crank runout
,
trx250r crank pin tolerances
,

trx250r crank rebuilding

,
trx250r crankshaft rebuilding
,
trx250r crankshaft runout
Click on a term to search for related topics.