Author Topic: Specifics of classic production class limitations  (Read 7374 times)

0 Members and 1 Guest are viewing this topic.

Offline gschuld

  • Full Member
  • ***
  • Posts: 91
Re: Specifics of classic production class limitations
« Reply #15 on: November 03, 2018, 07:25:52 PM »
This resolves the displacement question:  from Drew Gatewood, tech inspector at BMST

Question:  So what is the final word on displacement overbore for Classic Production?  The CB750 is 736cc from the factory.  There is an overbore allowance, but the full overbore allowance puts the 736cc to a little over 750cc.

Answer: As long as the factory stock bore is at or below the class entered (e.g. 750.000cc) a +.050" maximum over bore is allowed to take is over the class size,
and still be legal in that class. Stock displacement is 736.463cc - +.050" overbore would make it 758.205cc, and this is acceptable.

George

Offline donpearsall

  • Sr. Member
  • ****
  • Posts: 872
    • http://soundappraisal.com
Re: Specifics of classic production class limitations
« Reply #16 on: November 04, 2018, 06:41:01 PM »
That is good news!  However that is not what the book says. It says you can bore up to .050" "to remain within the class limit". And the class limit is 750cc.

Make sure to print out the answer and take it with you to inspection! Whoever does the measuring may disagree.

But Drew is the final answer so if he interprets it that way, then that is what will be judged when it comes time to measure.

Don
550 hp 2003 Suzuki Hayabusa Land Speed Racer

Offline Stainless1

  • Administrator
  • Hero Member
  • ***
  • Posts: 8948
  • Robert W. P. "Stainless" Steele
Re: Specifics of classic production class limitations
« Reply #17 on: November 04, 2018, 08:00:18 PM »
Don, you are reading it wrong  :|

12. D. PRODUCTION, CLASSIC (PC)
Same as 12.A but with a production date prior to 1981. Allowable
overbore in this class is + .050- inches over OEM standard bore to
remain in displacement class.

Stainless
Red Hat 228.039, 2001, 65ci, Bockscar Lakester #1000 with a little N2O

Offline donpearsall

  • Sr. Member
  • ****
  • Posts: 872
    • http://soundappraisal.com
Re: Specifics of classic production class limitations
« Reply #18 on: November 04, 2018, 08:20:14 PM »
Not to belabor the point, but there are two points to the rule.
1. You are permitted to bore .050 over the ORIGINAL bore.
2. You must remain in the displacement class.

So if the overbore takes the displacement to 758cc, you are not within the displacement class.

But it is moot anyway, as Drew interprets it to say that you can go over 750 and as far as I know he has the final say.

Don
550 hp 2003 Suzuki Hayabusa Land Speed Racer