NC30 Race Motor rebuild

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boyracer34
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NC30 Race Motor rebuild

Post by boyracer34 » Tue Apr 17, 2018 6:57 am

Hi folks, apologies if I am repeating post info from elsewhere.
Did a big end on race motor, rebuild time. Ouch.

Q1: can failed VFR crank be repaired back to spec at all?

Q2: Parts Suppliers recommendations (Im in Oz) for:
Pistons , Stock and /or oversize
Shells
Gaskets kits
other motor component internals and externals

Any other must do jobs whilst motor is apart?
TIA folks.

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CMSMJ1
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Re: NC30 Race Motor rebuild

Post by CMSMJ1 » Tue Apr 17, 2018 8:58 am

Ouch indeed :)

Get your monies and credit facility flexed and get a hold of Mike Norman and his boys at G-force racing - mngforce dot something will get you their website. As far as I am aware, they are the most reliable contact for shells and these odds and sods.

Good luck
IMPERATOR REX ANGLORUM

The V4 is the law..

NC30 - No9 > My old mate
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magg
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Re: NC30 Race Motor rebuild

Post by magg » Tue Apr 17, 2018 10:44 am

Honda does not produce oversize engine bearings, although they are available on ebay etc. from China. Is the crank damaged or just the bearing.

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Yakama
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Re: NC30 Race Motor rebuild

Post by Yakama » Tue Apr 17, 2018 1:22 pm

Mike Norman does oversized bearings now

magg
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Re: NC30 Race Motor rebuild

Post by magg » Tue Apr 17, 2018 1:55 pm

Mike Norman has bearing sizes for Honda production tolerance sizing. Crankshafts with damage will not be within Honda production tolerance and will need oversize bearings, provided repair is possible/practical/desirable. Hence my question as to whether it is a simple bearing failure or a damaged crankshaft.

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gavins
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Re: NC30 Race Motor rebuild

Post by gavins » Tue Apr 17, 2018 2:37 pm

As Yakama already said, Mike Norman is supplying oversize bearings as well as direct replacements for the Honda ones. http://mngforce.typepad.com/nc450vdev/2 ... rings.html

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Re: NC30 Race Motor rebuild

Post by magg » Tue Apr 17, 2018 3:21 pm

I think you will find that Mike Norman bearings sizes match the Honda production tolerance sizes, not the oversize required for a crankshaft that has been ground oversize to repair a damaged journal.

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gavins
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Re: NC30 Race Motor rebuild

Post by gavins » Tue Apr 17, 2018 3:55 pm

From Mikes website:
Also, for special circumstances, I have created some extra-thick Bearings. These will be used primarily for crankshafts that are undersized. This can occur if the crankshaft has been polished several times. Also, in the event of a mild bearing seizure, there may be an opportunity to polish it out and run thicker bearings.
Description Bearing Thickness G-Force Part No. Price/Shell Special Notes
Bearing, Conn-Rod, BLU 1.506-1.510 132P9S-NCV-220 $20.80 These are a stronger overlay for Racing
Bearing, Conn-Rod, BLK 1.502-1.506 132P9S-NCV-230 $20.80 These are a stronger overlay for Racing
Bearing, Main, Outer, BLU 1.506-1.510 13310-NCV-120 $23.50
Bearing, Main, Outer, BLK 1.502-1.506 13310-NCV-130 $23.50
Bearing, Main, Inner, BLU 1.506-1.510 13320-NCV-210 $23.50
Bearing, Main, Inner, BLK 1.502-1.506 13320-NCV-220 $23.50

magg
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Re: NC30 Race Motor rebuild

Post by magg » Tue Apr 17, 2018 10:39 pm

Polishing out a mild bearing seizure is not a journal regrind. Thus my original comment regarding the level of damage as Mike Norman's bearings are not suitable. The Chinese replacements are claimed to be 0.25, 0.50 and 0.75mm oversize but quality unknown and would require surface hardening.

boyracer34
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Re: NC30 Race Motor rebuild

Post by boyracer34 » Wed Apr 18, 2018 5:22 am

Thanks all, gathering good info, yeh the MasterCard gonna hurt.


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