Author Topic: Rod weight, one rod 2 grams lighter than the rest.  (Read 898 times)

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Offline KayOne

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Rod weight, one rod 2 grams lighter than the rest.
« on: October 31, 2013, 07:35:00 PM »
Starting on the engine build on the K1. Removed the rods to check the bearings and weighed them. Three rods 281 grams, one 279 grams. Should I lighten up three rods to match the lightest or just leave them alone?
CB750 K1 restored
1979 CB750Fz - original except for exhaust, 14000km
1984 VF45F Interceptor - all original, 12000 km
1968 S90 - all original, 2100 miles
1973 H2a, Restored
1973 H1D, next project
CB750K1 (sold)
1976 KZ900 (sold)
1981 CB900F (under restoration)
2015 Yamaha FJ09, my appliance rider

Offline Don R

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Re: Rod weight, one rod 2 grams lighter than the rest.
« Reply #1 on: October 31, 2013, 07:50:19 PM »
You took the time to measure, I'd lighten 3.
  I didn't do that to an engine 30 years ago, it still bugs me that I didn't take the time, although it runs strong as ever.
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Offline Dream750

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Re: Rod weight, one rod 2 grams lighter than the rest.
« Reply #2 on: November 01, 2013, 06:53:33 PM »
Starting on the engine build on the K1. Removed the rods to check the bearings and weighed them. Three rods 281 grams, one 279 grams. Should I lighten up three rods to match the lightest or just leave them alone?

Looks like you are within weight specifications according to this Honda service bulletin:

http://manuals.sohc4.net/CB750SB/750_31.pdf


Offline KayOne

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Re: Rod weight, one rod 2 grams lighter than the rest.
« Reply #3 on: November 01, 2013, 09:07:17 PM »
Very interesting reading Dream! I don't think I will worry about it after seeing this article. It's not like I don't have enough work to do already.
CB750 K1 restored
1979 CB750Fz - original except for exhaust, 14000km
1984 VF45F Interceptor - all original, 12000 km
1968 S90 - all original, 2100 miles
1973 H2a, Restored
1973 H1D, next project
CB750K1 (sold)
1976 KZ900 (sold)
1981 CB900F (under restoration)
2015 Yamaha FJ09, my appliance rider