[79 CX500]

Hey guys I am rebuilding a 79 CX500 and ordered a new crankshaft and main journal bearings to put with it. I had them measured to this new crankshaft so that I got the right ones. The problem I have is the crank does not turn easily… I have put PLENTY of engine assembly lube during the install process. Everything looks good I followed the manual. Any ideas? Any help would be great!

 

[CXPHREAK]

What oil clearance was allowed for in the measurements?

FSM says 0.0008 - 0.0023 thou.

 

[79 CX500]

What oil clearance was allowed for in the measurements?

FSM says 0.0008 - 0.0023 thou.

You are right on the oil clearance… I have not measured for that. I bought the bearings according to the manual though.

 

[CXPHREAK]

You went by crank and block codes and ordered the appropriate coloured main bearings?

Other possible reasons for tightness is misalignment and the bearings being burred or bruised by the installation process.

 

[MCReviver]

You probably won't believe this, but about 10 or 12 years ago a friend brought me his VT500C to replace the crankcase, due to a crack on the bottom. It only needed one half so I found a used one on Ebay and had it shipped in. When I went to put the crank in I found it too tight. What to do now? I took some abrasive paper and worked the proper clearance into the bearings. I crossed my fingers that it would work. The bike had about 14,000 miles on it and it is still working great at 30,000+ miles. Not ever did it make metal in the oil filter.

 

[79 CX500]

You went by crank and block codes and ordered the appropriate coloured main bearings?

Other possible reasons for tightness is misalignment and the bearings being burred or bruised by the installation process.

I did! And yeah I removed the crank and saw a few abrasions on the rear main journal that must’ve happened when I put it in… so a metal sanding cloth is what I need to take those out

 

[79 CX500]

You probably won't believe this, but about 10 or 12 years ago a friend brought me his VT500C to replace the crankcase, due to a crack on the bottom. It only needed one half so I found a used one on Ebay and had it shipped in. When I went to put the crank in I found it too tight. What to do now? I took some abrasive paper and worked the proper clearance into the bearings. I crossed my fingers that it would work. The bike had about 14,000 miles on it and it is still working great at 30,000+ miles. Not ever did it make metal in the oil filter.

Thank you for the reply! I removed the crank and found just that on one of the bearings. I will be doing what you said

 

[CXPHREAK]

When you install the crank again tape over the primary drive spline.

Gently ease the crank in to the front bearing and place the rear bearing carrier onto the back of the crank and offer it up to the block.

Install all of the bolts and do them up about three turns.

Slide the crank back so it is sitting mid way between the two ends.

Tighten all bolts sequentiallyl a half turn at a time making sure at each step to slide the crank back and forth and checking that it rotates freely.

Keep at it until the crank carrier seats to the block and if all OK torque.

 

[Paul.slough.uk]

Where did you get the main bearings? I understood they are unobtainable and rod shell bearings very limited supply.

 

[79 CX500]

Where did you get the main bearings? I understood they are unobtainable and rod shell bearings very limited supply.

My friend I called a powersports shop and they found a few in the United sates for me at different owned locations, yet only one place out of the 4 that said they had them actually did. But you have to mic them and find the correct color codes. Get the right part number and see what powersports stores are near you.
I wish you luck.

 

[Paul.slough.uk]

Okies, you got lucky.
I tried asking Honda to have a look in their darkest recesses but they weren't very helpful - got lucky and found an old, unloved bottom end, cases, crank, rods and pistons all serviceable on eBay.
What would we do without eBay!
Thanks for reply.

 

[79 CX500]

I had the crankshaft turning relatively easy after installation with everything new. I install the pistons and rings and I put on the main gears and crank bolt, torque it down to the correct instructions by the manual, 58-69 ft-lbs…. And now I can’t turn the crank lol
But I take off the gears and I can tighten the bolt and turn it over again with ease….
Please help me again

 

[Paul.slough.uk]

I had a similar issue - the primary drive cogs on the front of the crank, one wide the other narrow, the narrow one has one less tooth.
They both engage with the clutch drive ring so the outer narrow crank cog has to slip slightly relative to the inner crank cog as it rotates with the clutch cage fitted.
The crank slip ring, spring washer and bolt provide the resistance.
I couldn't find anything written about this or the reason for it but assume it's to take up backlash between the primary drive gears.
Mine would turn freely clockwise and counterclockwise for about 10° before the narrow cog had to turn relative to the wider cog - this could be anywhere in the crank revolution.
I'm new to this and to cx500's but mine was the same and it's covered 500 miles now and all good. Maybe someone with more experience would confirm this.
Good luck.

 

[CXPHREAK]

When you torque the primary drive gear to the crankshaft this sets the end float of the crankshaft. There is no figure for this in the FSM. This suggests it is basically zero clearance and will cause some restriction to rotation compared to not having the bolt torqued.

It certainly shouldn't lock the crank though.

Check that the anti backlash gear is assembled correctly.

With the bolt backed off so that you can again rotate the crank wind it over a number of turns and tighten the bolt bit by bit while rotating. You might get lucky.