connecting rod bolts

NewHavenMike

NewHavenMike

1976 XS360C
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I have the Hanyes manual for my 360 that Im trying to finish building here..

I bought a used jug and had it bored and honed with NOS oversize pistons and rings.
Just got my new con rod bearings and timing chain also.

Now I just need the smaller stuff like washers, springs, and nuts, bolts...

Im reading in the manual and it says that I should use new connecting rod bolts because the old ones might be weakened or stretched?

Well, I cant find them anywhere.. Has anyone reused the old nuts/bolts? Any alternates?

Thanks for any adivce.
 
How many miles are on the bolts? I have always reused bolts and nuts and never had a problem, but nothing ever had more than about 30K on it and it was rebuilt just to rebuild it .... not because it was trashed..... Big D-


In most situations I would be an outcast ... here I am merely normal ...
 
I always used new as such a stressed part might let go.

might have to do a cross reference to see if other bolts fit
 
Find the spec on a new unused bolt.... then measure yours and see if they are stretched..... Big D-


In most situations I would be an outcast ... here I am merely normal ...
 
Last edited:
I don't know enough about our chosen bike yet but I'd suggest new rod bolts. In building other engines I've discovered the weaknesses of "Torque To Yield" rod bolts with disasterous results. These are designed as a 1 time fastener and once torqued & then removed their tensile strength is seriously compromised. If nothing else I'd use the strongest fasteners you find. But go to a reputable hardware supplier. General Hardware is not up to the task. Someplace like an industrial supplier where you can be assured that your bolts will be up to the task.
 
I am at this stage in my build too. Does anyone know the stretch factor for xs400 connecting rod bolts?
 
Just bought a bunch on ebay for dirt cheap, I'll see once they show up if the are correct, If not they have a 30 day return policy. They were listed by a reputable dealer in California.
 
My engine only had about 4000 miles on it. I cant imagine they would be worn out, unless they are stretch-type bolts.. I dont see why they would be stretch bolts anyway.
 
My experience with Torque to yield bolts is with a few car engines & a couple snow blower / lawn mower engines that I've rebuilt. They seem to be used on assembly lines in order to reduce assembly time. Imagine on an assembly line if you have to re torque rod bolts they would eliminate a station on the line for the second torqueing sequence. I know of an engine rebuilder who reused them on a vintage engine rebuild that had catastrophic results. The car was an original "numbers matching" 52 Chevy. When the connecting rod bolts failed at 60 mph on a 1500 mile road trip the engine was destroyed. The rebuilder was liable for the complete cost of the replacement and loss of value because of the non original engine.
 
Are there any interchangeable rod bolts I can use?

I accidentally order a set of NOS rod bolts. the part # is 341-11654-01. They look to be the same size but the first three digits of the part number are different.
They have a larger hex key head instead of the thinner type used on the xs360/400. UGH very angry here lol
 
NewHavenMike said:
Are there any interchangeable rod bolts I can use?

I accidentally order a set of NOS rod bolts. the part # is 341-11654-01. They look to be the same size but the first three digits of the part number are different.
They have a larger hex key head instead of the thinner type used on the xs360/400. UGH very angry here lol
Click to expand...
can't you just grind the profile?
 
I was thinking to regrind them. But It would be hard to balance them with ordinary tools and ive found out they will not work.

I may end up reusing the old bolts and put loc-tite on them.
 
Personally you might be playing with fire if you use the old bolts. As I've said earlier a very costly mistake was made by a reputable engine builder because he scrimped on those bolts and cost his customer immeasurable loss of value on a classic car. I'm sure there are a number of industrial hardware suppliers near you willing to help with your bolt issue. As for Loctite on your bolts it's not an issue of them loosening up it's an issue of the bolt shank being weakened from the initial torqueing when your engine was first assembled. Your threads will most likely lock down just fine with out Loctite that's part of the reason they are a fine thread bolt.
 
Anyone here have a bolt out that they can measure and maybe post a picture of it?

To be honest I have never seen the inside of a XS400.
Have worked on engines from 0.80 CC's up to 64,351.8 CC's but never had the bottom end off an XS400!
 
I just bought this set of OEM con rod bolts from Speed and Sport out of Pennsylvania (as recommended by Drewpy) www.yamtopdog.com. Here is a photo. Note the oval head shape. It keeps the bolt from turning when tightening.
IMG_20160719_163435_edit_edit.jpg
 
When I looked for a set a few months ago I had the local yamaha dealer put a parts request out with other dealers. Within four days a shop had responded and I got a set of four for $40.
 
I called the Speed and Sport place. They had 3 in stock, I told the guy I wanted them and he went to grab them to be sure they were there. He had them!

Then he noticed that 2 bolts were different from the other one. He happened to have a NOS connecting rod and compared them.. The 2 bolts were different and ONLY the single NOS bolt would work. It was pretty disappointing.. The connecting rod was my next question and that was running somewhere around $200.

Still on the phone, I brought up about reusing the bolts to BIll. I asked him if he had a caliper to measure the length. I'm not sure how he measured them but he spec'd them to 46.9mm.

So now Im back to the idea of reusing them. Im thinking, because the torque value isn't particularly high, I might be able to take off a pound or so from both stages of the sequence.. This is in order to avoid more stretch. Ive also read that TTY bolts are sequenced a couple times before being finalized and I should have one more use out of them.
 
Surprise! I doubled checked the receipt from when I ordered the "incorrect" part. The guy that took the order put the wrong parts in the bag. I gave him the right part number!
 

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