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The 2-Stroke Garage => Turning Wrenches => Topic started by: forexer on December 09, 2021, 07:46:42 PM

Title: RD400 Rear Axle Nut
Post by: forexer on December 09, 2021, 07:46:42 PM
I removed the rear wheel last week to clean it up and after re-assembly I cannot torque it to the required spec because if I do it will not rotate. Everything moves freely and normal when loose however as soon as I go past snug the wheel starts to have resistance the more I tighten the worse it gets. I figured snug is fine as the wheel is double nutted and cotter keyed. However I thought I'd ask the group if anyone else has experienced this same thing and if so what was the fix?

One more thing that maybe the culprit , not sure - does it matter which chain tensioner goes on what side left or right because I cleaned them both up and now I don't know which one goes where. I looked at them both in detail and they look exactly the same just mirror opposites I couldn't see any difference between them 
Title: Re: RD400 Rear Axle Nut
Post by: Jspooner on December 09, 2021, 07:51:56 PM
Did you have the bearings out? If you did and did not reinstall them properly they will bind when you tighten the axle. They need to be seated all the way. IF both chain adjusters are the same (I thought they were different) it shouldn't make any difference with the problem you are having.
Title: Re: RD400 Rear Axle Nut
Post by: forexer on December 09, 2021, 08:13:26 PM
Bearings were never removed just the end caps - The Yamaha parts diagram calls out 2 different parts numbers one for the left and one for the right drive chain adjuster puller however on eBay and other sources online sell them individually without specifying left or right so I'm assuming there interchangeable they sure look they are.....
Title: Re: RD400 Rear Axle Nut
Post by: RDFL on December 09, 2021, 08:53:09 PM
The larger hole one goes on brake side, larger for the caliper bracket. The binding might be the dust seals.
Title: Re: RD400 Rear Axle Nut
Post by: rodneya on December 09, 2021, 08:59:16 PM
Check if it is binding on the caliper when tightened
Title: Re: RD400 Rear Axle Nut
Post by: forexer on December 09, 2021, 10:17:47 PM
the hole sizes appear to be the same diameter on both adjusters. ( Going off memory here )  I believe the stock OEM adjusters have a notch on the top side of the adjusters to help determine the evenness on both sides when adjusting the chain. The goal is to match the notch on the adjuster with the marks on the swing arm making them even on both sides. Neither of my adjusters have the factory notch and I think that if the hole was too small the axle wouldn't of been able to slide all the way through as it would be bound up.

Do you think its fine leaving how it is (not torqued to spec ) -  the chain is just about even on both sides within .020 measured using calipers and the rear wheel is snug on the large nut and tight on the small nut and cotter keyed. I can't see it coming off I guess I need to ride it tomorrow and see how it handles - see if it wobbles or vibrates etc...etc.... I wish I could of remembered how tight that nut was coming off maybe that's how it was.
Title: Re: RD400 Rear Axle Nut
Post by: RDFL on December 10, 2021, 05:49:04 PM
If one hole is not bigger and only work on brake side, you either don't have 400 or don't have 400 rear end.
Title: Re: RD400 Rear Axle Nut
Post by: forexer on December 10, 2021, 05:53:03 PM
Maybe the ones I have are aftermarket and that's why the holes are the same size  I do know that the brake caliper bolt fits the hole and the bike is definitely a RD400
Title: Re: RD400 Rear Axle Nut
Post by: forexer on December 10, 2021, 05:55:49 PM
Also I took it out today for a ride no issues no concerns it handled perfectly fine

I'd rather have the wheel be able to rotate then to have it tight and dragging with resistance.

I just find it odd that I was  unable to torque it to spec

I was wondering if anyone else has ever experienced this issue
Title: Re: RD400 Rear Axle Nut
Post by: RDFL on December 10, 2021, 06:21:43 PM
Here is pic of 400 adjusters, maybe you have 2 brake sides? Would be slop on other side then. The 400 swingarm has larger slot on that side for the nut thing to fit thru to hold brake bracket. https://www.ebay.com/itm/163189210914
Title: Re: RD400 Rear Axle Nut
Post by: RDFL on December 10, 2021, 06:25:58 PM
Quote from: forexer on December 10, 2021, 05:53:03 PM
Maybe the ones I have are aftermarket and that's why the holes are the same size  I do know that the brake caliper bolt fits the hole and the bike is definitely a RD400
It is for the sleeve nut (I think that is what you would call it) the axle goes thru.
Title: Re: RD400 Rear Axle Nut
Post by: forexer on December 11, 2021, 01:07:16 PM
After looking at the eBay link that you provided I can definitely see the difference in the hole diameters.
However both of mine appear to have the same size holes so I'm thinking I must have two big hole adjusters because you're saying the smaller diameter hole is too small for the sleeve nut ?

Is this correct will the adjuster with the smaller hole fit the sleeve nut or is the diameter to small?
Title: Re: RD400 Rear Axle Nut
Post by: RDFL on December 11, 2021, 05:15:51 PM
Will only work on brake side with the big one, number 20 needs the larger hole. Is why the swingarm slot is much larger on that side. Do spacers etc. look the same as diagram on your bike?  https://www.yamahapartsnation.com/oemparts/a/yam/500419cbf8700209bc7855b8/rear-wheel       
Title: Re: RD400 Rear Axle Nut
Post by: forexer on December 11, 2021, 05:46:37 PM
Yes my adjuster fits the number 20 part as shown in the diagram

I guess my question is will having two large hole adjusters instead of one small and one large cause a torque issue.

One has a large hole and the other has a small hole however do you know if the 2 adjusters are same thicknesses?
Title: Re: RD400 Rear Axle Nut
Post by: RDFL on December 11, 2021, 06:12:39 PM
I would doubt it but guess there is a chance if you have another large one (other side should be similar in diameter to axle) maybe when tightened axle gets crooked in the slop.
Title: Re: RD400 Rear Axle Nut
Post by: RDFL on December 11, 2021, 06:18:06 PM
As for thickness I have some loose ones somewhere will have to look, wouldn't think could be much if any difference but if is could explain your problem.
Title: Re: RD400 Rear Axle Nut
Post by: forexer on December 12, 2021, 06:14:32 AM
Perhaps you're right the bigger hole adjuster maybe allowing just enough slop where the axle becomes crooked when torqued. I guess the only way to know for sure would be to buy another adjuster - one with a small hole for the left side and see if it makes a difference.

Please let me know what you find out when measuring the thicknesses and thanks again for your input  :thumbs:
Title: Re: RD400 Rear Axle Nut
Post by: RDFL on December 13, 2021, 06:32:41 PM
They are same thickness.
Title: Re: RD400 Rear Axle Nut
Post by: 1976RD400C on December 15, 2021, 07:12:49 AM
If you have an adjuster with a big hole where the small hole one should be how do you make sure the wheel alignment is correct because the marks on the adjuster and swing arm will be off?
Title: Re: RD400 Rear Axle Nut
Post by: Striker1423 on December 15, 2021, 08:43:50 AM
You don't. Swap the adjuster to the correct one as it will allow the axle to travel around. No bueno.

But, a simple way to do a chain adjustment is to measure the length of the bolts once you get chain slack set. Of the bolts are even on the ends and the chain is straight to the eye, tighten it down and double check. So long as the adjuster bolt thread count or length matches you're good.
Title: Re: RD400 Rear Axle Nut
Post by: Jspooner on December 16, 2021, 12:23:06 AM
I measure from the center of the swing arm pivot bolt to the center of the rear axle when I adjust my chain.
Title: Re: RD400 Rear Axle Nut
Post by: forexer on December 19, 2021, 08:31:20 AM

I've always adjusted the chain the same way STRIKER suggested however, I use a Vernier caliper to measure with and as long as each side is within .030 it's good to go

"A simple way to do a chain adjustment is to measure the length of the bolts once you get chain slack set. If the bolts are even on the ends and the chain is straight to the eye, tighten it down and double check. So long as the adjuster bolt thread count or length matches you're good"

measuring from the swing arm is also a good option however I found that I lose some accuracy trying to measure over that much distance - It's hard to keep the tape measure at the exact same angle on both sides.

What matters is - in the end is that both sides are even as possible
Title: Re: RD400 Rear Axle Nut
Post by: forexer on December 19, 2021, 08:36:43 AM
Quote from: 1976RD400C on December 15, 2021, 07:12:49 AM
If you have an adjuster with a big hole where the small hole one should be how do you make sure the wheel alignment is correct because the marks on the adjuster and swing arm will be off?


I found out that the ones on this bike are aftermarket adjusters and therefore do NOT have "any marks on the adjuster" like the OEM ones have and whoever installed them installed 2 big hole adjusters instead of one small and one large.

to answer your question - you make sure the wheel alignment is correct by measuring both sides



Title: Re: RD400 Rear Axle Nut
Post by: SoCal250 on December 19, 2021, 12:51:55 PM
Quote from: Jspooner on December 16, 2021, 12:23:06 AM
I measure from the center of the swing arm pivot bolt to the center of the rear axle when I adjust my chain.
+1  :thumbs: