Stripped threads centrifugal clutch

[iamtherealJayy 0]

Recently got a 1999 Honda TRX300 4x4 for a steal since the kid said it needed a new one way bearing. Things a heap but I got it cheap. Apparently the guy prior to him replaced the one way bearing and centrifugal clutch but installed the bearing backwards. When I got it the unit always moved in gear so I tore it apart and started replacing stuff and I got to reassembly and the nut to hold the clutch on wouldn’t tighten so I examine it closer and there’s no threads on the shaft or in the nut. I’m not advanced enough in this yet to know what that shaft or nut it called so I’m speaking in general terms. I know it’s reverse thread and it holds the clutch on. I’m wondering what I need to do to get it tightened on there. Is this replaceable? What’s it called if so? I’ve found replacement nuts for the change clutch but not the drive clutch.

[Fishfiles 20,147]

12 minutes ago, iamtherealJayy said:

Recently got a 1999 Honda TRX300 4x4 for a steal since the kid said it needed a new one way bearing. Things a heap but I got it cheap. Apparently the guy prior to him replaced the one way bearing and centrifugal clutch but installed the bearing backwards. When I got it the unit always moved in gear so I tore it apart and started replacing stuff and I got to reassembly and the nut to hold the clutch on wouldn’t tighten so I examine it closer and there’s no threads on the shaft or in the nut. I’m not advanced enough in this yet to know what that shaft or nut it called so I’m speaking in general terms. I know it’s reverse thread and it holds the clutch on. I’m wondering what I need to do to get it tightened on there. Is this replaceable? What’s it called if so? I’ve found replacement nuts for the change clutch but not the drive clutch.

 

Hi , welcome to the forum , 

sounds like you stripped the end of the crankshaft , you would have to split the case to change the crank ---- 

[iamtherealJayy 0]

I didn’t strip it, I removed it replaced everything and the threads are gone, it was only hand tight when I removed it. Is there a size of nut I can get that’s one size smaller that could thread on? I’ll redo the threads I just don’t know the sizes as I’m not familiar with that much. I’m more familiar with standard sizes, also generally smaller sizes aswell. 

[toodeep 1,759]

Is there enough left on the crankshaft to use a thread file to clean up the threads and use a good nut or is it smooth and beyond repair?

 

From Honda: 90235-HA0-680  NUT, LOCK (20MM)

[iamtherealJayy 0]

There’s something there it’s like the threads have been rounded, you can catch your fingernail on the threads, you can push the nut on but not pull it off

[iamtherealJayy 0]

Here’s some photos

[jeepwm69 7,725]

Get a new nut, and get the proper sized tap and retap those threads.

 

If it doesn't work, you'll have to tear the whole engine down and replace the crank.

 

 

[iamtherealJayy 0]

Any ideas on proper size? I’ll order whatever I need if leaded in the right direction? The nut is a 27mm. I can get other measurements if needed

[jeepwm69 7,725]

There's the nut.

 

The nut says 20mm.  I found a thread nosing around online that says the crank threads are M18x1 left hand thread.  Does that sound right @toodeep

 

 

https://www.hondaatvforums.net/threads/crankshaft-threads-need-die.10409/post-1317065

 

That's an old thread (since everybody left that site LOL) and all I can find are M18x1.5 in a left hand die.

 

 

 

[iamtherealJayy 0]

They are reverse threads, my nut is a 27mm though and online in the parts catalog it says 20mm. This bike has been apart prior. Previous owner before the previous owner is the one that ruined it. Clutch installed wrong one way bearing in backwards kick start return spring dangling in there etc. I’m going to assume fellow didn’t know it was reverse threads and cranked on it and lost the threads and had some other nut to throw on there. In one of the videos I watched is there supposed to be a pin to hold the nut? Mine was lacking this pin if so. 

[jeepwm69 7,725]

No pin on that nut to hold it.  27MM is the socket you use.  This part is the proper factory nut.  Remember the size isn't the socket size but the shaft diameter (for example all the 10MM and 8MM headed bolts on your 300 are listed as 6mm, because they go by the size of the threaded portion, not the size of the head)

 

https://www.partzilla.com/product/honda/90235-HA0-680?ref=f5e4ae2f6771acf982305687f4d732c78eb61e58

 

You just need to figure out the thread size/pitch of that nut so you can order the proper die to try to rethread your crankshaft.

[iamtherealJayy 0]

I’m not super familiar with meta work etc how would I go about figuring the thread pitch? Also unrelated but your name being jeepwm69, are you interested in Jeep’s?

[iamtherealJayy 0]

If I get an M18x1 die and redo the threads can I get a generic m18x1 nut and put on there? Since I can’t find anything specifying whether the Honda nut is M18x1 or M18x1.5?

[jeepwm69 7,725]

31 minutes ago, iamtherealJayy said:

I’m not super familiar with meta work etc how would I go about figuring the thread pitch? Also unrelated but your name being jeepwm69, are you interested in Jeep’s?

 

You might say that......

 

As for the nut/die, I would get the OEM Honda nut, and you should be able to take it to a fastenal or similar place and they can tell you the pitch.

 

 

[450S 15]

It looks like there is enough threads left on the crank to measure the pitch with and a thread pitch gauge on Amazon is only a few bucks.

 

Amazon - 52pcs Thread Pitch Gauge

Edited October 28, 2022 by 450S

[jeepwm69 7,725]

26 minutes ago, iamtherealJayy said:

If I get an M18x1 die and redo the threads can I get a generic m18x1 nut and put on there? Since I can’t find anything specifying whether the Honda nut is M18x1 or M18x1.5?

 

You could hypothetically do that, but I'd use the Honda nut.  It is designed so that  you can stake it to keep it from backing off of the crank once it's tightened.  That's the thin little collar around the top.

 

The pitch gauge would certainly work

 

[toodeep 1,759]

I don't have anything handy to measure right now but the 20mm 1.00 thread pitch at the start of that thread jeep posted sounds correct. All I have ever used to clean up those kind of threads was a thread file.

[iamtherealJayy 0]

I ordered a tap and die, I’m going to try and redo it. I also ordered a new nut and a wheel stud lol. I’ll wait until they’re in to go any farther. Mind if I dm you a question regarding my jeep lol? I need help with something or atleast an idea of what to do. The tap die set I got is an M18x1 left hand thread. 

[toodeep 1,759]

Why order a 18mm die to trace threads on a 20mm shaft? 2 mm doesn't seem like much but trust me, she will know the difference. Honda lists the nut as 20mm, the thread jeep posted (except for that last user posting from nowhere) has it at 20mm. I would say it's 20mm.

[iamtherealJayy 0]

I googled a 20mm and it showed the thread being 18.632 or something around that. So I assumed a 20mm shaft would be an M18. I dunno I can order both. Never hurts to have extra tools. 

[iamtherealJayy 0]

Got both on order, m20 will be here later as I couldnt find it from anywhere but China. 

[Goober 1,555]

Try Ace Hardware i saw they had thread pitch tools

[shadetree 5,970]

if for some odd reason ( i'd expect it this way ) if you can not fix the threads on the crank ?, you are looking at a engine tear down, replacing the crank that has better threads on the end.

[ATC4ever 1,084]

Maybe i missed it but you say its LH threads? So the Die you ordered is also LH?

[shadetree 5,970]

59 minutes ago, ATC4ever said:

Maybe i missed it but you say its LH threads? So the Die you ordered is also LH?

few post up, he said he ordered a LH tap and die set ^^, not sure how he did this ?, as i've never seen a LH set ??..lol.