How to grind a hardened steel cheap?

[skiri251]

Okay, my restoration of '68 Honda CL125A Scrambler is almost complete.
I am currently at the break in stage (new pistons, etc.) and need to keep the rpm low.
I have a 17T counter shaft sprocket I bought for my CT90. It almost fits CL125A. The problem is the spline tooth on CL125A is a bit too wide (around 1/32").
I tried to file it wide but the sprocket appears to be hardened and HF cheapo file couldn't cut it.
Is there any way I can grind that extra 1/32" from sprocket cheap?

 

[dan filipi]

Dremel disk?

 

[Ansimp]

Die grinder or drill with stone tool

 

[skiri251]

Thanks for the advices.
I have real Dremel but ran out of disks.
Will visit HF in search of stone bits.

 

[slabghost]

Small sharpening stone or diamond sharpener.

 

[zman]

I would find a better file, The power tool would certainly work but with something like that I would opt for a perfect fit removing a little at a time, I would just find a good file like a Grobet or other designed for hardened steel, Maybe cost 10-20 bucks but they will come in handy for future projects.

 

[skiri251]

Thanks again.

Where should I go to get sharpening stone/diamond or good file?
Somehow I doubt HF have them..

 

[zman]

skiri251 » Sat Jun 14, 2014 6:11 pm[/url]":1qig6aqn]
Thanks again.

Where should I go to get sharpening stone/diamond or good file?
Somehow I doubt HF have them..

Just looked and they didn't have any real good ones, they do have a diamond set, I think those will cut hard steel. You have a place in Torrance called Nates tool..Looks promising. A place up here is King Bolt..I remember seeing good quality files there, open Sundays too.

 

[Steve83]

When going to Harbor Freight, stop for a haircut on the way - maybe a drill press will follow you home! :hihihi:

 

[mike in idaho]

Try not to get carried away with keeping the rpms low. The worst thing for a 125cc twin is to lug it with too-tall gearing, especially with a brand new top end. Let it rev up , it will run better and last longer.

 

[tuna boy]

Be aware that diamond stones/files would take weeks to remove 1/32 " of hardened steel. The sprocket may be case hardened 8620 steel. If that is the situation the hard case is only .001-.002 thick. If you can grind the surface off you could then use a file to do a cleaner more accurate job.

 

[skiri251]

zman » Sat Jun 14, 2014 6:23 pm[/url]":3plzfo3y]

skiri251 » Sat Jun 14, 2014 6:11 pm[/url]":3plzfo3y]
Thanks again.

Where should I go to get sharpening stone/diamond or good file?
Somehow I doubt HF have them..

Just looked and they didn't have any real good ones, they do have a diamond set, I think those will cut hard steel. You have a place in Torrance called Nates tool..Looks promising. A place up here is King Bolt..I remember seeing good quality files there, open Sundays too.

Nates tools.
Wow that's almost walking distance. I will give it a visit.

Should I bet $8.99 on HF diamond point grinding set?
Hmmmm...

https://www.harborfreight.com/10-piece-14-shank-rotary-diamond-point-grinding-set-69661.html

 

[skiri251]

mike in idaho » Sat Jun 14, 2014 7:39 pm[/url]":3e9q67oo]
Try not to get carried away with keeping the rpms low. The worst thing for a 125cc twin is to lug it with too-tall gearing, especially with a brand new top end. Let it rev up , it will run better and last longer.

How should I break in the engine?
I don't have country highways nearby so I can't ride @ 30MPH unless I am in bicycle lane or something..
For the same engine, I believe Scrambler got a bit lower gearing than street version SS125.
I want to shift up one more from the top gear as is so hopefully taller gearing will work at least on level ground.. if I can go 45~50 MPH w/o really over rev'ing the engine.

 

[skiri251]

Steve83 » Sat Jun 14, 2014 6:36 pm[/url]":2z93qku1]
When going to Harbor Freight, stop for a haircut on the way - maybe a drill press will follow you home! :hihihi:

Yes, I need a new one!
Hopefully more powerful than current wimpy 1/2 HP item. :fiddle:

 

[skiri251]

tuna » Sun Jun 15, 2014 5:38 am[/url]":1kidrhma]
Be aware that diamond stones/files would take weeks to remove 1/32 " of hardened steel. The sprocket may be case hardened 8620 steel. If that is the situation the hard case is only .001-.002 thick. If you can grind the surface off you could then use a file to do a cleaner more accurate job.

Thanks for the info.

 

[dan filipi]

My understanding is break-in should be done by varying rpm's and not 'lugging' the engine.
Even wide open throttle and high rpm's are ok.
That is what I was told 25+ years ago by the re-builder of the last V8 I had done.
Could be different with air cooled motors?

 

[Joep]

Iirc... when I bought my first bike the manual said under 50 mph for the first 100 miles.. change oil and then good to go.. a friend if mine who I ride with to learn to ride....just kept rpms reasonable.. he did that with all his vehicles except a 66 dodge charger bought used.. only ran with wired open 4 bbl.. two hours from OKC to Albuquerque.. lol

 

[skiri251]

The brand-new China engine I put on CT90 had a label saying "Don't go over 40 KmH (= 25 MPH) for the first 300 Km (190 miles)" which is fairly vague but w/o a tachometer that's the best they can specify?

I will install cheapo electronic tachometer on my CL125A.

 

[joedrum]

i always find the smoothest least vibrating rpm ...usually about halfway in rpm zone plus some maybe and run there in that zone ... this carves the smoothest path in my book ... after redoing hooch this is the method i use ... i did not rebuild everything but did enough to deserve the same treatment .... hooch rockets to the top of rpm virtually noiseless from motor ... but many things were done to tighten things up ... but thats my way of doing it ...i never listen to the blab from others about how to do it ... this way seemed to make the most common sense to me

 

[Mysteryrider]

Joep » Sun Jun 15, 2014 9:40 am[/url]"]
Iirc... when I bought my first bike the manual said under 50 mph for the first 100 miles.. change oil and then good to go.. a friend if mine who I ride with to learn to ride....just kept rpms reasonable.. he did that with all his vehicles except a 66 dodge charger bought used.. only ran with wired open 4 bbl.. two hours from OKC to Albuquerque.. lol



that sounds like one very tall tale from history lol.... 540 miles between those two places ...