Resend my activation email : Register : Log in 
BCF: Bike Chat Forums


Aprilia RS125 Damaged Crankshaft

Reply to topic
Bike Chat Forums Index -> The Workshop
View previous topic : View next topic  
Author Message

Danonymoose
Derestricted Danger



Joined: 03 Aug 2019
Karma :

PostPosted: 10:05 - 18 Aug 2019    Post subject: Aprilia RS125 Damaged Crankshaft Reply with quote

Hi.

I recently posted with some issues with my 122 engined '05 RS125. I thought the issues were to do with the carb/fueling. Boy, was I wrong.

After getting a break in the bad weather recently, I've been able to start fault finding on the bike again. I figured that the bike was, indeed, getting fuel, and it seemed to be an ignition/spark problem.

The spark was okay, but not the best I've seen. I started testing the electrical components one by one. Ignition switch? Fine. Coil/lead/cap? Fine. CDI/ICU? Fine. I finally got down to the pickup. I took it off, cleaned it up, tested it, and it was fine. However when I took the pickup off, I noticed the air gap was pretty large. So upon refitting it, I got my feeler guage out and made the sure it was gapped properly. Lo and behold, a decent spark! Or, at least, it was much better than before, if still not perfect.

Anyway, I noticed that the stator cover was pretty dirty. I decided to remove it to give it a good clean. Welll... This is when I noticed that something wasn't right. After removing the cover, I decided to also remove the stator itself. This is when my world came crumbling down around me.

The woodruff key was lying on it's side in what was once the slot that it fits in on the end of the shaft. It looks as though it's somehow wriggled loose, and has eroded away at its home in the shaft, leaving a half moon shaped pit where the slot originally was.

Does anyone have any experience with issues like this? I've been searching online, and while there are plenty of places that offer crank rebuilding, this only really seems to cover seals and bearings etc. and not work on the actual crankshaft itself.

I can throw some pictures up later to show exactly what I mean, if needed.

Cheers
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts
- This post is not being displayed because the poster has bad karma. Unhide this post / all posts.

redeem ouzzer
World Chat Champion



Joined: 06 Oct 2015
Karma :

PostPosted: 11:13 - 18 Aug 2019    Post subject: Reply with quote

You’ll be wanting it rebuilt with a new crank web then....
____________________
Be a REAL MAN!
 Back to top
View user's profile Send private message You must be logged in to rate posts

Riejufixing
World Chat Champion



Joined: 24 Jun 2018
Karma :

PostPosted: 11:41 - 18 Aug 2019    Post subject: Re: Aprilia RS125 Damaged Crankshaft Reply with quote

Danonymoose wrote:
I've been searching online, and while there are plenty of places that offer crank rebuilding, this only really seems to cover seals and bearings etc. and not work on the actual crankshaft itself

Telephone a couple of them and tell them that the key seat in the crankshaft's damaged, and talk it over. It's possible that some firm has odds and ends lying about which could be used (or could re-cut the seat in a different position, but that might be more expensive). Also, look arount for used components; there's a "crank with siezed bearing" on eBay now, or a "bottom end" which has a crank in it for £110 "or best offer" (EDIT this also has the generator rotor which you will probably need & stator, who knows the thing could actually be usable and might have parts you could resell). Dunno whether a supplier could get you a new shaft to be pressed in (?).
 Back to top
View user's profile Send private message You must be logged in to rate posts

Nobby the Bastard
Harley Gaydar



Joined: 16 Aug 2013
Karma :

PostPosted: 12:00 - 18 Aug 2019    Post subject: Reply with quote

Are you sure the slot is damaged? Slots for woodruff keys are meant to be a half moon shape.

In addition, having sheared a woodruff key in the past, they are a lot weaker than the crank. I seriously doubt that the woodruff key had damaged it.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050
 Back to top
View user's profile Send private message You must be logged in to rate posts

Riejufixing
World Chat Champion



Joined: 24 Jun 2018
Karma :

PostPosted: 12:27 - 18 Aug 2019    Post subject: Re: Aprilia RS125 Damaged Crankshaft Reply with quote

Danonymoose wrote:
I can throw some pictures up later to show exactly what I mean, if needed.

G'won then... pictures are always good.
 Back to top
View user's profile Send private message You must be logged in to rate posts

Pete.
Super Spammer



Joined: 22 Aug 2006
Karma :

PostPosted: 13:28 - 18 Aug 2019    Post subject: Reply with quote

Put up some pics. Odds-on that the broken key has chewed up the taper a bit. How fixable it is depends on the amount of damage. Quite often all that is required is a small clean-up and a new woodruff key.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy
 Back to top
View user's profile Send private message Visit poster's website You must be logged in to rate posts

stinkwheel
Bovine Proctologist



Joined: 12 Jul 2004
Karma :

PostPosted: 13:54 - 18 Aug 2019    Post subject: Reply with quote

If you're lucky, you'll be able to lap the flywheel back against the taper and fit a new key.

As above, Key steel is usually a LOT softer than the steel of the crank. Woodroffe keys are usually half-moon shaped anyway.

Check for play on the end of the crank (grab the end and wiggle it up and down and in and out, it shouldn't move). I've seen flywheels spin-up or altered pickup clearance (on older bikes, broken points baseplates) because of play in the main bearings.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.
 Back to top
View user's profile Send private message You must be logged in to rate posts

Riejufixing
World Chat Champion



Joined: 24 Jun 2018
Karma :

PostPosted: 14:16 - 18 Aug 2019    Post subject: Reply with quote

Needs pics, as he said. I can't reconcile "The woodruff key was lying on it's side in what was once the slot that it fits in on the end of the shaft. It looks as though it's somehow wriggled loose, and has eroded away at its home in the shaft, leaving a half moon shaped pit where the slot originally was" with an undamaged key seat (and possibly a knackered key slot in the rotor).

PIC, Danonymoose, pics! Smile
 Back to top
View user's profile Send private message You must be logged in to rate posts

Pete.
Super Spammer



Joined: 22 Aug 2006
Karma :

PostPosted: 14:22 - 18 Aug 2019    Post subject: Reply with quote

I've seen moon-crater-like damage from a busted key. Much depends on the extent of the damage.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy
 Back to top
View user's profile Send private message Visit poster's website You must be logged in to rate posts

Danonymoose
Derestricted Danger



Joined: 03 Aug 2019
Karma :

PostPosted: 14:52 - 18 Aug 2019    Post subject: Reply with quote

[/url]https://imgur.com/gallery/SfLTGdl
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Danonymoose
Derestricted Danger



Joined: 03 Aug 2019
Karma :

PostPosted: 14:57 - 18 Aug 2019    Post subject: Reply with quote

There's no play at all on the crank
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Riejufixing
World Chat Champion



Joined: 24 Jun 2018
Karma :

PostPosted: 15:07 - 18 Aug 2019    Post subject: Reply with quote

Danonymoose wrote:

Mmm, lovely. Eurgh!

Go back to post "Posted: 11:41 - 18 Aug 2019"!

Edit: What damage to the generator rotor?
 Back to top
View user's profile Send private message You must be logged in to rate posts

Danonymoose
Derestricted Danger



Joined: 03 Aug 2019
Karma :

PostPosted: 15:16 - 18 Aug 2019    Post subject: Reply with quote

Riejufixing wrote:
Danonymoose wrote:

Mmm, lovely. Eurgh!

Go back to post "Posted: 11:41 - 18 Aug 2019"!

Edit: What damage to the generator rotor?


Sorry, I thought I'd already replied to that comment.

I'll be making some phone calls tomorrow to see who can do what.

I don't know what damage has been done to the rotor. In all honesty, I don't know what I'm looking for, damage wise.
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Nobby the Bastard
Harley Gaydar



Joined: 16 Aug 2013
Karma :

PostPosted: 15:16 - 18 Aug 2019    Post subject: Reply with quote

You need a new crank. That's not fixable. You may be able to get away with finding a crank withe the other end fucked to get the nessecary parts cheap but you are still looking at a crank rebuild.

I'd be looking for a decent rebuilt crank as the cheapest solution.
____________________
trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050
 Back to top
View user's profile Send private message You must be logged in to rate posts

Danonymoose
Derestricted Danger



Joined: 03 Aug 2019
Karma :

PostPosted: 15:19 - 18 Aug 2019    Post subject: Reply with quote

Nobby the Bastard wrote:
You need a new crank. That's not fixable. You may be able to get away with finding a crank withe the other end fucked to get the nessecary parts cheap but you are still looking at a crank rebuild.

I'd be looking for a decent rebuilt crank as the cheapest solution.


That's more or less what I imagined was going to be the case. I'm looking for cranks with a knackered opposite end that I can salvage that half from.
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Riejufixing
World Chat Champion



Joined: 24 Jun 2018
Karma :

PostPosted: 15:27 - 18 Aug 2019    Post subject: Reply with quote

Danonymoose wrote:
Riejufixing wrote:

Mmm, lovely. Eurgh!

Go back to post "Posted: 11:41 - 18 Aug 2019"!

Edit: What damage to the generator rotor?


Sorry, I thought I'd already replied to that comment.

I'll be making some phone calls tomorrow to see who can do what.

I don't know what damage has been done to the rotor. In all honesty, I don't know what I'm looking for, damage wise.


I meant that the advice there is what you need to do.

Examine the slot in the rotor, where it should slide over the woodruff key, and see if it's knackered or whether it's clean and undamaged. I would bet that it is knackered, and I would not put a knackered rotor back on a repaired/replaced crankshaft.
 Back to top
View user's profile Send private message You must be logged in to rate posts

Riejufixing
World Chat Champion



Joined: 24 Jun 2018
Karma :

PostPosted: 15:38 - 18 Aug 2019    Post subject: Reply with quote

https://www.ebay.co.uk/itm/APRILIA-RS125-2T-Crankshaft-With-Seized-Bearing/254333148747?hash=item3b376fde4b:g:k3oAAOSwRn5dDjcS (will need recon)

+

https://www.ebay.co.uk/itm/Aprilia-RS125-Rotax-122-Flywheel-Fly-Wheel-Rotor-Magneto-CDI-RS-125/320827802029?hash=item4ab2d3c1ad:g:2q4AAOxyJ8ZRgeTl

OR:

https://www.ebay.co.uk/itm/apilia-rs125-rs122-122cc-1996-2010-fly-wheel-rotor-AP0295677/273407251109?fits=UKM_Make%3AAprilia&epid=848466574&hash=item3fa85792a5:g:A3IAAOSwhDBZ6Jas

OR:

https://www.ebay.co.uk/itm/APRILIA-RS125-GENERATOR-ROTOR-WINDINGS-ROTAX-122/331722910475?hash=item4d3c39eb0b:g:vI0AAOSwfZ1WXva4


INSTEAD PERHAPS:

https://www.ebay.co.uk/itm/APRILIA-RS125-rotax-122-ENGINE-botttom-end/153555583183?hash=item23c0a040cf:g:EloAAOSw0cVdINiC

"The unknown alternative".
 Back to top
View user's profile Send private message You must be logged in to rate posts

Pete.
Super Spammer



Joined: 22 Aug 2006
Karma :

PostPosted: 15:46 - 18 Aug 2019    Post subject: Reply with quote

If you want to box that up and send it to me I will "try" to weld it up and make a new keyslot, then straighten the taper well enough so that it will run the rotor true. I expect that the rotor is also fairly well battered.

Actually if you send me the crank and the rotor I could try cutting a new keyway in both in a different location. You got nothing to lose.
____________________
a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good Very Happy
 Back to top
View user's profile Send private message Visit poster's website You must be logged in to rate posts

Riejufixing
World Chat Champion



Joined: 24 Jun 2018
Karma :

PostPosted: 16:03 - 18 Aug 2019    Post subject: Reply with quote

Pete. wrote:
Actually if you send me the crank and the rotor I could try cutting a new keyway in both in a different location. You got nothing to lose.

That's a *lovely* offer!
 Back to top
View user's profile Send private message You must be logged in to rate posts

Polarbear
Super Spammer



Joined: 24 Feb 2007
Karma :

PostPosted: 16:08 - 18 Aug 2019    Post subject: Reply with quote

Pete. wrote:


Actually if you send me the crank and the rotor I could try cutting a new keyway in both in a different location. You got nothing to lose.


That's got to be the best/only way to save that crank. Thumbs Up
____________________
Triumph Trophy Launch Edition
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

Danonymoose
Derestricted Danger



Joined: 03 Aug 2019
Karma :

PostPosted: 16:30 - 18 Aug 2019    Post subject: Reply with quote

Pete. wrote:
If you want to box that up and send it to me I will "try" to weld it up and make a new keyslot, then straighten the taper well enough so that it will run the rotor true. I expect that the rotor is also fairly well battered.

Actually if you send me the crank and the rotor I could try cutting a new keyway in both in a different location. You got nothing to lose.


That's an awesome offer, thanks. I'll send you a PM!
 Back to top
View user's profile Send private message Send e-mail You must be logged in to rate posts

redeem ouzzer
World Chat Champion



Joined: 06 Oct 2015
Karma :

PostPosted: 17:25 - 18 Aug 2019    Post subject: Reply with quote

You could get away without the key provided the taper laps in ok but you’d need to use a dial gauge to set the timing when fitting the rotor (proper race ignitions don’t use a key). The key doesn’t actually do any driving, it’s just to make assembly easier.
____________________
Be a REAL MAN!
 Back to top
View user's profile Send private message You must be logged in to rate posts

Easy-X
Super Spammer



Joined: 08 Mar 2019
Karma :

PostPosted: 22:11 - 18 Aug 2019    Post subject: Reply with quote

I don't suppose my usual "a dab of JB Weld will sort that right out" will help...

...I'll get my coat Wink
____________________
Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter
 Back to top
View user's profile Send private message You must be logged in to rate posts
Old Thread Alert!

The last post was made 4 years, 224 days ago. Instead of replying here, would creating a new thread be more useful?
  Display posts from previous:   
This page may contain affiliate links, which means we may earn a small commission if a visitor clicks through and makes a purchase. By clicking on an affiliate link, you accept that third-party cookies will be set.

Post new topic   Reply to topic    Bike Chat Forums Index -> The Workshop All times are GMT + 1 Hour
Page 1 of 1

 
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You cannot download files in this forum

Read the Terms of Use! - Powered by phpBB © phpBB Group
 

Debug Mode: ON - Server: birks (www) - Page Generation Time: 0.10 Sec - Server Load: 0.13 - MySQL Queries: 17 - Page Size: 131.02 Kb