Jump to content

Sherco help for a newbie


bluegnu
 Share

Recommended Posts

 

Yup, looks like it's been severely neglected.

I don't think the pipe is blocked, it looks as though its been burnt at some point! Although I hadn't realised this was a breather, in my ignorance I'd assumed it was an overflow, so I'll check that's not blocked either.

When I took the impeller off to change the seals the washer behind it was completely shot and you could see where it's been leaking.

However, I could not begin to shift the bearing out of the case to change the seal on the inside

 

IMG_1700.JPG

IMG_1701.JPG

Link to comment
Share on other sites

 

You were spot on Oni Nou!

The woodruff was cleanly sheered when I finally got the flywheel off.

Got a couple on order now and will try retarding the timing when I get the parts.

TBH there's not a lot of room for manoeuvre as the backing plate is already rotated very close to edge, but should be enough to give a few mm.

It was pretty well caked in crud as the cover hasn't been sealed very well, there's also a tiny bump in the case where it's been hit that lifts it slightly.  

Looking forward to getting it running again :)

IMG_1718.JPG

Link to comment
Share on other sites

 

If you look at the top slot there should be a line punched on the stator, rather than retarding the ignition I would line that up with the edge of the casting which is standard position & see how it goes. Mark looks a long way from where it should be

The earlier ignition covers with built-in sprocket cover never sealed right, they distort basically right in front of the sprocket & throw chain flings water through the gap. I changed to the 06 on cover as soon as they became available & haven’t had a problem since, use sealant instead of the original o-ring to maximise benefit

Edited by tony27
Added detail
Link to comment
Share on other sites

 

Agree with tony27, set timing to standard and work from there. You have discovered one problem in the woodruff key, don't create another unnecessarily.

Also, if the woodruff key is sheared then it is possible the flywheel nut has not been torqued properly in the past. Woodruff keys are not intended to stop the flywheel rotating on the shaft, they are to allow correct alignment of the flywheel relative to the stator for correct ignition timing. It is the tightness of the tapered boss in the flywheel mounted on the tapered shaft and tightened to the correct torque setting that ensures the flywheel turns with the crank. It is a good idea to ensure the condition of the mating tapered surfaces is good (smooth without scrapes etc), spotless and free of oil etc before refitting the flywheel to ensure the proper tightness is achieved. Can't help you with the torque setting though...Splat Shop maybe?

Good luck.

Link to comment
Share on other sites

 

If you suspect the tapers are not as good as they should be, lap them together before finally re-assembling. Leave out the key, smear som grinding paste on the shaft taper and then oscillate the flywheel on the shaft. After a few seconds of that you can wipe the paste off and inspect both tapers. If they're a nice even grey, the job is done so just get on and assemble. If not, put more grinding paste and work away until you have got to near 100% contact between the two tapers.

Link to comment
Share on other sites

 

Thanks for all your input chaps.

I cleaned up the stator and housing, aligned the mark on the back plate with the right edge of the mounting and off she went!!

You can't see from my picture but the mark is just to the right of the mounting nut, about 5mm from the edge.

It took some kicking the first time, but I suspect I'd flooded the engine again.

On the whole, she runs a lot more smoothly and the exhaust is no longer melting hot. Mix screw is around the 3.5/3.75 turns with idle somewhere around 3.

But with the new reeds and correct timing the pull is immense, although a bit scary and jumpy - had me clinging on for life a couple of times  : |

I was hoping to try retarding the stator in order to make starting the bike easier and give a bit less bite.

Next job though is a new thermostat, because the fan is only running for a few seconds when really hot and keeps stopping.

Parts ordered for the weekend :)

 

 

Link to comment
Share on other sites

 
  • 3 weeks later...

As luck would have it, I came by a very clean looking stator plate and a few other parts (clutch housing inc. pump and a pristine radiator inc. hoses). 

 

IMG_1719.JPGIMG_1732.JPG

Edited by bluegnu
Link to comment
Share on other sites

 
 
  • 1 month later...

I'm still unsure about some engine tapping/rattle.

Starting it is a lot better since replacing the stator, also a lot less unpredictable on the throttle I think (unless I'm just getting used to it)

I'd like to get the cylinder off to see what condition the piston is in - but if I get in there, wondering if I should replace piston rings as a matter of course.

Or, if the piston is looking badly worn, am I better off just saving for the piston kit?

I imagine if there's not too much play in the piston I might get away with a top end bearing and rings.

How frequently do these things need doing, on a bike of this age, depending how hard it's been ridden?

 

In the meantime, going to swap for a Slow Action throttle because it is far too sensitive...  :)

Link to comment
Share on other sites

 
  • 2 weeks later...

Thanks for the encouragement and guidance.

I've not had time or courage to tackle taking it apart yet...

For the most part she's running well and the slow action throttle makes a hell of a difference.

What is strange is starting from cold with choke is often first quick, but restarting when hot can be a bugger and take many kicks with throttle open!

I also found the intermittent fan was down to a loose connection between the thermostat :facepalm: (now bypassed)

Maybe tackle the cylinder this weekend, cautious about causing more harm than good.

Link to comment
Share on other sites

 
 
  • 2 months later...

Can anyone tell me why the exhaust header pipe I just got on a well-known auction site has a narrow neck where it joins the cylinder?

First I thought it was from a smaller CC, but looking at other ones online I've seen them advertised from the 290cc. My bike goes well with it on but will it overheat?

 

IMG_1966.PNG

Edited by bluegnu
Link to comment
Share on other sites

 

I finally lifted the cylinder head and it wasn't as bad as I'd feared (pictures below)

The piston and head were completely caked in carbon, so obviously hadn't been open for a very long time, but once cleaned off didn't look bad at all. It's probably the original piston!

 

IMG_2014.JPG

IMG_2016.JPG

IMG_2017.JPG

IMG_2018.JPG

IMG_2019.JPG

It looks like it's taking in too much fuel judging by the residue in the cylinder and on the spark plug?

Edited by bluegnu
  • Like 1
Link to comment
Share on other sites

 
 

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
  • Create New...