Hi
Getting puffs of blue smoke from between magneto and rear of timing case.
I’m sure I put a new mag seal in not too long ago.
When the mag seal is put on is the mag drive/timing gear supposed to press/squash the seal onto the inner timing case to make the seal?
If seal not being pressed up, any solution.
Anyone had a similar problem.
Any advice appreciated
Johnb
Best check you did put a new seal in and it is the correct way round. It is also worth checking that your pinion is also good and has not chewed up the seal.
Might also be worth checking your breather is working as it should, although there's not a lot to go wrong with them.
The gear does not press the seal into the case...The seal should be a light but firm fit into the crank case...However, the cases will often become worn in the seal housing if the bike has been run for any length of time with the mag straps loose resulting in a loose seal....If that is the situation it will need to be remedied...
Assuming the seal fit is good, when the mag is fitted to the mag platform the armature should be more or less in the centre of the seal with the straps fully tightened...Remember here that the mag drive gear mesh should also be correct after fitting...If the mesh is too loose the gears will rattle, too tight and they will whine when running but, more importantly in the case of insufficient clearance, excessive load will be applied to the drive end mag bearing...There should be minimal but clearly discernible play between the gears. Hold the large intermediate gear to prevent it moving when making this check...
The base of the magneto body and the surface of the mag platform on the crank cases should both be flat and unworn (in a perfect world)...If either is badly worn remedial action will be needed to correct everything...If wear is slight a shim(s) can be placed under the magneto to restore correct positioning...Usually it will be found there is slightly more wear at the contact breaker end of both the magneto and magneto platform so check this if you decide to fit shims...
The shoulder on the back of the drive gear is where the seal runs...This should have a good parallel surface along its length with no, or very little wear and/or corrosion...Replace the gear if badly worn... Also, fit a 'modern' lipped oil seal to replace the original type if you haven't already...
If , for any reason, you ever need to slacken the mag straps or if they work loose by themselves always check the gear mesh after retightening...Ian
email (option): ian@wright52.plus.com
Assuming the seal fit is good, when the mag is fitted to the mag platform the armature should be more or less in the centre of the seal with the straps fully tightened...Remember here that the mag drive gear mesh should also be correct after fitting...If the mesh is too loose the gears will rattle, too tight and they will whine when running but, more importantly in the case of insufficient clearance, excessive load will be applied to the drive end mag bearing...There should be minimal but clearly discernible play between the gears. Hold the large intermediate gear to prevent it moving when making this check...
The base of the magneto body and the surface of the mag platform on the crank cases should both be flat and unworn (in a perfect world)...If either is badly worn remedial action will be needed to correct everything...If wear is slight a shim(s) can be placed under the magneto to restore correct positioning...Usually it will be found there is slightly more wear at the contact breaker end of both the magneto and magneto platform so check this if you decide to fit shims...
The shoulder on the back of the drive gear is where the seal runs...This should have a good parallel surface along its length with no, or very little wear and/or corrosion...Replace the gear if badly worn... Also, fit a 'modern' lipped oil seal to replace the original type if you haven't already...
If , for any reason, you ever need to slacken the mag straps or if they work loose by themselves always check the gear mesh after retightening...Ian
thank’s for the description and explanation of how things should work regards the seal and fit.
it seems worse on kick over and start up, will check it all over.
Much appreciated
JohnB
Might also be worth checking your breather is working as it should, although there's not a lot to go wrong with them.
Thank’s for the suggestions, all helps.
Thank’s for the reply.
JohnB
And check that the cylinder nuts are tight
A leak at the rear of the cylinder can look like it is coming from the maggy.
email (option): bsansw1@tpg.com.au
A leak at the rear of the cylinder can look like it is coming from the maggy.
Thanks for the tip
JohnB