Subject: Re: Still more on points/timing
Author: Patrick Hayes
Date: Aug 27, 2002, 12:26 PM
Post ID: 1710890924
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In a message dated 8/27/2002 11:55:29 AM Pacific Daylight Time,
arim-@cemrc.org writes:
| The suggested approach was to check the timing on both cylinders and to re-adjust the points gap as necessary to achieve proper timing on both cylinders. |
Firstly, this suggestion can only apply to the Tonti and later Guzzi bikes.
Your loopframe only has one set of points. You can't set one side and then
adjust for the other without upsetting the first.
Well, if the machinist did a perfect job making the crankshaft, camshaft,
gears, distributor drive and distributor lobe cam, then your argument fails.
On paper, once the left cylinder is timed, the right cylinder HAS to be 100%
properly timed. Its all a matter of math and degrees.
Now, throw in the machinists skill level and a normal amount of manufacturing
tolerance for each part in the chain, then yes, only one side will be perfect
and the other side could be off a degree or two. In such a latter case, one
could comprimise the setting between the two and have both sides not perfect,
but not so far off. This was the reason the Tonti framed Guzzi went to dual
points so that each side could be independently perfected. Remember, the
front pulley marks only work for the left side cylinder and there is no way
to time the right side cylinder on a loopframe unless you attach a degree
wheel up front. That's a lot of work.
Why do you think we went to electronic ignition triggers rather than points.
You do all this timing perfection and as soon as the motor starts turning,
there is an infinitesimal but theoretically wear on the fiber lifting block
of the points. Your PERFECT timing is only good for the first few
revolutions of the motor. Sure, it might take 20K miles for the block to
wear completely and fail to open the points, but there is a constant
microscopically measurable change or reduction in your point gap EVERY time
you ride it.
REALITY CHECK. This is an archaic, agricultural history motor. Surely you
jest. I drove an Eldo once of 96K miles on the factory points. I drove for
years with NO timing light. Just loosen the distributor, whack open the
throttle along the road, if it doesn't ping, advance it a little. When it
starts to respond with a ping, then retard it a few degrees. Sheesh, you
guys need to ride a little more.
:-)
Patrick
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<HTML><FONT FACE=arial,helvetica><FONT SIZE=2>In a message dated 8/27/2002 11:55:29 AM Pacific Daylight Time, arim-@cemrc.org writes:<BR>
<BR>
<BR>
<BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">The suggested approach was to check the timing on both cylinders <BR>
and to re-adjust the points gap as necessary to achieve proper timing on <BR>
both cylinders.<BR>
</BLOCKQUOTE><BR>
<BR>
Firstly, this suggestion can only apply to the Tonti and later Guzzi bikes. Your loopframe only has one set of points. You can't set one side and then adjust for the other without upsetting the first.<BR>
<BR>
Well, if the machinist did a perfect job making the crankshaft, camshaft, gears, distributor drive and distributor lobe cam, then your argument fails. On paper, once the left cylinder is timed, the right cylinder HAS to be 100% properly timed. Its all a matter of math and degrees.<BR>
<BR>
Now, throw in the machinists skill level and a normal amount of manufacturing tolerance for each part in the chain, then yes, only one side will be perfect and the other side could be off a degree or two. In such a latter case, one could comprimise the setting between the two and have both sides not perfect, but not so far off. This was the reason the Tonti framed Guzzi went to dual points so that each side could be independently perfected. Remember, the front pulley marks only work for the left side cylinder and there is no way to time the right side cylinder on a loopframe unless you attach a degree wheel up front. That's a lot of work.<BR>
<BR>
Why do you think we went to electronic ignition triggers rather than points. You do all this timing perfection and as soon as the motor starts turning, there is an infinitesimal but theoretically wear on the fiber lifting block of the points. Your PERFECT timing is only good for the first few revolutions of the motor. Sure, it might take 20K miles for the block to wear completely and fail to open the points, but there is a constant microscopically measurable change or reduction in your point gap EVERY time you ride it.<BR>
<BR>
REALITY CHECK. This is an archaic, agricultural history motor. Surely you jest. I drove an Eldo once of 96K miles on the factory points. I drove for years with NO timing light. Just loosen the distributor, whack open the throttle along the road, if it doesn't ping, advance it a little. When it starts to respond with a ping, then retard it a few degrees. Sheesh, you guys need to ride a little more.<BR>
<BR>
:-)<BR>
<BR>
Patrick</FONT>
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