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 Post subject: Re: Cam Timing
PostPosted: Mon Apr 26, 2010 10:40 am 
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Location: Australia
model: 906 Paso
year: 1989
romus
It's great to here you got the job done. :thumbup: I appreciate your feedback and kind words. I rode with the cams at 106 deg for a few weeks and I was happy with how the bike was running and, like you, I found the bike was great around town. It also performed well on the open road,160kmh was what I took it up to and it felt smooth all the way, no sign of pinging. I changed the timing to 110 deg a couple of weeks ago. So far the only noticeable difference is at the higher end rpm, above 6500rpm. The weather is starting to turn colder so the desire to go for rides is fading.I want to try the timing at 114 deg before winter gets here, but I would be happy to set it back at 106 deg,to be cont.........


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 Post subject: Re: Cam Timing
PostPosted: Mon Apr 26, 2010 2:56 pm 
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paso grand pooh-bah
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Location: Hilltown,Pennsylvania
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year: 1990
Quote:
No noticeable difference to air fuel mixture (AFM). I have a gauge showing AFM as I ride and it seems to be reading the same, but I need more driving to be sure.


Hey Warwick,out of curiosity have you tried to adjust your air mixture screws since doing your cams. Wondering if you still have the difference as before or if they can be adjusted in a more balanced fashion ?
Higgy

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 Post subject: Re: Cam Timing
PostPosted: Mon Apr 26, 2010 2:58 pm 
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paso grand pooh-bah
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Location: Hilltown,Pennsylvania
model: 906 Paso
year: 1990
Ken
Your impressions on the different cam timings would make a nice addition to your Timing doc :thumbup:

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Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
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92 907ie


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 Post subject: Re: Cam Timing
PostPosted: Mon Apr 26, 2010 9:42 pm 
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Location: Brisbane, Australia
model: 906 Paso
year: 1990
higgy wrote:
Quote:
No noticeable difference to air fuel mixture (AFM)...
Hey Warwick,out of curiosity have you tried to adjust your air mixture screws since doing your cams. Wondering if you still have the difference as before or if they can be adjusted in a more balanced fashion ?
Higgy

Yes, I am almost the same adjustment for both air mixture screws, now that the cams are timed together. Just a 1/4 more turn for the rear cylinder to account for the bend in the rear manifold.

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 Post subject: Re: Cam Timing
PostPosted: Thu Aug 05, 2010 8:59 am 
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paso grand pooh-bah
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Location: southern Germany
model: 750 Paso
year: 1987
Hi,

a friend of mine is prepairing to optimize his ignition. He would like to correct the ignition timing of the rear cylinder also to improve the engine`s smoothness (which is only possible with some modification). Appearently the ignition timing of the rear cylinder is by 2° less advanced than the front cylinder to reduce thermal load. The pick up bracket seems to indicate this, too. The strange thing is that noone, incl. some Ducati mechanics seem to know about this.
Anyone out there know something ?
Image

G.


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 Post subject: Re: Cam Timing
PostPosted: Thu Aug 05, 2010 11:02 am 
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paso grand pooh-bah
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Location: Hilltown,Pennsylvania
model: 906 Paso
year: 1990
Hey G
Seems to me I remember an article at a tech site about fixing this. I'll take a look tonight to see if I can find it again :thumbup:
If I remember it was an Italian site with a guy using the modified Two plug heads in his cart

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 Post subject: Re: Cam Timing
PostPosted: Sat Aug 07, 2010 5:47 pm 
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paso grand pooh-bah
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higgy, if you find it let me know :thumbup:


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 Post subject: Re: Cam Timing
PostPosted: Sun Aug 08, 2010 11:05 am 
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paso grand pooh-bah
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Location: Hilltown,Pennsylvania
model: 906 Paso
year: 1990
Still looking G :banghead:

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There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie


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 Post subject: Re: Ignition Timing
PostPosted: Wed Sep 01, 2010 11:14 pm 
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Location: Brisbane, Australia
model: 906 Paso
year: 1990
higgy wrote:
Still looking G :banghead:

This is an interesting question. I was wondering about ignition timing.

So far I have done the good improvements on the carb and cam timing. I understand that ignition timing is one of the other factors that should be adjusted right.

What is this thermal load anyway, that they would want to fix it by retard ignition timing for the rear cylinder? Why would it be a mistake to be fixed?

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 Post subject: Re: Ignition Timing
PostPosted: Thu Sep 02, 2010 3:21 am 
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Location: Cleveland O.
model: 907 I.E.
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romus wrote:
higgy wrote:
Still looking G :banghead:

This is an interesting question. I was wondering about ignition timing.

So far I have done the good improvements on the carb and cam timing. I understand that ignition timing is one of the other factors that should be adjusted right.

What is this thermal load anyway, that they would want to fix it by retard ignition timing for the rear cylinder? Why would it be a mistake to be fixed?


I have only heard of this being done on air cooled vee twins that do not get enough air over the rear cylinder to cool it. Is there some one out there with more info?


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 Post subject: Re: Cam Timing
PostPosted: Thu Sep 02, 2010 8:27 am 
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paso grand pooh-bah
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Location: southern Germany
model: 750 Paso
year: 1987
It`s not a mistake that has to be fixed. The engine should run smoother when removing this though. The question is how much thermal load will change.
Some random thoughts: if the timing is not set correctly the rear cylinder may be more than 2° off. Causing the engine to run rough. Some guys report that the engine runs better when the carbs are not perfectly synchronized but adjusted slightly towards the rear cylinder.
A friend measured the degree marks on the flywheel and they are accurate. Hence due to one pickup being 2° off the marks on pick-ups and flywheel don`t perfectly match. Only one mark can. So how do shops adjust the pick up (bracket) ? Considering that noone asked knew about this they probably set the pickup bracket to the "middle" meaning they try to match front and rear marks which in the end causes both cylinders to be more off correct timing.
Btw anyone used a TDC finder to precisely measure if the TDC marks are accurate ?

G.


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 Post subject: Re: Cam Timing
PostPosted: Sun Sep 05, 2010 12:56 am 
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paso grand pooh-bah
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Location: Hilltown,Pennsylvania
model: 906 Paso
year: 1990
Quote:
Btw anyone used a TDC finder to precisely measure if the TDC marks are accurate ?

I still have my old two cycle dial indicator set .When I do finally get around to doing my cam timing I'll let you know what I find
Was planning to work on the bikes today,wife had other ideas :banghead:

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Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie


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 Post subject: Re: Cam Timing
PostPosted: Mon Sep 06, 2010 3:14 pm 
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Joined: Thu Jun 21, 2007 12:00 am
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Location: Gothenburg, SWEDEN
model: 907 I.E.
year: 1991
Quote:
Btw anyone used a TDC finder to precisely measure if the TDC marks are accurate ?


Engineer friend did this on a DB2. TDC mark was just 1-2 degrees off.

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907 I.E. -91
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 Post subject: Re: Cam Timing
PostPosted: Sat Mar 26, 2016 5:36 pm 
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paso grand pooh-bah
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Location: southern Germany
model: 750 Paso
year: 1987
It`s mentioned in the file:

Quote:
BE VERY,VERY GENTLE WHEN ROTATING THE ENGINE WITH THE
PISTON STOP IN AS YOU DON'T WANT TO PUT THE STOP THROUGH
THE TOP OF THE PISTON.ALSO, DO NOT ROTATE THE CRANK A FULL
360 DEGREES WITH THE STOP IN AS THERE IS A CHANCE THAT THE
VALVES MAY MAKE CONTACT WITH THE STOP.

This is specially the case if larger valves are installed or cams with increased lift or like in my case both.


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