Czakky’s T3

[czakky82]

Stupid idea on my part. Likely due to my frustration....

Thanks

[s1120]

I would not remove anything from the rod itsself.

[LesP]

I had contact at the cylinder head with the later fat push rods so milled them for just enough clearance, not that that is the problem here.

[czakky82]

I removed a good amount of material from the cylinder. Probably not as elegantly as your heads.

I would recommend that anybody with gilardoni cylinders pop a rocker arm off and check your pushrods next valve adjustment.....

[Antietam Classic Cycle]

Best to check pushrod clearance during assembly.

[czakky82]

Best to check pushrod clearance during assembly.

Even better! Is there a trick to doing this? Not much room to see with everything together.

[czakky82]

I for the life of me can’t figure out why I can’t seem to get a good idle.

Cold start it needs choke for a few seconds or so when it’s 50-70f outside. It will idle great until I go for a ride and come to a stop when it’s all warm. Then I need to blip the throttle to keep it running. Adjusting either the idle speed adjustment or idle air screws has little effect.
I’ve adjusted the air screws many times and always end up in the middle of the range (1.5-3 turns).
Most frustrating is that it will eventually idle when throttle is closed.

Stock bore T3 on points
Individual air filters with stock velocity stacks
Bub pipes
50pilot
142main
Stock (new) needle on second to top clip
Atomiser is new and stock size as well
Individual flip chokes.

Could my ignition coils be weak?
I’ve checked for air leaks at the intake....

[Antietam Classic Cycle]

When did you last retorque the heads and adjust the valves?

[czakky82]

0 miles ago. I’ve tried that a few times. I set the valves at .006/8.

I’m left with a bad top gasket on the carbs...?
Weak coils
or a wrong sized pilot, but it acts like it’s right when adjusting air screws.

[Chuck in Indiana]

(Ahem) Carburation problems are generally ignition..  although it doesn't "sound" like ignition from a few hundred miles away..

[czakky82]

It doesn’t feel like ignition either. I’ll have a couple pilot jets coming (47 and 52) and see if that helps. If not I’ll try fresh coils, but I’m not hopeful....

[czakky82]

FWIW I went through my work again and did a quick and dirty compression test with my thumb and found hardly any compression on the left cylinder. Intake valve was super tight. Normally when setting valves I set them rotate the engine and then re-check. I didn’t do that last time after fresh gaskets.... Lesson learned. Hopefully I can take her out next weekend and test.

[pehayes]

Normally when setting valves I set them rotate the engine and then re-check.

DOH!  New gaskets (either base or head) will dramatically change the linear dimensions of your valve train.  Likely you will need to re-torque the heads and properly re-adjust the valves three times.  First after one or two heat cycles.  Again after about 500 miles.  Again after about 1,000 miles.

Patrick Hayes
Fremont CA

[czakky82]

Will do, I’ve never seen such dramatic changes so quick.

[czakky82]

The whole time I’ve had this bike it made some strange rattle around 6k rpm. I always ride with a full face helmet but a couple weeks ago I decided to diagnose this annoying rattle by riding with no helmet. Low and behold she’s pinging...
I went through the distributor last winter and replaced advance springs, etc.
I did a thorough tune up on Saturday and reset timing/points.
Guzziology shows that the low performance distributor should have full advance around 4200rpm (by memory) but this will advance all the way up to... you guessed it 6k rpm.
I tried retarding the timing and it ran like crap and only pinged a little less at 6k.

New timing chain/tensioner, I always run 91 ethanol free, 145 mains, pods w/internal
stacks and Bub exhaust fwiw..

What gives? could I have installed the springs wrong?

Doesn’t look like any Guzzi mechanically advances past 4500rpm.

[pehayes]

What is the mileage and status of your cylinder heads?
Guzzi does not use seals on the valve guides.  After high mileage, the valve guides wear to an oval condition.  The suction stroke can then pull raw oil between the intake valve stem and the ovalized valve guide.  It takes a VERY tiny amount of oil contamination to cause a dramatic reduction in the relative octane rating of your fuel/air combustion mixture.  Just because  you paid for 91 fuel doesn't mean that your combustion mixture is still 91.  High load pinging is the first sign of impending valve work.  Oil consumption and visible smoke come along much later.  Warm the bike and ride it down a long steep hill will the throttle backed off.  Have someone follow you to see if it generates bluish smoke or stinks like oil at the bottom of the hill.

Patrick Hayes
Fremont CA

[czakky82]

Sorry forgot to mention. Freshly lined valve guides too. Heads are fresh, compression is 150psi both, leak down test at 80psi showed all most zero loss. Piston crowns look very clean.

[moto-uno]

  When you say you retarded the timing a bit , just how much ? Did you use a timing light ? What seems like
a bit at the distributor is frequently much more than you may think it is . After almost a half century of doing
this in shops and on my own bikes , I'm still surprised at how much of a change an almost immeasurable twist of the
distributor results in . And I just bought another timing light to verify the previous remarks . So unless you have
leaner main jets than your motor requires , I'm gonna suggest borrowing a timing light ( if you don't have one ).
As always , good luck .  Peter

[czakky82]

Thanks for the response Peter. When I backed off the timing I had it set to the full advance mark at 6k rpm (when it finally stops advancing). I would say that at that point I had backed off the timing by 3-5 degrees.
Yes do own a timing light.

I guess my question at this point is what would cause this distributor to advance timing so far past its alleged RPM threshold of 4200?

[Chuck in Indiana]

Thanks for the response Peter. When I backed off the timing I had it set to the full advance mark at 6k rpm (when it finally stops advancing). I would say that at that point I had backed off the timing by 3-5 degrees.
Yes do own a timing light.

I guess my question at this point is what would cause this distributor to advance timing so far past its alleged RPM threshold of 4200?

I don't have one sitting in front of me, and my memory doesn't remember much about the Guzzi distributor.. but..it sounds to me like *something* is worn out. It's mechanical after all.. a guy should be able to figure it out with some measuring. Sorry, but that's the best I can do.

[czakky82]

You’re right Chuck... I just wanted to verify if this dizzy isn’t operating correct. I’ve seen ignition curves and read how to check dynamic timing but some say to check at full advance and some say to check at ....RPM. I’ll tear into it again... Waiting on a clutch cable anyway.

[80CX100]

     I don't completely understand the cause/effect as it would apply to your pinging issue, but I've read lots of accounts of owners that have had problems caused by the poor quality of a lot of the new ignition parts available, ie condensers,points and springs.

     Is it possible that the new springs you installed over the winter could be part of the problem not solution?

     Just thinking out loud, fwiw.

     Good luck

     Kelly

[wirespokes]

Thinking this through logically, stiffer springs would delay full advance. If the timing doesn't jump around I don't think wear is the issue.

One way of handling pinging is to smooth out sharp edges in the combustion chamber. The idea is that sharp edges radiate energy that can ignite fuel.

[czakky82]

Timing is as steady as I’ve ever seen a Guzzi or comparable engine. I’m pretty content with the operation of the combustion chamber etc. I’m (rightfully or wrongfully) stuck on the advance. I just don’t know or know why if it’s supposed to advance so far past 4200. Maybe I should post a pic of the timing.

[s1120]

Ive not worked on a Guzzi Dist, so I might be wayyyy off base. I spent a LOT of time recurving automotive distributers though. So could be a few things.. Its advancing too slowly, so its taking that long to get full advance.. or the curve is right... its just advancing too far. It was common to mix and match springs, weights, cams, and stop bushings to get what you were looking for.  Ill say it is strange to me that its only pinging at that high RPM. Normaly you see it at lower rpm when its pulling through a heavy load.

[czakky82]

So I can confidently say that it is advancing too far. As far as if it is hitting the curve too late I am not sure.
Here’s my process
Rebuilt dizzy
Set gap
Set static timing
Checked dynamic, full advance is right where it should be at 4K or so RPM, past that it pulls past full advanced mark and when on the road it will start pinging past 5500RPM.
FWIW the static mark does show up at idle probably a bit advanced but visible in the window.

[Tom H]

I'm not going to re-read the whole thread. Here are some thoughts.

Dual point dist correct? I have not used one, but I read they can be a bear to set up. Get one side timed and then the other is off.

Are you sure your looking at the TDC and the static advance for the correct side?

I'm playing with a V1000 engine. I'm using a single point Loop dist.. Depending on static timing, your full advance will change. For instance my 2deg will give me 33deg full advance. If I moved it up to 5dsg, that would raise the full.

Good luck,
Tom

[moto-uno]

  I'm less convinced that distributor wear is leading to the extended rpm necessary to get full advance.
  Wear ( if there's lots ) , could lead to a rather retarded low speed ignition timing . Assuming , as he has
said , that the full advance is correct.
  But if the spring set is too high a tension , then attaining full advance will simply require more rpm . And if
the timing mark at full advance looks stable , then wear is less likely the problem . I've seen ( years ago ) a
Le Mans 2 with the distributor gear so worn that you could watch the timing at steady engine speed literally
wander in and out of the timing inspection hole . That caused erratic running .
  That the engine at idle responds to low speed mixture adjustments is no guarantee the the idle jet is the
best one for your engine . When I'm in doubt about jet selection I try more major changes (ie; 40 to 45 or 35 )
and it's then easier to sense which direction to go for more fine tuning , small changes are not always so convincing
at the beginning . Keep us posted , this has been one heck of a process ,( having read from the beginning).
Peter

[czakky82]

I pulled the distributor and it looks like the higher tensile spring is a few tenths of an inch too long. I can easily pull it to full advance with minimal resistance. I ordered another new set of springs hopefully that solves it....

[wirespokes]

If the full advance mark is lined up at the correct RPM, then the springs are good.

The problem is the advance weights aren't up against the stops, so can fling out farther (advancing the timing) as RPM rises. I'm not so familiar with these  distributors yet to see them in my memory, so can't tell you how to do it, but you need to take a look and figure out how to stop the weights sooner.