Rebuilt Cali vintage has a misfire

[lazlokovacs]

Hi everyone,

My recently rebuilt Cali has a small misfire, frustrating.

3 main symptoms -

at idle, tacho needle jumping up and down, or on guzzidiag, numbers jumping as much as 300rpms. I know from experience that the idle can be very smooth on these bikes and that it certainly shouldn't be 'hunting'.  here's a video of a perfectly idling one just for reference https://www.youtube.com/watch?v=k2E-g7Xwg-c

-When I've had the gauges on to sync the TBs I get a jump every so often on the LHS cyclinder.

-While riding, it's a little rough transitioning at just off-idle and there is the occasional misfire.

Work I've done

-full engine rebuild, with all reciprocating mass balanced by HMB guzzi and lightened flywheel.

-running a beetle Calvin specific map   

-correctly baselined TPS and balanced TBs

In trying to troubleshoot this problem I have

-changed coils for new ones
-changed and tested all HT leads, spark plug caps and spark plugs
-changed ECU
- tested for voltage at Relay, this is steady during operation.
- checked injectors unscientifically, as in ran the Guzzidiag injector test and saw a good spray come out of each injector.
-ran the guzzidiag ignition test on all plugs, found a very healthy spark capable of jumping a fair distance on all 4 plugs.
-tested the cam position sensor, got a reading of 745ohms. this may be marginally out of spec.... Anyone know for sure?  (EDIT.... book says 680ohms +/- 10%  so I'm in spec by a margin of 3ohms!...)
-checked correct position of cam sensor.

Still the misfire persists!

Any further ideas gratefully accepted

and... further mystery... After I changed the coils, the problem went completely away, but only for the first 30seconds then back to misfiring. strange.

specific question, anyone out there know how the FI controls the idle speed?

[stratoguzzi]

Wear in the TPS....or just needs a cleaning with Deoxit. I took mine off after I marked its position with a marker. Then flooded it with Deoxit thru the plastic cover. Blew it out with compressed air. Repeat. Put back on paying attention to mark. Success! 

[berniebee]

Keep in mind that a lightened flywheel will exacerbate any missing or left to right balancing issue at idle or just off idle.

[Rich A]

My problem with the misfire on my Jackal was a bad fuel injector, see: https://wildguzzi.com/forum/index.php?topic=111227.0

You might check the throttle bodies to see if there's a lot of carbon build up on one side. You might be able to check that by removing the air bleed screws to see if one side is especially sooty (check how many turns out they are from seated, if any, before removal)

I set the TPS to 150 mV (I think) with all of the linkage screws backed off, then I used the screws and linkage to set the idle (around 525 mV) and balance.

Rich A

[John Croucher]

Wear in the TPS....or just needs a cleaning with Deoxit. I took mine off after I marked its position with a marker. Then flooded it with Deoxit thru the plastic cover. Blew it out with compressed air. Repeat. Put back on paying attention to mark. Success!

The TPS  will come apart easily.  I have seen the insides worn badly in the area the throttle is used most. 

Check spark plug wires and caps.  Start the bike grab a good ground with one hand and run the other hand over the plug wires and caps for voltage leaks. 

[guzzisteve]

The TPS  will come apart easily.  I have seen the insides worn badly in the area the throttle is used most. 

Check spark plug wires and caps.  Start the bike grab a good ground with one hand and run the other hand over the plug wires and caps for voltage leaks. 

I have seen the stock wires fail under load & test fine. Put a timing light on it while running under load to see for sure. The most that fail is the inner set.

[Wayne Orwig]

Maybe the timing sensor is near an ignition coil or ignition coil wire. That may interfere with the signal from the sensor.
Maybe the timing sensor actually is bad. I've never seen one read that far off of 680 ohms.
Maybe the cam chain has too mush slack, or the lightened flywheel is an issue. If the ECU sees anything in the timing sensor pulses that is confusing, it will shut down until it sees a perfect signal. It doesn't want to risk preignition, that can destroy the motor.

[Kiwi_Roy]

When you measure the timing sensor switch the meter leads around and measure it again, it should read exactly the same, if not that's a sign of imminent failure.
As Wayne says 745 Ohms is suspicious.

[bmc5733946]

I think the secondary ignition system sounds fine. I would concentrate on primary ignition, extraneous signals disrupting primary signal, possible timing sensor problem or loose timing chain, the stock tensioner may be overwhelmed by the power of pulses from the lightened flywheel causing flutter in cam gear and hence timing signal. The injectors can be tested out of the manifold with Guzzidiag but they really need to be tested for spray pattern under pressure if possible, look for a diesel injector testing / repair facility nearby.

Brian

[lazlokovacs]

wayne, roy, bmc,steve

thanks guys,

New timing sensor arrives tomorrow, and then injectors will be cleaned later in the week. After that there's not much left to replace!!

I'm running Caruso's steel timing gears up front so flutter not an issue.

Timing sensor does seem the most likely culprit. Let's see.

I believe a failing timing sensor throws some kind of code to guzzidiag (tooth count or something), so will check that as well as soon as it stops raining!

Really appreciate the help guys.

 

[lazlokovacs]

UPDATE

timing sensor made no difference
swapped all the relays for new ones as well, just in case.

That only leaves faulty injectors or maybe maybe sticking valves??

Injectors should arrive tomorrow.

Meantime, if it stops raining long enough to get her warm, I'll do a compression test.

Will let you know.

The spare dellortos in my drawer begin to develop some allure.

[pat80flh]

I've used bottled LP gas, or acetylene introduced around the intake, to try and prove or disprove an injector that isn't passing enough gas . Does a little extra fuel smooth it out?

[lazlokovacs]

thanks for the tip, will try the injectors first and see if there's any change

[lazlokovacs]

compression was good both sides

new injectors went in and....

idle is much more stable and I have no misfires

Been riding her far and wide since....

It's very good to be back on a well sorted Cali!!

Thanks for all your input

[guzzista]

I am curious to find out the actual mileage or if there were extenuating circumstances requiring a   rebuild on the CalVin

[lazlokovacs]

rebuild circumstances

gave the bike to a friend, elvis, who posted on here a couple of times.

oil light started flickering, he ignored it and the engine seized.

bike had 20,000 miles.

On disassembly it appeared that the oil pump sprocket had made it's way off the shaft, woodruff key gone and the the chain tensioner smashed to pieces. This on a stock bike that had never been worked on. 

I posted pictures on this site at the time...

Rear main was welded to the crankshaft, spent 20 minutes giving them heat just to see if I could get them apart but no joy..

Then I bought a Honda CB1100EX thinking it would work as practical transport, but it had the worst engine I've ever encountered in a motorcycle so took it back to the dealers. Looked at the Cali in bits and thought, time to bring it back to life....

I had a fully balanced and lightened flywheel 1100 engine sitting around so in it went.

I'm not 100 per cent sure if I like the lightened flywheel in the Cali. Shifting is so much better, it spins up quicker, but at the expense of extra vibes especially low down in the rev range...  I've only done 2000kms since the rebuild so not qualified to judge yet, time will tell