Both plug models were ok 

morning

Quote from: greenmonster on April 01, 2026, 03:12:29 AM+1.

I`m wondrin how a snapped belt could damage a plug like here?
Usually only causes piston and valve to meet or?

The belt didn't snap. It might have jumped teeth.

Quote from: Juanchojt on March 25, 2026, 06:48:42 AMNew update: The timing belt is intact and appears to be in good condition. Here is the video:

https://youtube.com/shorts/bVtvMjHaBsM?feature=share

The next step is to pull the cylinder head to see what's happening inside.

Regarding the spark plugs: I went to AutoZone, and they recommended the NGK DCPR8E based on my bike's year, make, and model. Previously, I was running Champion RA6HC. Do you think the cross-reference could be the issue? I suspect a piece of the broken plug may have dropped into the cylinder and caused the obstruction/damage.

i have owned my 750ss  along time , but the carbs have always been a little of beat and rear cylinder is hesitant at idle , My other ducatis dont do that ..


The  Mikuni BDST 38s run great above 2k rpm all the way to over 125mph++ but are lumpy a at tickover and rear cylinder is hesitant at tickover until 1500 rpm then its fine all the way to 8k rpm . and always have been for last 20 years but its annoying me , so i have the carbs apart again , they were ultrasonic cleaned twice last year and i rebuilt them with new parts , gaskets ,orings , new emulsion tubes ,new diaphragms , new bypass rubbers ,, etc etc but it made no difference ,, only parts i did not change 5C19 was needles,,, and slow running jets , float height 14mm ,, this is bugging me for many years LOL
 
140 main jets,
70 pilot jet 
1.4 slow jet   
5C19 needles new emulsion tubes
13mm Float height
New airscrews  and Orings etc etc

NO AIR leaks , Engine Valves are perfect etc etc
electrics are also all new plugs , Ht leads, coils pickups etc etc ,,

bike runs lovely but once off idle ,,, I want it perfect like my Monster 750 only difference is M750 has stage 2 Dyno jet ....

+1.

I`m wondrin how a snapped belt could damage a plug like here?
Usually only causes piston and valve to meet or?

Have a good look at the idling system. Idle synch is reported to reset with three runs of cycling ignition on/off.
Idle stepper system can get dirty and cause problems. Access the area via tank removal and clean those components.
Check the condition of the idle breather hose to the airbox.
Oh, and do all the other stuff suggested.

Quote from: Howie on March 31, 2026, 07:04:58 PMThe tube ain't too bad, it's the prep.

I wasn't referring to a butt cam, if that's what you're referring to. That's a whole lot of nothing other than the prep, as you say.

There are other orifices that the medicos like to probe that are far less make the beast with two backsing pleasant.

The tube ain't too bad, it's the prep.

Or you could use the shogun method if you like wasted work and money.  Check for vacuum leaks. then adjust idle speed, set CO and synch.  Still no good, most likely the idle speed motor

I'm not surprised at all.  I went to a dealer and he asked me to put at least 40 miles on the bike.  I mabe did 15.  Great, much better bike than the 750.  I was thrilled to be back and stretched out on my Monster.  I also liked  the 750 more than the 1000.

Welcome!