Engine noise, vertical cylinder

If you need technical information or help with your BOSCH ignition squarecase Ducati 900SS - Darmah engine - post your FAQs, comments & questions here.
Post Reply
Uncle Steve
Cucciolo - the Lil Pup
Posts: 5
Joined: Mon Aug 01, 2016 9:49 pm

Engine noise, vertical cylinder

Post by Uncle Steve » Tue Aug 09, 2016 8:37 pm

Just wondering if anyone has come across this noise before, its a ticking noise predominately from the vertical cylinder, it is not evident at start up but appears after a few seconds or its first rev, it is loudest at idle but not consistant like a tappet noise, it becomes worst as the temperature increases, I checked all the valve clearances and camshafts etc for any play, I checked that both crank nuts and the clutch basket were tight [something I picked up in this forum], I decided it sounded like a loose valve seat so I removed the motor, both heads for inspection and could find no evidence, so I moved down the line, there were no marks on the pistons but very slight movement in the vertical big end in certain positions so I had a crank rebuild, honed the cyls, new rings, new bearings throughout inspecting everything along the way, it started first kick when I put it back together and my noise is still there, a bit of an anti-climax. Listening to the vertical cylinder with a stethoscope the noise is most evident on the exhaust downpipe and around the front of the cylinder head, its in bits again now, I have decided to replace the exhaust valve seat I wonder if anyone has any other ideas?

wdietz186
888
Posts: 677
Joined: Sun Sep 10, 2006 4:40 pm

Re: Engine noise, vertical cylinder

Post by wdietz186 » Fri Aug 12, 2016 6:51 pm

Have you checked the valve guides? They can come loose in the head and bang up and down with the valve when running. Also have a look at the rockers and spindles, extreme wear is very rare unless a closer shim was too thick, have a close look at the cam, if the closer is too tight it will clearance itself by wearing metal off the cam.

Lumpy
SD900 Darmah
Posts: 310
Joined: Sun Mar 25, 2007 4:49 am

Re: Engine noise, vertical cylinder

Post by Lumpy » Sat Aug 13, 2016 1:23 am

Noises can have a habit of telegraphing. That is the noise can be elsewhere and the noise kind of transmits.
You don't mention the bike in question. Reason I mention all this is I saw a similar thing on a friends GTS860 and it was the sprag/chain on his starter motor. Long story short, I had a quick look at the bike for a friend who suspected top end issues but I was'nt so sure. I felt the ticking was lower down. To settle the argument I removed the chain(was quite loose too) and the noise stopped.
I do offer this info a little apprehensively as I personally have never owned a bevel with an electric leg. All mine had the system removed before purchase or never had it at all. So my experience with the system is very limited.

Uncle Steve
Cucciolo - the Lil Pup
Posts: 5
Joined: Mon Aug 01, 2016 9:49 pm

Re: Engine noise, vertical cylinder

Post by Uncle Steve » Sat Aug 13, 2016 12:09 pm

Thanks people, sorry forgot to say 81 registerd Darmah, however the engine is probably earlier, squarecase, electric start. no kickstart, oil level sight glass, I notice also it has two different era cyl heads, horizontal has valve stem seals in the guide and the vertical has the mushroom type, obviously its been played with a lot in the past, I will have another look at the top end components but have not picked up anything thus far, I cant see any movement in the guide, I always thought the starter chain was a bit noisy, I will have another look, thanks for any further thoughts, Steve

Post Reply

Return to “Squarecase BOSCH Ignition Engines > SD, SSD Darmah, late 900 SS & 900 GTS”