Valve damage

husadaddy501 · Jul 12, 2006

Hi Guys
Hoping for a bit of confirmation from you really, recently i was sent some tappet screws of the wrong variety, (dont know how many read the thread). i did enquire about this and was told they would definitely fit my engine. The tappets screws were for a very early berg but i was sent the modern swivel feet crews, after installing the screws i tried to turn the motor to get some adjustment on the tappets but they were in full contact all the way through the cycle, and seemed to get stuck. i sourced some screws myself and installed these, the bike started fine and ran ok, then after riding for 10 minutes the engine siezed, on inspection three valves were snapped.
My question is this, i think that when the wrong screws were put on the bike, when the engine was turned it caused the valves to make contact with the piston as they could not close due to the tappet screws being too long, causing damage to the valves and leading to the failure.... any views on this?

ned37 · Jul 12, 2006

my thought is that if there was enough of an interference problem to be a big problem, you never would have gotten it started to blow it up. i'd look elsewhere but in the same area.

ned

Taffy · Jul 12, 2006

no it's not that as said. there is 5-6mm between the piston and the valves so you didn't screw them through 6mm did you!

no.

try cam timing being miles out or slipping, camchain got loose. what else? try watching the angle at which the valves were opened? did the swivel feet fall off the valve and try and get back on?

lokk at the tips of the valves for trouble!

regards

Taffy

husadaddy501 · Jul 12, 2006

Taffy you dont seem to have grasped my point, yes the tappet screws with swivel feet are at the very least a good 8th of an inch longer than the original tappet screws without swivel feet, if you screw them all the way in the feet are locked to the underside of the rocker arm and no the feet didnt come off i only turned the engine over manually. the cam chain is still fine, the timing is still fine, this engine was only rebuilt less than 1 hour ago by dcr. Dale is probably the only person to help me with this as he's probably the only one to know anything about bergs this early.

dsducati · Jul 12, 2006

I would say for the engine to get stuck when turning it over with the 1/8 inch longer feet, the valves were probably hitting the piston. Hint....If you bent them very much the bike would have been hard to start. So the question is, how hard did you turn it with the valves possibly touching? Hard enough to bend them? And how difficult was it to start after installing the correct screws. Answer those questions and you'll probably have the answer to your first question. If this doesn't confirm your theory, maybe something else happened later such as a cam chain problem like Taffy sugested.

dan

Taffy · Jul 12, 2006

phuqing hell have a go at taff ydoncha?

there is 6mm between the valve and the piston normally. there is no way on this earth you held those valves open 6mm before turning the engine and therefore taking up the gap twixt valve and piston. ok?

for it to run ten minutes i think the valves may have tangkled becasu you had the wrong valve springs perhaps?

more information required.

please look at the top of the piston.

report on;

whether the head and piston have been tapping?
describe the damage to the piston
look into the 4-valve pockets machined in the piston. any sign of tapping here? how many valve springs do you have on each valve?
where did the valves snap? was it just behind the valve head?
describe the break in the valves? clean, around edge ragged clean in middle etc etc etc

you need more sex mate! chill!

regards

Taffy

mikst · Jul 12, 2006

When the valves are open, during the stroke, I have 0.9 mm clearance on the inlet side. I have a FE501-02.

husadaddy501 · Jul 13, 2006

to illustrate, the old tappet screw is above, the new ones below, as you can see the new one is a lot longer than the old, this difference being entirely made up in the foot at the bottom, which obviously is underneath the rocker, the difference is more than 6mm, this would push the valve onto the piston?
The bike took a little longer to start but it did start, it wouldnt rev through more than half revs, i thought this was a carb problem, could it have been a valve?

I wasnt havin a go taff me old mucker i get enough sex from your lass!!!

pics of stripdown ;

see anything interesting?, on the pic labelled inlets touching you can see there has been contact before the failure. On a better note i think i've sourced a new engine so the oldest husey in town may be running again by the end of the week YYYEEEHHAAWWWW!!!

Taffy · Jul 13, 2006

husadaddy

the valves have been hitting the cut-outs in the piston! :cry: :cry:

this will be the cause of your problem then.

i have 6mm gap on the 400 yet mikst has less than the minimum required... which should always be 1mm to 1.5mm.

there you have it!

regards

Taffy

husadaddy501 · Jul 13, 2006

In the words of some old crooner or other...... What a difference a day makes!! from the pics above to this;

I must be a lucky git this week, stripped the engine down this morning, got hold of a lovely working 501 engine this afternoon and got it in tonight, haven't started her up yet as the babys in bed but cant wait while the morning hahah.
Thanks go to DCR, for sorting me the engine out sharpish.

Lplates · Jul 13, 2006

some body works in mysteriose ways
hope i get mine back this week i feel the need for speed

husadaddy501 · Jul 14, 2006

Good luck with that one bud hope you get out soon, like missing a leg innit?

Valve damage

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