Damaged piston (VFR400)

[johnnyrod]

It does indeed sound like cobblers. I also fail to see why a valve repair is so cheap compared to a piston repair (whatever that means exactly) as there is a lot of labour in both. Unless it's dropped a valve though it should still run even badly

Bike has always been stored in a garage.
I'm going down to the bikeshop now and will see what they say.

Thanks for responses.

[fastdruid]

On the VFR400 the barrels are part of the cases, so to replace a piston you need to drop the engine and split the cases[1].
To replace a valve you just need to pop a head off which you can do with the engine in the frame. Still not a simple job but far simpler than doing anything with the pistons.

To do the same job on the SV would be a fraction of the cost as the barrels are separate to the cases.

Druid

[1] you _may_ be able to drop the sump, unbolt the conrod and pop it out that way, never thankfully had to do anything like that.

Ok just got back from the shop.The guy doesn't know what's wrong with it.

What he's done is;

He did a compression test. There is some compression, but not enough for it to run.
He thinks it may be a sticky valve, which he thinks he can cure by using a hammer and "gently tapping" it.

He said, if this doesn't sort it, chances are it will be a piston.

Hmph, will look forward to finding out what it is that is wrong.

As said though id imagine that it could run on 3 cylinders, my dads old 400 four got him home on 3 cylingers, the 4th had exited the engine! he he. So I cant see why you would have absolutely no start.

What is happening when you go to start it?

Originally Posted by EssexDave

Ok just got back from the shop.The guy doesn't know what's wrong with it.

What he's done is;

He did a compression test. There is some compression, but not enough for it to run.
He thinks it may be a sticky valve, which he thinks he can cure by using a hammer and "gently tapping" it.

He said, if this doesn't sort it, chances are it will be a piston.

I presume that is on one of the cylinders, not all of them

If its a "sticky" valve, then it would be wise, would it not, to have the ehads off and have everything cleaned, right?

Could it not be a head-gasket (or other gasket) problem? Mind you, my dad had that problem on his VFR, and the engine ran but only on 3 cyl.

I think it is work popping the heads off...its not like its a horrible task, gear-driven cams mean everything just lifts out, no cam chain tensioners etc to worry about and resetting the timing is easy

The starter motor sounds like it's on speed. (faster than normal)
That's about it, it doesn't start, simple as.

Does it sound like the engine is turning over at all?

I'm not sure it's been quite a while since I had the bike, they are taking ages to sort it out. They've had it a week and only done a compression test.

I think it was turning over, but can't be sure.