Top end work, 1100 Sport

[luhbo]

...

If the pushrod length is incorrect or the valve seats get deeper after reworking, this symmetry is disturbed. ...

 

Could be things become clearer for all if you'd provide some sort of calculation, or estimation at least, how much offset would be caused by the use of a regrinded camshaft in combination with unadjusted pushrods.

 

Hubert

[raz]

Could be things become clearer for all if you'd provide some sort of calculation, or estimation at least, how much offset would be caused by the use of a regrinded camshaft in combination with unadjusted pushrods.

That would help, yes. I don't know the ratio of the rocker, though I should be able to find that out. I also don't know how much would typically be milled away from my cam, or how much deeper in the seats my valves will sit. I'm beginning to get a better picture in my head but it lacks the concrete numbers. This is more complex than it first appears, though it may be more or less academic (like Gene implied) depending on how much, in absolute numbers, these changes will actually affect things.

 

As far as I understand, the rocker arm angle will be determined by the valve seat regrind, and only that. It can't be adjusted except shimming the rocker plate or modifying the valve stems. Apparently HD sells valves with a 0.76 mm shorter stem, to compensate for reground seats. Maybe that's an indication of what order of figures we're facing.

 

The cam regrind on the other hand, only determines how much of the adjustment screw length will be used. The more it is wound down compensating a reground cam, the more sideway forces will be put to the pushrod cup and adjuster ball. But it will not change the rocker angle. If we want to use less of the screw length, we need either longer pushrods or a milled head/barrel.

 

Again, it may be completely academic but I can see why milling the heads should, in this case, only do good for the geometry while just dropping in the FBF pistons would not.

[gstallons]

If it would make things better have someone (in the valvetrain mfg/sales area) make you some longer pushrods or something (spacer)to drop into the bottom of the lifter that the pushrod can sit on.

p.s. i think all this worry is in vain..............

[Tom M]

Again, it may be completely academic but I can see why milling the heads should, in this case, only do good for the geometry while just dropping in the FBF pistons would not.

 

 

Raz, I'm new at this too but if I were you I'd throw in those FBF pistons, set them level with barrel tops if they aren't already there with the appropriate thickness base gasket, replace any worn parts in the heads and have the mating surface lightly skimmed, regrind the cam and replace the followers, then bolt it all back together. If it pings a bit next summer you can always pull it apart again next winter or later and do all the machining if needed [edit: or put the stockers back in. There are many people out there like Guzziguy and Mal who are completely happy with their FBF pistons, and they didn't do anything to the heads.]

 

FWIW I had absolutely no piston or head damage from the pinging that my bike has had since I got it almost 5 years ago. Winter wrenching projects are better than watching TV!

[raz]

Raz, I'm new at this too but if I were you I'd throw in those FBF pistons

I put out an ad on a local forum so depending on how that goes I may reconcider again Also, just keeping the FBF ones on the shelf is not too bad since I'll almost certainly will own a V11 at some point in the future.

Edit: Damn, a stock piston ring kit is almost 100 €

 

Edit again: Double Damn, need two of them, that's 200 € - what I bought the whole FBF set for.

[motoguzznix]

As far as I understand, the rocker arm angle will be determined by the valve seat regrind, and only that. It can't be adjusted except shimming the rocker plate or modifying the valve stems. Apparently HD sells valves with a 0.76 mm shorter stem, to compensate for reground seats. Maybe that's an indication of what order of figures we're facing.

The cam regrind on the other hand, only determines how much of the adjustment screw length will be used. The more it is wound down compensating a reground cam, the more sideway forces will be put to the pushrod cup and adjuster ball. But it will not change the rocker angle. If we want to use less of the screw length, we need either longer pushrods or a milled head/barrel.

Again, it may be completely academic but I can see why milling the heads should, in this case, only do good for the geometry while just dropping in the FBF pistons would not.

There are two angles to be considered:

The rocker arm to the valve. Can be adjusted by shimming the rocker spindle bracket. At 1/2 valve opening the angle must be 90°. Attention: this changes when the valves seats get deeper or when a cam with a different valve lift is used! This must be adjusted first.

The rocker adjustment screw to the pushrod. Here very similar: at 1/2 valve ópening the valve adjustment screw must be in line with the pushrod.

 

This is not academic. Setting this right makes the valve train work as it should. At first sight the difference won't be big. But after 50 or 100 thousend km the valve train will be in a very different state of wear.

[Slavomir Musilek (R.I.P.)]

I put out an ad on a local forum so depending on how that goes I may reconcider again Also, just keeping the FBF ones on the shelf is not too bad since I'll almost certainly will own a V11 at some point in the future.

Edit: Damn, a stock piston ring kit is almost 100 €

 

Edit again: Double Damn, need two of them, that's 200 € - what I bought the whole FBF set for.

 

search ebay Raz,

 

there is somebody selling new original ring set for 60€ and has some in stock

[Greg Field]

I put out an ad on a local forum so depending on how that goes I may reconcider again Also, just keeping the FBF ones on the shelf is not too bad since I'll almost certainly will own a V11 at some point in the future.

Edit: Damn, a stock piston ring kit is almost 100 €

 

Edit again: Double Damn, need two of them, that's 200 € - what I bought the whole FBF set for.

 

Raz: We've got 'em for $39.95 US per side, so with shipping it'd be about $110 for both sides.

[luhbo]

....

This is not academic. Setting this right makes the valve train work as it should. At first sight the difference won't be big. But after 50 or 100 thousend km the valve train will be in a very different state of wear.

 

Based on what? Experience? Gossip? Academic studies? Come over with some numbers. How much out of balance would the system become if the pushrod was 1mm too short or too long?

You have milled your heads down. How did you address the mentioned problem? Did you shorten the pushrods?

 

Hubert

[Murray]

Reading all this stuff is a bit of a concern my 1100 sport has 120 000kms on it and hasn't been seriously looked at. Raz what made you think it was worn and needed work?

[raz]

Reading all this stuff is a bit of a concern my 1100 sport has 120 000kms on it and hasn't been seriously looked at. Raz what made you think it was worn and needed work?

I suppose I could have just ridden it for another 50,000 kms, or double that, before any real need to fix things. That goes for many other jobs I've done to this bike. I tend to look a little too much because I like to nurse it in winter. Other people buy carbon fiber sprocket protectors, I grind my cam

 

I broke an exhaust stud a couple of years ago and had to shoot it away with EDM. So I had to strip that head and when I did I noticed the guides were worn and springs a tad short. Since then I've planned to overhaul the heads at some point in the future, but no hurry. Then I bought the FBF pistons cheap from Antonio and I figured fixing the heads before replacing pistons would be the Right Thing^TM.

 

BTW, I left my cam at the shop today and he said I caught it so early he will just have to take a couple of tenths of millimeters from it. So it won't change my rocker geometry. But now I'm attached to the idea of milling the head anyway

[luhbo]

....he will just have to take a couple of tenths of millimeters from it. ....

 

That's a lot and probably not a good exercise. Before you let him copy the faults from one lobe to the next: have you thought about putting another profile onto the lobes? Maybe you could get a new, unused V11 cam or one of Scola for some days (of course not from Scola himself) so your grinder could copy it on your camshaft. That's what the Gurus do for 250 or 300 Euros. You've to send them your old camshaft, they give 80 Euros to their associated shop and then send back to you a regrinded one.

 

Hubert

[raz]

That's a lot

That's a lot? Please elaborate.

 

I trust this guy, it will be fine. Changing profile is an idea, but it would mean more material removed or new material added, more work and money and I'm happy with the OEM profile. Hotter cam means more wear and I'm sick of valvetrain wear now.

[Skeeve]

Based on what? Experience? Gossip? Academic studies? Come over with some numbers. How much out of balance would the system become if the pushrod was 1mm too short or too long?

 

Phil Irving.

 

Nothing more needs to be said.

[Murray]

I suppose I could have just ridden it for another 50,000 kms, or double that, before any real need to fix things. That goes for many other jobs I've done to this bike. I tend to look a little too much because I like to nurse it in winter. Other people buy carbon sprocket protectors, I grind my cam

 

I broke an exhaust stud a couple of years ago and had to shoot it away with EDM. So I had to strip that head and when I did I noticed the guides were worn and springs a tad short. Since then I've planned to overhaul the heads at some point in the future, but no hurry. Then I bought the FBF pistons cheap from Antonio and I figured fixing the heads before replacing pistons would be the Right Thing^TM.

 

BTW, I left my cam at the shop today and he said I caught it so early he will just have to take a couple of tenths of millimeters from it. So it won't change my rocker geometry. But now I'm attached to the idea of milling the head anyway

 

 

Righto cheers my bike doesn't get shut down due to winter you would probally argue we don't really get winter here. I am planning a major birthday soonish though.