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Discussion Starter · #1 · (Edited)
I picked up a 999S engine from an individual that had to suffer through a failed main bearing issue. A good person that did not deserve for his dream bike to have an engine failure.

The engine is apart, obviously, and I am deciding what to do.

1) The cylinders were trashed by the skirts of the pistons wobbling with the play of the bad bearing. I may just have 100mm sleeves done and keep them.

2) The end of the crank has some issue, but nothing major. I'll clean it up. I think I may pick up a 748 engine and put the crank and rods in after balancing with HC pistons. That should make for a fun engine. I am thinking of that and putting carbs on. Why? Because.

3) If I can sleeve the cylinders I will stroke the engine with a 66mm or 68mm crank, put in the 848 or XX98 gear drum, and call it an event.

I may have 3 engines by the time this project is done. A stroked 999, a 748 with a 999S crank and rods, and the 996 engine... that I intent to detonate some time next year.

I would like to add that seeing the crank and rods are something beautiful and weight substantially less than base model. There are figures on paper, then the items that feel like they are imbued with helium.
 

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Check the crank is straight.
Replate the cylinders.
Sleeve the end of the crank.
FCR carbs
Bigger intake valves. Stock exhaust valves.
Don’t think hi-comp pistons worth it.
 

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Discussion Starter · #3 ·
Check the crank is straight. ---- Ok
Replate the cylinders. --- I can catch a nail easily. Can a replate fix that?
Sleeve the end of the crank. --- I will find someone that can.
FCR carbs --- Will look into it
Bigger intake valves. Stock exhaust valves. --- For what? The cams? 1 or 2mm more?
Don’t think hi-comp pistons worth it. --- Noted
Response in quote.
 

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Hello Voldemort. :)
Nickasil plating is quite thick. Chances are that it is still salvageable. Note that when they strip the original nickel, the brass welsh plugs need to be replaced. 10mm plugs I’ve heard are hard to find in the US.
While you have the engine apart, 2mm intake bigger intake valves wake the thing up.
Should be able to get 140+ at the rear wheels.
Lighten the original steel flywheel while you’re at it.
If you can juggle the cam timing so it gives more after 10k rpm. You get a broader power spred but at a higher rpm. The advantage of this is you can lower the gearing and still have good top speed.
 

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I rode Brownies bike back in the day when he was developing it and it had that shitfull Haltech mechanical fuel injection. Beautiful handling bike that was extremely difficult to manage, power delivery wise, mid corner and exit. When that was fixed it died in arse at 8k and when we tried get something in between it didn’t do anything well. He tragically persisted with the damn thing and I refused to ride it. I think we had a bit of a falling out after that and never rode it again. Before that I did manage to do a few laps on his “750” F1. Beautiful little bike. I’ve ridden plenty of FCR fitted Dukes but still think that they are a bit pricey for what you get. CV’s aren’t that far behind but more difficult to tune without the airbox.
Sorry about the trip down memory lane.
 

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Discussion Starter · #7 · (Edited)
The nut that holds the primary belt drive gear is the same nut that holds the gears onto the cams, correct?

If there is not a performance difference between sleeveing the cylinders versus re-Nickasil, it'll sleeve since it is more convenient.
 

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Discussion Starter · #9 ·
I will.

To answer my own question, the primary belt drive gear nut is not the same size as the cam shaft gear nut.
 

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‘05 749R, ‘89 851/926, 749R/999RS project
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Discussion Starter · #12 ·
I gathered as much without really looking. I am am awaiting feedback on the compatibility and life of the OEM rings in sleeved cylinders.
 

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Let's see some pictures when you finish the project! I wish I had half of your mechanical skill!
 

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Discussion Starter · #14 ·
Let's see some pictures when you finish the project! I wish I had half of your mechanical skill!
I certainly will. I'll provide you with more details as well. Work and and family slowed things a bit this week.

For now, I plan on stroking the engine to 66mm or 68mm. Do a proper cleaning, replace the main bearings, and replace or sleeve the cylinders.

For the crank, I'll have it fixed if it can be fixed and put in a 748 engine that I'll build a bike around.
 

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Evening Jonathan. If you’re going to stroke it and you are using pankel rods you may want to check the rod to layshaft clearance.
 

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Discussion Starter · #17 ·
Evening Jonathan. If you’re going to stroke it and you are using pankel rods you may want to check the rod to layshaft clearance.
The Pankels will stay on the OEM crank. I'll use stock rods on the 66mm or 68mm crank. Given that each rod bolts is $150 and a one time use bolt, they will stay where they are. I'd pick up Carillo first. Lay shaft clearance is an issue, and if I was going to go the Pankel route I think the shaft would have to be machined down a small but for clearance. Thanks for the notice.

Honestly I am not sure that an engine worth to be repaired in stead of just buying a used one
No mistake about that if I wanted to keep it a 999S spec engine. As is, I should come out ok.
 

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Discussion Starter · #18 ·
I haven't looked into it because I am lazy. Are the valve clearance check on the Testastretta different from the Desmo? Easier, yes. But is the method different b/c they are all over the place on this engine.

Every last one of the openers are tighter than the closers, I would like to know that I am doing something wrong.
 

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Discussion Starter · #19 · (Edited)
When checking the preload should the primary gear with the nut for that side be properly torqued for proper measurement? Or is it correct to let the crank sit freely with the cases mated and measure? First measurement on assembly is .5mm. Too tight, crank sitting freely in the bearings.

Only other time that I dealt with this was swapping the transmission in The Time Machine, and the crank remained tight on the primary gear side. I shimmed the crank down to .15-2mm b/c it was sitting around .25-.3mm if I recall correctly. 10k miles on the bearings.
 

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why would you have the primary drive gear nut on when checking crank shimming?

valve clearance check is poke feeler gauges between cam and rocker. it is what it is, don't try to make sense of it, just fix it.

i wouldn't sleeve a cylinder. nikasil is great, cast iron wears.
 
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