griff851
I decided to start a new thread for the engine rebuild and conversion to 888. So far I have put in 34mm inlet valves in the 748 drop cam heads. Cleaned up the combustion chambers and inlet ports. Matched the inlet manifolds to the ports. Fitted new bearings to the crank cases.
7307 2TB x1
7207 2ETN x1
6305 C3 x2
NJ203 ECP C3 x2
NU202ECP x1
6004 C3 x1
Last week I measured the crank for nasties and found it to be perfect except for a 0.015mm wobble at the alternator end, but I'm not going to quibble about that. Journal is 41.998mm. They will be set up with 0.05mm crush, in this case 0.16mm of shim each side. The three bond gasket is given 0.03mm thickness.
Today I began fitting the monster S4 gearbox US$120 (it's close ratio with a 5mm longer out put shaft that the sprocket sits on). The gear end floats were all with in limits except the 3&4th idle gear on the secondary shaft. The book says a max of 0.25mm and I had 0.65mm. I did try to squeeze in another thrust washer (0.5mm) ,but it bound it up, and as I really didn't want to grind one down (I did start to), I left it as it is. I question Blob and he said it would be Ok the oil has to get in somewhere.
So far I have set the end floats. Primary is 0.13mm, secondary is 0.15mm, and the clutch drum is 0.27mm. I have also begun setting the selector forks, with the primary being done first. Its a bit tricky, but easy once you have grasped the idea that the dog gears drag the gear into engagement and you can sit there and look at the way it works. I have 0.07mm clearance on both selections between the fork and slot in the gear with the gear home. So I'm happy about that as well. Next week I'll do the secondary shaft.
This week my other parts should arrive. I'm getting a set of Corrillo rods, and S4/ST4s cams. I was trying to find a set of 996sps cams, but I couldn't be bothered waiting for a cheap set. The second hand cams cost US$120. I believe they will give me the torque increase I want (Thanks Brad) considering the rev range I'll be operating in, and still have enough air going through to get me to 10000 rpm comfortably due to the slightly larger valves.
In the extras dept I have the Ducati performance lightened flywheel, the smaller alternator rotor and the S4 gear selector mechanism and jockey wheel for the end of the drum. An oil cooler from a monster that cost nothing as its slightly damaged. I'm also eyeballing a radial brake master cylinder, but the set up I have works pretty darn fine, compared to an 848, so I don't now about fitting it.
All in all I think it will be an alright package. I intend to run it for a couple of years then fit the 900ss crank I think. That should keep me amused for a while.
Griff
marvin
Griff,
That should be a "snappy" engine with the high compression and those cams! Are you going to lighten the crank? Might as well as you have to balance it anyway. 😁
griff851
Hi Marvin, I'll probably not be lightening the crank anymore than necessary. It is for the road after all, and if it gets too snappy it will just chew through tyres. If that turns out to be the case I'll just stick the old flywheel back on. I was concerned about having to use the steel plates with my MPL clutch, now I tending towards thinking it might be a good thing to get a bit of rotational mass, remembering that handling is effected by removal of rotational mass as well. Lighten the gyros, speed up the turning. If the worst comes to worse I'd have to fit a steering dampener I guess. Last ride I had legs in the air due to a tank slapper at 150kmph in the middle of a corner. Very amusing. 😄
It's just not easy to find the right balance for use, but at least with bits to swap around I can play.
Griff
marvin
Griff,
Remember that your clutch rotates at 1/2 engine rpm so not all that important IMO. I had stock weight crank in my engine with a Nichols flywheel and clutch basket, it wasn't a problem at all.
WolfManSpecial
hey this will be a really fanny motor😄
Mr.R
This all sounds very interesting Griff, please keep the updates coming.
Can you tell us/me the cam timing figures and lift for the ST4S cams?
If my memory is correct the ST4S was basically a 996cc motor with the same size valves as the rest of the 996 range but tuned for more torque than the 996 Bip, which (The 996 Bip) had Strada cams the same as fitted to our base model 851/888's and the 748/916's.
Are the ST4S cams a 1/2 way house between the Strada cams and the 996SPS items?
Or are they Bip or 996SPS cams that are re-timed for more torque?
I'm intrigued...
I'm with you on leaving the crank standard weight for the road.
Super lightweight cranks tend to be OK if your accelerating hard, or using them on the track, but a pain when trying to ride on a steady throttle and even worse on a bumpy road.
It's very tempting when you've got the motor apart and tuning it to go for all out power, but full race motors aren't really suitable for everyday use on the public highway.
Something that I've found out over the years.
In the past i've built some very hot motors for street use only to feel the need to calm them down a bit afterwards.
Full race motors on the road are often slower in use in the real world than Tuned for the Road motors.
It's hard to keep a race motor on the boil, (Keep your licence and stay alive!) by the time you've danced on the gear lever and got her on the cam, the torquey road tuned motor has dissapeared into the next corner and then into the distance on a switch back road.
Steve R
griff851
Hi Steve they are almost the same as standard except the inlet close is at 60 instead of 70. (Thanks Brad).
http://www.guzzi.com.au/performance//camtime4v.html
http://www.guzzi.com.au/performance//monsters4diff.html
Griff
hqracing
Nice project.
I race an 888 here in the Netherlands but cracked up the crankcase last august after 4 years of racing.
Now I'm also building a new engine using the 900ss crankcases.
After rebuild it will have the following mods in addition to the mods 4 years ago:
All 6 interior wheels lightened, lightened crankshaft (done 4 years ago), G cams, lightened flywheel, newly nikasiled cilinders and FBF HC pistons.
Last 4 years the engine produced 116 BHp and I hope to gain at least another 5 with the open mufflers and tangential exhaust.
Racing starts again in april 09 so still way to go before the show opens up.
griff851
Do you have a short throw throttle? An ex TT rider mate I know reckons they are worth another 5 hp on the track. Its a feel thing.
Griff
PS Ernest was a hell of a bloke.!
loony888
balancing the crank will almost be mandatory i would think griff, mainly due to the light flywheel, i fitted one before bevan did the big rebuild and the vibrations were a bit annoying!! add to that the carillo's which are almost 100gms lighter than the pankl steel rods and if you fit aftermarket pistons as well you may as well say there's another 100gms each ( mine has wiseco and i picked them because they had SOME skirt for long life) and your rotating mass will be lighter by well over a kilo at least!!!!! after dynamic balancing of my assembly it's super smooth with no vibration at all and it's very very light, spins up super quick, especially compared to my S4R.
paul.
hqracing
I don't run a short throttle because the engine is already very trigger happy when it comes to throttling up. Last season the rear had a tendency of easy spinning when accelerating out of tight corners.
As for the coming season I'm really curious how the new engine will behave. Mine will ofcourse be completely balanced again as I wouldn't dare to race with it otherwise. I had it balanced 4 years ago that is probably the reason why the engine survived for so long. Usually the rpm's were around 8.000 to 10.500 rpm's most of the time. 4 years ago the cranckshaft was enlightened and pankl titanium rods and new standard pistons were installed.
Now only the pistons are replaced with FBF HC's ones and a new lighter flywheel will be installed.
The max Hp to be extracted from the engine would be around 140 Hp but the engine probably won't survive one season anyway which makes it a bit to expensive. Anyway it's more about riding technique and suspension setup than the horsepower anyway.
Besides I drive two carbon rims which make a hell of a difference even with the magnesium ones which I had before. Accelerating is magnificent as are the turning capabilities. Not one of the strongest points of the 888. However with Ohlins suspension for and aft and letting the forklegs come up as far as possible lots can be improved.
Mr.R
loony888 wrotebalancing the crank will almost be mandatory i would think griff, mainly due to the light flywheel, i fitted one before bevan did the big rebuild and the vibrations were a bit annoying. paul.
The original flywheels on the 851's were balanced seperately from the crank, just bolting on an after market lightweight item without having it balanced would run the chance of having vibration rearing it's ugly head.
I use as a rule of thumb, 'anything over a 2" OD gets balanced'.
I've had my Kamna Racing alloy flywheel balanced with the original centre, also the (Self) lightened alternator rotor.
Steve R
griff851
When changing piston/rods anything over 5-8 grams should be rebalanced I read somewhere. Personally I do it whenever I've had a crank out (Car or bike) because you might as well. Its just one more thing you know is right.
Griff
loony888
Mr.R wroteThe original flywheels on the 851's were balanced seperately from the crank, just bolting on an after market lightweight item without having it balanced would run the chance of having vibration rearing it's ugly head.
I use as a rule of thumb, 'anything over a 2" OD gets balanced'.
I've had my Kamna Racing alloy flywheel balanced with the original centre, also the (Self) lightened alternator rotor.
Steve R
my flywheel was a factory SPS item from a 996. they had the four triggers as the 996SPS ran a P8 so it worked fine, it was less than half the weight of the std 888 flywheel though, thus the vibrations that were felt.
paul.
griff851
Corrilo's arrived today. It pays some times to take a punt on second hand parts. The rods are nearly brand new. The shells on the BE could be used again, and the little end is hardly scuffed. Bargain price of US$400. Which worked out to a little over 2 million in AUS dollars 😁 (Just joking). How much did you pay for yours through Californian cyle works Paul? AUS $1000-1200?
Shopping is definitely part of the fun of these projects. It does take time however.
Griff
loony888
i bought mine direct from carillo and paid $775.63 including freight and converted to the aussie banana,err dollar and that was aug 06.
Speedmade
My mate in Melbourne and I call them "Dingo Dollars"
griff851
Another day of delightful toil today. The secondary shaft and I went into battle. Not as successful as I had hoped due to time restraints. One more disassembly and it will be done. 5 so far, including one where I put it together without the bearing inner attached (The Sales bloke came in telling me about taking a deposit on a Bayliss replica) and another with the same configuration as I started with by accident. A calculator would have been handy to have. I had to use my brain. Scary stuff! Luckily an endless stream of coffee was available.
I also delivered the crank and the flywheel to the balancer bloke who showed me how it all worked. Very entertaining and informative, we had a cool conversation about space age cylinder wall surfaces. Just by looking at it he came to the same conclusion I had. The flywheel needed balancing. The inboard outside edge had been machined down at 45° through the balance holes.
Griff
griff851
Yesterday I got the SP4 crank assembly and fly wheel back from being balanced. The second hand DP flywheel had been lightened more by some lad (45° machined off inboard outer) but not balanced. It was 3 grams out. It weighs in at about 775grams now (Kitchen scales).
No wonder the race engine it came from self destructed.
Piston weight(Standard flat top)-384g
pin-78.5g
rod(Corrillo) LE-106.5g
rod(Corrillo) BE-313g
balanced at 50%
Intended balance range 7-9500rpm
Bob weight 1197g
I've almost finished the gearbox set up. I have end floats within 0.01 of optimal, but I'm not real happy with fork clearances on the secondary shaft. I got a point where I would get 0.076+mm on one side and 0.03mm on the other. Then after mucking around with available shims I managed to reverse that. I gave up about then. I only had 3 hours to play. I really need to lap down a .5 shim to .4 I think.
Next the pistons go off to have the skirts ceramic coated, I'm still debating getting the tops done. This is not helped by the fact that the previous owner had it done. One Piston is fine, the other has had the coating flake off the top and the skirt coating warn away. Something bad went on there. I will chat to coating bloke.
My second hand exhaust valves (4 valves for $50) were a bit dinged on the sealing surface, they have now be lapped and dings removed and I'm in the process of finishing off with 1800 grit compound. They now have a bearing blued contact area of 0.063" with no lip on the the valve. They won't hack another lap and will need to be ground next time.
A spot of bad news, my horizontal S4 cam inlet opening lobe is rooted, it has a nice point on it. I paid $165 for a set, so I'm not unhappy, thats part of doing things on the cheap, sometimes it doesn't work in your favor. Now I have to find another or buy a new one (loathed to do that).
Griff
griff851
As part of the balance, one of the Corrillo rods was lightened at the little end by poofteenths. 1.5-2 grams or something. The process was done with a linisher belt. about 0.003" off the entire end. So in an effort to be good I sent them off to be shot peened. I was in contact with Corrillo and they were agreeable and happy to part with knowledge.(well one guy I found there anyway, the other wanted me to send them the rod so they could magnaflux it. That was a bit odd, he must have been a new guy).
Now have rods that can lead a well balanced and stress free existence. 😄 $70 worth of contentment (about an hours worth of machine shop time).
Next, the great self debate over the pins, using a highly tuned precision instrument. My old dial indicator type verniers, and a swiss army pocket knife magnifying glass, I have come up with a clearance on each of 0.0003-4", 0.0005" tops. They feel good, so I won't be getting out the handy dandy honer device just yet. Spewing bad over that, as I have been wanting to give it a whirl for a while now. I'll use a micrometer next week when I get a chance, to see what the real story is.
Griff
