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Breather system for SP1000

RKS_DK

Tuned and Synch'ed
Joined
Jun 19, 2016
Messages
32
Location
Denmark, Hadsund
Hi,

Anyone got experince with this system - stein-dinse.biz/product_info.php?products_id=6364
Developed by Dynotec. - theres a german PDF there explaining how it works, and I see some of the big cafe builders use it.

Block the original system and connect a hose to the front cover at the tacho drive connection, lowest point on it connects to the 2 rocker covers. one connection to open air..

I installed it on a SP1000 project bike, lots of oil comming from the flywheel house now, the bike has been sitiing for some years now so i suppose the engine seal needs replacing, but I can't help to wonder if this very tidy system creates more pressure inside the engine than the original system?

Thoughts?
 
I don't see any advantage to this system over the one used on the original 850T. harpermoto.com/breather-box-14145700-use-14155700.html
 
Its stainless for one, removes all the clutter between the cylinders, also the valve is gone.

but the question was really if the function really is good enough venting from the front cover instead ?
 
Its stainless for one, removes all the clutter between the cylinders, also the valve is gone.

but the question was really if the function really is good enough venting from the front cover instead ?


Answer is maybe. However best venting is from the large pipe attached at the rear of the block. Why would you want to give up the tachometer drive?
 
I have electronic ignition, and the cam in it now doesent have the drive anyway :)

It just blows and rediculous amount of oil from the clutch housing, and I was afraid that this venting was the cause..

Guess I can just connect a hose to the valve at the original breather on the block, and still have the return via the rockercovers.
 
I have electronic ignition, and the cam in it now doesent have the drive anyway :)

It just blows and rediculous amount of oil from the clutch housing, and I was afraid that this venting was the cause..

Guess I can just connect a hose to the valve at the original breather on the block, and still have the return via the rockercovers.


If you are blowing oil from the clutch housing, I suspect your rear main seal is failing. Possibly the connections that are at the rear of the block, the upper vent, and the return tube. Return isn't via the rocker covers, but the small tube that goes to the bottom of the block.

Item 37 in this diagram
Upload 2021 2 4 21 54 5
 
For 225 Euros I'd say that it is one expensive box - I don't quite get how it is plumbed. Having a drain to the timing chest might be a good thing but chain wear doesn't seem to be a problem and you don't want to aerate the oil any more than necessary.

If I remember correctly the SP1000 uses the same breather box as the Lemans 1 & 2. The way it came from the factory is not optimal - guzzi fitted two PCV valves between the crankcase and breather box inlets instead of at the outlet.

A PCV valve is necessary to stop hot crankcase air mixing with cold wet atmosphere air causing mayonnaise - a K&N filter as some hot rodders like to do isn't a solution.

The gas coming out of the crankcase is pulsing from positive to negative (depending on the condition of your rings) so you need the valve to stop back flow. The PCV valve should be at the pipe that goes to atmosphere.

If you are in Australia a probably not a problem. If you are in England big problem.

If it uses the frame based breather box there really is nothing wrong with it but it can be improved by packing the frame with stainless steel wool.

If you have the Lemans style box remove the ball bearing valve that is between the crankcase and box, disable the flapper valve in the breather box with a screwdriver and hammer. Pack the box with stainless steel wool (same with the frame based breather) - this greatly improves the efficiency of the box. You can refit the ball valve if it is in the proper orientation - it works on gravity. A duckbill or a spring loaded valve off of a car is better bet IMO. A valve from a high revving four banger is what you want.

The original Lemans 1 had a neat feature - the breather box outlet was directed at the rear tire so you could tell when your rings were on the way out and keep your tire nice and lubed. Very useful.

Stick a catch can on the outlet hose so you can monitor it yourself - an aluminum can of Brio zip tied to the frame is the elegant italianate solution.

John might be right that the main seal is going away but before you dig in check that the big pipe that goes to the main crankcase vent is not leaking and dripping into the flywheel housing.

If it is the main seal then check that the bolts holding the bearing carrier have some sealant on them - some go through to the crankcase - and replace the flywheel bolts with new ones - they are place bolts and should only be used once.

Chris R
 
Also you might want to check how much blowby you have - remove the main pipe and put your finger over the pipe to gauge what is going on. If you want to be scientific fit a rotameter and measure the blow by relative to RPMs. I think the SP1000 came with nicasils so you are probably fine. If your rings are done no amount of breather box capacity will help.
 
Thanks Chris, much helpful.

My SP is a rebuild project and much is changed.(changes listed below)

The dynotec box was smart for me hidden under the tank, return to rocker covers and outlet from the front cover with a 16mm hose- no valve,and a connection to open air. stainless on top.

But I wont take any chances so i fitted the agostini box as recommended and added this valve - hmb-guzzi.de/Back-pressure-breather-valve.
I read somewhere the outlet of it should be kept high along the frame.


82 - SP1000
- new cylinders and pistons
- new hmb cam/ valvedrive (hmb-guzzi.de/Valve-drive-Kit-HMB-D-81-no-drives )
- hmb oil pump
- new timing chain and tensioner
- new phf 36 carbs.
- plastic inlet maifolds phf36
- head reworked including widened ports and new valves etc.
- Ignition System Sachse ZDG3 with dyna mini coils.
- sachse rectifier. new brushes
- motogadget m-unit blue and complete new wiring.
- oil sump extension with external rear oil filter and oil cooler connection (hmb-guzzi.de/Oil-sump-extension-for-oil-cooler-with-rear-external-filter )
- Setrab oil cooler

Probably more stuff :p
 
That sounds a major project.

The agostini box is fine - the bigger the better. I would stuff it with stainless steel wool. The outlet shouldn't be high. it should be low -you need gravity to do its thing.

Glad you weren't tempted by timing gears - the steel ones are the only reliable ones and they are expensive, hard to get and the performance gain is marginal.

I don't think you will need the oil cooler - the guzzi is designed to sit idling in traffic all day. I had one on my racer and removed it because if anything it didn't allow the engine to get to temp quickly and it didn't overheat. If you live in the outback you might need it. The sump extender is definitely useful and looks well made. I designed a windage tray with a crank scraper and anti-slosh baffles - maybe I should have commercialized it.

The biggest performance gains outside of cam and porting is twin-plugging. it will let you set the advance back by 6 degrees or so full advance. You need to recurve the timing.

Also I paid a lot of attention to getting the squish as close as possible. This really helped.
 
Chris, I'm nearing completion- but started in 2016 1.5 years in afghanistan, moving, divorce and all sorts of problems prevented me from working on it.

however it's already running now, in haste i dident replace clutch and main seal, which ofc is leaking now, so I need to get that soreted.

Yeah I regret installing the oil cooler, so much hassle I many times considered taking it off and fit something else, however it has a thermostat that engages at 90c so the engine wont run cold.
The filter sits behind the engine now, which dont make room for the standard H pipe, so thats also an issue to adress.

I asked HMB to twin plug it, but he said there were no real gains on the sp vs le mans for instance, because it has flat piston tops where the le mans has domed.

Read so many bad things on timing gears I dident want to take the chance on that either.

Reliability comes first, but it will be ridden sportively for sure so any gains are welcome.

I consider the breather closed, (will find some wool for the box)
only downside is now there is no room for the Le Mans style airbox, but guess I will find something else...

Next is the clutch/ flywheel... but better make a new thread I suppose :)
 
I don't think the H pipe adds much performance if at all - the front one as on the original lemans cooked the alternator and didn't add power or broadened the power curve. I think the 40mm la franconi's help a bit. there is real power to be found in getting the exhaust right but you need a dyno to do it.

He might be right re the low comp pistons - Twin plugging does make a significant difference with the lemans pistons. It is not a trivial exercise to do correctly.

When you replace the oil seal do check that the bearing carrier bolts are sealed with something like Loctite PST - some of them are through holes and will leak if not sealed. Do replace the flywheel bolts with new ones - they are place bolts and are only one time use. You really don't want to revisit having to split the engine-gearbox. Before you put it together I would pressurize the crankcase to like 5 psi and check for leaks - the original factory service manual suggested that you fill the crankcase with water and pressurize it! Weird!

The clutch assembly is really a matter of taste - if you are going to ride it aggressively you really can't lighten the flywheel enough IMO. There are aluminum flywheels out there - I have no experience with them so can't comment. There was an earlier spline design that has been superseded by a beefier design. I machined my flywheel and the material Guzzi used was a real bear - I went through multiple carbide cutters.

If you haven't already done it I would be thinking about a geared starter - if you have the Bosch starter it will be barely up to the job and requires a big battery. You can save at least 15-20 pounds and improve reliability

So those are my two cents worth...
 
Thanks for the advice Chris,

I have a set of open universal Leo Vince I had from another guzzi, they sound good and it perfomed well with them, however the looks are 90 style so eventually they will go.

I have a new Valeo starter on it.

How do you pressure test it exactly? put pressure on oil filling cap?

Plan is to get the flywheel/ starter gear lightened and balanced.
Complete new clutch assembly.
New main seal, guessing new seal on gearbox input too?

I had bought a Le Mans style airbox as i read it had good performance. however, with the agostini breather box the intake pipe wont fit anymore... was thinking to just remove the pipe and still use the airbox, or is there a better alternative?
 
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While you have the geabox out I suggest you take a look at the input and output bearings. Originally the factory used steel cage 3205 double row bearings, but later changed to plastic cage 3205 double row bearings. I have seen the plastic cage bearing fail, usually on the input. I don't know the year of the change over, just that the old Eldorado used the steel cage, and just about every one after them is the plastic one.
 
'How do you pressure test it exactly? put pressure on oil filling cap?'

How you plumb it is up to you and what plumbing bits you have around - the point is to seal the crankcase and feed in air. I think I linked the head breathers together and fed the air in via the main drain pipe - you will have to seal all the potential leaks like tacho drive etc. Then it is a matter of listening for leaks and soapy warm water. You only need 5psi or so - do not over pressurize.

I forgot to add that the oil return pipe should be shortened if it isn't already - the original one extended below the oil level with the net result that if the crankcase became pressurized it would pump the oil out. The sump extension helps this from happening.

I have a Lemans 5 (and a lemans) not sure if it is same as the box you have. The Lemans five box is good - better IMO than sticking on K&Ns. The snorkel is slightly restrictive and can be improved if you are looking for improvements - I removed it. This may also buy you sufficient space for your breather box? I kept the 'in frame' breather box which I think works very well when fitted with a proper PCV.

John's advice is as ever invaluable - fit the steel 3205s.
 
Thanks both of you.

I send the gearbox in to get checked and ahve seals and bearings replaced.

yes I got the le mans airbox, and was thinking removing the snortkel as you suggest, but an odd problem is the 2 rubber inlet tubes are just 5mm too short to reach the carb.. not sure if it's because they are not originaly or round fins create a light different angle or what?
Will try an bolt something on tthe carbs to get it connected proporly
 
If it's not too late, make sure the gearbox seals are replaced with Viton ones (brown, not blue), they're a lot more durable.
Ref your leak from under the clutch, check the blank fitted to the hole machined for the camshaft, it's above the crank seal housing. They're know to leak and can be sealed using JB Weld metal putty. Replacing the gearbox splined hub with a 4mm deep splined hub is also a good upgrade.
 
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