Dual-Plugged 1000S, but what about the oil vents?

[Guest bbhflts]

Hi all.

Firstly the Relevent bike specs/mods:

-1991 1000S with 40mm carbs (Tonti Frame) (Lemans V engine for those not familiar)

-Airbox removed and replaced with K&N airfilters

-Twin/Dual plugged by TLM in Holland

-Removed distributor, coils etc and replaced with Silent Hektik tripple spark electronic ignition set on ignition curve 5 (http://www.silent-hektik.com/index.html)

-La Franconi exhausts and headers.

 

I've finally got the twin plugged heads on and the bike running. Unfortunately there is a problem that I didn't anticipate. Now that the oil wells/breathers have been removed from the heads (As a part of the twin plugging process), there are no rocker cover breather tubes to run to the frame cross member. These were the original oil return path for oil coming from the central engine pipe attached to the frame central backbone (See page 5-50 bottom diagram in Guzziology). I was under the impression from reading Guzziology that the oil breathers would be moved in the twin plugging process, not removed. As the central engine oil breather runs to the frame backbone (which is above the two return vent attachments on the cross member), the oil vapour has to go somewhere and it's not a good idea to leave the oil to run out of the old hose connections onto the engine. At the moment I have not plugged the old frame hose connections on the cross strut.

 

Considering that the old breather arrangement worked well and the oil/water vapour needed a way out of the rocker covers, what is the solution for this? I had a look through Dave Richardson's 'Guzziology' and haven't found an answer. I'm worried that if I simply plug the frame connections there will be no outlet for the oil/water vapour and alternatively if I run breather hoses to the road, I will be running out of oil very quickly. I'm also worried about the lack of breathing of the top end (rocker covers) considering that they were designed to breath. The biggest concern is that there will be to much pressure in the rocker covers and this will force oil past the rings. What is the standard solution for this after twin plugging?

 

At the moment I have oil dripping all over the engine. Other than the mess, the potential danger of oil being sprayed onto the back wheel and running out of oil every 50 kilometers, I'm in a bit of a bind:-(

 

TIA.

[pete roper]

So who did the twin plugging? Obviously someone not familiar with the breather system.

 

Look, there obviously has to be a return path otherwise the condensate will simply fill yup the frame until it gets to the breather to atmosphere and blurt out there, at the same time emptying the sump.

 

My suggestion would be to drill and tap the rocker covers to allow the installation of a banjo bolt with appropriate banjo fitting and, because the cover is quite thin, retain it with a nylock nut on the inside. Obviously you have to be fairly careful about where you position the hole as the nut will foul on the rocker gear if it's in the wrong place.

 

The thing is the condensate has to be returned to the engine. Where it goes in isn't that important but prefferably it should be above the level of the oil in the sump. If you don't fancy the drill and tap method you could buy the drain plug/banjo plug and pipe from one of the early Hi-Cams that allows the return of oil through the drain plug. With this though the return is below the sump oil level.

 

Another option would be into the timing chest. Does your bike have a mechanical tacho or an electronic one? If the latter you could drill the old tacho drive boss and run a pipe with a speedflow fitting on the end to that and siamese the returns from the frame, (Or just use one and block the other.) and run them to that.

 

Drill and tap the sump extension to take two banjos. The list is endless. all you have to do is get the condensate back into the case. In fact, I'd think that the last option might be quite good. While it would be returning the condensate to below the level of the oil in the sump at least the casting is good and thick so you wouldn't need to use a lock-nut.

 

Pete

[Admin Jaap]

-Twin/Dual plugged by TLM in Holland

Strange, these guys are doing this for 20 odd years... I would contact/phone them (they speak english) and ask.

 

Teo Lamers Motorrijwielen

Nijverheidsweg 26

6541 CM Nijmegen

The Netherlands

 

Tel.: +31-24-3711111

Fax: +31-24-3711110

 

Email: guzzi@tlm.nl

[Guest mtiberio]

early square fin motors had no breather lines to the heads or valve covers.

these same bikes had only one nipple on the frame crossmember.

this nipple was connected via a rubber hose to a metal hose that ran to the bottom of the clutch chamber, and thru a banjo bolt dumps the oil collected from the frame back into the sump.

 

later square fin motors had two nipples on the frame cross member. these returned oiil to the motor via the valve cover ares. these were not vent lines, but returns.

 

you could add banjo bolts to your valve covers. personally I don't like extra hoses, and don't like this.

 

you could re-install the old round fin and early swuare fin oil return line but this would require pulling the motor out of the frame, and pulling the flywheel. you would also have to cap off one of the frame nipples. I prefer this method.

 

the most expedient method would be to fabricate an oil return that worked thru the dip stick hole. I have seen many racers do this, but ultimately it will compromise the looks of the bike. you cannot simply run a hose to a drilled out dip stick, you must braze a copper or brass tub so the end of the return line is below the level of oil in the sump.

[Alex-Corsa]

Hi all.

Firstly the Relevent bike specs/mods:

-1991 1000S with 40mm carbs (Tonti Frame) (Lemans V engine for those not familiar)

-Airbox removed and replaced with K&N airfilters

-Twin/Dual plugged by TLM in Holland

-Removed distributor, coils etc and replaced with Silent Hektik tripple spark electronic ignition set on ignition curve 5 (http://www.silent-hektik.com/index.html)

-La Franconi exhausts and headers.

 

.................

TIA.

 

 

Here is a resource I have on a twin spark motor. I have marked the position of the Oil-return hose..

P.S. Dunno if it has to be like this in your motor.

 

How about this triple spark ignition thing? Is it working O.K.. I thought this is an 'aid" to be used if you don't have a twin spark convertion!!

Edited December 26, 2005 by Alex-Corsa

[Guest mtiberio]

Where it goes in isn't that important but prefferably it should be above the level of the oil in the sump.

71867[/snapback]

 

 

not so. if the return line is connected to the crankcase, it must be below the level of the oil, or the motor will breath out thru the return, and the oil breather (frame backbone in this case) will fill up and overflow.

 

the only reason oil returns to valve cover area work is because that area is not subject to the pulsations of the crankcase.

[jrt]

Do you really need a return line? The older bikes didn't have one- I thought they returned the vapor through the pushrod tunnels.

[Mike Stewart]

The V11 series bikes do not use an oil return from the upper end as well. Their crankcase vent is at the top of the engine block which then goes to the frame and then the drainback goes back to the sump. Should be easy to do on any older block.

 

Mike

[Guest mtiberio]

The V11 series bikes do not use an oil return from the upper end as well. Their crankcase vent is at the top of the engine block which then goes to the frame and then the drainback goes back to the sump.  Should be easy to do on any older block.

 

Mike

71884[/snapback]

 

from the original 1967 V7 up to the appearance of the 2nd gen square fin breather systems with "2 frame nipples and only return lines to the head", all guzzis had oil breather box return lines that ran from what ever their box was thru an unsealed hole in the top of the dry clutch bell housing then routed thru a metal pipe to the banjo at the base of the flywheel area. Any of the early bikes that had this as well as breather lines to the valve covers (T-on up till 1982) did not use the valve cover hoses as returns. and frankly I have always capped mine off and removed the hoses, it makes maintenence much easier. early round fins had no such valve cover breathers, as they are simply not needed. I raced many round and square fin motors, using no/plugged valve cover vents, just the return to the sump with absolutely no oil pumping or leaking problems. my race bikes were bone dry, they never leaked, nor did they pump oil out the breather. if a bike does that, its because the seal at the rings is poor, and the crankcase is being pressurized by combustion gases on top of piston movement. the breather system can easily handle the crank pressure of a healthy motor, if the motor is sick, than all bets are off...

[Guest bbhflts]

Here is a resource I have on a twin spark motor. I have marked  the position of the  Oil-return hose..

P.S.  Dunno if it has to be like this in your motor.

 

How about this triple spark ignition thing? Is it working O.K.. I thought this is an 'aid" to be used if you don't have a twin spark convertion!!

71879[/snapback]

 

Thanks Alex.

 

Yep, looks like TLM don't put a new return on the heads anymore. There is nothing on my heads like yours. Although perhaps thats the difference between a round fin head and a square.

 

Well the Silent Hektik system can work with single coils for single plug or with coils for dual plugged (the dual plug coil has two HT outputs). The concept of the tripple spark is to get a cleaner burn as far as I know, however the high domes of the high compression heads is still a problem for the flame to travel all the way accross the cylinder I believe. So twin plugging is still optimal it seems. The beauty of the Silent Hektic system other than the tripple spark is that the coils punch out a hell of a lot stronger spark than stock systems and they also have 16 different curves, so you can choose the exact one that's right for your bike. Having the choice of different advance curves was what sold me as I couldn't find any others at the time that allowed you to do this and were customised for Guzzis.

 

Cheers.

 

Ben.

[Guest bbhflts]

So who did the twin plugging? Obviously someone not familiar with the breather system.

 

Look, there obviously has to be a return path otherwise the condensate will simply fill yup the frame until it gets to the breather to atmosphere and blurt out there, at the same time emptying the sump.

 

My suggestion would be to drill and tap the rocker covers to allow the installation of a banjo bolt with appropriate banjo fitting and, because the cover is quite thin, retain it with a nylock nut on the inside. Obviously you have to be fairly careful about where you position the hole as the nut will foul on the rocker gear if it's in the wrong place.

 

The thing is the condensate has to be returned to the engine. Where it goes in isn't that important but prefferably it should be above the level of the oil in the sump. If you don't fancy the drill and tap method you could buy the drain plug/banjo plug and pipe from one of the early Hi-Cams that allows the return of oil through the drain plug. With this though the return is below the sump oil level.

 

Another option would be into the timing chest. Does your bike have a mechanical tacho or an electronic one? If the latter you could drill the old tacho drive boss and run a pipe with a speedflow fitting on the end to that and siamese the returns from the frame, (Or just use one and block the other.) and run them to that.

 

Drill and tap the sump extension to take two banjos. The list is endless. all you have to do is get the condensate back into the case. In fact, I'd think that the last option might be quite good. While it would be returning the condensate to below the level of the oil in the sump at least the casting is good and thick so you wouldn't need to use a lock-nut.

 

Pete

71867[/snapback]

 

 

Thanks Pete.

 

Unfortunately the tacho is mechanical so that one is not an option. I'm guessing that TLM will give me a good answer or have some kind of kit to do the job once they get back from the Xmas break. Still you guys have confirmed my thoughts + added a lot of inovative solutions. Looks like the rocker covers are my only option other than returning the heads to Holland which is a rather expensive option. At the moment the only way I can really ride the bike is to have a bottle sitting where the air tank used to be and feed the hoses into that:-) Then keep checking the oil level and keep topping up the oil and draining the bottle. At least it keeps me mobile for the time being;-)

 

Cheers.

 

Ben.

[pete roper]

not so. if the return line is connected to the crankcase, it must be below the level of the oil, or the motor will breath out thru the return, and the oil breather (frame backbone in this case) will fill up and overflow.

 

the only reason oil returns to valve cover area work is because that area is not subject to the pulsations of the crankcase.

71881[/snapback]

 

I've found the precise opposite to be true Mike! On many machines I've 'cured' excess oil blurting by cutting the return pipe, (As used up to the Mk III LeMans.) off flush with the case so the return is ABOVE oil level.

 

On some bikes, most notably old shiters like my first SP, with an 88mm or larger bore and cast iron liners which by their very nature dont seal as well as Nicasil there is sometimes a problem, especially if the original roundfin Tonti 'Elephants Trunk' air filter and air box is used, of crankcase pressure forcing oil back up the return from the sump until it floods the airbox to the level of the inlet trumpets. When this happens oil is drawn into the motor through the carbs and the motor goes 'BLLLAAAAAAARGGGGG!!!!!! and everything behind you disappears in a white fog First time it happened to me I nearly shat meself!!!! That's the main rason that Guzzi adopted the sump extension on later models, to increase the crankcase volume so the difference between *Max* and *Min* volume was reduced and hence presurisation.

 

The rocker areas are just as prone to pressurisation as the case proper, (well, maybe not *Quite* as much?) because of the oil drain holes through the barrels. Like you, on my roundfins I've pissed the rockerbox breather lines off as their main purpose is to try and discourage the formation of mayonaise in cooler weather, they don't work anyway Guzzi have always been a bit schitzoid about them anyway. Early roundfins didn't have them, then they did, then they disappeared with the advent of the Mk III and T5 and then they returned with the big-valve motor but were also used for condensate return and then with the spineframes they disappeared again so who knows??????

 

Chris Rampen and Kev Foote have both got Mk V LeMans and their system is, (I think?) to remove the PCV valve from it's rather odd place in the crank vent spigot and re-locate it at the end of the breather to atmosphere. This has hepled reduce the ingress of cooler, damp air to the motor and hence elliminated the mayonaise problem. I'm not sure how the condensate is returned????

 

At the end of the day I think we both agree that the condensate should be returned to the motor. Where I don't think really matters as long as a.) the breather box is big enough and b.) the ring sealing and guides are in good condition. Whatever works is fine, as long as it works. In Ben's case the problem is that currently the condensate isn't being returned so he's effectively running a constant loss lubrication system which will a.) Piss the greenies off to the max and b.) could, in extreme circumstances, lead to running the engine out of oil so I do think it should be addressed.

 

Pete

[Guest mtiberio]

====

I've found the precise opposite to be true Mike! On many machines I've 'cured' excess oil blurting by cutting the return pipe, (As used up to the Mk III LeMans.) off flush with the case so the return is ABOVE oil level.

====

 

certainly Guzzi breathers are a bit of a black art. and I could try and come up with an explaination why you see what you see, but why bother, it works. I could see it working with no check valve, with the differential diameters of the tubes forcing the issue...I always toss the check valves as well as a matter of course, I figure if the motor can suck some of the mist back down the exit tube, there is that much oil that doesn't have to come back down the return. no doubt your experience will point to the opposite... 8^)) is this a coriolis thing??? 8^))

 

====

On some bikes, most notably old shiters like my first SP, with an 88mm or larger bore and cast iron liners which by their very nature dont seal as well as Nicasil there is sometimes a problem, especially if the original roundfin Tonti 'Elephants Trunk' air filter and air box is used, of crankcase pressure forcing oil back up the return from the sump until it floods the airbox to the level of the inlet trumpets.

====

 

was wondering how you know this? the stock doughnut breatherbox, which is way tiny, might just be filling up from the normal crank exit?

 

====

When this happens oil is drawn into the motor through the carbs and the motor goes 'BLLLAAAAAAARGGGGG!!!!!! and everything behind you disappears in a white fog First time it happened to me I nearly shat meself!!!! That's the main rason that Guzzi adopted the sump extension on later models, to increase the crankcase volume so the difference between *Max* and *Min* volume was reduced and hence presurisation.

====

 

yup, been there done that...

 

 

====

The rocker areas are just as prone to pressurisation as the case proper, (well, maybe not *Quite* as much?) because of the oil drain holes through the barrels.

====

 

those small diameters offer up hydro-pneumatic damping which I think does keep the pressure down or at least less wildly fluctuating.

 

====

Like you, on my roundfins I've pissed the rockerbox breather lines off as their main purpose is to try and discourage the formation of mayonaise in cooler weather, they don't work anyway Guzzi have always been a bit schitzoid about them anyway. Early roundfins didn't have them, then they did, then they disappeared with the advent of the Mk III and T5 and then they returned with the big-valve motor but were also used for condensate return and then with the spineframes they disappeared again so who knows??????

 

Chris Rampen and Kev Foote have both got Mk V LeMans and their system is, (I think?) to remove the PCV valve from it's rather odd place in the crank vent spigot and re-locate it at the end of the breather to atmosphere. This has hepled reduce the ingress of cooler, damp air to the motor and hence elliminated the mayonaise problem. I'm not sure how the condensate is returned????

====

 

see my coment on check valves, you may want o experiment, but I'll guess you already have... if the V's are like IV's then the return is thru the dual lines to each head.

 

====

At the end of the day I think we both agree that the condensate should be returned to the motor. Where I don't think really matters as long as a.) the breather box is big enough and b.) the ring sealing and guides are in good condition. Whatever works is fine, as long as it works. In Ben's case the problem is that currently the condensate isn't being returned so he's effectively running a constant loss lubrication system which will a.) Piss the greenies off to the max and b.) could, in extreme circumstances, lead to running the engine out of oil so I do think it should be addressed.

====

 

absolutely...

[pete roper]

Replied on WG viz the 'vert headers. The whole system is Mk IV LeMans!

 

Pete

[Greg Field]

I've had two different LM 1000 engines dual-plugged.

 

In both cases, the return lines from the frame were routed to nipples added to the back edge of the sump extender.