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HiCam Oil Pressure, Gross Stupidity and why you should always listen to Chuck


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Thanks Tim

Looking at some of the comparisons, I think the valve in the bike as of now isn't as good as when I conducted the first test. Whether this is because this valve isn't preloaded (allowing some, or more, float), because the PRV clearances aren't as good or something to do with the lower setpoint I don't know.

Hopefully I shall find out when I change the oil and replace the current valve with the TLM valve and Griso spring (still awaiting the new spring to arrive) which I will preload to 2 or 3mm. The idea being to mess with the valve internals as little as possible

Looking at the first test and the most recent comparitive results are below, obviously nothing is exact here so a little latitude in reading the results is required.

The main points I'm interested in are the 80C readings at elevated RPM. The second test valve has a lower setpoint and given that is the case (around 66-68psi) the idle results are all pretty much in line and way more than required. However the results at 80C 3&4k rpm are pretty stark around a 15psi difference. From what I see pretty much after 2.5-3k rpm oil pressure is constant with revs

Same oil and same cooler (a 13 row, but smaller area, Setrab, with -8 hose and full flow fittings) so the only variable is the PRV. Motul 300V 15/50, full synth lube.

20C/idle 80psi 68psi

40C/idle 70psi 66psi

60C/idle 60psi 62psi

80C/idle 38psi 40psi

80C/3k 75psi 60psi

80C/4k 75psi 62psi

Even as is it stands though its a big improvement over say the 43psi reported on @Lucky Phil thread page 5 by @Kevin_T . If I could get that 13-15psi back I'll be a very happy bunny, but for now at least I can rev it a little without fear of damage

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I think I've now about reached the end of this but wanted to post some more prelim data for now and some more test results tomorrow. Who'd have thought I could spin out a 4 page thread on a bloody spring.

So here's what I've found as a rough guide regarding shimming the OEM valve with the Griso spring. 

Below are 2 results, the first colum is static test data. In other words putting the valve in an oil tester or pumping up the valve on oil, if you use air the results will be different, probably lower from what I saw.

I gave up on using air as a medium the leakage was so bad I couldn't obtain repeatable results. The oil I was using was a 15-50 full synth room temp 18-20C, cold oil for both the static test and the crank test.

When static testing the valve just starts to crack then around 5psi later is well off the seat so it's difficult to pin down an exact lift value, but easy to get a ballpark within 5psi for when the valve lifts

All results psi, shim numbers in mm.

On all of these there was no crush washer or shim on the spring retaining nut on the PRV top, some have these installed others not. IMHO they serve no purpose, however, if they are in place they will subtract from the shim value as the nut will not penetrate as deeply into the valve body and compress the spring

Shim  Static  Oil Pressure

None  80-85     68

1.5     105-110    82

3       125-130    95

I think the results were pretty well linear in behaviour, so as a "Rule of thumb" for every 1mm of shim compressing the spring you'll see 14psi increase in static lift pressure and approximately 9psi on the oil pressure.

Can only base this on my own anectodal evidence, but knowing that no shim gave me 68 and 3mm shim gave me 95, a 27psi difference, 1mm equated to 9psi. 1.5mm should give me pressure in the bike of somewhere around 80-83psi. When I crank tested it was somewhere between 80-82psi.

If you have a facilities to static test by all means do it, you may get different numbers to me, but be aware that the static lift values are higher than what you'll see inside the engine.

The figures here are just what I saw and posted up as a rough guide and starter for anybody mad enough to try it

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  • 2 months later...

I’ve read the heads on these hi cams get very hot. My plan was to have them coated with Swain Tech high-tech coatings

He is the original developer of ceramic coatings and I’m still trying to figure out how to do that and send it off.  I spoke with Charlie Pro 1 Racing Heads and he is interested in doing the work. V twins are V twins and there isn’t a bunch of complications involved in a Guzzi engine.

I am really interested in his Q 4 Head technology. I think a combination of that and high tech coatings. We can get this engine running pretty strong. I like short stroke over-square engines in general. We could do the 100mm bore and leave the crank as is, that’ll get you 1225cc.

I do like the idea of bigger crank bearings. Since you have yours all buttoned up I suppose I’ll be the one to try. 

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That's an interesting way to go @Mikko I'd never really considered, I'm also in the UK so even if I wanted to it's not really an option, although there are quite a few places in the UK who do offer hi tech coatings as part of their range of services.

As you'll have seen a lot of owners have HiCams that run cool, I think I've just got the red headed stepchild.

Where did you get the idea of larger crank bearings, I've never heard of that, or any mods to the crank/rods that I know of.

Some of these engines have been extensively modified, @Paul Minnaert and @Lucky Phil have far more knowledge and skill than me when modding these engines, perhaps they'll chime in

Personally I'm happy enough with the amount of power these blocks generate. I don't have any plans to start trying to tune them, I've enough trouble as it is.

There are mods that can be done to reduce the oil consumption, eliminating the second bearing on the service shaft and converting it to a single bearing stub shaft is one I've heard of, I do believe there are others.

A good place to start if going down that route would be to look at the MGS-01 engine parts book and any other information on it. Modifications were made on that engine to alleviate some of the shotcomings of the original Daytona/Centauro designs.

Good Luck with it, so is your engine apart at the moment then?


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No, it’s in the Centauro I bought from a dealer in Florida. I live in Michigan, he was storing it for me till he sold the place and the new guy said “get it outta here” so now she’s home.  It sat for quite awhile, took a bit of fiddling with it, but she runs really well for 21,000 miles showing on the clock.

The bigger bearing is a Dynotec mod. I wanted to ship the engine there to have them build it. I was quoted $1,200 to Germany and I assume about the same back.  So I am looking here for options. 

I’ve owned a couple very fast motorcycles in my day. 

Thats Eraldo Ferracci and I working on my brand new Tamburini F4. He got her making big power. There was some special parts from MV in that bike that they used in subsequent models. The F4CC is one I know uses the same cams.

Unfortunately, I made the mistake of selling it when MV was in trouble. I have no idea where she is now. I never could sort it out. It was hard to control and it was unruly.

Amazingly beautiful and god awful fast... Jesus...you whack the throttle on that, you best have your things In order.  So really, it’s not that I need nor want that again. An extra 30-50 horses will give me all the artillery I need. Btw, I love those Australia’s.. I seen one for sale and almost..... almost... but I have another MV I’m going to start messing with once my Guzzi is done.

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Thankyou @Mikko, I have 4 bikes but the Ducati 1098 is going, it had more than enough power to scare the Bayjasus outta me.

That'll leave me with the 3 Magnis at my age my riding days are numbered (especially with the Scotish weather) so the 3 of them are more than enough, I'd have loved to get my hands on a Giaponne, but would rather stay married.

Lashings of BHP would only get me into trouble that I don't have the skill to extracate myself from.

The Australia when I first purchased it a good few years back below. I'd hate to sell any of the Magnis it'll break my heart when the time comes. Its an Australia 98, they were built in 2 batches, I think the first were built in 92, using the original Daytona/HiCam engine with a sort of Hybrid frame that's a cross between the Beam and Tonti type frames. The second series used the Daytona RS engines/HiCam 'C' Kitted (almost identical to the Centauro but with slightly different cams) and a beam frame very similar to the one Guzzi used. There are some other smaller differences between the 2 batches and at first glance they're hard to tell apart (engine colour and forks are the giveaway). I believe there were around 130 built in total, Magni's plan was to build a lot more but Guzzi couldn't supply him with the engines/gbxs and running gear.


Good luck with modding the HiCam I'd certainly be interested if you start a thread on what your doing and how it progresses.

As with all of my bikes I'm that useless I just count myself lucky if I can get them to run in factory spec.

I'll settle for the HiCam not overheating, making good oil pressure and remaining oil tight.


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I do.. it’s here: Scura Build my love affair with MV started when I was 16 and went to Italy to live with my Uncle. He had two daughters, no sons. I went as sort of a surrogate to help him with his business.

He is also a big motorcycle nut and one day he took me to a warehouse where he kept all his bikes and cars. He had a MV and a old military Guzzi among all the other stuff.

My life changed when he fired that MV up. I never heard anything like that. It was nuts. I fell in love. Of course I never had the chance to ride anything.. he turned out to be a petty Mussolini type. So after almost a year of indentured service I left and went to  West Germany.

All these years later my cousin calls me and tells me about a old man who had passed away and his family was selling off his things. One of those things was a 750 MV he had dismantled and it’s still in pieces.

I have it here, it’s missing some stuff and I’ve been in contact with Magni about getting the chain drive, and a set of those lovely pipes. 

At the end of the day, my wish is to have a Magni Guzzi and my MV sitting together. 

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  • 2 weeks later...

So finally our esteemed leader lifted our local down last Friday and the weather aligned, so on Monday I could go for a ride after not leaving the city in over 9 months, probably closer to year.

The first thing, science experiment (101), was to determine how the HiCam would behave on the open road in clean air.

Since putting in the Griso spring I also added a bit over a litre of oil to bring the level up closer to the underside of the Roper Plate, prior to this I'd been running at around 1/2 on the dipstick. Trawling through 40 pages of posts on the COG forum looking at oil threads specifically. I discovered the sumps should be filled up to the underside of the Roper Plate, around 10mm higher than the high point on the dipstick (COG quoted figures of 17mm above the high mark on the stick approx equal to the underside of the plate). Yet another lesson learned (thanks @Lucky Phil for posting about this earlier which initially drew my attenion to it).

TBH I'm still a bit sceptical about the broadsump design, my Sporti has the same setup and it tends to run on the hot side as well (not in the same league as the HiCam though).

Anyway, I found with the addtional oil it's a bit slower to heat in traffic, but still too fast for comfort.

Completed over 150miles, ambients in the low 20C. Once running in clear air my pressure varied, typically around 55psi 4k rpm in the 40-50mph region and 60-65psi when running 60mph and above again around 4k rpm. After running in clear air if I did get held up the pressure would drop into the mid 50s or thereabouts, but once back into clear air recover pretty quickly to 55-60 and if extended running I'd get back up close to 65psi. I'm relieved that on the open road the bike runs well and the pressures are high enough for it not to be a concern. Had a lot of fun getting it out into the bargain what a hoot that bike is to ride.

Idling after a clear air run pressure around 15psi at 1200 rpm.

I never got the chance to get data on the temps, but I'd hazard a guess (from experience with pressure and temps) in clear air oil temp is somewhere between 105-115C, high but not excessive enough to cause damage to the engine.

Once back into the city in a 30mph zone for 7 miles (or a bit more) with quite a few traffic lights, but no horrendous snarl ups, the bike was back to its old evil ways and about 2 miles from home was stalling at idle, the heat coming from the engine was obvious. Literally yards from the house the low pressure light came on at idle and revving a little showed the system was struggling to maintain pressure around 20psi as I recall at a little over 2k rpm. Checking the sump temp when I got it in showed 130 C on the gauge.

Going to check tappet clearances and open them up to 0.15 and 0.20 as recommended by Karsten per Lucky Phil's post (page #1) and recheck oil level. I still can't see oil at the base of the Roper Plate, pretty sure it can't be far off though.

I just cannot understand why it runs so hot, I'd heard that these engines have a reputation for it, but searching the COG and on here, all the evidence points to the opposite being true.

Over the Winter I'll be looking at a larger cooler and changing the 15/50 in her at present to a 10/60. The 10/60 will probably do very little but if it lowers the starting pressure and raises the running pressures even a little its all going in the right direction.

Hopefully I'll get it out again this summer to confirm the data


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I just cannot understand why it runs so hot, I'd heard that these engines have a reputation for it, but searching the COG and on here, all the evidence points to the opposite being true.

Weird. Dorcia and I have sat in stop and go traffic at the Daytona bike week and clown show :rasta: with the Centauro for extended periods without any heat related issues at all. I dunno..

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Hi Chuck

Phil thinks the fairing could be at least partly to blame and I do need to get the bike out for a short run without the bellypan to see if it makes a difference

As stated earlier, there is another Australia owner I know and his bike runs cool as well. That bike though has a deep sump (from the pictures though it doesn't look anything like as deep as Vee sump) but the bike is C kitted.

Anyway the fairing is off and I'll check the tappets today and ensure the CO screw is turned up rich inside the ECU box.

Plugs were dry after the run and looked pretty reasonable to me, generally grey, far from white as you'd see on bike running lean.

Guess I won't get to the bottom of it unless I'm prepared to pull the whole engine to pieces and maybe not even then

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I can see where that fairing would not be traffic friendly. Looks like it's reaching for 225 kph just sitting there!


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Agreed @docc the bellypan doesn't have a great deal of clearance at the base either making a Vee Sump impossible.

Add to that the reduced clearance perhaps restricting the ability of the finning to reject heat and the heads also being partially enclosed, won't help either

The other Australia I mentioned is a series I bike and I wonder if it has a more generous belly pan then the series II

Anyway apart from a larger oil cooler perhaps in the Winter I don't think there's much more I can do or check.

Looking on the bright side though the bike is fine once on the open road, but city traffic is to be avoided at all costs.

It is nice to look at though :rolleyes:

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