66HP at rear wheel

Looks thin and small enough to work with Mikunis on a std Laverda frame, me like. Any dimensions for carb spacing?
 
redax5 said:
we have been racing Paul's #63 for 4 seasons and my #86 for 2 seasons with the custom open velocity stacks
we strip both engines at Xmas to prepare them for the next season and with #63 that runs the same set up with the open Velocity stacks as shown in the "pretty picture" all we have changed in the top end in 4 seasons has been two valve shims, she has run 4 seasons on the same pistons, rings, valves and valve seats and still tests at zero leak down

A week has gone by, I can't believe that there have been no posts from any experienced engine builders about letting this post be accepted as fact and influence  the inexperienced members who visit Technical to get good advice.

If a race bike did actually compete for 4 seasons without using any air filtration, and never had any engine components changed as quoted, I would expect to see any coatings originally on the piston skirts to be completely worn away and the piston/bore clearance  excessive. Piston slap would probably be evident. The bores would have score marks all over them. Compression would be down. The pistons would appear sandblasted in the squish area. The valves and valve seats would be in very poor condition.

My experience is this: Starting with a brand new engine having, say, around 1-2% Leak-down and based on the information Redax has provided above, I would expect the Leak-Down figures on #63 to be around 20+%, probably more like 30%.

How is zero leak down possible in this case? 

Please let's hear from some of the more experienced members, without fear, because I, and many others no doubt, would certainly like to know this magical secret of engine building and change my opinion if the evidence warrants it.
 
As stated in another thread, I replaced the pistons in my 3C after about 60000km.  The engine was rebuilt with H-C Assos in 1990/91.  No filter was fitted, only an empty stock airbox.  The engine still felt quite healthy with next to no oil consumption, bike was dynoed at 95hp shortly before I decided to commence my crank and piston rehab.  Liners and pistons look as if they would be fine for the same mileage again if it wasn't for the wear in the top ring groove (the pistons were replaced with 78mm items, I was hoping to fit the Assos to my RGS.  Not going to happen, but thankfully I have a new set of 75.6mm Assos on the shelf :D).  I find the same sort of wear in engines that have run for decades with a filter as well, so nothing really unusual. The engine has led a non-pampered life, with prolonged continental tours and about 10 track days thrown in for good measure.

I'm not at all convinced that filters will effectively prolong piston or bore service life (except if you're crossing the Nullabor on a regular basis). But I do see the advantages of a proper big air box in regard to engine performance.  Decent, flow bench developed intakes are a considerable step forward if space is not available for a proper air box. A filter will most probably protect the cheese-grade Dellorto sliders though.  :D

piet
 
Greg,


I remember being introduced to you at the track about three years ago - it was something I looked forward to, given your success at racing a Laverda over a long period of time, with good success, and the good standing you had amongst the local Laverda riders, on the road and on the track.


However, my introduction to you came as you were being particularly bitchy towards Red over his 750 engine building, and you seemed to display nothing less than total contempt for Red, as if he were challenging you for some kind of imaginary crown.


It disappointed me greatly to see you - with all your history and success - being possibly more competitive, and less respectful, off the track than you were on it.


Reading through the last two posts on this thread that you have made, it appears to me that nothing has changed.


What kind of vinegar are you drinking?  Life is good mate, and Redax and DAM do a lot of good for us Laverda owners.


Yogi



 
Yogi said:
However, my introduction to you came as you were being particularly bitchy towards Red over his 750 engine building,

It disappointed me greatly to see you - with all your history and success - being possibly more competitive, and less respectful, off the track than you were on it.


Reading through the last two posts on this thread that you have made, it appears to me that nothing has changed.


What kind of vinegar are you drinking?  Life is good mate, and Redax and DAM do a lot of good for us Laverda owners.


Yogi
Thanks to everybody who replied.

From my experience Red's claim of zero leakdown is impossible to achieve after 4 seasons of racing, with or without filters.
If Red has any information about how to achieve these figures then we could all benefit from seeing it.

Yogi I have sent you a PM
 
redax5 said:
she has run 4 seasons on the same pistons, rings, valves and valve seats and still tests at zero leak down

And the earth is flat.
It's not about happy pills, it's about entering into a constructive dialogue that is based on known facts. Do a leak-down test.
Forum Members contemplating a decision to remove airfilters deserve more from senior contributors than retoric for the sake of making a contradicting post.
 
rosies barrel after 2 seasons and heaps of dyno pulls-only apart cause i fucked the gear box (or cam chain was a while ago)
 

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OK, something fishy in QLD for sure.
Modus Operandi: When asked to substantiate claims just respond with abuse, well done.

And yes it's getting tedious dealing with the codswallop. Do a leakdown test!

I reiterate here the critical information for the members so they can make an informed decision:
Zero Leak-down after 4 years of racing with no air filtration and where no component has been replaced or refurbished is an impossible figure to quote as a Fact.

Anyone wishing to test their brand new engine at home can find a good single gauge type tester here. https://damclassicracing.com.au/a108-080678-standard-4-stroke-leak-down-tester/ (read the notes on single and dual gauges in the description)

I'm going fishing... South Coast where the fish sizes quoted are real.
 
Leak down tests are pretty much meaningless anyway because nobody knows what they're measuring. Compression tests are more useful.

I'll now sit back and wait for the howls of derision.  :D

 
Here's what I think air filters are good for street however up until the RGS which finally came with a proper paper filter then everything before was more a strainer to keep the big chunky bits out.
A lot of engines have seen a lot of service without considerable wear on the bores or pistons from my experience as long as the oil changes have been kept up to them.
Most often and yep there are exceptions of course and I understand but the culprit for the oil usage and smokeyness is down to the valve guides and on factory built engines no stem seals for the exhausts.

Airbox yep a great idea as long as can be set up correctly for the application as an incorrectly designed airbox can cause more issues that they solve.  There again depending on the application I see a hell of a  lot of race engines which run bell mouths or open carbs in fact Paul found that running Mikes 500 without any bell mouths or filters on it picked up a couple more horses... so its the old analagy which comes to mind here, horses for courses  :o

Also I noted at the last Festival that the worlds fastest Enfield ran the shortest bell mouth I have even seen.

As for the Redax bikes, trust me Greg I have seen the results of the leak down test first hand and can attest that the claims are not frivolous, very impressive, though we need to remember that these engines are built to ultra fine clearances and the fact that they are seeing north of 125 BHP.......the failures mainly have been from the gearbox designed to cope with 2/3rds of that type of power oh and a cam chain when one of the riders decided to give it a "tweak without removing the cover " .I think the pic's of Rosie's barrels show the negligence of any wear present.

Also worth remembering is that these are pure race engines so they are not running on the street. I would never recommend running on the street without some form of filtration, as you need to protect again dust and other particulate matter that is out there in the harsh Aussie environment.
Have a look at a pollen filter out of a modern car  which has been operated for around 12 months or so on the street here in Australia for any length of time.

Apart from the wear in the engine internals which can occur as a result from prolonged use in dusty area's you run the risk of wear on the slides, needles, needle jets and such.
Also well worth remembering that race engines get fresh clean oil on a much more regular basis than do street engines which again helps keep any nasties which do get in there as a result of combustion and such in suspension.

Leak down tests are a great diagnostic tool as long as you understand the principles of them and how to use them correctly. Have seen a lot of qualified technicians not use them correctly, let along do a compression test the correct way. 

https://mobiloil.com/en/article/car-maintenance/car-maintenance-archive/how-to-do-a-leakdown-test
 
Greg Parish said:
Anyone wishing to test their brand new engine at home can find a good single gauge type tester here. https://damclassicracing.com.au/a108-080678-standard-4-stroke-leak-down-tester/ (read the notes on single and dual gauges in the description).


FFS Greg - do you need to keep putting ads up for things you mention in posts?  I think it would be better if you advertised in the For Sale section, like most others do,  Let?s keep the advertising links for our businesses out of threads, or else I?ll start putting links for my work up as well.  By the way, if anyone is looking to spend a few mill on a new floating gin palace, then I?m your man.  I also mow lawns on the Central Coast NSW on the side and used to hold the 350cc lap record at Amaroo Park in the 70s - slowest lap, that is..


Have a good time fishing and let?s pray for an attitude adjustment with regard to slagging off Redax when you come back.  The country is big enough for the both of you, and I don?t think Redax is looking to denigrate you any further than you have done yourself.  You have a successful business and a son setting records - be happy at that before you start to implode.


Lighten up, Greg!


Yogi
 
Thanks Brett,
I'm still here getting my can of worms together.
Very good to finally get some clear thoughts on the subject of filtration or no filtration from someone with knowledge enough to provide concise information for others to decide whether to go open or not, and not degenerating into wanting to stuff fish up peoples' rectums. A very classy post that one.

Don't get me wrong, the Redax bikes are exciting and I said to Red at Eastern Creek how much I liked what he was doing with them. Plenty of racers run without filters, plenty of them with filters too. And I agree the leakdown tests will often be incredibly impressive on new race engines, no argument there, 1% is premium... but the claim of 0, yes absolute zero, after 4 years of racing is still pure exaggeration, totally misleading to those reading this thread and should have been be withdrawn immediately. My goodness it took a long time to get here simply because we got tied up with all the tailenders jumping into bat while the captain who actually made the statement watched them all fall, while remaining silent in the wings. No chance of sensible debate there. I'm not going to comment on what I see in the photos, they prove nothing apart from being photos.

My thoughts for a  still-air airbox to be effective on a Laverda triple it would need to be at least 12-15litres minimum, the bigger the better, hence the spaceframes are perfectly suited to the development of it. The length of the velocity stacks are still determined from the testing, can be nill to 100mm or more depending on carb size, cam timing, exhaust design etc etc. there is no argument about the advantage of an engine sucking still air, that is what is doing in the dyno room, the room is the air-box. It's a totally different scenario once the wind is whipping past that outside carb at 200kmh and the turbulence behind the cylinders. tie a couple of ribbons in there and aim a GoPro at it. But it's still better not to run with an airbox if the volume cannot be made sufficiently big enough.

Carlo is on the dyno next week and it will be very interesting, for me personally, to see how little or how much power is lost with the filters over the bellmouths. He has several lengths to play with from 30 to 80mm and sock filters to try both oiled and dry. Not sure how to get those 80mm stacks under the tank/frame but still interesting for him to compare them.




PS
.... just saw your post Yogi. No problem on not posting links. Others just say, "pm me I've got 30 of them on the bench." and then post photos of them all lined up in rows.
When I post a link there is usually good useful information in the description.

I'm not slagging off, Red posted a gratuitous self-appraising statement that had no basis in Fact, simply to be contradictory. Got my can of worms together. Let's see what Carlo discovers next week.




 
Rivalries are good as long as they are done with respect, does Reds claim make someone decide to send his engine  to him over Gregs? I don't think so, do you guys compete head to head? I guess it would be race wins that might make someone decide one over the other, Win on Sunday ,sell on Monday.
 
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