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Let's keep twostrokes smoking.....
The pipe, smell and sound
So i thought maybe you like to see how my coned pipe got made:
Usually i use italian Messico exhausts as they proved to offer best performance with my Mugen engines. I have tried a lot of different exhausts but the italian beauty simply offers the best package: awesome mid and top with great overrev.
I have a total of 13 exhausts for three 125cc Hondas...not a bad collection
So since i will stick only to the best the others will collect dust hanging on the wall...i won't use the others again since i now have 3 Messico pipes which already look awesome:
BUT - i still looked for that special coned pipe. Problem is Scalvini pipes don't perform. I was lucky to got to know a young Italian though italian MXBars forum. That guy was doing such coned pipes upon demand. I asked if he would do me a coned pipe for my bike with the measures of a Messico and he said "no problem" since he too had a CR 125 and also used a Messico before. So he had it on hand to take measures. I further asked him to change shape so i would be able to mount that exhaust not only on the '90 VRP but also on my current AF bike with the CRF chassis. That bike has the radiators sitting lower than the old VRP therefore the exhaust needed to have a different bend. After some measuring and sending pictures of my modern bike he started my custom exhaust:
Computer drawing:
Cutting all the segments (there's another pipe on that same sheet)...looks like a puzzle
Laid out:
1st step are some cones:
Backjard workshop:
Some details:
It starts to look like a pipe:
Custom handmade by a 19 year old...Italian Cristian Massaua is the man who did this MRP pipe (Massaua Racing Pipe)
I just like the look:
And here's how it sounds:
If you sound closely you can detect that irritating sound off the vibrating glide plate i mentioned before. It was when i did this video that i detected the glide plate beeing the reason for the annoying sound which basically ruined my day on the 1st outing with the rebuilt VRP.
His VRP is the '89 version with the mentioned aluminium airbox and gas tank with the funnels. We were just now discussing if we could do a vintage race together in the north of Italy...i hope i can join the championship for just this one race.
It's CR 125 Mugen VRP alu frame ( Frame , Subframe/airbox, swingarm and alutank )
The Shop
The head of my kit is not changed so they must have used either a lower piston or a shorter conrod to avoid the piston hitting the head. So then the port timing would be identical. Rinaldi used to lower their cylinders aswell and use a lower piston. Then maybe they did this was to get lower crankcase volume?
Acerbis made special front number plates for the vented VRP fuel tanks:
It's wp 4054 adjuster front fork , Alu work tripleclamp, Ohlins rear shock.
Anyway, I shimmed up my cylinder with thicker gasket material to standard height and it runs great! Big difference compared to stock. For comparison it runs pretty similar to my stock YZ 125 97. Though I have not all the mods that you have Nino. I run stock carb and exhaust valve, Boyesen rad valve, HGS pipe and ported intake (wider).
that's exactly the numberplate i was running back then
Anyway: i didn't perform such drastic modifications. I concentrated on getting the best performing setup from intake to exhaust.
When you say you still use stock carburetor and stock valves i can tell you that you miss a whole lot of ponies hidden in there.
A bigger 38mm carb let's it breathe a lot better and adds a healthy dose especially mid-top. I also tried a modern PWK Air Striker carburetor everyone raves about but i still haven't found a carburetion that can match the performance of my 23 year old Keihin PJ
HPP governor with the two shims that get added:
Modified HPP governor with added preload for later opening of the valves:
You can also change opening timing by installing those adjustable HPP covers by Wirtz or HPR. But those springs are a little weak and only allow for smaller changes but this way it's done easily on the track:
Wirtz HPP cover
On the intake side i use either Mototassinari VForce3 or lately a heavily modified Boyesen RAD. The stock Boyesen RAD reedblock had really ugly edges around the rubber collector between carburetor and the aluminium casting. I got rid of that by cussting the whole thing off and instead adapting the stock rubber collector to it.
A look into the stock Boyesen RAD reedblock...note that ugly edge all around
My modified Boyesen RAD. Also note the extremely rough inside. Instead of peoples believe a rough surface actually helps airflow (Golfball principle):
The Boyesen this way adds in the middle without any downside elsewhere when compared to the VForce3.
As far as the HPP valves are concerned you might try those off '98/'99 models as they definitely offer the best performance of all HPP valves. They have that L-shape which makes for a much better seal when closed thus improving low-end and when compared to 90-92 the guides are much slimmer which improves top-end dramatically.
1998-1999 HPP valves&guides. Note the L-shape which makes for much better seal right where the red arrow points to.With older valves you usually have a opening there where exhaust gas blow by. These valves fit in ALL HPP engines and really make a difference (also on my Mugens):
Once its on the pipe, it really pulls like a train.
Newmann - was it you the had the on-the-line bike?
That was an epic machine, I think everyone still wishes you had it.
Checked out the Messico pipe online and there are 2 different versions. Is there any difference i performance between the two or is one of them just a nicer build with finer materials?
Regards Marco
I'd rate the FMF Fatty pipe second. The Messico has just a little more mid-top. Bolting it on is like waking up of the engine.
Regarding the weight the Messico is also lightest and combined with the DLR silencer below we look at almost 1 lbs of weight saving.
Messico exhaust:
I actually don't like the Messico silencers too much. Performance-wise there isn't a whole lot to be gained with a silencer anyway and i tested a lot of them as well. A winner was the italian DLR. (Di Leone Racing). DLR was THE silencer used in MotoGP when they still raced with twostrokes. All Aprilia factory bikes had them as well as many other teams. As mentioned this is the only silencer i could really tell a difference in performance. And the weight is also lower when you use the carbon version. I add that steel band just for security reasons as i once broke off the carbon thing that attaches the silencer body to the bike. But that was after years of use.
DLR Carbon
FMF Powercore
Messico
Pit Row
https://www.youtube.com/watch?v=7x1Xgk-kB18
As mentioned already VRP stands for Verona Racing Parts and is a small company in northern Italy. The main man behind is Carlo Verona who back in the 80s-90s was famous for doing those aluminium gas tanks and rear subframes on offroad machines. But few avtually know he also worked for HRC and Kawasaki, he did custom bikes for the Paris-Dakar Rally, he did those sweet aluminium chassis , but he also did his own 125cc cylinders back in the day. He had his own dyno and was also doing very fast engines.
So fast that he decided he would do his own 500cc Grandprix roadracer. Chassis & engine...all made by VRP !
Anyway - Here's an article on that VRPs 500cc roadracer back in the day.
-----> Remember - ALL done by the man himself : chassis & engine !!
These days Carlo Verona is still into racing. But he moved his interest onto speedboats where his engines won several worldchampionships already:
Serious power inside....
The man himself wrenching...
Il capo: Carlo Verona
Yeah-it's impressive. Reminds me of Kiwi John Britten who did a whole superbike which in the end also won the Indy 500 against worksbikes from Ducati. That was even more impressive
The Britten-Story (awesome to watch):
https://www.youtube.com/watch?v=m9N1gfLQ--k
The Britten story is incredibly inspiring and also just as sad that he was taken so young when there was still so much more to achieve.
PS does your pipe builder take commissions or was that cone pipe a favour just for you? Been searching for someone to build a pipe as pretty as that for my 91 KX
In Holland there's another pipe maker who does such pipes for Vintage/Evo bikes. I have his contact somewhere.Or you can go through MX Legends on Facebook. Paul Dean is the man behind MX Legends who sells those pipes and is a specialist for these kind of bikes. He did my graphics too. By the way - MX Legends is in the UK.
"In 1990, On The Line Line Racing imported Verona Racing Products (VRP) aluminum Honda frames from Italy. Initially they cost $6000 for the frame, but the eventual consumer price was $3500 (minus swingarm and subframe). A VRP swingarm was $550, the subframe $175 and aluminum gas tank $390. Given that this was seven years before Honda made their first aluminum frame — was was a bargain."
Link to the picture:
http://motocrossactionmag.com/home-page/mxas-gyro-gearloose-invention-o…
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