Time for Stage I
05-27-2009, 10:29 AM
#241
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Okay, 3 angle valve seats are cut and all 8 seats are lookin sweet! This is the sort of thing you should do yourself if you can so you'd know they were done right...
31-45-60 I'll get some pics up ASAP too
The intake valves were the hardest to get right cuz they are 1mm oversized so the seat had to be moved out quite a bit using the 60 degree Neway cutter head. The exhaust were 0.5mm OS I think and they were easy as pie!
The procedure is pretty simple once you get the hang of it. Cut the seats where you think they should be and blue paint the valve and lap using fine paste then look at where the seat hits the valve and mic it for width. Repeat till they are perfect...any questions?
31-45-60 I'll get some pics up ASAP too
The intake valves were the hardest to get right cuz they are 1mm oversized so the seat had to be moved out quite a bit using the 60 degree Neway cutter head. The exhaust were 0.5mm OS I think and they were easy as pie!
The procedure is pretty simple once you get the hang of it. Cut the seats where you think they should be and blue paint the valve and lap using fine paste then look at where the seat hits the valve and mic it for width. Repeat till they are perfect...any questions?
05-27-2009, 12:55 PM
#242
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Yeah, why only a 3-angle job? I thought this was a performance build, that means 5-angles at a minimum or better yet a full radius. Isn't 3-angle a stock setup? I'm running a 5-angle on my engine.
05-27-2009, 12:57 PM
#243
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05-27-2009, 03:02 PM
#245
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05-28-2009, 04:15 AM
#246
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Actually, yes. In fact, infinite number of angles is best - that is what is called a full radius.
Right, and a 3-angle valve job is not really considered a performance setup, more like a basic service job. A 5-angle is pretty much what everyone does, I haven't heard of a 3-angle valve job being done for decades.
05-28-2009, 05:26 AM
#247
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Actually, yes. In fact, infinite number of angles is best - that is what is called a full radius.
Right, and a 3-angle valve job is not really considered a performance setup, more like a basic service job. A 5-angle is pretty much what everyone does, I haven't heard of a 3-angle valve job being done for decades.
Right, and a 3-angle valve job is not really considered a performance setup, more like a basic service job. A 5-angle is pretty much what everyone does, I haven't heard of a 3-angle valve job being done for decades.
I'd like to see your dyno results...we could compare old school vs. full radius
05-28-2009, 08:17 AM
#248
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don't worry about only having 3 angles. a 3 angle vavle job is actually 5 angles. Still in very wide use in racing engines. I know. I've seen them. The placement on the valve face is the most important thing. A full race engine uses a narrower seat to maximize the flow area, but sacrifices longevity.
I'm not going to argue. Just recommend that you run it and be happy.
I'm not going to argue. Just recommend that you run it and be happy.
05-28-2009, 08:43 AM
#252
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05-28-2009, 10:39 AM
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It's pretty much textbook man. As I've mentioned a couple of time already, nobody really does 3-angle jobs anymore. 5-angle valve jobs have been the mainstay of performance builds for as long as I've been modifying motorcycle engines (over 20 years). In fact, those are going away and being replaced by full-radius seats. That's the hot setup.
To put it bluntly - a 5-angle will beat a 3-angle all day long. It's all in the science of how the gasses flow around the valve seat at low valve lift values. Seat-of-the-pants says that it's a noticeable difference. All of my race engines have used 5-angle seats, I won't bother with anything else now (maybe a full-radius next time).
05-28-2009, 10:42 AM
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It's pretty much textbook man. As I've mentioned a couple of time already, nobody really does 3-angle jobs anymore. 5-angle valve jobs have been the mainstay of performance builds for as long as I've been modifying motorcycle engines (over 20 years). In fact, those are going away and being replaced by full-radius seats. That's the hot setup.
To put it bluntly - a 5-angle will beat a 3-angle all day long. It's all in the science of how the gasses flow around the valve seat at low valve lift values. Seat-of-the-pants says that it's a noticeable difference. All of my race engines have used 5-angle seats, I won't bother with anything else now (maybe a full-radius next time).
To put it bluntly - a 5-angle will beat a 3-angle all day long. It's all in the science of how the gasses flow around the valve seat at low valve lift values. Seat-of-the-pants says that it's a noticeable difference. All of my race engines have used 5-angle seats, I won't bother with anything else now (maybe a full-radius next time).
RC
05-28-2009, 11:00 AM
#257
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Oh, I thought you were doing a performance build?
Not in this case. A 5-angle will last as long as a 3-angle if done right. I've had them last a long time, I've got quite a few miles on my 5-angle and I have no worries about it lasting as long as I have the motorcycle.
Not in this case. A 5-angle will last as long as a 3-angle if done right. I've had them last a long time, I've got quite a few miles on my 5-angle and I have no worries about it lasting as long as I have the motorcycle.
06-08-2009, 07:35 AM
#259
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Finished my low performance 3 angle valve job for the OS Morwi valves on the ported heads and will be dropping them off today to my dyno tunner/mechanic for final assembly. Also, got the air scoops on and reversed the fan so it pulls cool outside air in through the rad instead of pushing hot air out...Also, wrapped front header in an effort to keep things cool. The bike definitely runs cooler going down the road...
Also, cut the top outta an old air box lid and installed the ring to hold down the K&N air filter and it is very evident re-jetting is needed with the open air box cuz there's lots of complaints above 6K rpms. The sound has changed too...much deeper grunt...
Stay tuned more pics to come...RC
Also, cut the top outta an old air box lid and installed the ring to hold down the K&N air filter and it is very evident re-jetting is needed with the open air box cuz there's lots of complaints above 6K rpms. The sound has changed too...much deeper grunt...
Stay tuned more pics to come...RC
Last edited by FL02SupaHawk996; 06-08-2009 at 07:36 AM. Reason: spell
06-08-2009, 01:35 PM
#260
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It will be interesting to see how the tuning goes with your airbox mod.
The stock induction system has air entering the snorkel at the same pressure that the float vents see. Th fairing vents supply cool air to the region between the cylinders.
the tuning of the carbs relies on an accurate flow calibration with the vents and intake duct at the same ambient pressure. I'm not sure how removing the airbox lid will affect it.
The stock induction system has air entering the snorkel at the same pressure that the float vents see. Th fairing vents supply cool air to the region between the cylinders.
the tuning of the carbs relies on an accurate flow calibration with the vents and intake duct at the same ambient pressure. I'm not sure how removing the airbox lid will affect it.
06-08-2009, 01:39 PM
#261
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06-08-2009, 02:52 PM
#262
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I don't know.....mine routed the air straight out of the fairing right by your knees.....no where near the carbs or the cylinders....... that is before I took them off and threw them away about 11yrs ago because the rattled. But as always YMMV 
06-08-2009, 05:01 PM
#263
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It will be interesting to see how the tuning goes with your airbox mod.
The stock induction system has air entering the snorkel at the same pressure that the float vents see. Th fairing vents supply cool air to the region between the cylinders.
the tuning of the carbs relies on an accurate flow calibration with the vents and intake duct at the same ambient pressure. I'm not sure how removing the airbox lid will affect it.
The stock induction system has air entering the snorkel at the same pressure that the float vents see. Th fairing vents supply cool air to the region between the cylinders.
the tuning of the carbs relies on an accurate flow calibration with the vents and intake duct at the same ambient pressure. I'm not sure how removing the airbox lid will affect it.
I've done some research and found somewhere that he may need to start some where around 195 F 200 R & G3 needle with #55 slow jet, whattcha think?
06-08-2009, 05:10 PM
#264
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It's not an easy mod to make work...... if you run into problems with it going lean in the mid range, I have a set of HRC needles that are made to run with no air filter (just more extra parts from my HRC jet kit) that I'll let go pretty cheep..... just let me know
06-08-2009, 05:28 PM
#265
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RC
06-08-2009, 08:45 PM
#267
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I think so. It's something I have pondered for a long time.
I finally came to that conclusion, when I made a mental comparison between the carbureted engine and the fuel injected RC51. They are analagous systems, except the carburetor uses a pressure signal to adjust the flow through the jets and the fuel injected system uses a barometric transducer in the intake tract and a manifold pressure transducer to convert pressure to an electrical voltage and uses them to adjust fuel injector timing.
Both systems estimate mass air flow and adjust fuel quantity accordingly. If the air intake on the carbureted engine is at a different pressure than the float bowl, the calibration will be off. If the ratio changes with vehicle speed, I'm not sure how you would calibrate it.
I finally came to that conclusion, when I made a mental comparison between the carbureted engine and the fuel injected RC51. They are analagous systems, except the carburetor uses a pressure signal to adjust the flow through the jets and the fuel injected system uses a barometric transducer in the intake tract and a manifold pressure transducer to convert pressure to an electrical voltage and uses them to adjust fuel injector timing.
Both systems estimate mass air flow and adjust fuel quantity accordingly. If the air intake on the carbureted engine is at a different pressure than the float bowl, the calibration will be off. If the ratio changes with vehicle speed, I'm not sure how you would calibrate it.
06-09-2009, 04:58 AM
#268
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Two suggestions:
Feed the vent lines into the bottom of the airbox (use a T fed through a grommet, hook up the line from underneath and have it sense air pressure from the sides of the T located in the box), this will allow the system to stay in equilibrium (note: most carbureted snowmobile engines run this type of set-up, helps prevent teh possibility of pressure differentials developping))
As far as the jetting is concerned, as this mod was recommended by Roger D, he must be familiar with it and can surely suggest a good baseline setting at the very least.
Feed the vent lines into the bottom of the airbox (use a T fed through a grommet, hook up the line from underneath and have it sense air pressure from the sides of the T located in the box), this will allow the system to stay in equilibrium (note: most carbureted snowmobile engines run this type of set-up, helps prevent teh possibility of pressure differentials developping))
As far as the jetting is concerned, as this mod was recommended by Roger D, he must be familiar with it and can surely suggest a good baseline setting at the very least.
