Your paint is a good idea although I would think using a pattern derived by old prussian blue method of matching components to each other would be both more precise & a bit quicker. In any case , looks like you're having fun , so keep it up ...............
So would we be able to get someone to measure the fiber plate “teeth” or “ridges” and then weld the fingers on the basket and cnc them down so that you can save the clutch basket while tightening the tolerances so you get far less chatter?
@@thejunkman oh of course but as I’m seeing now it’s getting increasingly hard to find parts for these and I’m sure it would be about the same expense to get a billet basket made.
Yeah in the future it might be a thing, but right now the parts are still pretty plentiful. Also the aftermarket makes clutch parts for the H1 which uses the same clutch on the F9.
Wouldn’t it be more effective to just take material off the side that opens first on the plate only, than both sides? Cause looks like the stroke is complete by time it closes all the way?
Very helpful tips, thanks. Question - I’m working on a ‘71 F8 and there’s some scoring on the case side of the rotary valve, a piece of debris must have got in. This is within and away from the large o-ring area, am I safe from a lean condition? Should I fill and sand the scored area with epoxy filler? Thank you
Depends on where it is on the valve. Is it in line with where the ports open and close? It probably won't mater all that much really. New and used valves are plentiful. If you are worried about it just buy a new/better one. Also check this video out on measuring the thickness. ruclips.net/video/P71y-pma3ZY/видео.html
+dustysquito Well sort of. The disc controls the intake timing and seals the crankcase during the power stroke. On more conventional 2 strokes the piston skirt and/or fiber reeds control and seal the crankcase. The benefit of this design is intake timing can happen independent of the piston's location within the stroke, thus longer duration of the intake can happen. The result is 2 strokes that can have very good low end torque (on par with 4 strokes of the day) without sacrificing mid-upper range power. The downside is they are more complicated to manufacture (more parts) and by nature of the design the whole engine has to be wider as the carburetor has to mount to the side, down inline of the intake tract. Also there are more areas to seal with this design, which is not a problem when new, but as they age those are more gaskets and seals prone to failing. The exhaust is still timed just like any other 2 stroke (piston port/reed valve) buy the piston skirt and crown. It has always been wondered if a rotary valve 2 stroke with a modern style variable volume exhaust valve would be the ultimate 2 stroke engine, but the mid 70's emissions rules and the motorcycle industries move toward more specialized bikes, such as inline 4 cylinders 4 street and dedicated racing only motocross bikes sort of saw engine development favor the more simple and lighter piston port/reed valve engines with eventual water cooling be the "wave of the future". Once water cooling in high strung single cylinder 250cc engines became reliable the rotary valve design saw diminishing returns. Also the "dual sport" (as we know it now, then it was known as Enduros) began to dwindle as riders either chose full on dirt machines or full on street machines. The days of the "Big Horn" a dual sport that you could theoretically race (by removing the lights, mirrors, and any other non essential parts) easily was just not practical if you were serious about racing.
thejunkman I do like the idea of a machine you're riding every day that has the power and suspension to be a full blown race bike when needed, though I guess that level of performance also comes with some reliability issues that slowpokes like my DR don't have. I still think one of the coolest features outfitted to a two stroke engine was when they added oil injection and took away the responsibility of the rider to pre-mix their fuel. Honestly, I probably wouldn't have ever sold my KDX200 if it would have had that feature. The two stroke powerband was just such a riot.
+dustysquito The KDX200 (and earlier KDX250 which I have) is probably the most underrated "cheap" woods bike you can get! After I hung up racing MX competitively I converted my 02 KX250 into a more woods friendly bike, mellowed the porting, and smoothed the suspension, to more closely match my KDX only much lighter. Thing is injection systems just add weight and extra complexity for all out performance. Also people forgot to keep the tank filled and ran them out frequently or ran them low creating air bubbles in the line that cause intermittent lubrication problems. I wrote an article years ago about why people seem to disable oil injection and this was a reason why, engine failures from operator error in keeping the tank full. Pre-Mix alows for maximum power to be made as the air/fuel mixture is kept at a constant because the oil/fuel mix is constant. In an injection system the mix is dependent on throttle position AND engine rpm as the pump is driven off the crankshaft. Thus of all out performance demands of motocross racing this keeps tuners "hunting" for the best jetting as the air/fuel mixture is always changing (oil doesn't burn or contribute to making power) Injection sacrifices performance for reliability, and in the motocross world the engines are built around 40 minute moto's with expected tear down and inspections every few races. Engineers only care if the engine will last long enough to win the race. This is part of the reason why hi-po 4 strokes (250/450) of the last decade got a bad rap as most people that bought them were more recreational riders that thought they were getting DR/XR/XT/KLR (predominantly 4 stroke air cooled) reliability/longevity, with RM/CR/YZ/KX water cooled 250cc 2 stroke power. They got the power, but the longevity had to be sacrificed to squeeze similar performance out of those modern 4 stroke engines. If you want to read about 2 stroke oil injection see it here. www.thejunkmanadv.com/2-stroke-oil-injection-systems.html
See, I had assumed that the oil injection would make things less prone to operator error. I guess I never really got a chance to see how they were really being used in the real world. The super short range on my KDX had become a massive liability when I took it out to Utah because I was burning roughly 1/4 of my total range just getting to where we were riding. I do really miss that bike when I'm out riding close to home, though. That's one of those things I'll probably find myself regretting farther down the road.
+dustysquito Well the KDX was developed as an offroad racer, not really meant for D/S'ing. The main focus was to give KX (the motocross race bike) like handling and light weight in a more offroad friendly chassis, more range and a more friendly engine power band. I have had the luxury of owning and riding so many different types of bikes from so many different era's in motorcycling that I have come to understand some of the how's and why's certain bikes, segments and technologies have evolved. Unfortunately the "dual sport" segment has dwindled and nearly been ignored by the manufacturers that choices are very limited unlike other segments of motorcycling. Even the observed trials segment has more development and choice in bikes than dual sports. Marketing and customer wants have distilled down into each segments ultimate want. If you are a motocross racer, all you care about is the highest performance in the lightest package, longevity be damned. In crotch rockets/repli-racers same deal. Playbikes, reliability and affordability, and volume is king, that means low performance and old designs. I could go on, but it boils down to people want bragging rights and your and my DR's (your 650 my 350) don't cut it on paper. They make dismal horsepower for their displacement and are pig heavy comparatively on paper. Seriously the argument is as old as time "My CRF450 makes 50 hp while your DR650 makes 36 hp" say the youngin's but of course apples and oranges. Somehow that number denotes how "good" the bike is to the lay person.
Good evening, I’ve just restored a 1974 Kawasaki F7 C 175 and have got it running. During the rebuild I removed the drain pump, cleaned it, checked it and it all seemed ok. I understand the purpose of the pump and I’ve read how most people block them off as they are not really that effective. I guess they were seen as high tech back in the 1970’s. My problem is that when I stop the engine I get a discharge from the pump, put it isn’t unburnt fuel, it seems to be gearbox oil. There is no smell of petrol at all. To me this implies some kind of leak from the gearbox into the crankcase but I’ve studied every diagram I can find and can’t see a seal which could be the problem. Do you have a similar/any experience ? I have considered blocking the drain pump as others have but I don’t have access to any engineering equipment to cut parts. I could replace the drain pump diaphragm with high temperature rubber gasket sheet to block it off; any thoughts on the effectiveness of this would be great. Thanks, Herbs.
Very Wonderful & super controlled modifications inorder2 improve F9 350 topend performance,very kool trick to make a mark 2 work wid
Buenas amigo me podría enseñar cómo se corta la válvula rotativa a grados , a
Your paint is a good idea although I would think using a pattern derived by old prussian blue method of matching components to each other would be both more precise & a bit quicker. In any case , looks like you're having fun , so keep it up ...............
hhow much do you take off the plate?
So would we be able to get someone to measure the fiber plate “teeth” or “ridges” and then weld the fingers on the basket and cnc them down so that you can save the clutch basket while tightening the tolerances so you get far less chatter?
You could I suppose. It would be a lot of work and expense to have a tool path made for that, but it could be done.
@@thejunkman oh of course but as I’m seeing now it’s getting increasingly hard to find parts for these and I’m sure it would be about the same expense to get a billet basket made.
Yeah in the future it might be a thing, but right now the parts are still pretty plentiful. Also the aftermarket makes clutch parts for the H1 which uses the same clutch on the F9.
Wouldn’t it be more effective to just take material off the side that opens first on the plate only, than both sides? Cause looks like the stroke is complete by time it closes all the way?
Very helpful tips, thanks. Question - I’m working on a ‘71 F8 and there’s some scoring on the case side of the rotary valve, a piece of debris must have got in. This is within and away from the large o-ring area, am I safe from a lean condition? Should I fill and sand the scored area with epoxy filler? Thank you
Depends on where it is on the valve. Is it in line with where the ports open and close? It probably won't mater all that much really. New and used valves are plentiful. If you are worried about it just buy a new/better one. Also check this video out on measuring the thickness. ruclips.net/video/P71y-pma3ZY/видео.html
So is that disk acting like a cam would on a more modern engine?
+dustysquito Well sort of. The disc controls the intake timing and seals the crankcase during the power stroke. On more conventional 2 strokes the piston skirt and/or fiber reeds control and seal the crankcase. The benefit of this design is intake timing can happen independent of the piston's location within the stroke, thus longer duration of the intake can happen. The result is 2 strokes that can have very good low end torque (on par with 4 strokes of the day) without sacrificing mid-upper range power. The downside is they are more complicated to manufacture (more parts) and by nature of the design the whole engine has to be wider as the carburetor has to mount to the side, down inline of the intake tract. Also there are more areas to seal with this design, which is not a problem when new, but as they age those are more gaskets and seals prone to failing.
The exhaust is still timed just like any other 2 stroke (piston port/reed valve) buy the piston skirt and crown. It has always been wondered if a rotary valve 2 stroke with a modern style variable volume exhaust valve would be the ultimate 2 stroke engine, but the mid 70's emissions rules and the motorcycle industries move toward more specialized bikes, such as inline 4 cylinders 4 street and dedicated racing only motocross bikes sort of saw engine development favor the more simple and lighter piston port/reed valve engines with eventual water cooling be the "wave of the future". Once water cooling in high strung single cylinder 250cc engines became reliable the rotary valve design saw diminishing returns. Also the "dual sport" (as we know it now, then it was known as Enduros) began to dwindle as riders either chose full on dirt machines or full on street machines. The days of the "Big Horn" a dual sport that you could theoretically race (by removing the lights, mirrors, and any other non essential parts) easily was just not practical if you were serious about racing.
thejunkman I do like the idea of a machine you're riding every day that has the power and suspension to be a full blown race bike when needed, though I guess that level of performance also comes with some reliability issues that slowpokes like my DR don't have. I still think one of the coolest features outfitted to a two stroke engine was when they added oil injection and took away the responsibility of the rider to pre-mix their fuel. Honestly, I probably wouldn't have ever sold my KDX200 if it would have had that feature. The two stroke powerband was just such a riot.
+dustysquito
The KDX200 (and earlier KDX250 which I have) is probably the most underrated "cheap" woods bike you can get! After I hung up racing MX competitively I converted my 02 KX250 into a more woods friendly bike, mellowed the porting, and smoothed the suspension, to more closely match my KDX only much lighter.
Thing is injection systems just add weight and extra complexity for all out performance. Also people forgot to keep the tank filled and ran them out frequently or ran them low creating air bubbles in the line that cause intermittent lubrication problems. I wrote an article years ago about why people seem to disable oil injection and this was a reason why, engine failures from operator error in keeping the tank full. Pre-Mix alows for maximum power to be made as the air/fuel mixture is kept at a constant because the oil/fuel mix is constant. In an injection system the mix is dependent on throttle position AND engine rpm as the pump is driven off the crankshaft. Thus of all out performance demands of motocross racing this keeps tuners "hunting" for the best jetting as the air/fuel mixture is always changing (oil doesn't burn or contribute to making power) Injection sacrifices performance for reliability, and in the motocross world the engines are built around 40 minute moto's with expected tear down and inspections every few races. Engineers only care if the engine will last long enough to win the race. This is part of the reason why hi-po 4 strokes (250/450) of the last decade got a bad rap as most people that bought them were more recreational riders that thought they were getting DR/XR/XT/KLR (predominantly 4 stroke air cooled) reliability/longevity, with RM/CR/YZ/KX water cooled 250cc 2 stroke power. They got the power, but the longevity had to be sacrificed to squeeze similar performance out of those modern 4 stroke engines.
If you want to read about 2 stroke oil injection see it here. www.thejunkmanadv.com/2-stroke-oil-injection-systems.html
See, I had assumed that the oil injection would make things less prone to operator error. I guess I never really got a chance to see how they were really being used in the real world. The super short range on my KDX had become a massive liability when I took it out to Utah because I was burning roughly 1/4 of my total range just getting to where we were riding. I do really miss that bike when I'm out riding close to home, though. That's one of those things I'll probably find myself regretting farther down the road.
+dustysquito Well the KDX was developed as an offroad racer, not really meant for D/S'ing. The main focus was to give KX (the motocross race bike) like handling and light weight in a more offroad friendly chassis, more range and a more friendly engine power band. I have had the luxury of owning and riding so many different types of bikes from so many different era's in motorcycling that I have come to understand some of the how's and why's certain bikes, segments and technologies have evolved. Unfortunately the "dual sport" segment has dwindled and nearly been ignored by the manufacturers that choices are very limited unlike other segments of motorcycling. Even the observed trials segment has more development and choice in bikes than dual sports. Marketing and customer wants have distilled down into each segments ultimate want. If you are a motocross racer, all you care about is the highest performance in the lightest package, longevity be damned. In crotch rockets/repli-racers same deal. Playbikes, reliability and affordability, and volume is king, that means low performance and old designs. I could go on, but it boils down to people want bragging rights and your and my DR's (your 650 my 350) don't cut it on paper. They make dismal horsepower for their displacement and are pig heavy comparatively on paper. Seriously the argument is as old as time "My CRF450 makes 50 hp while your DR650 makes 36 hp" say the youngin's but of course apples and oranges. Somehow that number denotes how "good" the bike is to the lay person.
how much material do you actually remove from the rotary valve?
You can find everything, including this right here! www.thejunkmanadv.com/kawasaki-f5-speed-kit-manual.html
thejunkman thank you
Good evening,
I’ve just restored a 1974 Kawasaki F7 C 175 and have got it running.
During the rebuild I removed the drain pump, cleaned it, checked it and it all seemed ok.
I understand the purpose of the pump and I’ve read how most people block them off as they are not really that effective. I guess they were seen as high tech back in the 1970’s.
My problem is that when I stop the engine I get a discharge from the pump, put it isn’t unburnt fuel, it seems to be gearbox oil. There is no smell of petrol at all.
To me this implies some kind of leak from the gearbox into the crankcase but I’ve studied every diagram I can find and can’t see a seal which could be the problem.
Do you have a similar/any experience ?
I have considered blocking the drain pump as others have but I don’t have access to any engineering equipment to cut parts. I could replace the drain pump diaphragm with high temperature rubber gasket sheet to block it off; any thoughts on the effectiveness of this would be great.
Thanks,
Herbs.
Hii thank for your work I want your job
blah blah blah ................ you talk too much m8