AlphaGeek
Member
As I've mentioned in previous posts, I have a GEBE mounted Tanaka PF-3300 that I'm upgrading one step at a time to quantify the effect of each upgrade. I was pleasantly surprised that my previous upgrade (to an ADA cylinder-type air filter) made a significant, measurable difference on a stock engine/carb/exhaust setup.
Since my last post on upgrades, I changed out the original 13T drive gear for the 14T gear. I ran on this for a while without any power upgrades other than the air filter, and definitely noticed the motor struggling in the middle RPM range on hills, and topping out on the flats without sounding like it was anywhere near max RPMs.
Yesterday, I swapped out the stock carb on my Tanaka 33cc for the "HP" (high performance) carb packaged with the performance pack. This was a bit more of a project than I thought it would be, though it was certainly not at all difficult for me. The main reason for this was that the upper end of the intake manifold shipped with my carb had the 10.5mm bore suitable for the stock carb, not the 12.5mm bore appropriate for the HP carb.
Fortunately, while the main bore is slightly more complex in shape than a simple cylinder, it does run straight through (no curves) making it easy to modify with basic tooling. After carefully measuring everything several times with the micrometer calipers, and verifying that my original manifold was exactly the same as the new one in case I screwed up, I clamped the new manifold in my drill press and reamed the bore to 12.7mm (aka 0.5in). It's worth noting that the manifold appears to be made of wood fiber, which does NOT machine like high-temp plastics. Be sure to use high speed and a sharp bit.
I used the Dremel with a small sanding cylinder to clean up the newly-enlarged bore, then gave the manifold a good cleaning. I also used a protective oil on the newly-exposed wood surfaces inside the bore. After that, everything went smoothly. I had to reuse the original carb-to-manifold gasket, but fortunately mine was in good shape and was fairly easily trimmed to match the new larger bore size. I was VERY happy to find that the HP carb had only one adjustment screw (not two as I had read) and that it was correctly preset to run perfectly on my motor.
Performance:
These are initial impressions only, will update again after a full commute to/from work tomorrow. Today's ride was 8.5 miles with a LOT of wind, but I was able to form some subjective impressions:
* More power available at WOT to keep my speed up above 28mph even when beating against a significant/gusty headwind
* A small but moderately steep incline (highway overpass) that previously caused my speed to drop from ~30mph to ~22mph caused a much smaller drop to ~28mph today. Very nice!
* Top speed in good conditions (i.e. calm or slight tailwind) was up by 10%. Specifically, I was hitting 34.7mph on level ground, up from ~31.5mph pre-upgrade.
I expect that I will see an even bigger increase in top-end power on the big downhilll coming home tomorrow night, since the HP carb should be able to flow 41% more air/fuel mix than the OEM carb. That plus the 14T gear could see me pushing 40mph on the downhill. Whee!
Summary: HP carb upgrade for Tanaka engines (with air filter upgrade) -- DEFINITELY worthwhile. Easy and hassle-free (if you get the right parts, sigh) and produces measurable and useful power gains.
Next up: tuned-pipe exhaust upgrade. As soon as my *&&)(*& vendor sends me the right exhaust manifold pipe. But that's a whole 'nother story.
-AG
Since my last post on upgrades, I changed out the original 13T drive gear for the 14T gear. I ran on this for a while without any power upgrades other than the air filter, and definitely noticed the motor struggling in the middle RPM range on hills, and topping out on the flats without sounding like it was anywhere near max RPMs.
Yesterday, I swapped out the stock carb on my Tanaka 33cc for the "HP" (high performance) carb packaged with the performance pack. This was a bit more of a project than I thought it would be, though it was certainly not at all difficult for me. The main reason for this was that the upper end of the intake manifold shipped with my carb had the 10.5mm bore suitable for the stock carb, not the 12.5mm bore appropriate for the HP carb.
Fortunately, while the main bore is slightly more complex in shape than a simple cylinder, it does run straight through (no curves) making it easy to modify with basic tooling. After carefully measuring everything several times with the micrometer calipers, and verifying that my original manifold was exactly the same as the new one in case I screwed up, I clamped the new manifold in my drill press and reamed the bore to 12.7mm (aka 0.5in). It's worth noting that the manifold appears to be made of wood fiber, which does NOT machine like high-temp plastics. Be sure to use high speed and a sharp bit.
I used the Dremel with a small sanding cylinder to clean up the newly-enlarged bore, then gave the manifold a good cleaning. I also used a protective oil on the newly-exposed wood surfaces inside the bore. After that, everything went smoothly. I had to reuse the original carb-to-manifold gasket, but fortunately mine was in good shape and was fairly easily trimmed to match the new larger bore size. I was VERY happy to find that the HP carb had only one adjustment screw (not two as I had read) and that it was correctly preset to run perfectly on my motor.
Performance:
These are initial impressions only, will update again after a full commute to/from work tomorrow. Today's ride was 8.5 miles with a LOT of wind, but I was able to form some subjective impressions:
* More power available at WOT to keep my speed up above 28mph even when beating against a significant/gusty headwind
* A small but moderately steep incline (highway overpass) that previously caused my speed to drop from ~30mph to ~22mph caused a much smaller drop to ~28mph today. Very nice!
* Top speed in good conditions (i.e. calm or slight tailwind) was up by 10%. Specifically, I was hitting 34.7mph on level ground, up from ~31.5mph pre-upgrade.
I expect that I will see an even bigger increase in top-end power on the big downhilll coming home tomorrow night, since the HP carb should be able to flow 41% more air/fuel mix than the OEM carb. That plus the 14T gear could see me pushing 40mph on the downhill. Whee!
Summary: HP carb upgrade for Tanaka engines (with air filter upgrade) -- DEFINITELY worthwhile. Easy and hassle-free (if you get the right parts, sigh) and produces measurable and useful power gains.
Next up: tuned-pipe exhaust upgrade. As soon as my *&&)(*& vendor sends me the right exhaust manifold pipe. But that's a whole 'nother story.
-AG