pewpew
Scoot Enthusiast
Posts: 254
|
Post by pewpew on Nov 26, 2020 9:12:57 GMT -5
Yes. 36 is huge...36mm venturi is the same size as a YZ250 motocross bike that produces about 50HP. Exactly this. 38mm is seen on some ported and highly tuned 125's. Even the 125cc 50hp TM KZ engines run a 30mm.Forget about that 36mm  it's just ridiculous. A big carb doesn't in the least bit mean big power. Have you ever put it on the dyno to have some sort of base line for power output and where the power sits? 36mm is just ridiculous. Check what size carb a 85cc dirtbike runs. Those are race bred engines and maybe take that as a guideline? Or maybe build a better exhaust, do some porting and flowing inside the engine, swap around reed petals, do some ignition tuning, do some carb tuning, airbox tuning before you swap to the big talk overkill carburetor sizes? Im currently building it, My 86cc tpr had about 26hp at 14900 rpm with 28mm keihin pwk, it worked fine with 32mm pwk as well. Now im going to have alot more power and better parts so i would like to have a 33mm keihin pwk but cant find them anywhere |
|
|
|
Post by Lucass2T on Nov 26, 2020 9:44:44 GMT -5
I mean if it works it works. However going off Brent's carb sizing chart and the size of motor a 36 is usually installed on I still think its too large. Yes i know its too big, but is it impossible to make work on this engine? It will have the mxs intake kit with kx85 vforce reeds and alot of porting Define 'make work'. Ofcourse it will start... Same goes the the other way around. You can put a 12mm carb on there and it will work. But it doesn't make any sense  |
|
|
|
Post by Lucass2T on Nov 26, 2020 9:47:07 GMT -5
Exactly this. 38mm is seen on some ported and highly tuned 125's. Even the 125cc 50hp TM KZ engines run a 30mm.Forget about that 36mm it's just ridiculous. A big carb doesn't in the least bit mean big power. Have you ever put it on the dyno to have some sort of base line for power output and where the power sits? 36mm is just ridiculous. Check what size carb a 85cc dirtbike runs. Those are race bred engines and maybe take that as a guideline? Or maybe build a better exhaust, do some porting and flowing inside the engine, swap around reed petals, do some ignition tuning, do some carb tuning, airbox tuning before you swap to the big talk overkill carburetor sizes? Im currently building it, My 86cc tpr had about 26hp at 14900 rpm with 28mm keihin pwk, it worked fine with 32mm pwk as well. Now im going to have alot more power and better parts so i would like to have a 33mm keihin pwk but cant find them anywhere Okay then, do it man |
|
|
|
Post by hippo008 on Nov 26, 2020 11:11:20 GMT -5
you should size carbs based on how much mixture the engine pulls. That’s why I referred to the HP vs Venturi sizing chart that Dellorto and Mikuni developed, you know the people who engineered the carbs to begin with. Let’s be really optimistic and say your Bidalot kit produces 30HP. It won’t, but let’s say it does. According to the engineers at Mikuni and Dellorto you should be using a 30mm carb. Way smaller than a 36. Now let’s get realistic. 2Fast motors (as far as I know) are the most powerful single cylinder scooter engines available. The 2Fast 100cc motor kits run something like a 28mm flat slide carb. I can assure you that a 2fast 100cc produces significantly more power than a Bidalot 88cc kit. Therefore you should be using a carb smaller than the 2fast guys. My suggestion is to skip anything in the 30mm+ sizes and use this chart to size your carb. Go with a 24 or 26 and call it a day. Easier tuning and better running almost certainly.  |
|
|
|
Post by twostroker on Nov 26, 2020 11:37:48 GMT -5
I know that the MXS dyno chart I looked at said they ran something like a 34mm carb. For their cylinder they recommend a 34-38mm carb. I would assume they also used the kx85 reed setup. I'll see if I can find the chart and post it |
|
|
|
Post by twostroker on Nov 26, 2020 11:42:13 GMT -5
|
|
pewpew
Scoot Enthusiast
Posts: 254
|
Post by pewpew on Nov 26, 2020 11:44:01 GMT -5
you should size carbs based on how much mixture the engine pulls. That’s why I referred to the HP vs Venturi sizing chart that Dellorto and Mikuni developed, you know the people who engineered the carbs to begin with. Let’s be really optimistic and say your Bidalot kit produces 30HP. It won’t, but let’s say it does. According to the engineers at Mikuni and Dellorto you should be using a 30mm carb. Way smaller than a 36. Now let’s get realistic. 2Fast motors (as far as I know) are the most powerful single cylinder scooter engines available. The 2Fast 100cc motor kits run something like a 28mm flat slide carb. I can assure you that a 2fast 100cc produces significantly more power than a Bidalot 88cc kit. Therefore you should be using a carb smaller than the 2fast guys. My suggestion is to skip anything in the 30mm+ sizes and use this chart to size your carb. Go with a 24 or 26 and call it a day. Easier tuning and better running almost certainly. It should have atleast 30hp or something is very wrong with the engine. Bidalot recommends atleast a 34mm pwk carburetor. I think 33mm should be optimal for this setup. There is alot of dyno videos with over 30hp, at max 35. |
|
|
|
Post by hippo008 on Nov 26, 2020 12:22:12 GMT -5
Then I stand corrected. I’m surprised an 88cc will produce over high 20s but hey there you have it. Rock the 32 and run with it
|
|
pewpew
Scoot Enthusiast
Posts: 254
|
Post by pewpew on Nov 26, 2020 12:43:54 GMT -5
Then I stand corrected. I’m surprised an 88cc will produce over high 20s but hey there you have it. Rock the 32 and run with it Its not always the engine size that matters. This cylinder is 100 times better than like 86cc tpr. |
|
winner3ty
Scoot Enthusiast
2 Strokes for life
Posts: 324
|
Post by winner3ty on Nov 26, 2020 16:04:35 GMT -5
Still annoyed that the US didn't get the Aerox :/
|
|
|
|
Post by Lucass2T on Nov 27, 2020 5:07:49 GMT -5
Still annoyed that the US didn't get the Aerox :/ Here in Holland they are super cheap. You can find em for €300, most are €5-600 and the nice ones €8-900. There's just no market for em anymore. |
|
winner3ty
Scoot Enthusiast
2 Strokes for life
Posts: 324
|
Post by winner3ty on Nov 27, 2020 14:29:24 GMT -5
Here in Holland they are super cheap. You can find em for €300, most are €5-600 and the nice ones €8-900. There's just no market for em anymore. My plan is to eventually import an aerox if I can |
|
|
|
Post by aeroxbud on Nov 27, 2020 16:05:20 GMT -5
Still annoyed that the US didn't get the Aerox :/ Here in Holland they are super cheap. You can find em for €300, most are €5-600 and the nice ones €8-900. There's just no market for em anymore. Here the start around £700. Even £1,500 can buy you one with damaged panels and high mileage. I paid more for a four year old one a couple months ago. Than I did for a brand new one in 2008. Two stroke ones are already commanding more money than a mint few hundred miles four stroke. |
|
pewpew
Scoot Enthusiast
Posts: 254
|
Post by pewpew on Nov 27, 2020 16:48:25 GMT -5
Here in Holland they are super cheap. You can find em for €300, most are €5-600 and the nice ones €8-900. There's just no market for em anymore. Here the start around £700. Even £1,500 can buy you one with damaged panels and high mileage. I paid more for a four year old one a couple months ago. Than I did for a brand new one in 2008. Two stroke ones are already commanding more money than a mint few hundred miles four stroke. I bought mine 150€ haha |
|
|
|
Post by aeroxbud on Nov 27, 2020 17:23:33 GMT -5
Here the start around £700. Even £1,500 can buy you one with damaged panels and high mileage. I paid more for a four year old one a couple months ago. Than I did for a brand new one in 2008. Two stroke ones are already commanding more money than a mint few hundred miles four stroke. I bought mine 150€ haha Broken plate, speedo, floor. Needs a starting motor. No mot. £850!!! www.gumtree.com/p/yamaha-motorbikes/yamaha-aerox-50cc/1390870213 |
|
it's just ridiculous. A big carb doesn't in the least bit mean big power.
