|
|
BBK Carb ?
by: steve - Jan 28, 2016 9:09:34 GMT -5
via mobile
Post by steve on Jan 28, 2016 9:09:34 GMT -5
Hi y'all!
I installed a Hoca 52mm BBK. It runs great, but I have some questions about my carb.
I have a 20mm carb. Do I need to go to the 24?
And, can I just use a stock 24 that is made for the 150cc?
Will the 150cc manifold fit on my head? Do the bolt holes match?
A 24mm carb made for a 50 is $100, and a 24mm carb made for a 150 is $30, what is the difference?
|
|
|
|
Post by JerryScript on Jan 28, 2016 10:35:55 GMT -5
No, a 24mm carb will be too large. Stick with 20 and jet it propely.
|
|
|
|
BBK Carb ?
by: ricardoguitars - Jan 28, 2016 16:42:55 GMT -5
Post by ricardoguitars on Jan 28, 2016 16:42:55 GMT -5
If you want to get a bigger carb, you would also need bigger ports/valves, and matching free flow exhaust to get advantage of the modification, without those mods you would just waste fuel.
|
|
|
|
BBK Carb ?
by: steve - Jan 28, 2016 18:48:16 GMT -5
via mobile
Post by steve on Jan 28, 2016 18:48:16 GMT -5
If you want to get a bigger carb, you would also need bigger ports/valves, and matching free flow exhaust to get advantage of the modification, without those mods you would just waste fuel. That's the thing, 52mm is the absolute largest bore you can put on a 139qmb. The valves and ports are huge, and made for the 52 mm. I noticed that Scrappy's includes a 24mm carb with their big bore heads they sell, and Hoca makes a 26mm carb for a 139qmb big bore. I may try it. I dunno. |
|
|
|
Post by ricardoguitars on Jan 28, 2016 19:18:35 GMT -5
If you want to get a bigger carb, you would also need bigger ports/valves, and matching free flow exhaust to get advantage of the modification, without those mods you would just waste fuel. That's the thing, 52mm is the absolute largest bore you can put on a 139qmb. The valves and ports are huge, and made for the 52 mm. I noticed that Scrappy's includes a 24mm carb with their big bore heads they sell, and Hoca makes a 26mm carb for a 139qmb big bore. I may try it. I dunno. Do you know the size of the head's intake port? It should match the intake manifold. |
|
|
|
BBK Carb ?
by: steve - Jan 30, 2016 21:05:57 GMT -5
via mobile
Post by steve on Jan 30, 2016 21:05:57 GMT -5
Yeah, it's 22.5, or 23.
I did not know that it should match.
So, I can go bigger?
|
|
|
|
BBK Carb ?
by: steve - Jan 30, 2016 21:09:32 GMT -5
via mobile
Post by steve on Jan 30, 2016 21:09:32 GMT -5
Sorry, it's 21.5.
I guess I can go a little larger?
|
|
|
|
Post by ricardoguitars on Jan 31, 2016 4:16:28 GMT -5
The ideal is to let the mix flow free, if something is on the way you won't get optimal performance, that's why it should match.
|
|
|
|
BBK Carb ?
by: geh3333 - Feb 5, 2016 0:15:06 GMT -5
via mobile
Post by geh3333 on Feb 5, 2016 0:15:06 GMT -5
The key is to match every port as close as possible. I have no problem with telling you to go with a 24 mm carb. My carb on the 150 with a 58.5 bbk is a 32mm . my intake manifold is a 30mm , and I'm not sure what the intake port is on the ncy 58.5 racing head ? But I'm sure its not 32mm . I'd say go with the 24 mm carb and see what size manifold u can get.
|
|
|
|
Post by steve on Feb 5, 2016 9:27:34 GMT -5
The key is to match every port as close as possible. I have no problem with telling you to go with a 24 mm carb. My carb on the 150 with a 58.5 bbk is a 32mm . my intake manifold is a 30mm , and I'm not sure what the intake port is on the ncy 58.5 racing head ? But I'm sure its not 32mm . I'd say go with the 24 mm carb and see what size manifold u can get. Thanks. I'm going to give it a try. I wish I knew the difference between the 24mm carbs made for 150cc scoots, that sell for $25, and the 24mm "performance" carbs made for 50cc scoots that sell for $150? I'm getting the 150 carb, and manifold. I will report how the manifold fits, and how the carb performs. |
|
|
|
BBK Carb ?
by: steve - Feb 5, 2016 10:19:34 GMT -5
Post by steve on Feb 5, 2016 10:19:34 GMT -5
The key is to match every port as close as possible. I have no problem with telling you to go with a 24 mm carb. My carb on the 150 with a 58.5 bbk is a 32mm . my intake manifold is a 30mm , and I'm not sure what the intake port is on the ncy 58.5 racing head ? But I'm sure its not 32mm . I'd say go with the 24 mm carb and see what size manifold u can get. Alright, GEH, I ordered just a stock 150cc carb for $20. And, a stock 150cc manifold. A couple of questions: It does not say what size main jet it comes with. I have the 52mm BBK. What size main jet should I go with. I run a 43 idle, and a 94 main on my 20mm carb right now. Should I put the 43 idle in the new one, and just roll with the main jet that is in it? I think it will come with a jet between 100-108, right? |
|
|
|
BBK Carb ?
by: geh3333 - Feb 5, 2016 23:18:01 GMT -5
via mobile
Post by geh3333 on Feb 5, 2016 23:18:01 GMT -5
The key is to match every port as close as possible. I have no problem with telling you to go with a 24 mm carb. My carb on the 150 with a 58.5 bbk is a 32mm . my intake manifold is a 30mm , and I'm not sure what the intake port is on the ncy 58.5 racing head ? But I'm sure its not 32mm . I'd say go with the 24 mm carb and see what size manifold u can get. Alright, GEH, I ordered just a stock 150cc carb for $20. And, a stock 150cc manifold. A couple of questions: It does not say what size main jet it comes with. I have the 52mm BBK. What size main jet should I go with. I run a 43 idle, and a 94 main on my 20mm carb right now. Should I put the 43 idle in the new one, and just roll with the main jet that is in it? I think it will come with a jet between 100-108, right? Honestly , I would throw the carb in " as is " and see what the performance and plug is like . |
|
|
|
BBK Carb ?
by: geh3333 - Feb 5, 2016 23:22:22 GMT -5
via mobile
Post by geh3333 on Feb 5, 2016 23:22:22 GMT -5
The main will be around a 106-108 and the pilot will be around a 35. Inbelive your 43 pilot was too big . the pilot is in play through out most of the throttle range so a 43 in my opinion is way too big. I would like to see a 106 main for your setup , with the 35 pilot. Even a slightly smaller main may be better but I would def just throw it in and see how she performs.
|
|
|
|
BBK Carb ?
by: steve - Feb 16, 2016 11:09:05 GMT -5
via mobile
Post by steve on Feb 16, 2016 11:09:05 GMT -5
Alright, I installed the 24mm carb. Just a standard carb for a 150cc. A 100 main was too large. I had to go down to a  . It came with a 31 idle. The 150 manifold does fit, but it is angled wrong, so I had to use a performance manifold for a 50. It definitely runs better with the larger carb. It loves it. I actually made an intake out of 1-1/4 " PVC pipe. The elbow fitting fit perfectly tight on the carb, and I ran it to the rear to cut the noise. Works great. I do wonder why I had to use slightly smaller jets on a larger carb to make it work? |
|
. It came with a 31 idle. The 150 manifold does fit, but it is angled wrong, so I had to use a performance manifold for a 50.