Jump to content
Sign in to follow this  

Best aftermarket carburetors?

Recommended Posts

So i was looking for a after market carburetor that doesn't require me to re-jet it for different elevations because i ride from sea level (at the beach) to around 7000+ feet up in the mountains. So i heard of the lectron carb and Ive only heard good things about it. It is jet less and easy to adjust but they are pretty expensive for how much i would like to spend. I was wondering if any of you guys knew of some good aftermarket carbs for trail riding and in the dunes. Also i ride a 2005 crf230f.

 

Thanks in advance! :thumbsup::ride:

Edited by kawi_rider_02

Share this post


Link to post
Share on other sites

If you jet that bike correctly to begin with you should easily be able to go from 0 to 7000 ft.

 

The problem is not jetting at high elevation, it's a lack of oxygen....which means you are down on power, no matter how you jet it.

 

The CRF230 has a very unsophisticated carb.  You could put on an FCR 39 carb from Keihin.... but I don't think it's going to solve any problems.

 

...but I would not put any money into that bike due to it's very low performance to begin with.

 

Lectron carbs are for two strokes (no accelerator pump...)

  • Like 1

Share this post


Link to post
Share on other sites

I have been unable to find an AP carb in a suitable size for a 230 (blue in my case). EnginesOnly sells a 30mm carb for your bike but I don't think its a pumper. Its $350. Krannie is right about that bike not being very sensitive to jetting. Lectron's are popular (ish) with two strokes because they tend to be much more finicky.

Edit: The reason I brought up the AP is that unless theres a bunch of power tied up in the carb's bore size, I wouldn't think an aftermarket carb would be worth the money unless it had an accelerator pump, as lacking one is definitely a deficiency on a 4stroke.

Edited by clappedoutkx

Share this post


Link to post
Share on other sites

If you jet that bike correctly to begin with you should easily be able to go from 0 to 7000 ft.

 

The problem is not jetting at high elevation, it's a lack of oxygen....which means you are down on power, no matter how you jet it.

 

The CRF230 has a very unsophisticated carb.  You could put on an FCR 39 carb from Keihin.... but I don't think it's going to solve any problems.

 

...but I would not put any money into that bike due to it's very low performance to begin with.

 

Lectron carbs are for two strokes (no accelerator pump...

That's false as jetting changes with altitude and 0 to 7000 feet is a drastic change. The higher up you go, the less oxygen there is to burn meaning you have to lean out your jetting. However, I do agree with the remark regarding the low performance of the bike. Unless the bike won't run at higher elevations, I'd stick with what you have. 

Share this post


Link to post
Share on other sites

That's false as jetting changes with altitude and 0 to 7000 feet is a drastic change. The higher up you go, the less oxygen there is to burn meaning you have to lean out your jetting. However, I do agree with the remark regarding the low performance of the bike. Unless the bike won't run at higher elevations, I'd stick with what you have. 

 

I ride 0 - 9000 feet all the time on three different carb'd bikes with no issues.

 

It's all in how you set them up.

  • Like 2

Share this post


Link to post
Share on other sites

Krannie is wrong about the Lectrons being 2 stroke only, If you go to cafe husky there is a bunch of info on the latest Lectron with the air bleed fitment fitted to 250s 450s 510s ect, All seem to have good results and no need for a AP

  • Like 1

Share this post


Link to post
Share on other sites

If it were me, for a CRF230F, I'd source a good used 36mm Mikuni BCS CV carb. The DRZ guys are taking them off thier 400's when nearly new and selling them for $50 to $75 bucks.

 

A CV type carb somewhat compensates for the elevation change due to vacuum perting the needle and the larger bore may permit a 'deeper breath' by the engine.

 

I am moving this thread to the CRF230f section as many there will provide you with spot on suggestions.

  • Like 2

Share this post


Link to post
Share on other sites

Chuck is right, as usual.  From Mike Coe:

 

"This is what I recommend for your bike and all others with stock engine with exhaust baffle and airbox snorkel removed. I ride my stock bike from 0 - 6500+ elevation with no changes in jetting between the desert and mountains.

120 main jet (used to be 132)
45 pilot jet
Stock needle with clip in fourth groove from the top
Accessory needle with clip in fourth groove from the top."

 

 

The Keihin PD series of carbs are archaic but incredibly forgiving.  Though you will not realize peak power the carbs will meter just fine in the most varying of conditions.  We ride ours in so many conditions without jetting changes it is hard to believe.

 

A 30mm carb on this engine is a waste of time and money.  Mike Coe used the XR250 30mm PD carb on his super-hot builds but did not recommend it for stock or mild builds.  The intake port is only 27mm so using a 30mm carb requires a lot of work on the intake side.  He gave up on trying to make them work on a stock engine.  I tried one and my lap times increased.  I had to hold gears longer and shift later.

 

Baja Trail Rider and Stevethe use a Kehin PWK28 on their bikes.  This is a nice compromise as it is not too big and the "D"-shaped slide promotes both low-speed and high-speed operation and performance.  Do not expect to just bolt one on!  You must have adapters and know what jets, needle, and slide to use!

 

Some in here have bored the stock carb just a bit as well.

Edited by VortecCPI
  • Like 1

Share this post


Link to post
Share on other sites

That's false as jetting changes with altitude and 0 to 7000 feet is a drastic change. The higher up you go, the less oxygen there is to burn meaning you have to lean out your jetting. However, I do agree with the remark regarding the low performance of the bike. Unless the bike won't run at higher elevations, I'd stick with what you have. 

 

Not true at all.  If a 120 main is right for peak power at sea level a 112 main is right for peak power at 7,000 feet.  Notice I wrote "for peak power" not "for the engine to run".  A 120 main at 7,000 feet will be 6% too rich.  This is not enough to keep a CRF230 from running.  Not even close.

 

We should not confuse jetting for peak power with jetting for the ability to ride.  A low-performance 4T engine can be way off on jetting and still run.  The CRF230 engine has got to be one of the lowest-performance 200-250 engines ever produced by The Big Four.  The XR200 engine was way "hotter" than the CRF230 engine which is why it will stomp a stock CRF230 and give a jetted and uncorked CRF230 a very good run for the money.  The CRF230 makes more power but the XR200 is lighter.  In that case it is mostly up to the rider and the setup.  And maybe a little luck.

Sorry...  Slight tangent at the end there...

 

All that being said I believe Powroll only used a 28mm on their hot 218 builds.  Those engines were only 5cc shy of the CRF230 engine and way hotter.  If a hot Powroll 218 only needs a 28mm carb a stock CRF230 does not.  A stock XR200 has a 10.25:1 CR as compared to the CRF230's 9:11 CR.  A stock XR200 cam is +10i/+15e bigger/longer than the CRF230cam.  A hot Powroll 218 is going to have a CR closer to 11:1 and a more aggressive cam.

 

To net gains from a larger carb requires some engine work first.  Even then the stock 26mm PD carb works great.

Edited by VortecCPI
  • Like 1

Share this post


Link to post
Share on other sites

Frank Nye did some tests comparing CV30 carb aganist the TM32, He said he could not tell the difference in performance but he noticed a huge difference in gas mileage, maybe a little better on the TM32 he said. I can confirm the results on my bike, I used a TM33-8012 pumper carb and the performance gain wasn't noticeable against the cv30. CV30 is a good carb IMO, I ride in PA and the weather goes from 20s to 70s and go up mountains and valleys and there is no real need for rejetting. Also no bog on sudden WOT. 

Here is what Frank Said:

"ok well we tried a TM32mmon our L with a250 kit 3 cam  EO pipe it ran great...but mileage was down ...reinstalled the stk carb....could not tell the difference on how it ran , it may have been a little better with the flatslide ...mileage shot back up to 90+   from 60/70 MPG , 130 main 38 pilot  holes in airbox lid 

washer under needle"
 
You can get CV30 from a crf230L/M models and from gy6 scooter if you remove the TPS, ofcourse nothing is a perfect fit like oem, you have to figure it out on your own.
Edited by Yap Yap
  • Like 1

Share this post


Link to post
Share on other sites
"ok well we tried a TM32mm on our L with a 250 kit 3 cam  EO pipe"

 

That is a very hot engine.  My guess is the OP has a bone-stock CRF230 as he did not mention any mods.

 

We need to be careful to keep things in context.  The needs of a stock CRF230 engine aren't even close to the needs of an 11:1 247cc engine with head work, Stage #3 cam, and Outlaw exhaust system.  Of course with an engine like that we need more carb.  A stock XR250 has a 30mm carb so there is no doubt an XR250 with cam and piston or Frank's killer engine requires something bigger.

 

We had an XRs Only Mikuni TM32 on our late-model XR250 for a while.  While the mid-to-top improved the low-to-mid suffered.  A 32mm carb on a bone-stock CRF230 would be a disaster.  Even the 30mm XR250 carb was too much for my stock engine for the type of riding we do.

 

All that being said a CV carb self adjusts to airflow needs so it could work but gains on a bone-stock engine would likely be little if anything.  When it comes to cams and carbs being on the small side is usually far better than being on the big side.

Edited by VortecCPI
  • Like 2

Share this post


Link to post
Share on other sites

That is a very hot engine.  My guess is the OP has a bone-stock CRF230 as he did not mention any mods.

 

We need to be careful to keep things in context.  The needs of a stock CRF230 engine aren't even close to the needs of an 11:1 247cc engine with head work, Stage #3 cam, and Outlaw exhaust system.  Of course with an engine like that we need more carb.  A stock XR250 has a 30mm carb so there is no doubt an XR250 with cam and piston or Frank's killer engine requires something bigger.

 

We had an XRs Only Mikuni TM32 on our late-model XR250 for a while.  While the mid-to-top improved the low-to-mid suffered.  A 32mm carb on a bone-stock CRF230 would be a disaster.  Even the 30mm XR250 carb was too much for my stock engine for the type of riding we do.

 

All that being said a CV carb self adjusts to airflow needs so it could work but gains on a bone-stock engine would likely be little if anything.  When it comes to cams and carbs being on the small side is usually far better than being on the big side.

I wasn't recommending the TM32, I was recommending the CV30 which comes with the stock crf230l/m. It's perfect for what he is looking for, almost no need for rejets and can stay in the game even if he modified his engine. Someone recommended the 36mm drz cv carb which IMO is too big. Just saying that the CV30 is already big enough for a modified 230, and it comes stock on other 230 models. 

  • Like 3

Share this post


Link to post
Share on other sites

I wasn't recommending the TM32, I was recommending the CV30 which comes with the stock crf230l/m. It's perfect for what he is looking for, almost no need for rejets and can stay in the game even if he modified his engine. Someone recommended the 36mm drz cv carb which IMO is too big. Just saying that the CV30 is already big enough for a modified 230, and it comes stock on other 230 models. 

 

A CV carb will not negate the need for jetting changes due to changes in air density.

 

As far as a 30mm carb on the super-docile CRF230L/M engine I would guess it was something Honda already had a part number for so they used it on those bikes.  Do we know how much time and money it will take to fit it to a CRF230F?  The 30mm PD XR250 carb is an exact fit, save for the fuel inlet nipple.  It literally goes right on so it can be done in a few minutes.

 

Seems like a lot of effort for questionable gains.  I agree with Mike Coe that there is no way a stock 223cc engine can make good use of a 30mm carb.  I'll bet the slide in the 30mm CV carb on the CRF230L/M never even opens all the way.  Just because a 30mm CV carb works on the CRF230 L/M does not mean it is THE BEST or THE RIGHT carb for that engine.  You can slap a 750 CFM Vac. Sec. Holley on an LG-4 305 or L-48 350 Chevy and it will run.  That doesn't make it right as those engines only need about 500 CFM of capacity.

 

My SRX 600 has two 27mm carbs and it is more than twice the size of the CRF230.

Edited by VortecCPI
  • Like 1

Share this post


Link to post
Share on other sites

Go

 

A CV carb will not negate the need for jetting changes due to changes in air density.

 

As far as a 30mm carb on the super-docile CRF230L/M engine I would guess it was something Honda already had a part number for so they used it on those bikes.  Do we know how much time and money it will take to fit it to a CRF230F?  The 30mm PD XR250 carb is an exact fit, save for the fuel inlet nipple.  It literally goes right on so it can be done in a few minutes.

 

Seems like a lot of effort for questionable gains.  I agree with Mike Coe that there is no way a stock 223cc engine can make good use of a 30mm carb.  I'll bet the slide in the 30mm CV carb on the CRF230L/M never even opens all the way.  Just because a 30mm CV carb works on the CRF230 L/M does not mean it is THE BEST or THE RIGHT carb for that engine.  You can slap a 750 CFM Vac. Sec. Holley on an LG-4 305 or L-48 350 Chevy and it will run.  That doesn't make it right as those engines only needs about 500 CFM of capacity.

 

My SRX 600 has two 27mm carbs and it is more than twice the size of the CRF230.

Nothing will eliminate the need for rejetting other than fuel injection, cv carbs are his best bet. Honda might have just used a 30mm cv for some reason but the beauty of CV carbs is that they change their bore based on the requirements of the engine. After all my name is Yap Yap and I yap alot and I could be wrong. Also I heard cv carbs don't flow as much as a flat slide so a 30mm is like a 28mm or something, not sure if that's true either.

Just leaving the 230L carb dimensions here, 35mm throat OD, 50mm intake bell OD,110mm from throat to intake, 145mm height.

  • Like 4

Share this post


Link to post
Share on other sites

Krannie is wrong about the Lectrons being 2 stroke only, If you go to cafe husky there is a bunch of info on the latest Lectron with the air bleed fitment fitted to 250s 450s 510s ect, All seem to have good results and no need for a AP

 

Cool. To replace the stock FCR though? Why would you need  to do that...,maybe they get worn out..

Share this post


Link to post
Share on other sites

Go

 

Nothing will eliminate the need for rejetting other than fuel injection, cv carbs are his best bet. Honda might have just used a 30mm cv for some reason but the beauty of CV carbs is that they change their bore based on the requirements of the engine. After all my name is Yap Yap and I yap alot and I could be wrong. Also I heard cv carbs don't flow as much as a flat slide so a 30mm is like a 28mm or something, not sure if that's true either.

Just leaving the 230L carb dimensions here, 35mm throat OD, 50mm intake bell OD,110mm from throat to intake, 145mm height.

 

Agreed on CV carbs, especially for street use.  My SRX600 has a slide carb as a primary and a CV carb as a secondary.  I get instant response from the primary carb and capacity as needed from the secondary carb.  It is an awesome setup for a big single and superior, in my opinion, to the dual slider carbs Honda used in the past on the XRs.

 

More from Mike Coe:

 

"The testing results exceeded my expectations! The engine made a tad less than 25HP at the wheel. 24.83 to be exact. The 30mm carb was worth a little more than 1.5 HP! The power band is wider than stock also!

I installed the stock carb back on specifically for comparison. The dyno curves overlap each other until @7500 RPM where with the stock 26 it levels out at 23.23 HP and falls off to 20HP when the rev limiter kicks in.

The 30mm carb allowed the engine to keep making peak power almost all the way to the rev limiter.

 

There is some added "work" that needs to be done to allow for the larger carb to work properly.

The main difference is obviously the opening in the carb. Where the 26 doesn't quite use the entire size of the carb body, the 30 mm carb does. This is also apparent in the std. intake manifold. (matches 26mm carb)

To perform optimally, you need to open up the manifold to match the new carb. I went a bit more and "ported" the manifold opening all the way to a full 30mm where it joins the head. I then blended in the entire manifold and intake port on the head to match to gain all the extra flow possible. The stock intake manifold and port is only @ 27mm."

 

 

So in summary we find the bigger carb nets 6.9% more power from an engine that was already making 30.3% more power than a stock engine.  To net that small gain required opening the intake port from 27mm to 30mm which is a lot of work.  The larger intake port alone accounts for a 23.5% increase in port area which is HUGE.

 

According to my many sources a well-tuned air-cooled single with good components should get you about 1 RWHP per 10cc at sea level.  By "good components" we mean a good cam and decent CR, not the dismal parts in the stock 223cc engine.  That means a 223cc engine with good components should make ~22 RWHP.  Add a really good tuned exhaust system and that number will increase.  That being said the 25 RWHP engine was not a race build by any stretch but it was also not just a 223cc engine with a cam and piston either.  It was likely an engine with more displacement and/or some head work and/or higher CR and/or bigger cam than usual.  We know Mike's personal trails/woods bike was making 27.5 RWHP and we also know he broke the 30 RWHP mark at the end.

 

So that still makes me believe a mildly-built 218cc / 223cc engine needs a carb not more than 26mm-28mm.  According to Powroll:

 

"If you have done most of the other breathing refinements you should consider Powroll's 28mm Mikuni.  You will realize a good gain at the top end but you will lose some of the low-end torque"

Share this post


Link to post
Share on other sites

I ride a lot, have three bikes and six engines. Each bike has a different carb.

Two of my bikes are 12.5-1 247cc one is over 13-1 269cc

I never wear the engines out, but I do constantly up grade all the time. Since I ride a lot, I want no down time so thats the reason for extra engines.

I ride from sea level to 8,000 feet ALL THE TIME depending on the particular riding area of the day.

Of course the power is down at 8,000 compared to sea level. So what? If I lived at 8,000 ft, they would be jetted spot on for there. Since I live at 50ft above sea level I'm jetted for home.

My most powerful and fastest bike (by far) has a 26mm XR200r carb

My funnest bike of all time has a 32mm Mikuni Flat slide.

My electric start bike has a 2004 49st XR250r carb

All are jetted perfect for where I live.

If I "Had To" re-jet all three bikes for all altitude changes, that would be absolutely absurd. I'm way to lazy, I just want to ride!

My bikes are dialed in during the week and absolutely flogged on the weekends.

IMO: if your not racing for at least trophies, or for cash $,

Then jet it for your favorite most frequent riding area and go ride it where ever you want and forget about the odd ball altitudes that you do ride in once and a while, but not very often.

  • Like 4

Share this post


Link to post
Share on other sites

+1 on above.  It is impossible to jet an air-cooled engine perfectly anyhow.  A perfect main jet will be different all throughout your riding day.

 

With proper float level and stock exhaust system a 120 main is the conservative "best" for a stock engine.  If you want to be less conservative install a 118 main.  A dyno might be able to measure he difference but you won't.

 

Peak power is almost never in the equation when you are riding trails/woods anyhow.  In that case throttle feel, response, and sensitivity trump peak power by a very wide margin as does setup, traction, suspension and line choice.

 

Now if we are talking about sustained WOT work like circle track that is a different story.  In that case that extra 1% can mean the difference between being #1 or #2 at the end of the day.

  • Like 3

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×