Should I do it?
#11
11-02-2006 | 07:31 PM
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Joined: Sep 2006
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RE: Should I do it?
I have to agree on the reference deal. They should not have a problem providing dirt bikes hat they have worked in the past. \
The price is good, shop labor to look at anything broken or not is around 85.00 after taxes here in FL.
You need a smooth tire for the dyno runs (pretty sure knobby dont work here) and if it did you will need a new one after the runs, unless the get lucky and get away with two runs.
Ask for a guarantee that the price will not increase due to having poblems getting it right. And who pays for the parts if they have to order ? do they have jets in stock?
I would do it if I had the money and a guarantee. check on the tire though
good luck
Hope you get it right
The price is good, shop labor to look at anything broken or not is around 85.00 after taxes here in FL.
You need a smooth tire for the dyno runs (pretty sure knobby dont work here) and if it did you will need a new one after the runs, unless the get lucky and get away with two runs.
Ask for a guarantee that the price will not increase due to having poblems getting it right. And who pays for the parts if they have to order ? do they have jets in stock?
I would do it if I had the money and a guarantee. check on the tire though
good luck
Hope you get it right
Not yet ...
#16
11-02-2006 | 10:11 PM
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RE: Should I do it?
Well, the shop called - they said it is ready. Didn't do any jetting, said it is running a little rich, but is not too bad and just left it. He said he didn't have the charts in front of him but thought the tech said the dyno showed 21 HP. He asked if that sounded about right and I said "Uh, no". I'm going to pick it up in a little bit - I'll question him more when I talk to him in person. I think this was a waste. I reckon I'll try and find another place and get a 2nd opinion. [sm=sigh.gif]
#17
11-02-2006 | 11:13 PM
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Joined: Dec 2005
Posts: 1,262
From: Just South of the Ocala Nationa Forest
RE: Should I do it?
Before you get down, understand dynos never read the same.
One dyno will read completely different from another. Depends on the operator, condition of and calibration!
Just thought you'd like to know.
One dyno will read completely different from another. Depends on the operator, condition of and calibration!
Just thought you'd like to know.
#18
11-03-2006 | 12:39 AM
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RE: Should I do it?
The actual dyno reading is 22.23, not 21, still not impressive but that's not the whole story - see below. The printout shows both the power (hp), torque (ft-lbs), and air/fuel reading showing where it is rich / lean.
First the power: max was 22.23, however. The curve is fairly linear linear from 5k to 7k and goes from 14hp to 22hp pretty linear in that range. Then it flattens out dramatically with a peak of 22.23 at about 8k and then it tails off quickly after that. They only went to 9500 RPM at my recommendation since the cylinder was still pretty new I didn't want to push it all the way to red-line of 10.5k. However, going to 10.5k wouldnt have mattered as the hp curve was heading downward pretty steeply at 9500.
The torque curve is pretty constant at 16.58 ft-lbs across the whole range until about 8k where it drops off quickly.
And the air/fuel curve shows it running about right at 4500 RPM but rich everywhere else with it's most rich location at around 5500. Regardless of what they say about the jetting being about right, I'm not believing that. In the 5500 range it is sputtering and even popping a little, almost feels like it is going to cut out sometimes. The CVK carb felt like it was pulling much harder in this range, as I've already mentioned a coupld of times. And at idle, it sometimes does cut out and takes a long time for the RPMs to settle. The FCR manual says what to do in this case and that is adjust the idle mixture screw. On it being more rich in the 5500 area than elsewhere, I think that might be a needle clip adjustment and in the overall richness across the whole range, I think that is a main jet size reduction.
What I think is, they saws how tight this carb is in there and they didn't want to hassle with taking it in and out multiple times and said, eh, close enough. But it is not close enough for me! Without the drop-off in power at around 7000 RPM, the curve looks like it could easily to 28 hp if it would pull even to just 9k, let alone red-line. And there's really no reason it shouldn't do that - unless our cams are ground to just now allow that. If it pulled to red-line it would be up over 30hp easy.
So, I'm not unhappy I had it done - there's a lot of good information there. What I am not satisfied about is that they didn't do any tuning. There's no reason this carb should be dropping off at 7k RPM and it should pull on up to around 9-10k IMO. But on the upside, things look pretty good in the in the 4-7k range and I believe there's a lot of room for improvement even there with proper carb tuning. That's where I spend most of my time while riding anyway so that's the range that I really care about. But it would be nice to have it pull all the way up to red-line - if nothing else to know that the bike is tuned correctly across its entire useful range. That might not be possible without a camshaft change, though.
BTW, they only charged me for the dyno and did not charge for any tuning since they didn't do any. [&:]
I'll try and take a photo of the chart and upload it so you can see the graph yourself.
So they say necessity is the mother of all invention. It is also what drives us to learn new things and it looks like I will soon be learning the intracacies of Keihin FCR tuning - not necessarily by choice, but by necessity. [&:]
Cheers,
First the power: max was 22.23, however. The curve is fairly linear linear from 5k to 7k and goes from 14hp to 22hp pretty linear in that range. Then it flattens out dramatically with a peak of 22.23 at about 8k and then it tails off quickly after that. They only went to 9500 RPM at my recommendation since the cylinder was still pretty new I didn't want to push it all the way to red-line of 10.5k. However, going to 10.5k wouldnt have mattered as the hp curve was heading downward pretty steeply at 9500.
The torque curve is pretty constant at 16.58 ft-lbs across the whole range until about 8k where it drops off quickly.
And the air/fuel curve shows it running about right at 4500 RPM but rich everywhere else with it's most rich location at around 5500. Regardless of what they say about the jetting being about right, I'm not believing that. In the 5500 range it is sputtering and even popping a little, almost feels like it is going to cut out sometimes. The CVK carb felt like it was pulling much harder in this range, as I've already mentioned a coupld of times. And at idle, it sometimes does cut out and takes a long time for the RPMs to settle. The FCR manual says what to do in this case and that is adjust the idle mixture screw. On it being more rich in the 5500 area than elsewhere, I think that might be a needle clip adjustment and in the overall richness across the whole range, I think that is a main jet size reduction.
What I think is, they saws how tight this carb is in there and they didn't want to hassle with taking it in and out multiple times and said, eh, close enough. But it is not close enough for me! Without the drop-off in power at around 7000 RPM, the curve looks like it could easily to 28 hp if it would pull even to just 9k, let alone red-line. And there's really no reason it shouldn't do that - unless our cams are ground to just now allow that. If it pulled to red-line it would be up over 30hp easy.
So, I'm not unhappy I had it done - there's a lot of good information there. What I am not satisfied about is that they didn't do any tuning. There's no reason this carb should be dropping off at 7k RPM and it should pull on up to around 9-10k IMO. But on the upside, things look pretty good in the in the 4-7k range and I believe there's a lot of room for improvement even there with proper carb tuning. That's where I spend most of my time while riding anyway so that's the range that I really care about. But it would be nice to have it pull all the way up to red-line - if nothing else to know that the bike is tuned correctly across its entire useful range. That might not be possible without a camshaft change, though.
BTW, they only charged me for the dyno and did not charge for any tuning since they didn't do any. [&:]
I'll try and take a photo of the chart and upload it so you can see the graph yourself.
So they say necessity is the mother of all invention. It is also what drives us to learn new things and it looks like I will soon be learning the intracacies of Keihin FCR tuning - not necessarily by choice, but by necessity. [&:]
Cheers,
#20
11-03-2006 | 01:24 AM
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RE: Should I do it?
Looks like the FCR carb is off my list now. Sorry to hear you got such discouraging numbers. I was expecting at least 30 horsies with that FSW tuned carb and your cylinder bore. I think I'll do the 300 kit conversion and leave the CV carb since it's easier to tune and I've really never had a problem with it's response for what I use it for. Now if I were MX'ing the thing it may have to go. But of course this bike is a very far cry from a full MX bike. I think that switching carbs is a bit overkill for this bike as it has never had a pumper carb on it stock. Once you do start going that way in the mod segment, it just opens up a whole can of worms that can lead to good or bad for the bike. I wish I could have dyno'd my bike a few months back to see where I'm at with my mods. I would hope I would be at least where they told you your bike is since it's only 4 horse over stock. Are you sure their dyno is working properly? That's almost unbelievable. Nonetheless, you can still try and tune it for more. But that's what I don't like about those carbs- where does it stop? You'll find yourself working on the bike more than you ride it. I went through this with a jet ski that was hopped up with a factory pipe, reeds, and a performance carb. The thing never ran right unless you were bouncing off the rev limiter and I was always working on it while my friends were out riding. I got rid of it. I wonder what numbers you could have gotten with the CV carb on. This bike just doesn't have any power, modded or not. I think that's why they call it a "playbike".