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Need some advice on carb setting

Old 05-21-2019, 04:57 PM
  #1  
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Need some advice on carb setting

Hi peepz,

so a few weeks back I tried to start my bike and things didnt go as I hoped, bike had been sitting in a dark corner for over a year.
First the bike didnt want to run on the fuel that was in the tank so Ive got the old fuel out and put some new fuel in.
Bike liked the new fuel and I was able to drive, after a short ride I checked my plugs and they where white, also the bike was stuttering in the low rpm range but had enough power from 4000 rpm.

So I decided to check my jets.

The jets dont look to clean.

Now Ive been cleaning the jets and my carb, but everything has to be mounted again and Im having my doubts about my old setup.
My bike was running a bit to lean before the cleaning and has a dip in the low rpm range, as I was told by the mechanis when I dyno'ed the bike.

Before the trouble my setup was:
Laser cans
Dynojet stage 1 kit (F 180 - B 185)
Needle on 4th groove from the top
BMC standard air filter
Mix screws 2 turns out

I know the FMS isnt set right, the bmc filter doesnt do much and the needles are probably to high.

My question: what would be a good setup to start with?

Ive been reading a lot and Im only getting more confused about where to start now...
THe plan is to put everything back together and do another dyno run.
I know it takes a lot of time to get it almost right and it isnt easy, but I would like to get things as close a possible.
Im a bit lost haha.
Are my mains right for this setup or should I change these?
Should I use a OEM Honda air filter instead of the BMC?

Thanks
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Old 05-23-2019, 02:26 AM
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I have a similar setup in mine and yes your jets are filthy. Clean them as best as you can, especially your pilot jets. It sound as though you have a pilot circuit issue because you are running poorly until you come up on the needle at about 4k. Also, if you are on the 4th clip with a BMC and after market cans, I recommend a .015 ~ .020 shim under the clip. One clip space is about .025 and at the point of adjustment you are at with the needle you are just starting to get on the taper and a small change will go a long way. So rather than go to the 5th clip, use a spacer that is less than one clip change. If your pilots are 45, turn the screws out to 2.5 as a starting point. You may need to go to 48's in the future rather than turning the screw out 3 or more turns. 48's can be had cheaply, but make sure your jets are clean before you change them to 48's. Make sure you can see light clearly through all holes. Lastly, check your throttle position sensor if you have an ohm meter.
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Old 05-29-2019, 07:14 AM
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Originally Posted by ACE VenTRa View Post
I have a similar setup in mine and yes your jets are filthy. Clean them as best as you can, especially your pilot jets. It sound as though you have a pilot circuit issue because you are running poorly until you come up on the needle at about 4k. Also, if you are on the 4th clip with a BMC and after market cans, I recommend a .015 ~ .020 shim under the clip. One clip space is about .025 and at the point of adjustment you are at with the needle you are just starting to get on the taper and a small change will go a long way. So rather than go to the 5th clip, use a spacer that is less than one clip change. If your pilots are 45, turn the screws out to 2.5 as a starting point. You may need to go to 48's in the future rather than turning the screw out 3 or more turns. 48's can be had cheaply, but make sure your jets are clean before you change them to 48's. Make sure you can see light clearly through all holes. Lastly, check your throttle position sensor if you have an ohm meter.
Hi,

Ive cleaned everything as good as I could and it looks much better now. Checked all of the holes in the jets and the look clean again.
Ill start by assembling everything back together and see how she runs. If it doesnt feel right I might check the shims and raise the needle.
Ive already used the shims that dynojet provides with the kit btw.

Im now waiting for my floatbowl rubbers, orderd some new ones cause the old ones where flat.

Today Ive installed the gasslides but I noticed that the diaphragms somehow fit differently.
The one in the front fitts perfect, the one in the back looks smaller and doesnt go around the flench that easy.

The front and the back slide dont have different size diaphragms or do they?
Also the slides open and close differently. (see vid)
Dont know if the previous owner changed the springs or slides... Tomorrow Ill check if the springs have the same length and check the diameter of the diaphragms.

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Old 05-29-2019, 11:54 AM
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The diaphragms are the same size front and rear and the springs should be the same length. It is likely that you have shorter dynojet springs, but both should be the same length. I find that sometimes one diaphragm will be a little tighter than the other, no biggy. Just make sure there are no rips or holes. Also, if you have a caliper you can measure the washers that dynojet provides, you may need a thinner one. Make note of their location being either above or below the clip, I think th einstruction say to place one above and one below. Although, now that I think of it, most people have poor luck with "performance" filters in the Vtr. Try running a stock or equivalent if you keep having lean issues.

AV
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Old 05-30-2019, 06:40 AM
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If the diaphragm rubber is swollen and no longer fitting, a trick that often works is to boil the rubber in clear water 5-7 min in boiling water, cool with fresh water test fit. repeat as needed.

The boiling water drives out petroleum products from the rubber most times. Its not 100% fix for all that ails rubber parts that are swollen, buts its worked enough times for me that I trust the process.
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Old 06-02-2019, 05:00 PM
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+1, true story
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Old 06-03-2019, 02:06 PM
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Thanks for the tip!

Ive pulled the diaphragms out and switched sides.
The smaller one seems to fit better on the other side or maybe Ive changed something in the assembly process.
But it fitts, slides open/close almost the same.

Next, lets see how she runs.
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Old 06-07-2019, 03:58 AM
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So yesterday I took the bike for a drive and everything seemed ok.

Only thing I noticed was when the bike is in idle, it sometimes skipps a beat and then comes back to idle.
So the rpm dies and than comes back to idle, its like it dies and then breaths again.

Also I wanted to check the plugs and see how the color is.
So I removed the tank and when I pulled of the vacuumline of the fuelcrane I found fuel in the vavcuumline.

So:
- So fuel in the vacuumline
- When in idle the bike dies and gets up. (only happend 2 times on the whole trip of 40 minutes)
- Plug color look OK...

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Old 06-07-2019, 04:07 AM
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Plugs look like they are burning ok, clean them up and re-use them. Double check the gap. As for the fuel in the line I would say that the petcock needs to be rebuilt, probably a tear in the diaphragm or o-ring. Easy peasy. While you have the tank off and are doing that...maybe it's time for a valve clearance check to eliminate that potential issue.

AV
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