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Help tuning a carb

Tourmeister

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Glad it is working better. It can certainly be frustrating!
 

Monica

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Glad it is working better. It can certainly be frustrating!
Oh it absolutely is. Thought I'd never find the light at the end of the tunnel.


Good to hear, as we need to get you down for a guest ride at Zars Ranch as soon as you get it rolling correct.
I was thinking about that actually on the drive back to SA. The riding skills I picked up earlier this year stagnated during my time off the bike :argh:
 

Monica

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Just keeping a running tab of the work now but I upgraded the fuel line size to 1/4" and installed a new 1/4" fuel filter. What I am attempting to resolve with this change is the bike would get fuel starved after a top speed run in 5th gear. I think the 3/16" stock line just couldn't keep up with the carb demand.

Also I adjusted the clutch, it had too much slipping and it would die on incline. So tweaked the clutch cable sleeve. The bike now will power up an incline in 1st and 2nd and the shift from 1st to 2nd is more positive and easier getting into gear.

I hope to test ride tonight after work. Been on a time crunch since inspection and registration are due this month, had to get this thing on the road. Stressing out over it that I hadn't been sleeping well, all the things to try running through my head and when I'd have time to do them and test them out without getting smushed in traffic with these hot-headed drivers around here.

Last things are:

- fix the TrailTech speedo, it died. I contacted their tech service and they're sending a new sensor out to me. Hopefully that will fix that problem

- fix neutral switch, it's wobbly or something and doesn't like to start after being run. I had to pull the clutch lever in to start. I discovered it will make a connection and start if I click up and down on the gearshift like a tweaker. I have a new switch I ordered a while back but I need to install it. Anyone know if I have to tip the bike on it's side so oil doesn't come out in order to change it?

Thanks for listening to my ramblings, helps to get it out.
 

Tourmeister

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I hope you at least get some feeling of satisfaction/enjoyment from doing all this work ;-)
 

E.Marquez

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The thought has crossed my mind. I hoped not to go back to the stock carb. The VM24 is an upgrade that, among other benefits(I've yet to see), eliminates the choke cable running to the bars (its a known failure point for this bike). It's definitely a hard pill to swallow being that I just bough this carb, new, at the beginning of the year. I looked at new ones, they've gone up $20! :doh: I've got the stock carb on the shelf, I'm halfway considering putting it on, but I'd need to fix the choke (I lost the little parts to the cable end when I removed it).

I'm not ready to give up on it yet...apparently, I'm hard headed and stubborn.
Sometimes the best solution is not to give up, but have a fresh set of eyes and hands take a crack at it... Consciously or not sometimes we overlook a possible solution or issue because "it cant be that"
For instance, its a "brand new carb" so its cant have a plugged passage and you don't even consider it, only it does have a passage blocked due to a drill passage plug being driven in too far and its partially occluding the passage. ..or "brand new carb" so it cant need to be cleaned.... only it does.... as some gas went off in the two weeks you had to take a break for work and family reasons and it shouldn't have...but it did plug a passage.


A recent it happened to me... Brand new Yamaha V Star 250's,. three of them... Dealer prepped and delivered... we struggled for weeks and many failed class use's trying to use these bikes as they would not run smooth, fouled plugs, refused to start after only a few hours use. No dealer support as these are DPS purchased in bulk and service is up to the company they are loaned to.

My mechanic at the time servicing that part of our fleet was having no luck solving the issue, he quit due to a new job offer.... I took over servicing our entire fleet.

I assumed nothing when I took in one of the bikes ..just grabbed one at random and figured get it figured out then apply that solution to the others. Pretty basic bike, so basic diag..it was a fueling issue no doubt and all things pointed to a fouled carb.. Carb out, looked "clean" but sonic tanked it anyway.
It ran better for a few hours, then same issues.
Carb out again and I did a better check of all passages... there was one, and micro hole in a tube that feeds fuel to I believe the idle circuit, it was almost unnoticeable due to where it is. jet cleaning wire seemed to indicate the hole and passage was clean...then I filled it with fluid and hit it with compressed air......and it all flew back in my face.... that passage was blocked someplace. I used some much smalled gauge wire (piano wire) and ran the hole....found the block, punched though it and tried the fluid and air deal again, out came some brownish stuff from the other end of the passage...

It was a brand new bike, it was dealer prepped, the carb looked clean... but at some point it had gas in it and sat long enough for that tiny passage to become blocked
 
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Tourmeister

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Excellent post!

At work, I occasionally have to step away from a problem and give my brain a chance to reset so I can things in a new light. Sometimes it only takes a few minutes. Other times it takes longer. I also have to check the work of another person before we can send it out. It is amazing how often I can look at something, expect something to be present and THINK I see it, when in fact is it NOT THERE!! I hate to really make myself go through and explicitly check each thing. It can be very frustrating!!
 

Monica

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Eric, appreciate the insight, And seems like it's the smallest things that plague. Glad you found that blockage on that bike, I can imagine the relief you must have felt. I'm finally feeling it now.

Tourmeister, you are correct about resetting the brain. When I step away my brain still cranks on it until BAM!, a solution. I got out, try it and, viola...there it is. What a challenge this bike has been.

Good news tonight, just got back from riding around town and the bike is running pretty decent right now (aside from my sketchy unpracticed shifting :uhoh:). Before I went out I installed a new neutral switch. That has solved the random no start issue. And somewhere in the ride my Trail Tech speedo even started working too. I guess it must have lost connection/calibration or something odd from sitting so long. The larger fuel line and new filter kept the carb supplied and it didn't die at any of my decels/stops. In a wierd way I kinda wished it would have, I wanted to try out the start button in neutral lol I pit stopped at the Valero just to have an excuse to turn off and restart the bike.

Ever since I got this bike I was curious how fast I could get it going...there's the top speed so far. I think I could have hit that last tenth but I was coming up to a stop sign and had to let off :thpt:

Also, can yall look at my spark plug, what do you think? Lean or ok?
 

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OldTLSDoug

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Is your speedo sensor mounted on the brake caliper? Or on a bracket. Sometimes the sensor is just far enough away that it will operate intermittently. I just had to mess with the one I installed on my DR-Z400S. My bikes have the Vapor wired direct to the battery. There is an internal battery that can go bad as well. But it sounds like sensor issues not battery issues.

IMG_09221.jpg
 

OldTLSDoug

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P.S. I think the plug is decent bordering on a little rich. Usually you get a little tan color on a properly running scooter.
 

Monica

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Doug, speedo sensor is mounted to the fork tube and I have it connected to the battery.
Noted on the spark plug, thanks.
 

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OldTLSDoug

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The sensor may be ever so slightly too far away and that may be causing the intermittent display. If you move it down say 10 mm (0.4 in) or so further down the fork leg, it might fix you up. You could also glue on a small rare earth magnet to "boost" the signal to the sensor. Lots of ways to skin this cat.
 

Monica

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K, I'll try placing the new sensor closer, should get here tomorrow. It's 1/16th inch away, so it's gonna be tight!

Had the bike out today and the sensor stopped working a couple miles in and it didn't come back. So, I dunno. Hopefully the new sensor fixes it. I read online where others had to replace their whole unit because it went bad.

On a happy note, inspection and registration are done.

Can you tell me more about boosting it with an earth magnet?
 

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OldTLSDoug

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You can get small rare earth magnets. Just align it so it sticks on the current wheel magnet and apply a little epoxy to hold it. Worked on my little mini bike wheel to use a bike speedo. I also think the sensor is more central in the plastic piece, hence my suggestion to lower it. I will get a picture of both of mine today and post them up.
 
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Monica

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Tried doubling the magnets, nothing. Installed the new sensor and wire, including the doubled magnet and nothing. Reset the unit, nothing. The unit itself might be broken :-( Emailed Trail Tech again, we'll see what they say.
 

StromXTc

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Tried doubling the magnets, nothing. Installed the new sensor and wire, including the doubled magnet and nothing. Reset the unit, nothing. The unit itself might be broken :-( Emailed Trail Tech again, we'll see what they say.
I believe you can use a digital multimeter and test the wires going into the back of the trail tech using the continuity meter and get a response out of the magnet pass. At least you would know if it's the lead or the console. Also may want to reseat the connection. Stranger things have happened
 

Monica

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Referencing this thread to help out someone tuning their VM24. Got to the end and realized I never followed up on the speedo issue.

I believe the problem was the Vapor unit afterall. In ordered and installed the Voyager and it's been working fine.

Trailtech was helpful through the process and bench tested the Vapor I sent to them. They said it worked great. After they sent it back, it failed again on the road after working for several miles. I don't think Trailtech road tested the Vapor mounted on a bike. I believe if they did they would have found the issue. I believe there was an internal contact problem that shows up when bouncing around, vibrating on the bike's handlebars going down the road. I changed out the sensor on the wheel three times. I'm confident magnet placement was not the issue since both units worked fine on the stand in the garage.

At the end of the day I'm glad to have an operational unit in the Voyager. At the same time bummed I had to pay again, but I was 2 weeks past the 1yr warranty period. So guess that was fair. Trailtech did cut me a discount which helped out. I'm thankful they were able to do that.

I do still have the Vapor unit if anyone wants to mess around with that for a rando project. I've got several speedo sensors but you'll have to get the rest on your own.
 
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