Hello forum, I'm new here, I would appreciate the help.
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Go with what @SpookDog said. If you removed the YEIS from the Carb Boot...your carb settings should be okay (perhaps a little lean), since you're not altering the air after the carburettor, merely increasing flow over the carb. If you remove the one on the inlet manifold then yes it'll be a huge air leak, but you didn't....
So that to me sounds like poor flow through the airbox system. So remove the airbox lid and give it a good clean. Make sure the snorkel isn't obstructed etc.
yeah, yamaha doesnt recomend cleaning the foam element with petrol, but as long as you dry it out its noy a problem. then lightly oil the foam and sqeeze out any excess in a bit or two of kitchen roll. make sure to clean the rubber 'snorkel' and any dirt/dust from the top of the airbox...
brake clutch cleaner works well too... -
@SpookDog @Calum Thanks again for the suggestions but let's go in parts, Jack said, I made sure the air filter was clean, then maybe I expressed myself wrong or it was the translator's fault, but I repeat, I didn't remove the yeis. I removed the black bottle that is bolted to the frame on the side and fits into the rubber that connects the air filter housing to the carburetor. That is, imagine the air entering in excess when opening that inlet and very little through the air filter box. The logical thing would be to think that it would work worse but it was when the bike worked better at least in wot and it did not have the damn failure despite the large excessive air intake, which makes me think that perhaps I still have an electrical fault that I have not yet detected and that would make a weak spark at high revolutions that is not powerful enough to burn the fuel in wot. I even tried with everything connected without the snorkel and although it improved it was still a little rich so imagine.
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@SpookDog @Calum Thanks again for the suggestions but let's go in parts, Jack said, I made sure the air filter was clean, then maybe I expressed myself wrong or it was the translator's fault, but I repeat, I didn't remove the yeis. I removed the black bottle that is bolted to the frame on the side and fits into the rubber that connects the air filter housing to the carburetor. That is, imagine the air entering in excess when opening that inlet and very little through the air filter box. The logical thing would be to think that it would work worse but it was when the bike worked better at least in wot and it did not have the damn failure despite the large excessive air intake, which makes me think that perhaps I still have an electrical fault that I have not yet detected and that would make a weak spark at high revolutions that is not powerful enough to burn the fuel in wot. I even tried with everything connected without the snorkel and although it improved it was still a little rich so imagine.
@facundo-duarte Yes that's correct.
On later models Yamaha fitted two YEIS bottles.
One to the inlet manifold, and then one to the carburetor boot. You've removed the one fitted to the carburetor boot.
It sounds like not enough air flow to me.
If you remove the air filter/carburetor boot altogether you can see if your problem goes away and that tells you it's the airbox.
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@Calum Oh well, I didn't know he also had the same name as the other one, good to know. On the other hand, if the motorcycle is original and not modified, why do you suggest that the problem could be in the airbox if it is in good condition? Or did I misunderstand what you mean?
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Do you have the Snorkel fitted? Is there anything obstructing the top of the airbox?
I think this based off what you've told me. Sounds like giving it more air has resulted in night and day performance. Ergo, it's intake related.
Always Originate, Never Pirate!
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Do you have the Snorkel fitted? Is there anything obstructing the top of the airbox?
I think this based off what you've told me. Sounds like giving it more air has resulted in night and day performance. Ergo, it's intake related.
@Calum That's right, I already tried with and without a snorkel. without it works better in wot, although it still needed a little more, that's why I tried removing the yeis that is screwed to the frame. If we look at the problem with the naked eye it would suggest that I have a main jet that is too rich, however I checked its sizes including the pilot and they are fine, they correspond to the DTR model.
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@Calum Now that I look at it I don't know if it has anything to do with it, but I have a four-wire connector disconnected near the water tank in the back, apart from the one for the lights and indicators. I read that it is for the neutral relay but it doesn't have it, I have to attach a cable or something. Could it have something to do with that?
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I agree @Calum , I will let you know if there is any news. Did you see the message above about the neutral relay?
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I agree @Calum , I will let you know if there is any news. Did you see the message above about the neutral relay?
There are loads of unused block connectors all over my 1988. Just cause it’s there doesn’t mean it HAS to be used…
Your jetting is perfect for a late model Mikuni 28mm flatslide…
I’d try removing the side of the air box yourself (don’t take somebody else’s word on it) and remove the the foam element. They fall apart over time, especially the aftermarket ones….
They need cleaning with solvent, or petrol but make sure it’s proper dry. Then you have to wet it with oil and squeeze out all the excess…
