That diaphragm ain't no PUMP. The carb is a constant velocity carb that uses engine vacuum to lift the slide thus carrying the attached needle up and increasing airflow and fuel. Yes the butterfly controls the air flow. Really nice as it reduces stalling on sudden throttle application.
Good to know the Chineezy slide and needle assembly works with the stock Mikuni emulsion tube. In cleaning the carb that came on my used 2000 Kodiak 400, I found the bottom of the slide was pitted and slightly melted (the result of a backfire perhaps?), so I shelved the unit (which I recently discovered is actually a rebuilt Mikuni BSR33 with the "Mikuni Made In Japan" ground off and the wrong sized jets installed - thanks a lot, ZoomZoom Parts!), and replaced it with a cheap Chineezy knock-off. After seeing your video, I'll be swapping out the entire slide assembly from the Chineezy unit to the old Mikuni once my rebuild kit with the right sized jets arrives. If Mikuni publishes manuals for their older model stock Yamaha carbs, do you know where to find them? Thanks again for the video!
I have a grizzly 450/ 2007. I recently removed the carb to clean the jets. I noticed the throat of the carb had a lot of debris in it ..much like yours in the video. I didn't think much about it and installed the carb back as is after cleaning the jets. Does that debris and dirt in the throat transfer into the cylinder? Kinda worried about sitting here thinking about it. I should have washed the atv first before servicing and then completely cleaned entire carb. What are your thoughts?
Unfortunately, the debris in the throat of the carb does get sucked into the cylinder. Hopefully none of that debris was sand/silica. Soil without sand will probably be ok once in a blue moon.
Any advice on it dying in reverse rides fine going forward but it’s been sitting for probably 3 years and haven’t cleaned the carb yet but it starts revs and drives fine but grinds going into reverse and will studded trying to back up
@@outdoorgorilla1493 yes I heard you say P Zed 1? It's was hard to make out what you said that's why I asked,I'm trying to get my carburator open but all my screwdrivers I have will strip it so I was wanting to get the kind you had ,if you're willing to point me in the right path?
I don’t think he does it but i would personally do it for about $75-100. Shops typically charge about $150-250. I would be using an ultrasonic cleaner with proper chemicals that wouldn’t damage, oxidize or darken the brass and aluminum. Most people forget to clean the emulsifier jet tube, needle jet and other small passages like the pilot air/fuel and startup-enrichment fuel pickup. The float valve seat, float valve, and diaphragm are often also overlooked.
Great video, the idle adjustment on my atv is pretty much as low as it can go and it still idles around 1000 - 1200 rpm with choke off so I'm going to check the intake boot next.
That's low mate. It should idle at 1450-1550RPM I don't know what makes you think its high but your either measuring it wrong or it not your idle that's the problem
@@outdoorgorilla1493 maybe it is idling where it should then, maybe it could be because the muffler is pretty much shot and needs to be replaced so it sounds louder than it should at that rpm.
