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Adjusting VM29 Mixture Screws? Trick?


Macduff

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My old slabby has always been a pig to start from cold or just warm. Originally the carbs were so far off it was mostly ridiculously rich as PO has raised float level and set mixture screws to 4+turns out (probably to try to adjust to running pod filters). I refitted a stock airbox with a K&N Factory style filter replaced the pilot jets float valves, reset float levels and mixtre screw settings to stock.

After that It usually started after tickling the accelerator pumps a few times with choke on and fiddling with the idle screw until it caught .

Since fitting the Yoshi starting has got harder, I suspect its got leaner due to the less restricted exhaust. I had a go at fiddling with the idle mixture screws and the two middle carbs are frigging a PITA to get at and then work out what you've set the screws too, outers are pretty easy with the right length screwdriver. So is there a wonder tool for doing the inner carbs ie did Suzuki techs have something to help or is taking the carbs off the only "easy?" way. 

As an aside I fudged the middle two  and set the outer two to about 3/4 out from fully in and it starts a lot better. I suspect the carb choke cct isn't working as well as it should on some of the carbs and at some point a full untrasonic clean or replacement with something else maybe on the cards. 

SO  any tips tricks or tales of woe on getting the carbs idle mixtures fiddled with in situe?

 

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4 hours ago, Macduff said:

set mixture screws to 4+turns out

Original setting is only half a turn out. 4+ turns out seems a bit excessive. (I'm assuming these are fitter on a slabby 750?) 

 

4 hours ago, Macduff said:

After that It usually started after tickling the accelerator pumps a few times with choke on and fiddling with the idle screw until it caught .

Sounds like you might have problems with the slow circuit such as clogged slow jets or air jets and you're bypassing them be using fuel from the accelerator circuit and choke to get the bike started. Does the bike keep running on tickover once warm or do you have to keep blipping the throttle or the bike cuts out?

Might be no harm getting the carbs ultrasonically cleaned and have all galleries and jets blown out with compressed air. Have mixture screws set at half a turn then and start from there.

 

4 hours ago, Macduff said:

So is there a wonder tool for doing the inner carbs

Type in '90 degree carb tool' on that auction site. This one is by Motion-pro.

motion pro carb tool.jpg

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Just to update I'm probably 3/4 of a turn out on mixture screws as a guess on middle carbs due to struggling with a small screwdriver and clearance. it starts a lot better than it ever has . will check out a suitable tool from the usual suspects though even with those it would seem difficult to tell if its seated in the mixture screw or turning in air?. I recall seeing an extended mixture screw for KTM fitted FCRs and wonder if they were available for the vm Mikuni?

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