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Re: Popping & Banging on the Overrun

PostPosted: Sat Jul 23, 2016 5:48 pm
by dandywarhol
Check item number 46, diaphragm, isn't perished with ethanol/age. It's an anti popping valve :D

https://www.motorcyclespareparts.eu/yam ... 43944.aspx

Re: Popping & Banging on the Overrun

PostPosted: Sat Jul 23, 2016 9:24 pm
by DAVID THOMPSON
posted this in case link goes dead

click to make it bigger

Re: Popping & Banging on the Overrun

PostPosted: Sun Jul 24, 2016 4:58 am
by starfield181
I wound the pilot adjuster screw out. Probably about 4 turns in total now and the popping & banging was much reduced. The tickover also speeded up a bit so. I will try another 1/2 turn out to see if it continues to improve.

Interesting concept of an anti popping valve. Wonder how its supposed to work. Looks as though you have to buy the whole assembly rather than just the diaphragm. Think I will continue with adjustments for the moment. Bike is certainly much better now.

PeterF

Re: Popping & Banging on the Overrun

PostPosted: Sun Jul 31, 2016 6:04 pm
by billr
EDFManiac wrote: "The Mikuni VM28/486 #40 pilot jet works. It doesn't look like the stock jet but it functions just fine and is available at almost any place that carries Mikuni jets."
I took that advice and changed mine out. No more popping and I'm at 3 turns out.
BillR

Re: Popping & Banging on the Overrun

PostPosted: Tue Aug 02, 2016 4:08 am
by breakwellmz
I see the biggest size these (UK) suppliers keep is a 37.5, what size is the standard jet?

http://www.ebay.co.uk/itm/142044406653? ... EBIDX%3AIT

Re: Popping & Banging on the Overrun

PostPosted: Tue Aug 02, 2016 3:50 pm
by Nabsteel
Have a look at my thread 'Does this spark plug look ok?'

I bought a Baghira a while back and it was backfiring on the over run badly. I turned the mixer screw out as much as i dare, which helped but didn't completely solve the problem. It was running lean, but wasn't completely sure, so put it on the rolling road and paid £80 in total to get it re jetted correctly and now it runs great and pulls better to boot!

viewtopic.php?f=3&t=8340

Re: Popping & Banging on the Overrun

PostPosted: Tue Aug 02, 2016 5:34 pm
by edfmaniac
breakwellmz wrote:I see the biggest size these (UK) suppliers keep is a 37.5, what size is the standard jet?

http://www.ebay.co.uk/itm/142044406653? ... EBIDX%3AIT



There's no way of telling what the stock Mikuni equivalent would be because they flow differently than a Tekei jet. But my bike was just slightly rich with the #40. A #37.5 might be right on the money.

Re: Popping & Banging on the Overrun

PostPosted: Tue Aug 02, 2016 5:40 pm
by edfmaniac

Re: Popping & Banging on the Overrun

PostPosted: Mon Aug 08, 2016 3:39 pm
by breakwellmz
edfmaniac wrote:
breakwellmz wrote:I see the biggest size these (UK) suppliers keep is a 37.5, what size is the standard jet?

http://www.ebay.co.uk/itm/142044406653? ... EBIDX%3AIT



There's no way of telling what the stock Mikuni equivalent would be because they flow differently than a Tekei jet. But my bike was just slightly rich with the #40. A #37.5 might be right on the money.


I got one from these people it turned up today, you can`t go wrong at that price but it`s gone up already!

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... _500wt_969

Re: Popping & Banging on the Overrun

PostPosted: Tue Nov 29, 2016 7:16 am
by Henry74
Hi, you are mentioning nbr 37.5 and nbr 40 Mikuni Pilot jets. But what do these numbers stand for ? the jet hole measurements maybe eg .40 mm ?

Re: Popping & Banging on the Overrun

PostPosted: Tue Nov 29, 2016 10:31 am
by dandywarhol
Henry74 wrote:Hi, you are mentioning nbr 37.5 and nbr 40 Mikuni Pilot jets. But what do these numbers stand for ? the jet hole measurements maybe eg .40 mm ?


Mikuni numbers indicate flow rate in cc/minute