Is anyone using Dynojet needles with the original Keihan Jets?

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mdb
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Is anyone using Dynojet needles with the original Keihan Jets?

Post by mdb »

I have bought a bike which has a standard setup, airfilter and pipes. While cleaning the carbs I have found it has Dynojet needles and 190 main jets fitted. It is way rich according to the spark plugs. I was considering fitting DJ 170 front and 175 rear but I have read several positive experiences with using the original Keihin main jets (which I think are 175 front and 178 rear) with DJ needles on 4th or 5th slot.

Has anyone used either a full DJ setup (170 mains) with standard bike or DJ needles with standard mains with good results.

I ask because DJ 170 is equivalent to a Keihan 190 so the sizes are not close.

Thnaks guys.
Mark
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freeridenick
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Re: Is anyone using Dynojet needles with the original Keihan Jets?

Post by freeridenick »

Here's where to start.

I personally can't see any reason why DJ needles can't work with non-DJ jets but it's not something you would want to try without a Dyno setup session. The 170 Keihin jets aren't the same size as DJ 190s iirc but I've not got the chart handy. There's no easy matching between the two companies though.

I wouldn't go off plug colour that just indicates the mixture when you switched it off - find out where the fuel screw is at first. As an illustration I ran DJ needles 4th from top, 190 DJ mains front and rear with aftermarket cans and link pipes plus DNA filter. I have the Dyno chart showing it was running lean.
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mdb
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Re: Is anyone using Dynojet needles with the original Keihan Jets?

Post by mdb »

Contacted Allens and they advised me not to reinstall Keihin jets after having Dynojet jets fitted as the dynojet ones alter the thread slightly when installed. Apparently Dynojet are universal for both Keihin and Mikuni which have different threads, so theirs are set between the two makes.

If this is not true then don't shoot the messenger.

Anyway, after receiving this info I ordered some 170, 175 and 180 jets from Dynojet.
tony.mon
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Re: Is anyone using Dynojet needles with the original Keihan Jets?

Post by tony.mon »

Ask them for the thread specification, they will all use a standard metric thread, I would expect.
It's not falling off, it's an upgrade opportunity.
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Stephan
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Re: Is anyone using Dynojet needles with the original Keihan Jets?

Post by Stephan »

I use dj needles with keihin jets without any problem.
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popkat
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Re: Is anyone using Dynojet needles with the original Keihan Jets?

Post by popkat »

Steve at Allens is a mate of mine and knows his stuff, but I have swapped between dynojet and Keihin and not had any problems.


Different make jets are different sizes, for example a dynojet 180 is not in any way the same as a Keihin 180 and that is not the same as a Mikuni 180, some are on flow rate some on size, I can't remember which is which though but think Mikuni use a tapered flow rate.
a dynojet 180 is equivalent to something like keihin 200 or more. There are comparison charts online although they won't be 100% accurate.


With modern fuel containing ethanol it's no longer easily possible to read a plug like you used to be able to do, to read a plug you need to fit new plugs, ride or plug chop the remove the plugs cut the thread off and look deep down in the porcelain, your looking for a dark or grey coloured ring.

You could jet old school, for pilots if it's rich the throttle will be fluffy, lean and tickover won't be stable, for mains pull the choke out, if it runs better it's lean. It takes time to get right, or you could go to a dyno, one that has a good rep for working with carbs.


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2014 CRMC Post classic Superbike champion.
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popkat
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Re: Is anyone using Dynojet needles with the original Keihan Jets?

Post by popkat »

Here's a chart found online, I can't vouch for it's accuracy but search a few more and you'll find a pattern, they are all approximations though.


http://www.jetsrus.com/FAQs/FAQ_mikuni_ ... _sizes.htm




.
http://www.bidefordmotorcycles.co.uk
2014 CRMC Post classic Superbike champion.
2014 CRMC Post classic senior production champion. On a Suzuki Katana 1100
My bikes, Firestorm, Suzuki GSX-s1000 Katana, VFR800Fi. Projects, 1986 popup Katana, 3 XJ600’s
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