Dynojet jet sizes - what's your setup?

[Saracen]

After realising there doesn't seem to be a hard and fast answer for converting from Mikuni to DJ sizes, I figured I'd see what others have done. I'm running a CCC can (debaffled), and have installed tank spacers.

What size Dynojets should I install? Opinion seems to be 140 or 142. What have others installed?

PS. Some quick replies appreciated as I'd like to order the jets today.

[haggis]

138 was the biggest size in my dj kit so that's what's in there.

Slip on can, pipercross filter, tank raised. Power curve is quite smooth at that, max 71.5bhp.



Can anyone tell me why do they supply smaller sizes in the kit? ie, 132, 134, 136, 138 when original is 137.5

[northwind]

Mine's bigger than yours :) 175 DJ main jets (should maybe be 170...) with a BMC Race RS filter, tank spacers, and WRP Lite race system.

Haggis, they do that for 2 reasons. One is that the standard jet is Mikuni, and the number systems don't match. The other is that the DJ kit's all over the place :) The Stage 1&3 kit contains, IIRC, 136, 138, 140, 142, 144, 146, then jumps to 180 and 185. Opinions vaery, but I work on the assumption that it was specced with the original, dodgy K&N filter, the one that was worse than standard.

[Saracen]

Come on boys, there must be many more out there with DJ kits installed. Looks like I'm going to go for 140 or 142. Don't want to run too rich either. I'm assuming 140 will be quite a bit better than stock?

[Fuzz]

Mikuni jet sizes are either measured by flow rate or aperture size. Dynojet jets are measured by aperture size only.

http://faq.f650.com/FAQs/JetKitFAQ.htm

It's odd though that the chart would mean a DJ138 is smaller than the Mikuni 137.5 equivalent.

[Saracen]

So what's it going to be? 140, 142 or 144? Please someone, so I can order the jets and get back on the road.

[Mike1234]

I'd go with 140s to start with. Given the cost of the postage versus the cost of the jets I'd get some 142s as well just to be on the safe side :-)

[Saracen]

It's just I really can't see myself taking the carbs off again. It's fiddly and I just wanna ride!

Hmm, narrowing down to 140 or 142?

[northwind]

I'd go with Mike...

[northwind]

So to speak :)

[TSM]

I put DJ150s in and it was running quite nice with a K&N + Quill T3.
A bit lumpy on cold but when warmed up it would pull much harder than before when it had DJ140.

[Saracen]

Hmm,

No K&N here, and no plans to get one, so perhaps I'll go for 142.

[Mike1234]

Sorry, I'm talking b*****ks. Aim for a 140 Mikuni and you should be on the money.

I forgot to put my thinking head on and was confusing DynoJets with Mikunis.

[northwind]

And after I backed you up too.

[Saracen]

OH no, back to square one! SO what's that in DJ?

[Mike1234]

Probably a 150.

See http://vmaxoutlaw.com/tech/dyno-mikuni.htm for a comparison.

[northwind]

See, I still reckon 150 will be too big for a bike with a standard filter and slipon. I don't trust those charts myself.

[Saracen]

See, those charts can't be right if the Dynojet kits include jets as small as 136 and a max of 144 or whatever. It seems from what I've read on the SVRider forums that it should be the other way round to a certain extent, ie. Dynojets are smaller than comparable Mikunis.

Of course the easiest thing would be to find a supplier of Mikuni jets!

[northwind]

As I said though, i reckon the DJ jet is just badly specced as much as anything else...

[Saracen]

From lots of reading in SVRider, it seems the reason for the confusion is that the Dynojet needles are thinner, so obviously that would confuse comparisons where you're running dynojet jets with stock needles. I've tracked down a Mikuni distributor so I'm going to try and see if I can get the Mikunis from them. If they answer the phone :roll:

[Saracen]

Right, got through and ordered Mikuni 142.5 and 145 sizes. Came to a total of £15! But I can't be bothered waiting around any longer. Which shall I fit then. Remember it's a CCC debaffled, standard filter and tank raisers.

BTW the place I ordered from is:

Allens Performance R&D
http://www.allensperformance.co.uk
01949 836733 - have to order by phone.

mikuni jet carb rejet dealer (just so this thread appears in forum searches)

[northwind]

That's a handy link that...

[Saracen]

Got them today, so is it going to be 142.5 (2 sizes up from stock) or 145 (3 sizes up)?

I reckon it was probably lean anyway, so a size up even with everything stock might have been good, then another for the can, and another for the tank spacers?

so shall I go with the 145s?

Must admit £15 for 4 tiny bits of metal is quite funny.

[donniej]

There's no point in using the tank spacers for any effect other than bling.
The bike would be lean from the factory so 1 size up might help there, with a full exhaust 3 sizes up might be a good place to start.

Also be sure to drill the plugs on your AF screws and turn them up to 2 - 2.5 turns. You should also synchronize your carbs.

The bottleneck you're stuck with is the filter. In order to get any real power out of your bike you need to de-snorkle it and use 150-155 main jets. Then maybe the tank risers would make a difference.

[northwind]

UK bikes don't need the mix screws drilled. We alkso get different needles and pilot jets...

[donniej]

UK bikes don't need the mix screws drilled. We alkso get different needles and pilot jets...

DAMN USA EPA!!! :D

Lucky you! :thumbsup:

[Saracen]

For once the US is worse off!

So which jets shall I use northwind?

[northwind]

Don't ask me :) 142.5 would seem your best bet, but I'm really not on the ball with the Mikuni bits.

[wreckah]

i've got in my raptor650:

- BMC race RS filter
- tank spacers
- DJ 165 mains
- stock exhaust pipework, but double open race exhausts (52mm each)
- i changed the needles to the 3rd groove, and they are DJ needles

it really goes awesome now, but it's maybe because it ran like **** for so long (it had restricted slides in it which i didn't know) and i got used to that...

anyway, no hesitations, and big power all the way from 2000rpm to the top. I'm going to a dynocenter tomorrow to back me up!

cheers, jan

[svrash]

Found this link for jets online, 2 jets for £7, can't be bad :wink:

MAIN JET LINK (http://shop.wemoto.com/index.dyn?type=carburettor+jet&flag=19)

can also pay him by paypal