I have my carbs stripped in an attempt to cure a bit of rough running. Apart from worn emulsion tubes; dodgy float heights; a broken gasket under the jet block; a damaged throttle slide guide and a partially blocked float bowl overflow; it appears I may have stumbled across a Dynojet kit that has been fitted. The standard main jets are 140, mine are 148 (I think the Dynojet kit should be 150); The diaphragm slide springs are quite thin and flimsy; The needle doesn't resemble the 5C19 stock item......mine have very fine tapers with no number on them. Is there anything I can do more to identify them for certain? Also, on top of one of the needle e-clips was a small diameter washer which measures approx 0.6mm and may be aluminium...the Dynojet shim washers are 0.5mm (I'll check the one I have again after I have cleaned my micrometer). Having been lent a Dynojet instructions leaflet, it appears there should be a washer on top of the e-clip and under the nylon end of the spring....so what use is it in that position? Any assistance appreciated............. AL
Its been a good while since I had a dynojet kit,but do the mains not have DJ before the number?Flimsy springs deffo ring a bell.Washer on wrong side of eclip smells of idiot........But it wasnt me!
Dynojet jets are the orrifice size i.e. 1.48mm. Std Mikuni jet numbers equate to a flow rate, i.e ml/min
No DJ on the jets and there isn't a DJ on some genuine Dynojets someone lent me.........but the Dynojet instructions specifically state the washer goes on top.....a few web searches suggests the same. AL
as far as I know dynojet didn't emboss their needles with a part number so, yes, identification is not straight forward and will come down to some fine mic-reading time spent comparing with a.n.other or two but finding needles for comparison could be the tricky bit. Dynojet themselves have been helpful in the past with a few guidelines. let me start with this reference anyway :- The Dynojet Stage 2 set-up for 'our' 750SS uses a DNT729 needle. the dimension at the very end of the taper but just before the final chamfer is around 1.16 mm for a kickoff. This kit did use a YJ148 main jet included in the kit and yes, that number does equate to one point four eight mm AL. This was suggested for use with free-flow type exhausts (so Termi etc) and a YJ144 was supplied for stock exhausts.
Cheers Chris...between you and Dynojet themselves (got a reply late today) it appears I have a Stage 2 kit fitted. Also discovered.....Dynojet offer a free exchange service for worn Dynojet needles. Thanks again.....AL.
Blimey, you are well out of date Phil......... ..........things have moved on some distance in the last year......:wink: Well my Mikuni OEM 140 jets don't seem to measure 1.40mm..........I really must get a new measuring thingy..... .....and it isn't flow rate for OEM Mikuni, but Dynojet are flow rate.......had two or three long discussions with Dynojet Tech Dept. AL
Mr Al, could I point you to post #3. Where it clearly states that Dynajet jets are orifice size in mm. Where std Mikuni jets are flow rate rated ie Ml/min. :biggrin:
Sorry Phil......that is incorrect....you could try taking it up with Dynojet though.....I have discussed it with them at length and I can't see their Tech Dept informing me incorrectly. AL
Well all I can say is the dynajet jets that I ran in my 583 measured in diameter to what the number that was stamped on them. So who is right or wrong I don't know.
I won't be arguing over it with you....(you're bigger than me and I'm off the steroids now....) :wink: AL
LOL no arguing Al it just is what it is, the jets in the kit were marked 140 and 148. and using incremental drills and a double check at work with inspection dept shadowgraph that is what they measured 1.40mm and 1.48mm. The standard Mikuni marked 125 or 128 IIRC does not equate to the respective diameters.
Maybe I got a nerd and he told me wrong (makes me wonder what else could be wrong, now....thanks).........I'll phone them again and sort it out....in the meantime, this might be useful..... Mikuni / Dynojet Size Comparison Chart [TABLE="width: 96"] [TR] [TD="width: 64, align: left"] Mikuni[/TD] [TD="width: 64, align: left"] Dynojet[/TD] [/TR] [TR] [TD="align: left"] 140[/TD] [TD="align: left"] 149.3[/TD] [/TR] [TR] [TD="align: left"] 150[/TD] [TD="align: left"][/TD] [/TR] [TR] [TD="align: left"] 142.5[/TD] [TD="align: left"] 152.0[/TD] [/TR] [TR] [TD="align: left"] 145[/TD] [TD="align: left"] 154.7[/TD] [/TR] [TR] [TD="align: left"] 155[/TD] [TD="align: left"][/TD] [/TR] [TR] [TD="align: left"] 147.5[/TD] [TD="align: left"] 157.3[/TD] [/TR] [TR] [TD="align: left"] 150[/TD] [TD="align: left"] 160[/TD] [/TR] [TR] [TD="align: left"] 152.5[/TD] [TD="align: left"] 162.7[/TD] [/TR] [TR] [TD="align: left"] 165[/TD] [TD="align: left"][/TD] [/TR] [TR] [TD="align: left"] 155[/TD] [TD="align: left"] 165.3[/TD] [/TR] [TR] [TD="align: left"] 157.5[/TD] [TD="align: left"] 168.0[/TD] [/TR] [TR] [TD="align: left"] 170[/TD] [TD="align: left"][/TD] [/TR] [TR] [TD="align: left"] 160[/TD] [TD="align: left"] 170.7[/TD] [/TR] [TR] [TD="align: left"] 162.5[/TD] [TD="align: left"] 173.3[/TD] [/TR] [TR] [TD="align: left"] 175[/TD] [TD="align: left"][/TD] [/TR] [TR] [TD="align: left"] 165[/TD] [TD="align: left"] 176.0[/TD] [/TR] [TR] [TD="align: left"] 167.5[/TD] [TD="align: left"] 178.7[/TD] [/TR] [TR] [TD="align: left"] 180[/TD] [TD="align: left"][/TD] [/TR] [TR] [TD="align: left"] 170[/TD] [TD="align: left"] 181.3[/TD] [/TR] [TR] [TD="align: left"] 172.5[/TD] [TD="align: left"] 184.0[/TD] [/TR] [TR] [TD="align: left"] 185[/TD] [TD="align: left"][/TD] [/TR] [TR] [TD="align: left"] 175[/TD] [TD="align: left"] 186.7[/TD] [/TR] [TR] [TD="align: left"] 177.5[/TD] [TD="align: left"] 189.3[/TD] [/TR] [TR] [TD="align: left"] 190[/TD] [TD="align: left"][/TD] [/TR] [TR] [TD="align: left"] 180[/TD] [TD="align: left"] 192.0[/TD] [/TR] [TR] [TD="align: left"] 182.5[/TD] [TD="align: left"] 194.7[/TD] [/TR] [TR] [TD="align: left"] 195[/TD] [TD="align: left"][/TD] [/TR] [TR] [TD="align: left"] 185[/TD] [TD="align: left"] 197.3[/TD] [/TR] [TR] [TD="align: left"] 187.5[/TD] [TD="align: left"] 200[/TD] [/TR] [TR] [TD="align: left"] 190[/TD] [TD="align: left"] 202.7[/TD] [/TR] [/TABLE]
just checking through Dynojet specs now in an attempt to sort out my 900 Elefant just to confirm Dynojet jet sizes are the actual dimension of the jet whereas Mikuni (with 'square within a square' trademark) are not . I don't know why a company decides to rewrite the rules but anyway, thanks for posting the equiv jet sizes for Dynojet. Some extra info here (maybe others can add to this) :- Stage 2 needles for 750SS (according to dimensions supplied from Dynojet UK today) are the same as Stage 1 needles for 900SS. it's a shame it has to be such an in-exact science due to no markings on the needles but for the record, above needle (Stage 1 900SS) is i.16 mm at it's tip whereas Stage 2 900SS is 1.13 mm.
Correct..........but I bet you didn't ask about the spring length.....:wink: AL PS.....Sometimes I doubt what DJ tell me as well......I have a Stage 2 750 SS set up.........and I have a Stage 2 900 SS kit (sussed by the jet sizes).... Measuring the 750 and 900 needles with a Micrometer, I'm b*ggered if I can measure a difference.
not bothered about spring length AL - it's hardly an exact science now is it I remember people making a similar fuss about a Lucas injection 'mixture determining spring' in the '70's. I only included the last notes as i'm happy that this is the case - they reeled off the needle dimensions to me without hearing mine - bl**dy crude state of affairs though. All the brass jets are easy - it's only the needles attached to the C.V. slide i'm concerned with. I hope some others can chip in with any relevant Dynojet specifications as they are invaluable to anyone trying to set a pair of carbs up - it's not the sort of job you want to do repeatedly is it.
I have several base specifications for Stage 1 and Stage 2 somewhere, also a Stage 3 for the 900SS.......I'll try to dig them out. AL
