mikuni vm 16

GoldenMotor.com

ivan H

Member
Oct 8, 2011
622
1
16
australia
Headtrauma u r a legend. If u like I can make u a cdi unit (jaguar ripoff, of his kdx ripoff) with 4 different settings. Allows much higher rpm & smoother right thru. U would need a coil off a small dirt bike, cr80 is best. I use metal film resistors, polypropylene charge caps, (280volt) & tantalum timing caps so they're reliable. I agree with u on the cranks. I was going to balance mine to 57% but the 2 bolt on plates had 1/2'' flat spot, looks like the bar stock they were made from had it,, so I didnt bother. I dont need high rpm with shift kit. They could do better cases too. Cheers
 

headtrama

Member
Jul 8, 2010
886
2
16
california
Thanks for the offer on the cdi , I have a jaguar cdi but I didnt like it . The bike felt and was slower with it and it quit working on me . I am no legend thats for sure lol , I had some free time on my hands so I made your manifold . This one came out better then mine here is a picture of your manifold .
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
Headtrauma that is fantastic. U have no idea how much I appreciate this,, & I feel priveliged. Let me know how to get some $'s to u. If u like u can email me at [email protected]. I wont be able to send money til thursday night, payday as I'm at the wrong end of the fortnight. 5 days. Uno, I've heard people having problems with the jaguar cdi. I think he uses prototype board (breadboard) without foil solder pads & the solder joints break. I've put a lot of miles on mine with no problem, plus the best quality electronic components I can find. Thanks a million mate. Hear from u soon. Cheers
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
I made a small error there,,, I meant "plus I use the best quality electronic components I can find." I dont think I use the exact circuitry he does, I just got the international model kdx schematic, read a few of his posts & then experimented. So far I've made 3,,, 1 for myself & 2 I gave to friends but they've been trouble free. Anyway, thanks again. I really do appreciate this. Cheers
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
Hi Headtrauma, thanks heaps for that,,, will do. I have mailed that to you along with a short note explaining how to change one resistor to alter the firing point if you want to. I run it with the upper left jumper removed & the upper right jumper in place but whatever works best,,, uno. I'll draw up the schematic & mail to you,. Thanks again. Cheers
 

headtrama

Member
Jul 8, 2010
886
2
16
california
Thanks for the cdi unit . I went a little bigger on my pilot jet today seems to run a bit better . It might be because of the weather change for the reason to rich in it up a bit .This motor doesn't feel like its beating itself up at high rpm. I got my fastest MPH on it today . I am happy with the carb and motor so far .
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
Hi Headtrauma, manifold arrived yesterday, fantastic job. Thankyou so much. Fits the carb so well. I test fitted it & when I removed it the O-ring was still on the end of the manifold, so I know it'll seal perfectly. I noticed on my carb the needle jet has bleeder holes which on mikuni's vm tuning page is listed as being for rotary valved 2 strokes & 4 strokes. Does any body else's carb have this. I'll try as is, change if nescessary. Cheers
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
Hi guys, contacted mikunioz regarding bleeder holes in Needle Jet. Dealer advised that replacemen N J's not available & advised it shouldnt give problems but if it does to try blanking off the air jet, explaing that this is what they do with the TM28 in same situation. Just waiting for Rock Solid head to arrive (tomorrow, hope) & I'll fit head & carb (after deck surfacing to 30 thou). Cheers guysh,
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
Hi Headtrauma, fitted carb today with 92.5 jet in. Started easy but when I ran it didnt like over 1/3 throttle & was smokey. Limped around the block, let cool & pulled the plug. Wet & black. Put 70 jet in. Crisp sound,,, no 4 stroking. Took it up to 65 kph, let cool & pulled plug. Greyish tan so I'll order a 72.5 & a 75 jet in the morning, & a 27.5 pilot. Rock solid head arrived today, I'm still deciding whether to dial the carb in before fitting it or put it on tonight. Cheers guys
 

headtrama

Member
Jul 8, 2010
886
2
16
california
Sounds like you figured it out already . I guess the bleeder holes made a difference in the jet sizes you used . You should bolt on the new head and jet it once . Once you get it dialed in you are going to see how much better the mikuni works.
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
Yeah,,, the bleeder holes must affect fuel delivery. They're only fine holes but there's a few of 'em. I'll count them when I change the jet. I have a .73mm jet for a nt carb that appears to have same thread size so I'll c if it fits in today, just till jets arrive. I could feel the difference even with it running lean, especially at part throttle & at varying part throttle settings. The differemce to the nt is like night & day. The nt was never quite right at part throttle. I'll wack that head on this arvo. Cheers
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
Well, ordered 72.5 & 75 main jet & 27.5 pilot ystrdy, fitted Rock Solid head after taking a bit off the top of jug. Brought compression up quite a bit. Jets arrived this arvo. Put 72.5 in. Needle jet has 5 bleeder holes, 3 on one side, 2 on the other. Put carb together & fired her up,,, & it p.....d down rain. Didnt even get to warm it up. Done hardly any riding lately with all the rain we've had. Maybe tonight, or in the morning. Cheers
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
Well the rain still hanging around but I got a bit of a full throttle run in. With this head on I may just need the 70 jet it came with. I'll grab a few plugs this arvo & do a few good full throttle runs if the rain allows. The one I did gave a darker color than I'd like & 4 stroked a bit at higher rpm in lower gears. So far I've removed 1/4" from the copper header pipe on the SBP expansion chamber twice, 1/2" in total, so I'll probably remove more to move the band up a bit as well and see how it goes. Cheers
 

ivan H

Member
Oct 8, 2011
622
1
16
australia
Ok, took it for few good long full throttle runs, 1st with 72.5 main jet. Once right up to temp, no 4 stroking at all & nice crisp "ring ding" exhaust sound. 65 kph in 6th of 8 gears. Let cool & changed to 75 main jet. Warmed 'er up & took for a spin. ,,, dull, flat exhaust sound, 4 stroking above 1/2 or more throttle, didnt make 50 kph so 72.5 main jet it is. Now I'll play with the air screw to see whether 25 or 27.5 pilot jet is best, & do a bit of tuning the pipe. Maintaining 60 kph is good enough. Cheers