Book says low speed screw controls good idle, pop-off controls idle to 1/4 throttle. I'm working on getting rid of a dead spot at this throttle position. I started the year out with 1.5 seats and 65gr springs, and got 25 pop-off book says it should be 32psi. 25 was too low and fuel drippled faster than a running toilet. Found my self closing the low speed screw completely off just to get it out of the no wake zone. I've tried using 1.5 seats and 80gr. springs and that gives me 33psi pop-off. mikuni book says it should be 38. I've tried a 2.0 seat and 115 gr and I get 30 pop-off. mikuni book says it should be 32. could my 1.5 seats on 38mm carbs be bad? This was done using at least 3 brand new springs. Seats are a few years old. I would like to know who has used 1.8 seats and who sells Genuine Mikuni parts. Low speed jets I've tried 70's, 72.5's and 75's. low speed screw always stays at 3/4 to 1/2 closed for good idle. This tells me I need to increase pop-off so I can run at least 72.5 jets or larger. I'm concerned about running too small of a low speed jet and leaning out my mid range. seizier? I've been told my stock reeds need replaced to solve this. Hope this is enough detail. Any thoughts?
Blaster genuine pop off springs and seats.
- Thread starter catpower
- Start date
Mike W
Infidel
- Location
- North Florida
Might be able to help you out if we know what kind of ski you have and what motor mods you have....pipe, head, carb etc.
62tcase 61x top. Case untouched, cylinders ported by group k stock intake and reeds. 38 mm twins bored by group k. Choke plate remove of course. Pro- tech pipe and head. I think 40 or 41 cc domes. 175-180 psi. Hot rods crank. Lighten flywheel, msd enhancer, boyesen reed stuffers. 10/16 hooker. Riva intake grate. Ewci. Water restrictor . Tuning the pipe helps clean up very bottom end but I have disconnected ewci and minimized water to head pipe until I clean up carb problem. Stock FA.
Bobert540
Site Supporter
- Location
- Rockford,MI
Did you buy the ski with work already done or did Group K do the work for you?
I didn't want to go there, but yes I talked to them. Carbs were originaly set up with mods performed by them. I end up using 1.8 seats and 115 gr. springs. I now have 35 psi on both carbs and is working much better. This is counter intuitive because my understanding is that a less restrictive carb and FA allows for lower pop-off. I should add I am now using Prok FA and outerwears. I didn't mention before but the my pop-off was actually 20-21 and 25-26 on each carb with 1.5 and 65 gr springs as set by Group K. My original post is asking about Genuine Mikuni parts. I question the accuracy of aftermarket parts. Lesson learned here for me with a sensitive carb setting is never trust any gauge or pop-off press chart or springs. My gauge is calibrated so yes I double checked gauge for error. Unfortunatley Harry dosn't have specs for Pro-tech and only works with an outdated Pipe "Factory" Great pipe just not made anymore to fit a Blaster. Don't even ask me If I called Pro-Tech and talk to C___ . Although I read a post on here that Factory doesn't have the brightest or freindliest desk girl. I Agree. Harry is very busy this time of year and I understand. He has been very helpful and understanding in the past to work with.