Cold weather riding 58 degrees

Location
usa
Riding today in colder temps. on full throttle runs a get a momentary pfitt feeling. like a momentary hesitation. Wondering if that is detonation and if I'm running too lean for air temps. It was more pronounce when second pisser off pipe going to stinger is opened fully.
 

Quinc

Buy a Superjet
Location
California
http://www.amazon.com/Mikuni-Pocket-Tuner-MK-550-TNR/dp/B0012TUUHG
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Location
usa
I think your trying to tell me, I'm too lean for cold temps. so if I'm running a 145 at 75 to 80 then at 55, I need to run a 150. can't i just make up that different with another 1/2 turn on high speed jet. although I was at two turns out today and I know you are supposed to ideally stay at two turns or below to avoid a lean condition at 7/8 throttle. do you need to change carb gasket everytime you change jets if is a new gasket? Maybe I'll go to 150 and go lower on high speed screw in the summer. I'm running group k bored 38's in case it matters.
 
Location
usa
Maybe it would be better to put 150's in there and turn down from there? what do you think? How many turns equals a jet size on the high circuit?
 

Quinc

Buy a Superjet
Location
California
Depends on where you are currently at. You want to be above 1/4 turn and no more then 2 turns out.

I have asked that exact question to Mikuni, who told me to ask the distributor who then told me to ask an engine tuner. And everyone of them has given a different answer. Figure 1 turn is between .25 and 1 jet size depending on your carbs threading.
 

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
I think your trying to tell me, I'm too lean for cold temps. so if I'm running a 145 at 75 to 80 then at 55, I need to run a 150. can't i just make up that different with another 1/2 turn on high speed jet. although I was at two turns out today and I know you are supposed to ideally stay at two turns or below to avoid a lean condition at 7/8 throttle. do you need to change carb gasket everytime you change jets if is a new gasket? Maybe I'll go to 150 and go lower on high speed screw in the summer. I'm running group k bored 38's in case it matters.
Some gaskets you can reuse, others you can't. @JetManiac sells some awesome HD carb gaskets that you can reuse. I grease them when I'm constantly taking off the carb to tune.

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john zigler

Vendor Account
Location
wisconsin
If you are at 2 turns on the high, you need to jet up. Personally I like to be 1 to 1/4 at most. IMO anything more is "band-aiding" for too small of main jet.

Also in Cooler water temps, you may need to restrict your water out, to help the engine build some heat.
 
Location
usa
96 blaster, riva red pipe dual cooling one pisser off head, one pisser off stinger, jetworks flow control on stinger, group k bored carbs, R&D flame arresters, msd ignition enhancer, milled stock head tapped for pisser. riva water injection not working, I was actually testing the water injection system yesterday, so I had the pisser blocked off the stinger and was running the water injection to the pisser to see if it worked. It didn't, the hesitation at full throttle was not present. Then, I unblocked the pisser from the stinger(no restiction, wide open to a stock blaster pisser), Then I started getting that hesitation, I came off water, blocked pisser again went back on water and it still happened once but not as quickly. This happens only at wide open throttle after about ten seconds.. THe other thing to note, Not sure if it's related, This was the first time out after removing reed spacer and placing new jetworks reeds in my boyesen RAD valves. When I got home I was able to re-torque those screws( the ones I could reach). I plan to take carbs off today and re torque the others. I am wondering if this hesitation could have been cause by a airleak in the reed area. not sure. thisisn't my expertise. Other info, first run was given me higher sustained RPMs about 6700. once I changed the water configuration the rpms went down to 6550 for the brief time I was out there. Again, not sure if this was related to reeds or water routing. Not sure if removing the reed spacer would require a increase in jetting. and not sure if drying the pipe requires a increase in jetting. Any help in understanding these things would help in the future. Thanks.

Oh, your right 58 was fine when properly dressed. It was my first time riding in temps that cold. I just coulcn't wait to try out the new pump shoe, intake grate, reeds, and having removed reed spacer. I broke out the dry suit and put some wind proof pants over the bottoms. I just have to figure out how to keep my feet dry. the bags I use over my fleece socks ripped. Overall my feet weren't that bad. I use to have the rubber socks to put over regular sock but I can't find them.
 

eastcoastjumper

James
Site Supporter
Location
Long Island
Not enough water in the box causes it to steam and lose rpm/ feel flat and lean. A dryer, hotter pipe needs a little more on the screws. 1-16th to 1/8 turn. When you're close you only need tiny changes.

Test the flow control against a dock and see where it opens. The adjustable spring wears out after a lil while. I don't even run it anymore due to wearing them out over the course of a season. A stinger restrictor is more consistent



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Location
usa
I just put in all new cooling lines a few weeks ago and took apart the jet works flow control to make sure it was working good. It looked perfect. I don't think that was the issue. The ski ran like a beast up till full throttle.
 
Location
usa
I took off the carbs to re-jet high speed jet to 150 from 145. i check the intake bolts with the torque wrench. they all needed a good amount of tightening. My conclusion at this point is air leak. Changing the jetting will enable me to run less turns out once it warms up outside. I'll let you know what I find when I get out again..
 
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