Jetting - midrange surging.
07-07-2008, 10:53 PM
#1
Senior Member
Superstock
Thread Starter
Join Date: Mar 2007
Location: San Diego
Posts: 268
Jetting - midrange surging.
Setup:
98 hawk with high mount ART exhausts
K&N Filter
Emissions removed
Dynojet kit, needles on 6th clip.
#48 pilots
185/188 mains
2.5 turns out
Before the bike had 188/192 mains, and it was rich in the midrange (freeway steady throttle cruising at 5k rpm. Pulled the choke out and it ran worse.
After the main jet swap, the bike runs lean at the midrange but perfect everywhere else. Low and and top end are fine, but freeway cruising it surges. I pull the choke out a tad and it runs better, so I know it's lean.
Should I bump up to 185/190? Or 188/190?
98 hawk with high mount ART exhausts
K&N Filter
Emissions removed
Dynojet kit, needles on 6th clip.
#48 pilots
185/188 mains
2.5 turns out
Before the bike had 188/192 mains, and it was rich in the midrange (freeway steady throttle cruising at 5k rpm. Pulled the choke out and it ran worse.
After the main jet swap, the bike runs lean at the midrange but perfect everywhere else. Low and and top end are fine, but freeway cruising it surges. I pull the choke out a tad and it runs better, so I know it's lean.
Should I bump up to 185/190? Or 188/190?
07-08-2008, 05:15 AM
#3
Senior Member
Superstock
Thread Starter
Join Date: Mar 2007
Location: San Diego
Posts: 268
Forgot to add that they aren't DJ jets. The only DJ jets I have are 180 and 185, the other ones I have are Keihin mains I bought from the local store..
Did some more riding, the surge is very prominent between 5k-6k, and got worse when I did night riding. When I pulled the choke out a little, it still bucked. Not sure where to go from here.
Did some more riding, the surge is very prominent between 5k-6k, and got worse when I did night riding. When I pulled the choke out a little, it still bucked. Not sure where to go from here.
07-08-2008, 05:46 AM
#4
Member
Squid
Join Date: Jun 2008
Location: Maryville, TN
Posts: 26
I've seen a lot of jet kit forums for the SH, as I did the jet kit route before. I took mine back off because I got tired of tuning and it destroyed gas mileage. See if you can't do a google search for some dynojet forums or something.
07-08-2008, 09:47 AM
#5
Senior Member
MotoGP
Join Date: Aug 2007
Location: Way Out West
Posts: 2,547
Anto;
Keihin and Dynojet main jets with the same number are not the same size jet, so any advice you get from folks who've installed Dynojet kits won't be worth much unless you put aside the Keihin jets and buy some Dynojet mains.
Keihin and Dynojet main jets with the same number are not the same size jet, so any advice you get from folks who've installed Dynojet kits won't be worth much unless you put aside the Keihin jets and buy some Dynojet mains.
08-20-2008, 05:03 AM
#7
Member
Squid
Join Date: Oct 2007
Location: Newcastle, Australia
Posts: 45
Hows it looking anto, mine has just started doing this, you are very rich on the bottom. If ur bike has gone lean with the smaller mains it make need going back rich again to stop it or.....Go leaner in the top and try 50 pilots.
Also check your breather line to the fuel tank isn't kinked. I replaced mine with thicker fuel line. If that's partially blocked it can starve for fuel.
Also check your breather line to the fuel tank isn't kinked. I replaced mine with thicker fuel line. If that's partially blocked it can starve for fuel.
08-20-2008, 05:27 PM
#8
Senior Member
Superstock
Thread Starter
Join Date: Mar 2007
Location: San Diego
Posts: 268
I picked up a stock airfilter and went (per your results) to 175/178 mains, with DJ needles on 5th clip with one washer, and 48 pilots, one turn out.
The bike runs WONDERFULLY. Pretty much perfect carburetion all around, no hesitation when I get back on the throttle going 60+mph, steady state cruise is perfect, no bucking or anything. I'm getting 40+ MPG, which I absolutely looove.
Last change I might make is going to 4th clip to see if that changes anything.
The bike runs WONDERFULLY. Pretty much perfect carburetion all around, no hesitation when I get back on the throttle going 60+mph, steady state cruise is perfect, no bucking or anything. I'm getting 40+ MPG, which I absolutely looove.
Last change I might make is going to 4th clip to see if that changes anything.
Thread
Thread Starter
Forum
Replies
Last Post
