KZR750R1

As for the thought why opening up the Pilot? Every time I have increased fuel it's responded in a positive way.... If I find the larger pilots are too much I can always place the 40s back in.

This is going to be another exercise in compromise but in this case way closer to the bike I remember back in the 80's.

kzr750r1 wrote:

Pilots are what I'm referring to. Probably around 1/3 to half is where the hesitation (burble) is happening at 6K.

If the problem is at 1/3 throttle, then a pilot jet change is not the correct approach. Use the needle clip position to affect around 1/4 throttle (in which i would include 1/3 throttle), and use the pilot jet size to address below 1/4 throttle.

Unfortunately I'm not trusting this tack any longer. When things get busy it swings wild in the hi range after 7K when on the pipe... :)More motion on the tack than on the road.

Do you mean "tach" instead of "tack"?

Wait for payday and will be at Derek's doorstep.

Looking forward to it...

I'll get some more runs in later this weekend and get a better handle on the throttle position.

10-4. Keep us posted...

Regards,

Derek

This sounds like a needle. If it starts lagging in the top end, thats the main jet. Midrange though is needle. Find a nice flat stretch of open road, put it in third and go smoothly from 2-3K-RPMs to WOT. Take notice of where it falls off or stumbles and go from there. Just my 0.02 but it seems like you'll notice real quick if at 7-8k it dies off on you or at 5-6k if it slows while passing through that range.

If it gurgles at 4-5k, slows from 5-6k, and runs hot till 8k where it dies off go up on your main and down with your needle. Or up on the main and get a needle with a different taper.

Once that goes well, hold a steady RPM, Pull clutch, kill bike, chop throttle, and check plugs. Do this for different ranges and see what is going on with your jetting.

Very shade tree, but it'll get you in the right ball park for those without a dyno and some other nice toys.

Thanks guys. Yes I mean Tach...

Trying to make a stand at some point with this. As Derek noted when I picked up the new mains. The Dyna-2 jet kit used did include drilling a hole in the diaphragm slider... Plus the fact this needle has almost no taper. It's pretty much a slug with a blunt tip.

I'll do my best to ID the throttle positions this is happening before making any other large changes.

Needles and other parts are a possibility. Just hope to get it close with these and see how it goes...

I wondered about the needles. I've got a some spare stock ones and a set from a suzuki set of BS34's and have thought about tapering them a little rather than the almost dowel pins that they are.

Took it out to Mines Rd out of Livermore and back to Tracy through Patterson. Not much straight flat road to mess with and by the time I was out of the mountains the wind was blowing me sideways. Took it back to port.

Also had not secured the throttle grip so no real indication just yet on throttle positions.

Interesting noticed the bottom end (pilot) may be ok and as indicated the issues start happening at Needle position locations... Still going to find some time to get out into the delta flats (barring cops) go do some more testing.

Funny part is the wife knows I'm tuning so she is generally interested in how the rides go these days.

Oh BTW I managed to bottom out the front suspension on the ride. My tie wrap indicator was full mash against the lower triple upon return to port. Never thought I'd see it there. Has a smidgen of paint transfer from the oil cooler to the front fender. Just a kiss.

kzr750r1 wrote:

Oh BTW I managed to bottom out the front suspension on the ride. My tie wrap indicator was full mash against the lower triple upon return to port. Never thought I'd see it there. Has a smidgen of paint transfer from the oil cooler to the front fender. Just a kiss.

What fork springs do you have installed?

Regards,

Derek

LE placed progressives in the forks. I'm probably going to preload them with a .5" slug, see how it goes from there...

This was a rough ride and the road surprised me a couple of times with ground shift dips... Go figure from a road through the mountains with fault lines etched through the surface.
I have not had this bottom out on a "normal" road.

Barring checking if the rain will persist from last night I may ride into the office today.

kzr750r1 wrote:

LE placed progressives in the forks. I'm probably going to preload them with a .5" slug, see how it goes from there...

The unladen sag should be 15-20% and the laden sag should be 28-33% of travel. The difference should be approximately 13% of travel. As examples, if you have 15% unladen then laden should be 28%, or if you have 20% unladen, then laden should be 33%. Your forks have a book spec of 150mm travel (you should physically verify this), so unladen sag should be 22.5-30mm and lagen sag should be 42-49.5mm. If you cannot get both the correct laden and unladen sag via the same preload adjustment, then the springs have the incorrect rate. I suspect you'll find this to be the case. If you do, then I will recommend the installation of the correct straight rate springs. In fact, I recommend that anyhow. Progressive springs have no place whatsoever in a fork with as much travel as yours has. Once you have the correct straight rate springs installed with the correct preload, you can tailor bottoming via the oil level. Make sure that silly cross over thingie is not leaking first!

Regards,

Derek

I've been doin the same.
Here's my throttle position indicator. Crude, yet effective.

Need to get out on the open road outside of commute traffic to do this. Plus it's been windy as all get out lately.

Mine throttle position indicator is a bit more crude. Using a notch cut into the grip and similar tape on the switch housing. Planning on setting a bit of white silicone in the notch for a temp marker. I don't expect it to stay long term. I have the silicone but can't find it at the moment. :S

I'll check D what is going on. For sure it's probably time for a fork oil change.

Found some pictures of the bike when I purchased it in 89...

Missing the chin faring at this point.