YZF750/1000R - The Fly 5

Slowed to a crawl for awhile. I picked up a Koso guage for the bike. It's a nice kit. I shaved down the stock front fairing mount, made a bracket and welded it on for the Koso mount.
 

Attachments

  • 186551694_2870465103270345_2195350192984226469_n.jpg
    186551694_2870465103270345_2195350192984226469_n.jpg
    210.8 KB · Views: 249
  • 186508563_834883290774246_9195303926727029791_n.jpg
    186508563_834883290774246_9195303926727029791_n.jpg
    257.8 KB · Views: 244
I come back to DTT after a few years away...and glad to see progress hasn't been too fast so I haven't missed too much! :p

She'll be a beast on track!
 
I come back to DTT after a few years away...and glad to see progress hasn't been too fast so I haven't missed too much! :p

She'll be a beast on track!

Lol, well technically this is a different YZF750 than the one you saw in here a year ago. #5 came to me in Dec 20' The #3 survivor is on my lift getting some coolant leaks figured out.
 
It's either me or this Koso gauge I've setup has been giving me trouble reading a reliable tach signal. I've tried a number of different ways and it only really works when I tied it to the crank trigger. Set it for 4 cylinders and it's waaay off, set it to 6 cylinders and it's only off by a 1000 or so over what the stock tach reads. No options with the Koso give me a reading close to the stock unit. Pretty annoying. It has a good fresh ground and ignition power to it so something is wrong but I haven't consulted with an "Internet Oracle" just yet.

It's hard to test the track bike you're building when there is only 6 track days a year and you've already missed a few due to work. We don't have a ton of Dynos in this town so I feel compelled to test on the back roads where I live. Traffic is really light during the weekday, visibility is very high, corners are easy to read and it's generally 50-60 mph limits posted. In under 5 minutes from my house, it opens up to two lane with lots of passing area, sweepers and elevation changes and no houses or buildings. I went straight from my house to the gas station and topped off. It was almost up to temp at that point but when I pulled out of the station, it started to bog at low rpms. It felt like a fueling issue? I gave it more gas to keep the rpms up and it would run pretty well as long as rpms were 6k?+.

I'll re-check the float levels and check the EXUP valve too. I may try to add some heat shielding between the carbs and the heads like the stock bike has. Gotta be ready by the 17th.

signal-2021-07-09-133959.jpeg
 
are you running the stock ignition? sometimes if you route the wires to close to the coils it can get a false reading. i had to isolate the tach signal on a bike once with a shielded sleeve that grounded to the frame. another time i had to get a signal wave transformer, changing the signal from a sine wave to a square wave for the tach to get accurate readings. all depends on what type of system you have.
 
are you running the stock ignition? sometimes if you route the wires to close to the coils it can get a false reading. i had to isolate the tach signal on a bike once with a shielded sleeve that grounded to the frame. another time i had to get a signal wave transformer, changing the signal from a sine wave to a square wave for the tach to get accurate readings. all depends on what type of system you have.

Yes, stock ignition. I need to pull the tank, airbox and carbs again anyway so I'll re-check my wire routing. I do believe I ran the sensor wire past a coil. Thanks Doc_rot.
 
How do you have the pickup wired? Is it wrapped around a plug wire or spliced into an ignition coil wire (gray or orange), itself?
 
How do you have the pickup wired? Is it wrapped around a plug wire or spliced into an ignition coil wire (gray or orange), itself?
I had tried wrapping a plug wire and tying to an ignition coil wire but now it's directly tied to the crank trigger, before it gets to the rest of the ignition system. The lead wire was run directly over a coil so I moved it and isolated it away from the coils and ignition components. I need to test it again but I'll be wowed if that fixes the tach trigger reading. The heat shield matting I ordered should be here tomorrow so I can isolate the head heat from the carb bodies. Then another road test or two before Saturday I hope.
 
Last edited:
The crank trigger may not be a good enough signal to use. I'd try orange or gray wire from the coils (if you haven't already).
 
My El cheepo Chinabay Koso copy worked for the first 6 months, then it started to work sometimes then it just went to redline from idle, it has now just completely shit the bed, does nothing, shows the clock. I need to come up with a replacement of some kind. may go back to mech. on both. The digital seems to not stay working for me.
 
I moved the tach trigger wire to the orange on the coils. I realized I was using the HT lead on the coils earlier, not the low tension wire. I've still got the carbs off for float measurement and another quick cleaning. I hope to get it back together tonight and test tomorrow.

Got the heat shield for the carbs setup too. It was a 12x24" piece of 2000 degree adhesive backed material. I peeled the adhesive backing and stuck it to itself for a 2x thick layer between the carbs and the motor. I hope it helps.
 

Attachments

  • yzf_heatshield.jpg
    yzf_heatshield.jpg
    324.3 KB · Views: 204
So... track days ROCK!

218456666_10221802997017603_6241970272091204906_n.jpg


My buddy Rich flew his paramotor over early am and got a neat shot of the track.


217703797_10224312305622507_9048098371647084122_n.jpg



I am DEFINITELY doing that again!!!!
 
Last edited:
New YEC replica adjustable rear sets from Peter Day Yamaha. They'll give me a bit more leg room .

yzf_yec_rearsets.jpg
 
So the track bike (#5) is giving me some fueling issues again. It pissed fuel into the exhaust last week when I started to warm it up. That's going to take a sec to figure out. Meanwhile it was time to get the survivor (#3) cleaned up and off the lift again. #3 had coolant leaking from the main manifold. It looked like Florida in there. I pulled a good one off another parts bike and got it swapped in to #3, refilled with coolant and buttoned the fuel system back up again. Did a fresh oil filter and changed the oil. Coolant leak is resolved at least. Naked shakedown was a blast. It's blowing a little black smoke after it's warmed up and I goose at high rpms on the open road. I suspect the 27 yr old valve seals. From what I've read about these, it's a thing and makes me think when I pull the head to do the seals, maybe a 902?cc piston kit would be cool. For now, I'll just ride it some more and keep an eye on things while I do my homework on the issue.
 

Attachments

  • newheatshield3.jpg
    newheatshield3.jpg
    925.2 KB · Views: 204
  • lookslikeFlorida1.jpg
    lookslikeFlorida1.jpg
    448.1 KB · Views: 201
  • nakedshakedown.jpg
    nakedshakedown.jpg
    435.3 KB · Views: 215
Last edited:
Back
Top Bottom