What did you do to your Yamaha today?

Thanks kmoe, that'll be another couple of hours reading then, good stuff.

 

Pulled my carbs off today as an experiment put the stock jets back in 120 . I had 124 main , was playing with the color tune plug I just received. Only rode a few miles but seems like it runs good did not notice much difference at speed only got it to 55 . I will see after I put some miles on and do a plug chop . Was pleased when I pulled carbs , when I took it to church last the bowls are clean as a whistle .

 

Took a comp day off yesterday and went for a ride with my friend 220 miles.
Started in Medford Oregon-
traveled the back way through Jacksonville to Grants Pass
Grants Pass FRWY YUK to Seven feathers Casino, spent $4.oo and won $50 had lunch and left.
Casino to Cannon Ville (tiller)
Tiller to South Umpqua Falls-Wonderful how the State made it more compatible for the Salmon to rest and spawn
South Umpqua Falls to Shady Cove
Shady Cove to Medford
Total miles 220 and a beautiful darn ride other than the FRWY. All back roads and some gravel here and there.
Bike ran like a champ 50 mpg.

Only miss hap was that my front wind shield hold clamp came loose and feel off. Luckily I have another from the one that broke in my accident.

 

That's a beautiful route.

 

Original Microsquirt. One of the first batch that was shipped. Modded with an NCV1124 instead of the stock B&G VR conditioner (original circuitry would completely lose it above 5K RPM or so).

I was using a wideband EGO for tuning only, and a narrow band for running, but the other day I went ahead and permanently installed the wideband. Mainly because the narrow band was acting very weird when I switched back to it. Overall, the four hole injectors, and/or the new tune, seems pretty good for most driveability and power. Still a couple of things to refine and re-refine. For instance, with the previous injectors I finally had things worked out so that anywhere from really cold to plenty hot it was just a single push of the starter button. Right now, it's only warm start that's perfect... cold start starts with one push, but dies after 40 seconds or so... cold start, cold afterstart, and warmup tuning are all a pain, too, because, when you don't get it right, you have to wait a few hours to try again. I'm thinking that the easy answer for cold start may just be to expand the parameters under which the wideband O2 sensor has authority... but I may need to tweak the warmup enrichment a bit as well.

Power from 4K to redline is great, though!

Interested to see what fuel economy looks like for the next long trip. Previously was getting about 52MPG for highway riding up in the mountains (6000 to 11500 feet).

 

Does the microsquirt allow you to measure total time of injection, so you could get somewhere near for cold start?
On overall cruising economy I guess you can get better than modern engines since you don't have to rich/lean cycle?

 

I can measure pretty much anything, but I don't understand where you're going with total time of injection.

Cold start is fine, BTW. It's warmup that needs some work.

 

Took a closer look at the cold start situation. It definitely needed more warm up enrichment. This engine really seems to need a lot more fuel until it's really good and hot. I added about 30% more fuel below 120F or so (that's 30% more than the enrichment that was already there... giving about 50% extra for an engine at 70F or so). I also ensured that the oxygen sensor could modify the mixture pretty much anywhere within the range. With the wideband sensor in there now, it's a lot easier to see what's happening as the engine transitions from cranking, to after-start enrichment, to warmup enrichment. I also added a bit more fuel in the 3000 to 4000 RPM part throttle area. I think I was hitting some places there was I was going too lean at cruise. We'll see how it goes when I have time for a test ride. Probably tomorrow.

 

Oil change. I've actually put enough miles on it post-customization that it was due. Annoying as f*** because the old MAC 4-1 pipe has to come off to do the change, which means the crash bars and front shock also has to come off, so lights come off meaning I remove seat and tank... something like 20 bolts and a front end stand before I can change the oil. Will be doing a custom exhaust next time.

 

Or get a newer Mac 4-1 which doesn't block the oil filter and drain plug...

That suspension setup looks interesting. How do you like it?

 

I went ahead and did a test run this evening. Still not perfect, but pretty darn close and the best it's ever been. Smooth through all of the range, great idle to off-idle transition. Idle stabilization is working perfectly. It's now about 10 years since I started this conversion process, and I think I finally have all the details worked out. I'll probably play a bit more with acceleration enrichment, now that the rest of the mixture makes sense... it accelerates great and strongly, but I could probably make the quick stab response a bit better. Probably will also need to recheck my altitude compensation... maybe take a ride up Pikes Peak with my laptop

 

I like it OK, can't comment on if its better or worse than stock as I never rode it stock. The rear is decent, very progressive rate so usually feels nice, and the unit I picked is from a bike of similar weight / travel so rate and damping are not far off. The main strength of the front is anti-dive; its basically a duolever with much steeper rake (20 degrees). Its adjustable for rake, trail, and dive; the current setup is max anti-dive and min trail and rake, so it handles like a 550 lb, 60 HP scooter. As such, its a joy for commuting. I have some head shake on long country highway stretches where traffic is doing 80+mph but the onset is very gradual; at speeds below 75 I can take my hands off the bars.

There's still some work to do. The front spring linkage needs to be replaced with a custom version to get an ideal spring rate curve; currently its overly stiff for the first inch of travel, and about right for the rest. I'm currently running a Hyabusa shock on the front, which maybe also is overly stiff (or not if I make a new linkage), but the GSXR 1000 shock I had was certainly to soft.

Over all, I'd say it compares decently with my (stock) 1985 FJ1100; its lacking the highspeed stability of the FJ, but is much more flickable, and much better on big bumps & dirt, plus has much better bump handling when braking. Its sort of a weird mashup of scrambler and sport bike...

 

Today.... got home from work, and replaced the handlebar grips.

Then, when the throttle cable had no spring-back, spent 15-20 minutes trying to figure out how I could've gotten such a simple task so wrong.

...before realizing it was probably because: "Oh yeah! I have everything disconnected at the bottom, so I could check for broken clutch springs!"

Moral of the story: Eat something first, when you get home from work.

 

Adjust timing chain and shorten the fuel line. Ran great.

 

Rode to work today. One press to start up in the morning. One press to start in the afternoon. Cold start and warmup seem great! May need to tweak the lower parts of the curve when fall comes around, but, for now, I'm happy.

 

It’s like a beer, you can’t have just one.
Got another xj750K today. Weird how it came to be. Over a year ago one of our own brought his bike to me for major work. Then sold the bike to young guy who had it stolen then recovered then crashed and posted on Craigslist last night. Saw the bike and it looked familiar???? Asked him did he buy it from Cody and he said how did I know?and it is now the remains are in my trailer. Good tires, carbs with all the church done and throttle shaft seals. New fork seals and steering head bearings. That stuff will fit in the one I have with bad cylinder.
Ding ding ding , just have to bolt it together, when I have time ... maybe October or next spring.

 

I took it to the dump.
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Then I inquired about appliance recycling fees, and rode back home.

 

What sorcery is this?

 

Tony Foale science-type stuff. Very cool.
Sebwlers has a thread here about it, and on a few other forums.

 

I sea

very cool build. I’m trying to wrap my head around the steering. I wonder if there is a video on how it works ?