Super difficult to start when cold

[al_pritchard]

I still haven’t been able to overcome my hard to start issues.

Set up:
2003 GPR
AirSal Extreme 80 / 40mm stroke
PHBG 21
96 main
262 AU needle jet
50 idle
60 start
40 slide
W7 needle 2nd from top
Premix 32:1 94 octane
B10ES plug gaped to .020 / .508mm

Antigravity AG-801 Lithium Ion Battery, 240 cranking amps

Very strong spark.

No air leaks

Still dialing in the idle, when cold it’s around the stall point. Once it warms up it’s still a little low but will idle

When cold, it is extremely hard to start off the starter. The reason for the antigravity battery is the stock speck battery would crank the bike but go flat very fast.

Cold start - With the choke on, crank the bike with the throttle closed. no love. After one or two tries cranking the bike with the throttle just cracked open - to when you hear the sucking sound. It will try to start. Let it sit for a moment and try again with no love. 3 or 4 attempts with a short 30 second brake it will attempt to start. You see the tachometer jump up as it tries to start. Finally you can get it to start.

It bump starts very easily after 2 or 3 failed start attempts. Drop it into 3rd and a short push down the drive and away you go.

When it’s hot it starts right away. Like when you stall it at a light. . But even after sitting for 30 min it goes back to it’s temperamental starting.

Any thoughts?

[jkv357]

A very good Ducati race tuner I knew found that high octane fuel makes some engines more difficult to start.

If you don't think you need 94 octane - try 91 and see how it does.

For idle mixture, I have found that riding a while, adjusting the idle mixture to get the highest RPMs, then going about 1/8 turn richer give a nice idle and a smoother transition from idle to mid-throttle.

EDIT: Is a #10 plug stock? Seems like it may be slightly cold.

Also, it's possible the 32:1 ratio may be contributing to the starting issue. Do you feel you may be able to go with less oil?

[jkv357]

Any luck, Al?

[al_pritchard]

This is the first weekend in 6 weeks with no rain. So I got to do a little testing…

Environment may play into this. I’m 60ft above sea level at the coast. This morning was about 68* with 70% to 80% humidity.

Same set up as before. Choke / in richer on, B10ES plug, gap at .020, 32:1 pre mix. Gave it 3 short start blips. This time the 3rd tries to catch - you see the tach start to clime.

After that I pulled the plug. It’s damp, but not overly wet.

Gave it a cheater spray of carb start, and installed a B9ES gaped to .030. Started up immediately, thanks to the carb start.

After a good 45 min run let is cool down for an hour. Restart attempt with the choke/enricher on she started right up.

Not sure if it’s the plug, or the gap. But it’s better. Let’s see what happens tomorrow after sitting overnight.

Couple of other thoughts. Before this summer I was running 40:1 pre mix. Now that I’m on 32:1 it’s much more responsive at the lower RPM - 7k / 7.5k range. Makes it much easier to get off the light. And it’s also snappier at the upper end of the RPM range. Thinking about dropping a main jet to see if I can continue to improve this. Currently at a 96.

At present I’m still getting a little black oily residual at the pipe. So that makes me think I’m still rich. Or I could book some time at Xtream Machines on the Dino and find out for sure.

Stay tuned.

[jkv357]

What oil are you running?

Motul 700 is a decent street oil at 40:1.

You shouldn't be getting much in the way of spooge from the pipe. It shows the oil is not burning off or the ratio is too high. I don't think that going from 40:1 to 32:1 would make a noticeable difference in performance.

I would think 91 octane should be safe. Are you using ethanol-free?

What does the plug look like? I would adjust the oil ratio before rejetting.

Cooler temps will make you run leaner.