"This one's going to stay stock" - Chadbullet's 96 Elite SR

[chadbullet]

Exhaust is sealed well now. I am up to 44 pj 112 mj. I know I'm supposed to start big and work down, but I guess I didn't expect jetting to be so high. Temperatures are still climbing really quick.

I feel pretty confident I don't have any air leaks at this point, so I guess I'll keep going up with jetting...

[chadbullet]

Finally tinkering with this thing again

The non-ethanol gas left in the bike left no residue and didn't go bad! I am at 42 pilot, needle in 2nd clip from the bottom, 118 mj. I think I need to move the needle clip back to the middle.

It pulls really strong! until it doesn't. I think I'm running the bowl dry. After messing with the jetting, the first thing I did was replace the inline filter. It started to run way better until a long pull would suddenly have a lean bog and temps would jump way up. I've ordered a new petcock to see if that helps, but if it doesn't I may switch to a manual petcock. Manual petcock will be hard to reach under the plastics, but I intend to have a second on/off inline valve closer to the carb where I can access it.

[chadbullet]

I had a little scare the other day after testing 122mj. Saw 411*F on the temp gauge

Decided I needed to make troubleshooting fuel delivery top priority. Threw on this little ATV fuel tank with a straight run for the fuel to see if I was able to keep the carb fed. No longer getting the sudden lean bog on a longer pull. I'll probably try another vacuum petcock before swapping to a manual one.



Jetting still seems outrageous. May try going up a couple more sizes on mj. May take it apart and do ANOTHER leak down test. May need to check timing? Wondering if the Malossi crank's woodruff key location made a difference. May check cylinder durations? I've heard people come across these Corsa cylinders with port timings completely incorrect. I'm not really sure what to look for, but I guess I've got the tools so could be worth taking a look.

[aeroxbud]

There is a port map of a Minarelli Corsa in the data base of it helps. 49ccscoot.proboards.com/thread/176

[chadbullet]

Jul 6, 2024 11:37:22 GMT -5 aeroxbud said:

There is a port map of a Minarelli Corsa in the data base of it helps. 49ccscoot.proboards.com/thread/176

Thanks! I'm curious how they compare between the two bikes. 

I also still have the contessa to compare with....and I'm tempted to reinstall

[90GTVert]

Test flow over time with your add-on temp tank and your normal setup. I do 30 second tests and just double the result for ml/cc per minute. I'd think you'd want to see at least 400ml/min to be sure you've got sufficient fuel flow. I was just testing 28-34mm carbs on my scoot and the carbs themselves could all flow 400+ml/min. One has a 220 main jet in it, so those should require more fuel, but my fuel system was over 800ml/min to the carb. Mine is gravity feed from tank > 3/16" tygon > Briggs style manual petcock > 3/16" tygon > filter > 3/16" tygon > carb. I have found that mixing fuel hose diameters can dramatically reduce flow. Still doesn't make sense to me, but I've tested it with a 1/4" on one side of a filter and 3/16" on the other and it doesn't flow as much as 3/16" on both sides. Seemed to be most critical at the filter, less so on the petcock... but now I try to run all one size; generally dictated by what fits the barb on the carb.

If you ever have more trouble with it, another thing to look for with a bowl running dry is that larger jetting will cause it to fail in less time. You go up in jet size thinking you've got a lean condition and you make it worse.