Main jet recomendations?

[AKAspree85]

Got the 80 main jet in today. I only had a chance to test it briefly, but so far it seems promising.

I am waiting on a new CHT sensor since I was lazy and didn't mount the original and broke one of the wires. D'OH!

Once I get that (hopefully Thursday) I'll do some real testing. And mount it properly...

Thanks everyone for your suggestions!

[AKAspree85]

I was thinking while I wait for the new CHT...

Since I am running a larger jet, do I need to switch to pre-mix or will the oil pump system be enough? It is a LOT louder than before, but I know that is at least in part due to the pod filter and the Slick Willy exhaust. I would rather not have to switch but I will if I have to.

[IvyOperator]

Oil pump will still be just fine, it will do its own thing and still get the job done. You aren't changing how much the pump needs to lubricate

If you were get say a big bore kit, you would have to run premix plus the pump, since there is more surface area to lubricate.

[AKAspree85]

Thanks Ivy! The last thing I want to do is blow her up just as I get her together!

Looking at your build, do you think it would be good for me to upgrade to an SB50 intake and reed cage? Is that a direct replacement for the Spree one? IIRC, that helps with air flow?

[IvyOperator]

Those will most definitely help you unlock higher rpm's. It is a direct bolt on for everything, though on the SB50 intake, one of the bolts isnt quite long enough so I have to make a run to the hardware store to find one long enough.

It was difficult to find the reed cage, just took a while of searching. The reeds I bought from noiseguy, not 100% necessary, and I am not sure if they affected anything, but the cage I got needed new reeds anyways.

[AKAspree85]

Thanks! I'll be on the hunt for one now lol!

I've got an 88 main in there now and she runs well! I think I'm going to try 90 just to see if it brings the temps down. I was a little under 300 today, after a good amount of riding, mostly WOT. I think that's ok?

[Wheelman-111]

Greetings:

Presuming your temp sender is a 14mm under the spark plug, 300F. is definitely NOT a problem. It might even indicate your mixture is a bit rich, if anything, so you're leaving some power on the table. 350 or so is ideal, 380 indicates caution, and 400 is really risky. What does the spark plug look like?

[AKAspree85]

Greetings:

Presuming your temp sender is a 14mm under the spark plug, 300F. is definitely NOT a problem. It might even indicate your mixture is a bit rich, if anything, so you're leaving some power on the table. 350 or so is ideal, 380 indicates caution, and 400 is really risky. What does the spark plug look like?

Wheelman, you are correct, I have the TrailTech CHT that goes under the sparkplug. I went down a size to an 86 main, and the temps stayed about the same. I should mention, I do have a higher temp BPR8 sparkplug in there to try it out, do you think I would be better off with the standard BPR6 plug?

It's pretty clean after a good ride this afternoon, lots of WOT:

Spark Plug.jpg (218.21 KiB) Viewed 17004 times

Thanks everyone for your input on this, the fine tuning is always the hardest part but I think I am almost there. She runs pretty well now, no stalling, I am hitting 35 MPH with my "substantially over the weight limit" self on there. That is quite a bit faster than I can go on my stock '85, but I know those are one of the "slow" years.

[AKAspree85]

These things are fun and maddening at the same time LOL.
I was messing with it and now it idles fine, and accelerates fine on the stand, but when you ride it it bogs down across the rev range and won't go more than 20 MPH. It seems like an air leak but I have replaced all the gaskets in the carb (again) and re-sealed the exhaust gasket with Hondabond HT, and looked at everything I can think of, except for the crank seals but they are brand new as well. I am going to look at those next as I am at a loss as to where this is coming from. Any thoughts? Also, I need to clean my air filter, but I don't thank that could cause this?

[AKAspree85]

Update... it WAS the air filter. And apparently how I had the wire from the ignition coil ran? I think it might have been picking up interference. It runs great again (for now), I am on the 86 main jet and it rips! I think I might go down one more to see how it runs as my temps are still in the high 200's. Unfortunately, one of the bolt holes on my carb is stripping so I will likely wait until next Spring to mess with the jetting anymore, I just want to ride it while I can now that it runs good again!