Hobbit continues to run rich

After spending a lot of time with repairs, I have a fully well functioning hobbit (starts, idles, etc). It’s been fitted with the 70cc Dr kit, Mikuni vm20 , and proma pipe. There is a very light score on the piston but still works well. Seems to be tuned properly on the low end, but on the top end and in transitioning to it after 1/2 throttle it runs really rich. I’ve downjetted several times and feel some improvement but I worry I’ll be at a really low jet size soon and the issue will persist.

Any ideas? I’ve ordered another jet set and that’s where I’m at

Thank you!

Re: Hobbit continues to run rich

What idle and main jet do you have in it? What needle, what slide and what's the clip position?

Re: Hobbit continues to run rich

Dirty30 Dillon /

#reeds

Good chance is your reeds are too light and are not returning at higher rpms. Have you replaced the stock with carbon/fiber?

Re: Hobbit continues to run rich

Jesse Nordlander /

If your needle is anywhere but top clip, move it there and try. If it's better but not enough, you will need a larger dmneedle or smaller atomizer. I have drilled atomizer near the top to imitate either of above, and it works perfect.

Re: Hobbit continues to run rich

What kind of air filter? I could never get mine tuned with that short chrome one. Installed a larger foam Uni and that made the difference for me.

Re: Hobbit continues to run rich

Totally agree with Dillon re the reeds. I recently tried stock reeds in the stockoshocko that I couldnt pull start. OEM reeds really limit things. I would definitely check that first and go to the two stage fiber reeds . Probably the not stiffest ones. Careful on the down jetting. It's coming off the throttle that's your enemy. That's when the max lean condition occurs, by my understanding. I only know Sha phbg and 24 flat slide jetting. What main are you at now ?

Re: Hobbit continues to run rich

Bad crank seals tend to make a bike act rich when under load.

Re: Hobbit continues to run rich

Torrey let us know how your fix goes. I never thought about the reeds causing the bike to run rich.

Re: Hobbit continues to run rich

Torrey Flaxton /

Thanks for all the replies so far everyone! Have been busy as hell and not in the garage, but since this got some traction I wanted to add some things about the bike, the light score on the piston is from a soft seize while I was doing kit break in heat cycles. I did some light sanding with super fine grit sandpaper when this happened to smooth it out just in case, could this case less power?

Im at 6500 ft of altitude and am currently running a mikuni jet 105 which is too rich. Needle clip hasn’t been moved from when I got the carb so I also should probably play with that before anything. Should also look into new reeds but will feel that out first

Re: Hobbit continues to run rich

Torrey Flaxton /

I’ve just been running with needle in top clip now and its not making a big enough difference. I’m going to order carbon reeds and possibly a bigger air filter. I’ve downjetted to 92.5 now and nothing is working. Hopefully this will work

Re: Hobbit continues to run rich

Do the fiber not the carbon reeds.

Re: Hobbit continues to run rich

Torrey Flaxton /

Been away from the garage for thanksgiving stuff and am ordering reeds now.

Can anyone recommend these ones?

https://www.treatland.tv/honda-hobbit-pa50-boyesen-power-reed-p/boyesen-honda-hobbit-reeds-mod.htm

If not I am looking at these:

https://www.treatland.tv/hobbit-0-4mm-boyesen-carbon-tech-reeds-p/boyesen-hobbit-reeds-cd-0.4mm.htm

Would love to hear some thoughts before the treats Black Friday sale ends!

Re: Hobbit continues to run rich

Yes. I use them. They work the best for my builds. Not too stiff.

Re: Hobbit continues to run rich

Bad crank seals will act rich in high vacuum situations.

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