09 ruck, HMF muff, no jetting, slow top-end.

Thanks AweShucks.
From what I've read here re- jetting is a trial and error ordeal.
Are you suggesting to go for the variator before grappling with the carb?

I also read here that someone placed a small square of paper at the air filter screen to reduce flow and balance the mixture to his mod exhaust. He claimed a small amount of success. It's an interesting and easy test but I wouldn't want to make that a permanent fix.
The ruck came with a blue air filter. If that is a honda filter then I understand it has less flow that the B&S that we tried. We found no difference either way. Is the blue filter a honda?

Not sure if were big on sharing threads from other sites here....But this is a great thread on how to do an aftermarket intake without rejetting. I used tape instead of aluminum...Really don't want aluminum in my carb! Works great though, I ran like this for awhile with no problems.

totalruckus.com/phpBB3/viewtopic.php?f=34&t=29365&sid=f730825a38533d7750cb71f4d9ba0a87

;DI totally agree with AweShucks, I read all the 5 pages of the thread on TR and not even one mention of adjusting the idle mixture, adjusting the mixture is a must if you are doing any messing with the airflow, just hoping that luck will get the mixture right is a no no.
Borrow, buy or rent a mixture adjusting tool and most of these problems will be solved, follow AS advice, he knows what he is talking about

The service manual does not mention "idle mixture" screw anywhere. However, it does address "pilot screw" adjustment. I believe this is the same as idle mixture screw.

More importantly, what is the procedure to adjust mixture to match my only mod, the HMF muffler?

I do not have a tachometer per se. I have an Actron multi-meter with dwell and rpm features. Regular probes with alligator attachment, not clamp on.The rpm scale does not go down to 1 cylinder.

Thanks AweShucks. We fashioned a tool but before we could get into tuning a NEW PROBLEM hit us:
The rucker has become a bucker. Upon acceleration it misfires. At cruising speed and top end it runs well and at idle it purrs beautifully. Always starts easily. We put in a new plug (CR8EH-9), new gas, some SeaFoam and ran it then let sit overnight. No improvement.

Here's some details. Last Thursday night my son drove it up and down the street a few times, maybe a couple of miles total. Let rest about rest 10 minutes then he went off again. After leaving the driveway and then accelerating on the street it bogged down, bucking, misfiring and almost shutting off. the "low fuel" light came on so we thought it just needed gas. There was about 1inch of gas directly below the filler hole. We put in the new gas with seafaom and no help.
We tweaked the idle mixture one way and then the other way a half turn each time for a total of 1 full turn cw and ccw. None of this seemed to make any difference except a weaker sounding idle when it was half turn ccw. Set the mixture back to original.

Friday I went to a scooter shop. One guy was sure it was water in the bowl. Another insisted that the pilot jet has debris from the low fuel tank. Also, all 3 dudes at the shop insisted that premium gas must be used. One guy even called a local Honda store and was told on the phone by the Honda people that 93 or better must be used on small high compresion engines.
Back at home we drained the carburetter bowl. The gas looked pretty clean and no real convincing sign of water. We only saw a tiny bb sized blob of something that might have been water at the bottom of a plastic container used to catch the fuel. That might have been residual water from the container that I might have not dried out fully.
Anyway, after that we put in 93 octaine gas (100% gas no ethanol). No help.
Idles very well, cruises well enough but accelerates like a bucking bronco. We noticed a lot of fuel on the intake side of the carb.
This is a Christmas present to my son and I'm very very disappointed.
Thanks in advance to anyone that can point me in a reasonable direction.
If I have to take apart the carb and clean the ports and jets I am prepared to do so. I am mechanically inclined having rebuilt boat motor carbs and several project cars('84 VW scirocco and '71 MGBGT). I don't want to go in there but I could if it comes to that.

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One more thing: The spark plug was originally looking wettish and rather darkish but not extreme.
After the misfiring began the plug looked dry but a nice tannish color. I haven't looked at the new plug yet.

Start out and work in. As 2pid1 mentions check the air box for both leaks and blockages.

No changes were made just prior to this issue? Your son didn't tinker on it by himself? I know I would have when I was younger

Well Alzoe not sure where to go from here other than a good carb cleaning.

I'm almost tempted to suggest you trade the HMF pipe for a stock pipe and some cash unless your attached to the bling and sound? The stock pipe is really the best performing pipe out there.


Good Luck

Sometimes the wisest thing to do is to give the experts a chance to fix it and then go modding ;D
I earn my living working with engines and that sometimes involve, doing an autopsy on a dead engine which also includes checking the spark plug for sings of mixture problems, but i am not confident enough to set mixture on an engine with just a glance at the spark plug, and i am suppose to be very good at it, do the main jet tuning with an stopwatch and a handheld infrared thermometer, and ONLY AFTER SETTING THE IDLE MIXTURE and finding out you need to change the jet

This thread like most threads never seems to find the solution when it comes to carb tuning. I picked up a two brothers cf black series exhaust. I am having 2nd thoughts on even installing it now. Tuning the carb seems like a nightmare. The information I’ve found for what size jets to use is very conflicting.