Request for 250R carb help...

[Robbie Z]

I got a short break from baby duty this afternoon to take the 250R I just picked up out for a 'try out' ride...full weekend coming up next weekend. I just got the trike and wanted to check it out on the local dunes/trails.

Trike came from CA to FL (where much more humidity in the air and today it was very humid). I mixed a fresh can of 93 octane at about 42:1 ratio.


WHAT THE TRIKE IS DOING: - Trike starts on first kick and idles solid, especially after a bit of warmup, but it stutters with throtte stabs (not always but more than not it stutters from idle if throttle stabbed).

Seems that closed to 2/3 throttle or so stutters. When the trike gets into the powerband it grabs pretty strong but stutters at WOT, but sometimes it will grab WOT strong for a second or two. 1st gear is tall, 2nd and 3rd are a bit longer, and 4th is like "warp one"...never got past 4th on the small riding area I was in - not enough room.

Setup - Brand new FMF Fatty Pipe with Powercore silencer (on a stock jug/piston). The airbox is stock and the guy I bought it from has the filter oiled up quiet a bit (guessing it's dusty at Glamis in Southern California), the air filter is oiled a bit more than I usually run in Florida.

I got the trike home, did a lap around the yard and it drowned on me. I pulled the plug it was dark, wet, oily - fouled.

Question #1 - What should I do to tune? Please Help as I am not experienced carb tuning. I read the jetting thread and that was helpful, should I go up one size on the main jet, or does it sound like needle jet adjustment (maybe up one groove) will work? What about air filter, should I run no oil, try to get more air???

This thing is scary fast, especially when it hits powerband WOT with no stuttering.

Quesiton #2 - Can the pipe be affecting how the gear ratios feel? 1st feels very tall, 2nd and 3rd are short and 4th gear is warp 1 rocket ship and pulls hard for a long time before she's ready to hit 5th.


I am taking her out next weekend for extended session, with a box of spark plugs I guess.

Question #3 - The throttle cable is a bit of a hard pull...after 15 minutes my thumb was ragged out, anyone have anything good or bad to say about going to a twist throttle for 250r's ? I am thinking of replacing the throttle cable to loosed up the effort on my thumb.

I am 37 and this trike kicked my arse in 15 minutes, she is fast even with the issues - she stutters more than not, but the powerband will still kick in strong at WOT for a few seconds every time as I am going through the gears. If I can get the carb / air issues tweaked out and tuned in for Florida humidity and weather, she will absolutely smoke anything I have ever been on (that had 3 wheels at least).

Any help would be sincerely appreciated. Apologize for the book here, but I wanted to ask for some feedback and needed to give the setup and what's going on....

Robbie Z

[Daddio]

It is definitely too rich. I would start by cleaning the filter and oiling it to your liking.

[Robbie Z]

P.S. - The trike came with new Dunlops on the read...but man, i run Fast Trackers on my Z and I can tell a huge difference - the Fast Trackers grab and chew and launch, the Dunlops seems to spin alot...at least in sand/soft dirt (obvious I know), but I didn't think there would be as much of a difference as there actually was. I am thinking of swapping my fast trackers to the 250R, but to be honest, I may not be able to handle the front wheel in the air in every gear... i can't believe how fast the R is (especially 4th gear, it's amazing acceleration) - my heart is still pounding.....

[Dammit!]

You can mess around with running it with the airbox lid on and then off to figure out if you're too rich or too lean on the main jet. Removing the lid has a similar effect to going down one or two sizes in the jet. Make sure your air filter is clean and oiled. Other than that, you're on your own. Read the jetting sticky until you understand how jetting works because nobody can jet your bike over the internet. Once you understand the theory it's pretty simple.

DO NOT switch to a twist throttle if you're an inexperienced rider. Opinions vary quite a bit on this but I personally feel twist throttles should not be used on trikes by inexperienced riders. I could go into detail as to why I feel that way but don't want to start a big debate.

[Billy Golightly]

I'd clean all the oil off of that filter to start with, thats a good place to start. I'd imagine from your description of it stuttering between closed and 2/3 throttle you have a pilot and needle that need to be dialed in. It sounds like it runs good in the topend (main) once it gets cleaned out from being rich on the bottom and mid. Get a new plug, crank it up and get it to idle for I dunno 5-10 minutes without touching the throttle or just barely barely opening it. Shut it down and check the plug, if its still dirty and oily you need to lean you pilot out. I typically buy jets 3-4 directions from wherever I'm at when I'm working on things because its such a pain to order them one at a time.

But clean the oil out of that filter first, and run it a little bit dry or with an aerosol only type of oil applied. Its way way to easy to put to much filter oil on it if you use a bottle. Try that and see how it runs, you can't just for a dirty filter cause if you clean it later on you'll be way leaner then you should be on the carburation and thats definitely not a good thing.


edit: On the twist throttle, I used to be a thumb person, but I'm a twist all the way now. I run the Magura 314 Duo series (much better then the crappy motion pro junk IMO) which is adjustable from a quick 1/4 turn (which I prefer) to a slower longer turn that is Enduro style. The Magura is available from Dennis Kirk and other suppliers.

[nate b]

I'm with these guys, also might want to make sure you have the proper spark plug and gap, also may want to pull carb and clean it, and then start learning how to jet your machine. might want to have a piston and top end gasket kit on hand. The thumb throttles are killers, I wont let my poor kids develope carpel tunnel, I run twists on everything.

[1upfront]

Either way thumb or twist it sounds to me like you might need a new cable the nylon lining might be getting worn out, just something to consider I always keep new spare factory honda throttle and clutch cables around for my trike.:)

[Robbie Z]

I appreciate all the advice, I will be trying to get the machine tuned in this coming weekend. I hope to post some more pics as we will be breaking in the new top end on the Z as well.

[ceaserthethird]

yes post some pictures , let us know the results.

[4cylinders]

hey, before you start jetting, check the choke/enrichment circuit, could be leaking/sticking.