OK.......what did i do to my 85 R?.......

[OldManDM]

just got a used FMF gold series pipe and silencer from jenndnn3 and got it home,cleaned it out and up real good,replaced the worn out fiberglas packing in the silencer and bolted it on.........bike has been running great recently mind you......crank it up and it isn`t running worth a crap!! pops ever so often (like a backfire kinda) at higher rpms and won`t idle.......before i go screwin with stuff,would the pipe and silencer affect my jetting that much?......by the way the pipe that i pulled off was an aftermarket,but i have no clue as to the brand.....and I was running the factory silencer/muffler......HELP!!!???!?!?!?!? :wondering :(

[Somekindofjerk]

Put your old pipe back on and see if you get prefered performance again. if not check simple things first like your sparkplug. dont start teering anything down till the easy stuff is done first.

[edog]

Probbly has to be rejetted.

[OldManDM]

anybody else?

[brapp]

put in a new plug and check it and does it only pop at a certin rpm range? figure it out and check the plug it will tell you if your runnign ritch or lean or right on.

[brendan802]

I'm sure the exhaust flow has increased and needs to be jetted now. Check your plug to see how it is burning. I bet you just need a larger main jet and a little fine tuning on the carb and it should run awesome.

[hrc85250r]

def jetting....just to be sure, make sure the baffle in the silencer is where its upposed to be...

[daputz]

I gotta agree with the above replies. An aftermarket pipe (especially on a 2 stroke) is gonna increase the flow of the engine, to keep the proper a/f ratio you need to rejet. Generally a higher main jet, and an adjustment on the low speed mix screw is enough....................but do your self a favor and check low, mid and high throttle positions via plug chops. The few bucks you spend on spark plugs should be considered cheap peice of mind for your engine.

[grundlegrabber]

True with the jetting, but I have never seen such blatant rideability problems result from simply instaling a pipe. It shouldn't miss and pop like that, even if the jetting is a little off. Try swapping pipes back, see if it goes away. One thing to check, which I have seen on an R before, is that the flywheel nut has not come loose. A friend had this happen. The motor was missing and acting up, but he still kept riding it (even when I told him several times to shut it down). Turns out the flywheel had come loose, and from slapping around, had broken out a chunk of the crank at the keyway :cry: Just throwing that out there, something easy to check.

[daputz]

this pic is not for the weak hearted :( ....................but inproper jetting can lead to very serious rideabilty issues

http://www.ttmtechnical.com/images/1_preIgn3.JPG

[OldManDM]

ok.....here`s where i`m at now.....switched from the 85`s round slide Keihin to an 86 flat slide Keihin(was plannin to do this anyway before the probs)....put a 145 main jet in the flat slide like is recommended on the FMF website.......ran a little better,but still crapped out on top end and bogged when the throttle was punched from idle.........dropped back to a 142 main jet and dropped the needle one setting(raised the clip one notch)and the air screw is only 1/4 turn out from all the way in......it runs good this way,but that 1/4 turn out bothers me.....i don`t want to burn up anything in the motor.......

and i know everybody keeps saying to do plug chops,but i don`t know THE first thing about plug chops,not to mention i`m in a residential area so i can`t jump on it and tear asss at full throttle like everyone says to do for a plug chop........not to mention having no 2 stroke or plug chop experience,i wouldn`t know the right color on the plug if it bit me!!!!!

sorry if that sounds whiny,but bear with me here,cuz i don`t have a clue!!!

[86250RZ]

I have the same set up on my R with the same jet settings you described and we live in just about the same type of climate and my R runs awsome with no problems at all.

[daputz]

This article is a great read and will offer some great advice on "tuning by ear".

http://www.eric-gorr.com/techarticles/carbtuning.html#a

[OldManDM]

ok....did a plug chop as best i know how....and the damn digital didn`t want to take clear pics of something that close up,but heres a couple pics of what i got....opinions?