350x with a Supertrapp

[atcmatt]

Hi guys, my low hour 350x has a Supertrapp on it. Standard headers and standard everything else except the Supertrapp muffler. Is it recommended that the jetting be changed from stock to something else with the fitment of this pipe?

The bike runs well on top end but will not idle for crap. It's erratic and pops and carries on and will sometimes just shut off completely without warning.

I have been through the carb more than 5 times with a full rebuild put through it. Have had a lot of help from flyinW also, thanks again man. Just don't know where I am at with it at the moment as nothing seems to fix my problem.

Any insight would be great.

Thanks,

Matt

[f76]

Yes you will more than likely need to jet up (bigger) from stock. There are numerous threads on this website and the rest of the Internet going into great detail on how to properly jet a carb. Give searching a try.

[atcmatt]

Thanks ATCking. Exactly what I was after. I'm going to try a leaky boot this afternoon and go from there. I guess there is so many variables. I'll try adjusting the valves also this afternoon and see how that works out. Hard to believe a machine with such little use can run like this, then again it is nearly 30 years old! With the Supertrapp, the more discs means? The less discs means? I know the jets in it are factory sizes and quality, thanks to flyinW who hooked me up.

Cheers.

Matt

[barnett468]

.
post a photo of spark plug if you want . . dry back is rich and nearly white is lean . . this won't help much for idle but it will still provide useful info.

if you don't have a propane torch, you can use flammable brake cleaner with the long nozzle and gently spray around the carb boot at the head and where the carb enters the boot . . the brake cleaner will increase the rpm more than the propane will so it will be easier to tell if there is a leak, especially if your idle is erratic.

you can put the bike in a shaded area then lay the spark plug on the engine with the coil wire connected then kick it over and look at the spark . . pale yellow is weak which most are and pale blue is very good . . most bikes run fine with a yellow spark, but if its blue we can eliminate low spark voltage as a potential cause of the problem.

if you have a quality compression gauge, I would check the compression with the throttle wide open then kick it over fast 5 times, however, look at the gauge after the first kick . . if it is less than around 90 to 100, you may have weak rings and/or valves.

[atcmatt]

So I have spent a few hours on it with help from flyinW. I checked all the valves and they were all in spec. Next I installed a 48 pilot jet in it today and it has seemed to improve a lot. I'm going to have a tinker with the mixture screw tomorrow and see how good I can get it. At least it doesn't stall randomly now.

Pulled all the discs off my trap today and damn it's loud and obnoxious! So I cleaned them all up and put them back on. 14 on there in total. Seems like a lot to me. But runs good on top end so will probably just leave it although it is pretty loud.

Thanks for the help. I'll let you know how I get on with it.

Matt