1985 XR350R boggs bad, need jetting advice please help!

[dwade277]

What a cool site. Loads of info.

I just picked up a 1985 Honda XR350R. Went riding over the weekend had a great time, but the XR would bog every time I would gun it. I would have to role of the gas let the rpm's rise then the bike would run fine.

The XR has a super trap slip on. I am asuming the jets are stock (150 main, 50 slow). I have checked the spark plug it looked fine, replaced it anyway. Cleaned and oiled the stock air cleaner. Removed the snorkel. Set pilot screw to stock setting and played with setting with no sucsess. No change in engine performance still boggs. I can only guess it needs bigger jets but I dont know what sizes to try. I dont think it is an electrical problem because the bike runs great after the anitial bogg.

please help Damon

[James_Dean]

See if you can get to the carburetor slide to lift the needle 1 step (by lowering the needle clip position). Ride it and compare.

James

[dwade277]

Thanks for the reply. will try to lift the slide needle one step.

Will get back with results.

Damon

[dwade277]

just lifted the needle one step road bike there is a small change but nut much. Still boggs. I can go one step higher with the needle, maby I can try that? pilot screw is set to 1.5 turns open. this seems to work best.

Damon

[HairyScary]

Older XR's (and even the current XR400) don't have a pumper carb, which means that they don't have that squirt of fuel to help transition from off throttle to WFO. Hence they will bog somewhat, even with "perfect jetting". I'm not sure if this is your 1st XR and you are expecting 2-stroke response, or if your bog is actually something more severe than the typical no-accel pump bog, but it is something to keep in mind.

[dwade277]

I hade a 1986 200r, 1988 250r and have riden some other Xr's. I understand the hesitation some older xr's have and I can live with that but when I gun my 350 it will stall if I dont let off the gas. Maybe I should play around with the jetting ???

[HairyScary]

Well, at least you don't have an 83/84 with the dual carbs ? or you would have an endless array of things to tweak and twiddle. I'm thinking that you don't want to go mega rich on the needle in an effort to band-aid around the lack of an accelerator pump, as doing so would eventually sacrifice crispness at part throttle operation. But I am not an expert.

The stock jetting on older XR's was a lot closer than say what you get on an XR400 today, since they knew everybody took out the baffle and air-duct restrictor almost straight away. If it seems way off the mark then maybe the bike has other issues that need to be looked into 1st, seeing as it is about 20 yrs old. ?

[dwade277]

Just opened up carb to check it out. looked clean. Also hit it with compresed air. The main jet was stock #150, but the slow jet had been changed to #52, stock is a #50. Dont know if this will effect the bogg or not.

Put carb back together set pilot screw to 1.5 turns out. bike ran the same.

I noticed when the bike is worming up and I have the choke set to half open the thratal is crisp and responsive, but when the engine is worm and choke is open the bogging begins?

may be still to lean???

[barton]

Usually if you close the choke and it runs better that means you are too lean, since the choke makes it run richer. The throttle position where you are having the problem should tell you which circuit to change.

And yes I DO have one of the 83 dual carb XR350R's. Luckily for me I've never had to mess with the jetting on it. It pretty much sits in the barn since I got the WR. Strangely, I never had to learn anything about jetting until I got the WR. Hmmm ?