XR 600 bog issue. Please help

[lostxr]

If possible I could use a little help with a bog issue. I will give all the details but first here are the specs of the bike.

2000 Honda XR 600
White bros pipe with 12 plates.
Uni Filter
Bought the bike in Phoenix AZ and I think the jetting was right for that area.
Jetting now 65 slow jett 158 main
stock jett was 62 slow and 152 main and 2 turns out
carb number PD8-AF
mixture on front side bottm of carb 3 turns out.
needle on 3rd
plug looks good to maybe a little rich. I just put a new plug in so I will keep an eye on that.
I am also running the colder weater plug the 7 instead of the 8

I live up in Snowflake AZ and I am at 5600 ft. and right now at about 40-45 outside temp.

The bike as a bog from about 1/8 to 1/4 throttle and then runs strong. Mid to top speed no bog runs very strong.

If I hit the throttle say 1/2 throttle and go through the gears ..bike seems to run good with a roll on throttle.

If I hit say 1/4 to 1/2 throttle from a slow rolling speed I get the bad bog and then it comes on strong.

I check float level and it seems to be right. .57 in measured at the step of the float not to the top.

I moved the needle from both the 2nd and 4th position and did not seems to help. Moved it back to the 3rd.

I reduced the mixure to 2 and then 1 turn out. Seems to help some but not a lot of change. It does not reduce the idle much at all but about 3/4 turns out it will just kill the engine.

I have also noticed that if I go half choke the bog goes away.

Should I go to a smaller slow jet.

I know that I am at a lot higher altitude than it might be jetted for.

Engine is in great running shape and runs very strong at levels above the bog.

Slow speed and under 1/4 throttle seems to be the only time I have this problem.

Thanks for the help on this. I know this is long but I just wanted to provide as much in as I could to maybe get this bog problem solved. Thanks again. Later...Clint

 

[Matt90GT]

The biggest problem with the XR600 is that the carb does not have an accelerator pump. That is what you are having the problem with.

Beyond swaping carbs, nothing is going to really solve the problem of whacking the throttle on. You may want to look into a JD jetting kit. Probably your best bet.

I use to have one and installed an edelbrock carb. I know they are not very popular, but made a big difference on that bike.

 

[Ol'89r]

Bought the bike in Phoenix AZ and I think the jetting was right for that area.

I live up in Snowflake AZ and I am at 5600 ft. and right now at about 40-45 outside temp.

I know that I am at a lot higher altitude than it might be jetted for.
...Clint

Clint.

Sounds like your jetting is too rich on the bottom.

If it were mine, I would try a larger cut-away on the slide. You have gone from near sea level to almost 6,000 feet where the air is much thinner. Without riding the bike and doing a plug chop, It would be hard to pinpoint the problem but a larger slide cut-away would definitely help. Do a plug chop and make sure you have the correct main jet also.

 

[sharky243]

Raising the jet needle up one may help.

 

[lostxr]

Thanks for the replies.. I will keep working on it and let you know if I have any good results. Thanks...Clint