Jump to content
Sign in to follow this  

Bad bog and cutting out.......

Recommended Posts

'03 RM85 stock everything and not sure how many hours......pump gas mixed 40.1

Bike was running great until after a 2hr DesertX race. My son said it was idling funny at the end of the race. It would cut out at mid to WFO throttle and bogging off the bottom. I took the carb out cleaned it real good. Took the reeds out and cleaned them and inspected them.......they look great. Put it all back together and same thing.........bogs off the bottom and cuts out mid to wfo.

Suggestions?

Share this post


Link to post
Share on other sites

How many hours are on the top end? How does the PV look? What about the plug?

Just start out with all the normally things that need attention on a 2st. I'm sure you'll find the bog/hestiation cause.

Share this post


Link to post
Share on other sites
How many hours are on the top end? How does the PV look? What about the plug?

Just start out with all the normally things that need attention on a 2st. I'm sure you'll find the bog/hestiation cause.

Don't know how many hours are on the top end...but it is probably ready. I bought the bike used Sept 07. Bike was basically new at that time. I was going to put a new top end in shortly...might as well do it now. Didn't check the PV or plug. Will give those a shot. :p Thx

Share this post


Link to post
Share on other sites

It might be a good idea to check all wires and tighten bolts holding those parts on. I had a problem like that it was missing a lot no powerband. All that was wrong was a bolt fell out of the bottom of coil put new bolt in runs great.

I was told carb problems, stator, top end. Ended up being 50¢ bolt not a $100 or $400 dollar fix.

Share this post


Link to post
Share on other sites

Put a new Wiseco top end in last Thursday......bike is doing the same thing. I have cleaned the carb 4 times.....reeds are fine, power valve is fine, new plug in....bolts, wires, hoses all checked and are fine...this sux for my son. Any other suggestions??

Share this post


Link to post
Share on other sites
Put a new Wiseco top end in last Thursday......bike is doing the same thing. I have cleaned the carb 4 times.....reeds are fine, power valve is fine, new plug in....bolts, wires, hoses all checked and are fine...this sux for my son. Any other suggestions??

Clean or repack the silencer

  • Like 1

Share this post


Link to post
Share on other sites

Is the bike getting gas? I would check that first..

  • Like 1

Share this post


Link to post
Share on other sites
Clean or repack the silencer

It was repacked before the race......2 hrs so far on repack.

Check to see the float is functioning correctly?

Checked that when I cleaned the carb......all 4 times.

Is the bike getting gas? I would check that first..

Yep getting gas.

Thx guys........appreciate the thoughts.:usa::thumbsup:

Share this post


Link to post
Share on other sites

I have no idea how to check it, but if the engine is getting gas and air, then it must be spark related.

Is the CDI box intact,grounded,etc.? Maybe clean/inspect the length of wires for chafing and unintentional grounds.

Share this post


Link to post
Share on other sites
It was repacked before the race......2 hrs so far on repack.

Checked that when I cleaned the carb......all 4 times.

Yep getting gas.

Thx guys........appreciate the thoughts.:lol::thumbsup:

:lol:

Check that the float needle is not damaged they will get a small wear ring on the end

Check the chock plunger it has a rubber disk on the end it may be damaged or a piece of crap under it. If it is the chock plunger it would ok run ok when it is off but when the RPM come up there is more vacuum and thus suck gas past the seal on the end of the plunger. The bike would load up with gas and run like crap!

Did you do the old spark plug check it should be tan

This is out of the manual

Reading the spark plug

Much information about engine and spark plug performance can be determined by careful examination of the spark plug

1 ride the bike a short distance at full throttle in one of the lower gears.

2 press the engine stop switch before closing the throttle and simultaneously pull in the clutch leaver coast and brake to a stop.

3 remove the spark plug and examine it should be tan

:usa:

Share this post


Link to post
Share on other sites

I took the bike to the track today to have some buds look at it. They said it might be a seal. The oil was a grayish color....none of us could smell gas tho. Anyway I drained the oil.......put fresh in and ran it for about 30 minutes. Checked the oil again and it was gray again.

Share this post


Link to post
Share on other sites
I took the bike to the track today to have some buds look at it. They said it might be a seal. The oil was a grayish color....none of us could smell gas tho. Anyway I drained the oil.......put fresh in and ran it for about 30 minutes. Checked the oil again and it was gray again.

As you ride the oil will change grayish because it is the clutch material that is worn off as you ride

The cooling system it up?

Share this post


Link to post
Share on other sites

did you change premix or check the fuel my 125 does that if its too rich funny that it pulls in the bottom and then cuts out on top and dies, i think its a little to do with the jetting but its the fuel any more than 40:1 and it runs like crap. it could be a bent or worn out needle to or set in the wrong clip, just a few more ideas.

Share this post


Link to post
Share on other sites
I took the bike to the track today to have some buds look at it. They said it might be a seal. The oil was a grayish color....none of us could smell gas tho. Anyway I drained the oil.......put fresh in and ran it for about 30 minutes. Checked the oil again and it was gray again.

The oil shouldn't be grey after just 30 minutes of riding.

Start doing leak down tests for the jug and cooling system.

Good luck:thumbsup:

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×