Jump to content
Sign in to follow this  

98 Suzuki DR350se Carb problems, and other questions

Recommended Posts

Hello, 

I'm new to the forum and it is very late so please forgive any confusion regarding this post

 

First off my bike is a 98 Suzuki DR350se and has what I believe is the Mikuni BST33 carb, different from the dirt models pumper carb 

The bike has been intermittantly leaking gas for about the past year, and I have finally found what I believe to be the source. The seal between the float bowl and body  of the cab is very slowly leaking gas out on the front side of the carb. It took me so long to find this because the leak is so hard to find since it seemed to have went away last year, but now it is back and worse than ever....sometimes. I've switched over the petcock to the on/ off type and have sealed the vacuum port on the right (throttle) side of the carb as I was supposed to and I usually shut it off before I park and the leak when I do that is only a few drops if any after sitting. If I leave the gas on there may or may not be gas underneath the bike if i leave it sit overnight or a few days.

 

So I'm sure the gasket does leak and needs to be replaced, but I am wondering if there is other internal problems with the carb, or is it theoretically possible, since the leaking spot on the carb is on the kickstand side and the lowest part of the carb only,  if the floats are sealing under normal circumstances BUT since the gas is slowly dripping out, if the bowl eventually drains to the point where any gas in the line refills the bowl once it gets below a certain point, even if the floats are set correctly and everything is working correctly? The most gas I have ever seen on the ground is maybe 2 fl oz?

 

Another thing I have noticed is that sometimes when I run the bike out of gas, it revs gradually upward to the point where i shut the bike off because it is too fast (5000 rpms) and sometimes it putters out. Aside from this inconsistency the bike runs and starts great, so I am wondering if my real problem is likely a simple leak or perhaps internal problems.

 

Thanks for the help, I hope someone can figure out what my sleep deprived self is trying to say

Share this post


Link to post
Share on other sites

Forgot to mention this, I also plugged the port behind the fuel line on the clutch side of the the carb earlier this year to see if it made a difference, none in performance and the schematic calls for a hose running to this but I have no idea where it is supposed to be routed, and all pics online of this carb on peoples bikes it is uncapped with no hose. I sprayed starting fluid into it before I capped it and the engine reacted, so I know it goes to the atmosphere and am wondering if this too is part of the old vacuum diaphragm system (the other port is supposed to be capped with a manual petcock as I have, but cant find out anything about this one)  I took this off yesterday and no change in performance except it idled high today when running out of gas rather than bog, which seems to be inconsistent regardless, thanks

Share this post


Link to post
Share on other sites

You might need a new float needle and/or the bit it sits in. Also there is an o-ring the latter part sits in which can leak...

Share this post


Link to post
Share on other sites

thanks thedktor I'm planning on getting a rebuild kit, the needle and gasket kit should come with that. Another thing is I noticed the drain cup underneath the airbox was full of gas or it seemed like it, but not overfull, and none came out of the airbox when I removed the drain. The airfilter wasnt wet nor did it smell like gas, so I'm wondering if this is from the crankcase vent? Do the contaminants in oil vaporize up the breather tube and eventually settle in this drain tube/ cup?

 

If it is not draining from the carb, the only other thing I can think of is when it tipped over last year it flooded pretty bad and stalled a few times while riding, but after a mile or so it was all good. Also, once early this year I was parked for about a half hour with the petcock on, and it took a very long time to start and ran rough for a few blocks, but the excessive cranking may have been caused by having the key in the edge of the park and run position, causing it to flood before I tried the key again, it has a tendency to stick on the edge between park and run sometimes if i'm not paying attention as it can be hard to feel the difference when not looking, I'm thinking thats the cause Other than that the bike has started and ran perfectly.

 

One other thing to this long winded post is that I keep seeing a milky white substance on the oil dipstick. I'm told this is condensation, and it should go away after a long run, but after a ride without shutting off for over 100 miles traces were still there, but keep in mind it was under 50 degrees outside. I changed the oil about 75 miles before storing it, and the temps went from 40 and foggy on my last ride to 0 the next day, so that certainly did not help with the issue of condensation I would not think. Also, this bike has a dry sump and the oil fill cap where the gunk shows up is by the handlebars. I've read that condensation goes to the coolest part of the system which would be the cap, and the design of this system may exaggerate these symptoms because of the seclusion of the oil cap from the hot parts of the engine, that may be why it is taking so long. Either way I'm likely going to change the oil tomorrow, mostly because I'm worried I may have some gas in the oil, and be extra sure to shut off the petcock and run as much gas as possible out of the carb before shutting it off. Also, I've got some berryman's b12 that I'm gonna try in the carb as a temporary "fix". New carb kit and lines on the way so it shouldn't do too much damage. 

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

Reply with:

Sign in to follow this  

×