Can I soak my carb

I have a 2006 wr450 new to me last fall previous owner had really old gas in her, but she has really low miles. I have sprayed the carbs several times now but she still runs very lean at idol to the point I have my Idol adjustment turned all the way up. brand new pilot jet cleand all other jets too...spotless..

So I thought I would soak my carb. I tore her down now and have a couple questions. I am planning to soak it in carb cleaner.

1:How can I get the seat out of the carb & do i need to in order to soak it. In the schematic it looks like there is a rubber oring in there is this true?

carb 1.JPG

2: How does the Air Cut Valve come out & do I need to to soak it? it looks like there is some plastic behind the brass in the picture?

3: Does the brass fitting for the fuel line come out any issues with leaving it in while i soak it?

4: Does the other brass fuel fitting with plastic on it need to come off Before soaking it?

5: Do I need to split the top half of the bowl off of the carb? ( the section that holds all of the jets.)

carb 3.JPG

What are you planning on soaking it in? Have other mods been done to the bike? Was it running lean before? Run all the passageways with a thin line. Some people like fishing line, I like broom bristles. Good luck.

You cannot use a carburator cleaner to soak the entire carb as it will destory all the rubber seals and o-rings inside. You can use simple green cleaner, it does a killer job cleaning gunk and varnish but doesnt harm rubber. It may tarnish the aluminum a bit if you leave it for too long though.

Soak in simple green, rinse with water then blow out with compressed air. You can use aerosol carb cleaner to check all the passages an displace any moisture then reblow everything out with compressed air again

1) Leave the seat in

2) ACV should be OK, Lots of us disable it anyways by flipping the diaphram over so..

3) Leave the fuel fitting.

4) Leave the vent hose fitting too.

5) Don't take the mid body off the carb unless you plan on finding the orings that go in there, (they are somewhat hard to find and not available OEM form Yamaha or any other brand). But you shouldn't need to anyways.

My bike had a super dirty carb from sitting when I purchased it but doing this cleaned it right up and since I was in there I re-jetted it to Krannies recommendations, put a heavy acc pump spring, a adjustable fuel screw in along with setting the acc pump, blocked the ACV, opened up the air box as much as I felt safe, removed the backfire screen and replaced the air filter with a twin-air unit with the anti backfire treatment on it. Oh and I replaced the vent tubes as they were brittle too.

After all that I had one small bit of junk clog the pilot once soon after I put it back together but nothing since (touch wood).

Dont forget to pull the petcock out, clean it and check inside the tank, plus replace fuel lines and consider using a fuel filter as cheap insurance.

Good luck.

Whats the simple green mixture to use 50/50? any recommendations for time too.. thanks for all of the advice so far..

The bike has no mods on it's all stock except for a brand new one size larger than stock pilot jet.

Yes, it ran the exact same when I got it. As far as how it runs. It runs okay once warmed up meaning for the first three or four minutes you have to have the choke on, or have some throttle applied if you stop it will die (throttle adjustment is all the way up). If you stop on a trail and talk for a no exaggeration 2-3 min you must repeat the process.

It seems lean at idol (tested this by blowing propane into the air box (adding more fuel when lean it will rev - if too rich it will tend to die) it rev-ed up with this test.

Preformed leak down test found no leaks in any seals(started at air box and worked way to engine intake).

Other than that the bike runs normal. HA HA..

I have always ridden two strokes this is my first thumper and I love the power but I am not sure what to think of the the mechanics these are complicated in comparison. Any advice to straighten out the issue at hand would be great.

Edited by NoMoreSmoke

I just used it straight to soak the parts, and submerged the body up to the top of the float chamber to get the torx bolts cleaned, only took a few minutes and a nylon brush to look like new. I raid the wifes storage containers in the kitchen to find a good shape so you don't waste much.

I did have a problem getting the acc pump squirter tube and the pilot/ fuel screw passages cleaned out as it was really gunked up, but a bit of soaking via a eye dripper and patience it opened up along with a rubber tip that sealed airtight on the end of a aerosol carb cleaner can. I think the tip came with a mighty vac pump for bleeding brakes.. It fits right on to the plastic tube and has a soft rubber tip to force the cleaner through, priceless!

Also all the rubber bits were rotten inside the carb from being exposed to the old gas so check all the diaphrams, o-rings, etc... Be certain to check the seal thats on the slide plate, if its damaged you will have a lot of problems.. As cheap as all the parts were I just replaced anything that was rubber including the acc pump diaphram with the shorter one from Yamaha to get the squirt duration set the way I wanted but thats another thread that I found on here where sombody had done all the work setting and testing..

You didn't say what size pilot jet you have and if you have an adjustable fuel screw. The 4t FCR carb works backwards to a 2t carb in that the fuel screw richens the pilot mixture unlike a air screw on a 2t carb that leans the pilot. Also the motors seem really senstive to pilot jet hence the adjustable screw, I have to fiddle with mine about every 20 degrees of temp change..

I had medicore starting issues with the 45 pilot and was running the screw way out, I changed to a 48 pilot and the starting improved dramatically and the fuel screw is correct at about 1.5, 1.75 turns out.

Read the pinned threads about this and tinker till it works..

Spend a lot of time making sure everything is set correctly (float level, acc pump etc..) the ownwers manual is priceless, these carbs do a lot and are very percise instruments with a narrow window of being correct.

This is very typical of a minor situation, way over analyzed and over done. I have seen many people, not familiar with what they are doing, feel compelled to 'make it better' when in fact, everything was probably very close to fine before they touched it.

Re-assemble the carb. It is critical you get the slide back into the correct replationship with the throttle shaft.

Get the TPS back on, get it adjust EXACTLY correct.

Get the AP timing reset EXACTLY.

This means by the book and with all correct measurements. Do not assume marks you made before will do it.

Ensure the thottle cables and the hot start have slack.

Do not second guess things. Countless people now have $1,000 paperweights because 'they thought better...'.

Set the fuel screw by the perscribed method

It's in the simple green bath I did 50 50 mix as that is what I found else ware on the web for cleaning carbs I hope this cures it. I really like the power this baby has.

I tried a new 45 jet before getting a new 48 jet still ran the exact same no joke

I will work to get it back together today

Does the fuel screw change things? My carb had some nasty blockage in the pilot passageways that took a good bit of cleaning. also make sure the fuel screw washer, oring, spring is installed correctly and you have a good fuel screw (I have a KTM hard parts one thats made by keihin but there are some other good ones, R&D has a sweet one with a remote adj knob). Ive been told that some of the cheap ones and even some of the not cheap ones arent the correct taper and dia.. Also I've been told that aftermarket jets can be inconsistant in tolerances so stick with OE jets.

Also the PO had really messed up the float level and other basic stuff so don't assume anything is right. The trickiest things to me are the fuel screw installation and the slide plate installation, look carefully at the diagrams in the manual and do some searches on here and google, there is a lot of good info and pics out there..

Thanks for all of the advice guys. She is back together and started it up and it seems to be good to go at factory settings HA HA. can't wait for it to warm up so I can puller her out of the shop and put her thru the paces...

Agian thanks for the simple green tip and all the other advice..

Wow I REALLY wish I had read this before I busted into my carbs; I definitely melted my diaphram with aerosol carb cleaner. Thanks for the simple green tip; I'll give that a shot from now on

Just in case you were wondering the here is the recipe I used…

1. Take the carb apart remove all Jets and diaphragms (I removed the bowl but did not split the bottom half of the carb apart see picture at the beginning of the post).

2. I removed the Slide and throttle assembly then mec for the accelerator pump push rod.

3. Took an old ice-cream bucket and mixed simple green and water 50/50 dropped the carb, jets and bottom of the bowl into the Mix for about three hours. Occasionally I went out and gave a slight agitation to the bucket and carb to move the mix thru it (No Need to Get violent)

4. Pull parts out, dump mix, Blew all Parts out with air compressor.

5. Rinse Parts in water - Then Blow out with air again.

6. Spray outside and inside passage ways in carb and all components with carb cleaner - EXCEPT THE RUBBER ONES... This step will keep your carb from corroding and remove any moisture left in the carb.

7. Blow out all passage ways with compressed air immediately after step 6.

8. Assemble carb & install carb.

Have fun.....

Edited by NoMoreSmoke

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