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I've decided to attempt the mid-body gasket replacement on my vintage 2000 slant FCR carb, stock on the DRZ 400 E. If you are like me you have scoured the forums for info on doing this service but found maybe 2 or 3 pictures of a taken apart FCR, dead end threads, and tons of negativity. 

BUT! Is it really that difficult of a repair to perform correctly? Well I have had my carb on and off at least a dozen times, trying different jets, cleaning, etc. For the last 3 years I've been getting by with the coast enrichener circuit bypassed to at least get enough fuel in the idle circuit to run ok. But it just wasn't working anymore. I could clean the carb out and get it to run for a little while, but after sitting it wouldn't start again. I tried ordering a refurb FCR-MX over a week ago and the guy has gone MIA and nothing shipped. I ordered from keihin-fcr.com. I would advise avoiding... But will update if I hear back and he has a decent reason for the delay. Anyways, it made me seriously look into the "unserviceable" midbody gasket. I mean, you can buy the gasket here: https://www.ebay.com/i/401380298480?chn=ps

So today I ripped the carb apart again, but this time to the very last fastener, separating the carb bodies. I even found my smoking gun, in the one picture with the hoop thingy removed you can see the gasket has expanded and spilled into a passageway. This passageway leads directly to the pilot jet, blocking it's flow. Though as you can see every rubber piece inside is completely trashed. Which makes sense, do you really expect these gaskets to last 20 years? Or in this case 18? If you have taken apart your FCR and went, wow that fuel bowl gasket is recked yo! I need a new one! Well you can bet your mid-body gasket looks the same. Really I see no reason I couldn't get this sealed back up with a new gasket and some fuel-proof RTV to replace the epoxy seal around the edge. Why wouldn't it work? Just doesn't make sense to me all the negativity you find toward this repair.... But I haven't finished yet so who knows if it will actually work on the bike. But I think it'll run like new when I'm done. I hope it works out for me and I can inspire some others who would otherwise be forced to buy an 800 dollar carb to do this repair instead.

Wish me luck!

SmokingGun.jpg

IntakeEnd.jpg

AirboxEnd.jpg

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Mine looked exactly like that a week ago. Just take your time and use a good fuel resistant epoxy. I used a bit of copper spray gasket on the oringsto get them to stay in place. Mine runs amazing now

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Do you think it's necessary to epoxy it back together or is any kind of fuel-proof sealant ok?

Literally looks like it's held together with JB-weld... Not too familiar with the strength of the stuff though, don't want to assemble it more permanently.

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I won't tell you that I used jb weld...

I won't say it....

But all the sealing is done with the rubber gaskets...

I won't tell you I used a toothpick and laid the thinnest bead of jb weld down

I won't say it

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Lol, I think it's a matter of if it's structural or not. I want to use RTV so I don't have to worry bout it being truly permanently assembled... But then again the stuff I spent an hour scraping off the carb halves looked a lot like JB weld. I have used it a few times. I work in a computer repair place and it's useful for old unibody macbook pro's which are basically held together with superglue, lol garbage. Change that stuff out for JB weld. ;)

If all it needs to do is seal there is easier to work with stuff out there than JB weld. I think I'll try a more removable sealant and if it doesn't work I can always go to JB-weld later.

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8 hours ago, ClutchinChrisG said:

Lol, I think it's a matter of if it's structural or not. I want to use RTV so I don't have to worry bout it being truly permanently assembled... But then again the stuff I spent an hour scraping off the carb halves looked a lot like JB weld. I have used it a few times. I work in a computer repair place and it's useful for old unibody macbook pro's which are basically held together with superglue, lol garbage. Change that stuff out for JB weld. ;)

If all it needs to do is seal there is easier to work with stuff out there than JB weld. I think I'll try a more removable sealant and if it doesn't work I can always go to JB-weld later.

I would avoid all RTV products, none of them are "fuel proof" and that is what you would need in this application.
I've done two of these now, well an FCR and FCRMX both work well after
I'm doing a third right now, my own FCR39.
All three carbs I used LOCTITE® EA 11C™ it is a two part epoxy .. 
The Adhesive on the Carb stock I feel is more structural then sealing ...I think its there to keep the two haves from moving..SO I choose epoxy vs other fuel resistant non hardening products. 

The issues with the job are common and results often in a failed repair..That leads to many saying its not a job worth doing. After speaking to a man that separates them often so the carb body can be bored...I came to understand it is just a job that has to be done precisely and with the correct repair items with no room for error or half steps.
That one little fleck of old gasket or epoxy you left, yup that will come back to bite you. Not fixing the new gasket in place at critical points and hoping it will stay there when you reassemble ..yup that will bite you as well. 

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1 minute ago, Erik Marquez said:

I would avoid all RTV products, none of them are "fuel proof" and that is what you would need in this application.
I've done two of these now, well an FCR and FCRMX both work well after
I'm doing a third right now, my own FCR39.
All three carbs I used LOCTITE® EA 11C™ it is a two part epoxy .. 
The Adhesive on the Carb stock I feel is more structural then sealing ...I think its there to keep the two haves from moving..SO I choose epoxy vs other fuel resistant non hardening products. 

The issues with he job are common and results often a failed repair..That leads to many saying its not a job worth doing. After speaking to a man that separates them often so the carb body can be bored...I came to understand it is just a job that has to be done precisely and with the correct repair items with no room for error or half steps.
That one little fleck of old gasket or epoxy you left, yup that will come back to bite you. Not fixing the new gasket in place at critical points and hoping it will stay there when you reassemble ..yup that will bite you as well. 

I agree. I assumed that that the seal was more for structural integrity which is why I didn't have an issue with using jbweld. And honestly, it was no issue rebuilding it and it made the carb run like new.

 

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I think I'll try the JB weld out as I have some on hand. What did you use to hold the gasket in place during reassembly? Oring lube or some kind of gasket sealer? I have oring lube on hand as well.

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5 minutes ago, ClutchinChrisG said:

I think I'll try the JB weld out as I have some on hand. What did you use to hold the gasket in place during reassembly? Oring lube or some kind of gasket sealer? I have oring lube on hand as well.

I used copper spray gasket on the gaskets only. I didn't want to get any on the carb on accident. It took a while to get gummy though. Everything fit really good, bit not perfect. So i just took my time. 

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25 minutes ago, ClutchinChrisG said:

I think I'll try the JB weld out as I have some on hand. What did you use to hold the gasket in place during reassembly? Oring lube or some kind of gasket sealer? I have oring lube on hand as well.

The tip of a tooth pick worth of Three Bond 1184. Its non hardening, solvent resistant, and I used the slightest about to get the packing ruing to stick, but so little over all if it dissolved over time it would do no harm 

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10 hours ago, Erik Marquez said:

The tip of a tooth pick worth of Three Bond 1184. Its non hardening, solvent resistant, and I used the slightest about to get the packing ruing to stick, but so little over all if it dissolved over time it would do no harm 

is this similar to Gasgacinch?

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Would like to update that keihin-fcr.com did finally get back to me. Seems like a cool dude, but prefers the phone over email. He was polite and said he'd refund my carb since he hasn't shipped it yet. Super cool. Can't speak for his quality of work but I would imagine any level headed guy can figure out how to clean a carb and put it back together. He certainly is.
Anybody know if I can edit previous posts? I'd like to update my first post so it doesn't tell everyone to avoid him.

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7 hours ago, ClutchinChrisG said:


Anybody know if I can edit previous posts? I'd like to update my first post so it doesn't tell everyone to avoid him.

His checkered past precedes you post.

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Whooooo!

My drz runs again! And this time, for the first time ever, with the CE delete done normally! I used to have the CE ports capped but now it runs with them bridged like they are supposed to be!

I picked up some JB Kwik weld to use as epoxy. Unfortunately it has literally JUST enough working time for this job. It was pretty scary starting to tack up as I spread the last bit down with a toothpick. On the plus side didn't have to wait for it to dry! 

I used gasgacinch to secure the gaskets during assembly. That was a great idea and Amazon got that to my door in two days. 

Well I got it slapped back together today and it fired up third kick. :) Then took it off choke and it had a bit of a hanging idle so I loosened the fuel screw and for the first time ever it did something and ran just right down low. I took it for a little ride and after warming up I was able to screw it back in a little.

So pleased my bike is a runner again! I think the last of my random no start problems are finally over!

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19 hours ago, ClutchinChrisG said:

Whooooo!

My drz runs again! And this time, for the first time ever, with the CE delete done normally! I used to have the CE ports capped but now it runs with them bridged like they are supposed to be!

I picked up some JB Kwik weld to use as epoxy. Unfortunately it has literally JUST enough working time for this job. It was pretty scary starting to tack up as I spread the last bit down with a toothpick. On the plus side didn't have to wait for it to dry! 

I used gasgacinch to secure the gaskets during assembly. That was a great idea and Amazon got that to my door in two days. 

Well I got it slapped back together today and it fired up third kick. :) Then took it off choke and it had a bit of a hanging idle so I loosened the fuel screw and for the first time ever it did something and ran just right down low. I took it for a little ride and after warming up I was able to screw it back in a little.

So pleased my bike is a runner again! I think the last of my random no start problems are finally over!

Good for you, I always enjoy hearing about when people get their bikes sorted out. It’s a good feeling for sure 👍

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Well when I got the bike it always had problems with running lean on the pilot circuit. Machine gun backfire slowing down, hanging idle, etc. I cleaned the carb up many times and tried different pilot jets and got a remote fuel screw and I just couldn't get it to run right down low. I ended up coming across the advice of simulating a coast enrichening event by capping off the secondary pilot air jet and was able to richen the pilot circuit up enough to get it to run pretty good. Though I still had no control over the pilot circuit, the fuel screw and pilot jet changes wouldn't do anything. However back in October I went for a quick ride and the bike was back to it's old crap of not wanting to idle. After this ride it wouldn't start anymore. Cleaning the carb would yield maybe 20 mins of running before it stopped again. I cleaned it twice and it kept having problems and decided the mid-body gasket had finally become shot for good and I needed a new carb or to replace the gasket. 

So if you are running recommended pilot circuit jetting and cleaning the carb doesn't help you most likely need this gasket. Honestly the job is easy enough, the gasket is cheap. If I had to touch an FCR that was over 10 years old for any reason I'd probably just replace it for peace of mind. Having done it once I don't see it taking more than a couple hours the second time. You could screw up the job yes, but not in a way that ruins the carb. Maybe you'd have to take it apart again but whatever. The only special materials I needed were JB kwik weld for the final assembly and Gasgacinch for holding the gaskets in place during assembly. I wish I had the knowledge and experience to do a truly useful write-up about this service. 

Would like to share I did get a full refund from FCR guy.
Can't say anything about the quality of his work. But if you order from him expect it to take a week for him to get back to you. I don't know if he had some kind of emergency or something but I never got any replies back since the initial one. I just decided to attempt contact daily since his initial reply and after a few days my refund showed up. But he never responded to my messages. Maybe not so polite.... I don't know. I don't like the idea of thinking someone wouldn't have a good reason for the crappy customer service. But he never did get back to me. Unless he really is a one man show rebuilding 20 carbs a day I don't see why he wouldn't have the time to answer customer emails. Whatever, I'm glad it's over.

Just put some of that refund towards a Tubliss setup for offroad riding. :) Some more will go to MX boots for offroading. Can't wait to tear up the trails on my mighty DRZ!

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CCG, thank you for the reply. I’m actually battling three different bikes that are all suffering from the same symptoms, 08 CRF150R, 09 CRF250R and an 05 CRF450R...as you can see size doesn’t seem to be a factor. All have fresh engines, perfect cam timing, new timing chains/tensioners, new spark plugs, tested and swapped electrical systems, etc. etc.  

Once you get them to start they run mostly fine at anything above low engine speeds, but getting them started is a major pain and they will not idle for anything. I’ve been everywhere with the pilot jet (+/- 4 sizes from ‘normal’) with new fuel srews and o-rings and nothing ever changes. I have even gone so far as to borrow a buddy’s ultra sonic cleaner and have ran all the carbs through it for 2hrs each. This seemed to help, but only in the slightest and was barely noticeable. I’ve ordered the gaskets and will be doing this as soon as they get here. Thank you for the info, and fingers crossed that this works, I have just about exhausted every other path. 

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I think all those bikes use the FCRMX carb. Not really sure. But if it is make sure you get the right gasket. 

My understanding is that using carb cleaner is a huge factor and destroys the midbody gasket.

Goodluck with the repair! If everything else is good and you have recommended jetting but the bike won't run right then it can't be anything but a carb problem. Go for it. Post pics as you go.

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