Help FZR250 3LN3 carb problem.

@G1D1
The litetek seal kits come highly recommended

 

Sure thing, @ruckusman I am in Redfern, would be keen to pull apart some carbs together if you are keen and doing it soon! I have a track day booked for June so keen to get this fixed before then! Would be happy to observe your 3ln1 before attacking mine, but depends when! I'm generally free on weekends.

Litetek has recommended I first try to change only this: http://litetekco.ipage.com/Guide_MikuniPilotMergeChamber.html

He suggested I try this before buying the full kit, as I am sure my bike has had a litetek seal kit in it quite recently (@Grasshopper might be able to confirm if he ever did it and when?)...

Thanks all!

 

OK if it's had the litetek seal kit through it already then just do the pilot merge chamber when you do the emulsion tube and needles.

That is a really easy job to do

 

@maelstrom - I hate to burst your bubble, but when I first did all of the seals and ultrasonic cleaned my carbs I did those bungs. They are a strange kind of material, call it crumbly aluminium and need care to be removed without excess damage - sliding a stanley knife blade under the edge and working around gently worked for removal

It is a good theory, @G1D1 might be able to do it on his before the emulsion tubes & needles, but I think I know the outcome already

 

@maelstrom - that's a good question, it was a long while ago, when I wheel the bike out of the garage I may just pull the carbs and check those bungs - from memory they will not say in place without the o-ring, so I'll see what's what.

I know the bike chugs, but without the countershaft replaced I cannot ride it, so hopefully it does it willingly...

 

Yes @GreyImport, that’s the bike.

I’m happy to try the 4 bung o-rings, will let ya’ll know how I get on

 

@GreyImport - can you provide any more information on this, running a fuel pump I assume, and did fuel heights check out whilst it was doing it.

Impossible to determine the cause now it's fixed itself

 

It’s having the problem that was exactly the same as @ruckusman , best described here in this thread (screenshot attached).

Have checked fuel filter, petcock, spark and plugs.

 

Isn't this just like the good old days - trying to sort out fizzer carbs.

@GreyImport - have you had chugging on your current fizzer which cured itself?

edit - you replied whilst I was typing - good repsonse BTW

 

Great, good to know I’m not alone. I agree, sometimes it seems avoidable by keeping the rev’s high, and never does it when riding ‘hard’. I only experience it when around the 6k mark, when it bog’s down. But it does concern me for the track.

I will check the tubes and needles, I will take some pictures to post too. Thanks for your help and input @GreyImport

 

That was what I used to do, 99% of the time I could keep it alive, it was just a bugger when it chugged if I was at the head of the lights in peak hour.

I'd be looking perhaps underneath those bungs and replacing the o-rings and checking float level/fuel height

I'm with you on that, every now and then when I get bored I go searching for mikuni needle jets which can be substituted - the needles are much more difficult - read that as nigh on impossible. From memory either @my67xr or @Linkin had noticed wear on the keyster needles after a relatively short period of time ~5K kms or so - I think that needle material is less durable...

 

This table had me doubting myself - the 3LN1 supplement lists the needle as 5CT7 only

I get some comfort from the fact that at least we now have access to replacement needles and emulsion tubes - I did the fuel height so many goddam times - I even cobbled together a stand for the carbs to check it, and an aftermarket pump, and flow/pressure restrictors and permanently installed fuel level tubes and tools always with me - drove me nuts, but has some legs towards redline