Accepted wisdom for carb removal from 30 year inlets - 1100M

[Nick]

Hiya,

Been a while, but I ended up having to put both my bikes into storage where I couldnt physically get to them for around a year. 

Now I have them back again, they both run like crap (GSXR11M and 11N) on the standard 40mm Mikuni's.

I've started to tackle the M first, and it starts but runs on three and wont rev, so I'm guessing blocked pilot jets and gummed up everything.  The plan is to have the carbs off and clean/new orings/tubes/floats etc...

So, having had the carbs off the N before, I know it's a bit of a faff, but I have got as far as the separating the airbox rubbers off and trying to remove them from the inlet stubs on the M.  They ain't budging, however, and the 30 year old rubbers don't wanna let go.

I've liberally applied silicon spray, and my next step was to rob the mrs' hairdryer and warm them up a bit and go from there.

What is the accepted best way of getting the carbs off?  I really dont wanna be too brutal with it (ratchet straps?!!), but I'm beginning to wonder whether i'm into a new set of inlet rubbers cos these ones are harder than Lenny McLean...

Also, is it worth throwing some new inlet orings at it?  The dome heads holding the inlets on look like they will round off as soon as I look them, so I wasn't gonna bother unless the inlets have to come off.

Any ideas/wisdom greatfully received...

 

Thanks,

Nick

 

[Nick]

Carbs are minging, as you can see...

(Spaceman wrap is velcro heat shield for the loom, btw...)

[Dezza]

Heating the rubbers with a hairdrier sounds like a sensible first step to me . Personally, I would remove the hoses for a little bit more space and wiggle the carb bank up and down a little as the rubbers are heated. Obviously make sure the clips that secure the rubbers are loose as they may stick a bit on the rubbers after the screws have been loosened.

Edited March 28, 2021 by Dezza

[Nick]

Thank you Dezza, got them off this morning with the hairdryer, gentle rocking and silicone spray.

Pics below show the green slime in the float bowls from the stale fuel (wtf do they put in it?!)

So, given the state of them (30 years worth of road shite) and the fact that I have two sets to do, I was gonna look into investing into an ultrasonic cleaner.

Can anyone recommend anything that will suit home use and take a full bank of 4 carbs, or is the correct way to split them from the rail?

I am currently soaking everything in plusgas in anticipation of stripping them.

Thanks again

[Dezza]

I think the first thing is to invest in a set of JIS screwdivers (says the person who has yet to follow his own advice), as it's going to make undoing the screws a lot easier. Use some long blocks of wood to support the bank and work round loosening everything: the ones that hold the tops and float bowls on and the ones that hold the carb bodies on the rails. Be careful with the tops as they crack easily, especially if an impact driver and hammer have to be used (last resort). If doing this make sure everything is well supported with wood or disaster can occur.

See if the pilot airscrews all turn too. If any are stuck be very careful and only go any further with a correct size screwdriver as if they are stuck they can be a real bastard to get out. Once the bank is split and each carb is completely disassembled, I have had good results by soaking each body and float bowl in a mixture of thinners and acetone in a sealed container and leaving overnight. This will destroy any plastic or rubber seals so make sure everything's removed. A small ultrasonic will take one carb body at a time after solvent soaking. If all this goes to plan, I usually have the rails and other steel bits re-zinced, and rebuild with stainless screws and new seals (lintex are good, from Thailand). Good luck.

[clivegto]

I use this for cleaning carbs, works a treat. Not the Kat tank sat on top. 

[Swiss Toni]

I read a post many moons ago, that if you remove your carbs from the bike, and just dump them in a bucket of water for a week, they come out amazingly clean! Many other posters agreed with this, with maybe the addition of a little detergent, or lemon juice.  Not saying you shouldn’t still put them through the ‘fizzy tank’ though. But, if you have the time to steep ... what’s the worst that can happen?

[FJD]

Yeah...and you could speak some prayers on a graveyard around midnight too....don't believe in that BS - ditzing in water won't do nothing to your carbs, maybe the screws get rusty - thats all.

Do it properly !

[wsn03]

I've done a million carbs over the years, and left bikes in long term storage most of the time.

My 10 pence worth:

I soak jets in thinners

I wash carbs in a bucket of petrol (probably no longer a clever thing to do but its how I was taught). If it was me I'd leave soaked in a tray of petrol for a couple of days - obviously rubber seals binned first and diaphrams out. 

Rubber inlets I replace because on my slabbie they are the biggest bastard cunt fuck pig wanker asshole of a thing to work with ever - bollocks! New ones are nice and soft and easy to work with, its like a whole new way of life.

I have screwdrivers ground down to fit the pilots exactly  - they break so easy.

Also rig up a remote tank to test your carb float valves aint leaking over 24 hrs - needle float valves, the weak spot - even aftermarkets will fail except Wemoto, but I always buy oem Mikuni myself (sell a kidney)

BTW check diaphrams - my low mileage Bandit 1200 started stuttering all over the shop in Holland - when I held diaphrams up to the light full of little holes - they do go, check them.

 

Finally - to store fill with Super unleaded (less or no ethanol), add STABIL 1 MARINE - it works a treat, stops the fuel going off and stops moisture getting into your tank. Tank is always full to stop rusting. Filter between tank and carbs. No issues except when I forget to do any of that.

Edited April 4, 2021 by wsn03

[Nick]

Thanks guys, the advice has been great.  I cannot believe what a sh*te state these are in, and it's a cautionary tale for anyone who leaves their bikes stood with modern fuel in the carbs.  I'm kicking myself that I have another set to do after this...

Still soaking up the pilot/main/needle jets in plusgas at the moment, but have managed to get everything else undone with JIS screwdrivers.  I'll put some allen socket heads back on (M5x16, it would seem) when rebuilding them...

 

 

[Nick]

Still waiting on the pilot screws amd jets - I'm surprised no one manufactures a proper screwdriver for em.  I have filed one down on advice from here, but the bastard things are still stuck soild so I'll keep soaking them for a bit longer and try a bit of gentle heat.

Do people bother swapping out the throttle shaft seals?  The Litetek kit I have coming has replacements included, but removing the staked screws looks a right faff and it's not really a road I wanna go down if I can help it.

I do wonder if soaking them in an ultrasonic bath/thinners will wreck the current ones in there though?

[Dezza]

5 hours ago, Nick said:

Still waiting on the pilot screws amd jets - I'm surprised no one manufactures a proper screwdriver for em.  I have filed one down on advice from here, but the bastard things are still stuck soild so I'll keep soaking them for a bit longer and try a bit of gentle heat.

Do people bother swapping out the throttle shaft seals?  The Litetek kit I have coming has replacements included, but removing the staked screws looks a right faff and it's not really a road I wanna go down if I can help it.

I do wonder if soaking them in an ultrasonic bath/thinners will wreck the current ones in there though?

I have soaked carbs in thinners overnight and then ultrasoniced them and never changed the shaft seals, and never had any problems. Saying that, I wouldn't leave them in thinners for longer than that. The shaft seals seem pretty resilient. They obviously are not made of the same material as are O rings or other hard plastic bits on carbs.

[Merijn]

Also, before you put the carbs back on again, you could try to throw the inlet rubbers in boiling water for a few minutes. Worked pretty good for me, could save you buying new ones.

[Nick]

Well, progress is slow due to a lack of time, but despite soaking the pilot screws and heating them, they were all stuck solid.

Managed to get three out by being careful and gently working them back and forth, but in true sod's law fashion, had to resort to drilling into the last one after the slot chewed off.

After the easy out failed, I ended up gingerly tapping a t16 torx bit into the hole in the screw and winding it out... lol!  If anyone else struggles with seized pilot screws, I can thoroughly recommend this method!

[Oilyspanner]

I've got an old GS650GT whose inlet manifolds are hard, I'm going to soak them in an oil of wintergreen (methyl salicylate)/ isopropyl alcohol mix for a couple of days - this rejuvenates the rubber, it's been used by some people I trust, so should work fine.

My 1100N's carbs have been off so many times the rubber hasn't had chance to think about toughening up !  I often put a thin layer of rubber grease on the rubber, this may help stop the aging process a bit.

[Dezza]

12 hours ago, Nick said:

Well, progress is slow due to a lack of time, but despite soaking the pilot screws and heating them, they were all stuck solid.

Managed to get three out by being careful and gently working them back and forth, but in true sod's law fashion, had to resort to drilling into the last one after the slot chewed off.

After the easy out failed, I ended up gingerly tapping a t16 torx bit into the hole in the screw and winding it out... lol!  If anyone else struggles with seized pilot screws, I can thoroughly recommend this method!

Ace: I will try this on my (many) spare EFE carbs with stuck pilot air screws.

[Biggmoinc]

Doing my own on a 86, ran it over a year ago and yep, left fuel in it, green and a mess, 2 of the pilot jets stripped out, drilled them out, praying threads are ok, ordered 4 new ones fingers crossed, I soaked them in clean dip, overnight, color changed a little but everything came clean, even the gas cap rusted and it knocked that off too, 

[rodneya]

On 5/12/2021 at 3:10 PM, Nick said:

Well, progress is slow due to a lack of time, but despite soaking the pilot screws and heating them, they were all stuck solid.

Managed to get three out by being careful and gently working them back and forth, but in true sod's law fashion, had to resort to drilling into the last one after the slot chewed off.

After the easy out failed, I ended up gingerly tapping a t16 torx bit into the hole in the screw and winding it out... lol!  If anyone else struggles with seized pilot screws, I can thoroughly recommend this method!

Cheap easy outs with the spiral flutes are pretty useless, and often break causing more headaches. I have a set that are basically a tapered square profile that you tap into the hole you drilled similar to the torx you used. They grab really well and have saved me a few times now.

[Nick]

3 hours ago, rodneya said:

Cheap easy outs with the spiral flutes are pretty useless, and often break causing more headaches. I have a set that are basically a tapered square profile that you tap into the hole you drilled similar to the torx you used. They grab really well and have saved me a few times now.

Yeah, think I have learned the hard way with cheap sh*te easy outs...!

So, progress has ground to a halt at the moment as I'm still waiting on a new set of Mikuni emulsion tubes from allens (suzuki oem were 50 quid a tube!).

Float needles and seats from wemoto turned up and are 'otto-moto' branded, whom I've never heard of before.  I'll be sure to bench test em before they go back on the bike and report back...

[CockneyRick]

My Recco's are as follows:

Buy a 22L fizzy tank, it'll pay for itself with all the other shite you'll wanna clean (although rubber parts do not appreciate it  )

JIS screwdrivers (Red/Black handled ones in Halfrauds)

Carb rubbers in a sealed bag sprayed liberally with silicon spray (push the air out) & left for at least 2 days.

Plusgas is a freeing agent, it won't clean parts that have already been free'd.

Always new Pilots/O rings/Jet needles & emulsions if you need/can afford them  

[Nick]

So, looks like I've missed the 'summer' this year, but finally managed to get a few hours to myself and get them back together after running em through the newly bought ultrasonic cleaner (5l, but big enough to fit two bodies in at once minus float bowls).

I've replaced all the o rings with a Litetek kit, as well as new fuel t piece rubbers and new float valves and seats from wemoto.

They went back together a lot quicker than they came apart, that's for sure, though the advice on here has been invaluable - thank you - and hopefully the next set I have to do will be much quicker.  As an aside, for anyone after emulsion tubes for these 40mms, they are Mikuni 'P2s' and also used on the 1100 waterboilers which made getting hold of them easier (Allen's sorted me out).

So, I'm currently in the process of rigging up an auxillary tank to bench test them for leaks, and weighing up whether or not to fight the inlet rubber screws off to change the 4 o rings which are likely 30 years old.

After taking off the oil returns on the back of the valve cover to get at them, the cast mountings make me nervous about being too brutal with em.  Last thing I wanna do is snap the 'ears' off and I wonder if its more aggro than its worth...?

I'd love to take the advice and just buy a new set of rubbers, but £240 for an OEM set is a bit more than I can justify at the moment.

Other considerations are inline fuel filters, as I don't fancy crudding up my carbs with tank jank.  Can anyone recommend any specific inline filters that will offer some filtration and won't starve it of fuel?  I'm on a rebuilt standard twin outlet tap...

 

Thanks!

[denisd]

240 quid for oem rubbers is never justifiable 

[Gixer1460]

18 hours ago, Nick said:

 and weighing up whether or not to fight the inlet rubber screws off to change the 4 o rings which are likely 30 years old.

After taking off the oil returns on the back of the valve cover to get at them, the cast mountings make me nervous about being too brutal with em.  Last thing I wanna do is snap the 'ears' off and I wonder if its more aggro than its worth...?

My 'go to' method is an Impact Driver, 12" extension and the large 'blunt' cross head bit in the set - never had a screw that didn't yield after a couple of whacks - replace with SS M6 cap head screws.

[CockneyRick]

And coat them (along with header bolts etc etc) with copaslip.

The heat will not affect them as it's in a threaded hole & tight as a tight thing.

Will save a huge load of headaches next time round  

[wsn03]

On 8/28/2021 at 5:40 PM, denisd said:

240 quid for oem rubbers is never justifiable 

I bought new rubbers about 15 years ago. £240 is justifiable. £2400 would be justifiable. My life went from Fucking hell bastard cunt fuck bastard @"@%!@!@!!! to just "ooooh....suits you Sir"

I'd hunt around to get them cheaper

Any motorbike supplier will have a decent filter, I've always used them

To prevent this hassle again use STABIL 1 MARINE when in storage