need a new carb diaphragm

[snydes]

so after peeking around at my carbs more i can see that one of my diaphragms comes down very very slowly and has some kind a hard point when lifting it. it also has some very light scratching on 2 sides of the slide. i thought this to be my issue why my one carb was not working and was shooting gas but i have not tested it yet.

does anyone know where i can get one cheap and easily? i see ebay ones like this but these are way different than mine
( http://www.ebay.com/itm/Carb-Diaphragm- ... -Q&vxp=mtr )
there are also these but they say for fzr400R(i have no "r") and my cars are 3bf on my 1wg engine
( http://www.ebay.ie/itm/YAMAHA-FZR400-FZ ... o1zIaZaldA )


I was planning on going to my local Yamaha dealer to see how much it would be for them to get one since places like bikebandit or partzilla don't have them. i have to check how big the slide is still.

[TomcatMJ]

A Mikuni Distributor should have the diaphragmas, at least http://www.mikuni-topham.de ....don´t know whos the distributor for Canada or US, but there should be a distributor for Mikuni anyways, topham is the one for germany, austria and suisse, but as far as i know hes also sending worldwide if needed

[snydes]

A Mikuni Distributor should have the diaphragmas, at least http://www.mikuni-topham.de ....don´t know whos the distributor for Canada or US, but there should be a distributor for Mikuni anyways, topham is the one for germany, austria and suisse, but as far as i know hes also sending worldwide if needed

I have found that there are a few places in Canada that distribute Mikuni, but under the link you said, how do I get to m actual carb? I have no idea if its like TM or BN or HS etc. All i know is that it is a set of 3bf's. and under manufacturer's i cant find any FZR400 models only the FZR1000 shows and im guessing that it has different carbs and slides/diaphragms.

under the distributor in Ontario Canada, they show a catalogue they have (http://www.winnerscirclecanada.com/flip ... html#p=158) now flipping through it I never saw any carbs that looked like mine but i can go to bikebandit and get the part number there and maybe call them and ask if they have one. I also have a Kimpex dealer here in canada that is apparently another distributor but i dont see any info about it on their site but ill look into it. if i have to order from USA its fine.

[snydes]

I was also thinking about buying this set of carbs for spare parts, i asked and they are 3bf as well and just need a cleaning to run so i may swap some parts on each to get a good working set that looks nice too!

http://www.ebay.ca/itm/1989-YAMAHA-FZR- ... 1956849873?

[TomcatMJ]

I have found that there are a few places in Canada that distribute Mikuni, but under the link you said, how do I get to m actual carb? I have no idea if its like TM or BN or HS etc. All i know is that it is a set of 3bf's. and under manufacturer's i cant find any FZR400 models only the FZR1000 shows and im guessing that it has different carbs and slides/diaphragms.

under the distributor in Ontario Canada, they show a catalogue they have (http://www.winnerscirclecanada.com/flip ... html#p=158) now flipping through it I never saw any carbs that looked like mine but i can go to bikebandit and get the part number there and maybe call them and ask if they have one. I also have a Kimpex dealer here in canada that is apparently another distributor but i dont see any info about it on their site but ill look into it. if i have to order from USA its fine.

Fact is, they don´t have these carbs in their directly accessible onlinecatalogues, but if you send them an email and state which carb or for which motorcycle-model (if, like in your case, the factory carbs are meant),they know the carbs and will send you a pricelist for the spareparts including orderingnumbers and so on...should be the same with your local distributor
Just think about the number of motorcycle-models which have been equipped with mikuni-carbs over the years and the amount of parts which where used there..every part is mostly used in different models, so how huge should a complete catalogue be on the webserver? Seems sometimes the available webspace and the decreasing database-speed if everything would be kept online might be a reason why they don´t list every part available also online (But more the costs for the space i guess )

[snydes]

ill send them an email about that thanks!
How do you feel about the other set of carbs though? I was kind of leaning more towards having a whole other set just in case I ever need it

[TomcatMJ]

I think ahving a spare-set of carbs is never wrong...as if you´ve once have trouble with your usual carbs you can go, get them out.place in the spare carbs, sync them and then check the removed set patiently for reasons for any malfuntcions (weras, scrachtes,damages, stuck jets etc.) but have the option to continue riding meanwhile instead of waitng some day or perhaps weeks for needes spareparts
The one in the linked auction looks like slightly modified (replaced mixture-screws for better accessibility?) but well so far...a bit cleaning (ultrasonic or with a mix of industrial cleaner + hot water and some nylonstrips for clearing the channels) and hoping no seal or fluelvalve would need an exchange and a resync to your motor (maybe checking mixture, too) and you will have a nice spare-carbset

[snydes]

I think ahving a spare-set of carbs is never wrong...as if you´ve once have trouble with your usual carbs you can go, get them out.place in the spare carbs, sync them and then check the removed set patiently for reasons for any malfuntcions (weras, scrachtes,damages, stuck jets etc.) but have the option to continue riding meanwhile instead of waitng some day or perhaps weeks for needes spareparts
The one in the linked auction looks like slightly modified (replaced mixture-screws for better accessibility?) but well so far...a bit cleaning (ultrasonic or with a mix of industrial cleaner + hot water and some nylonstrips for clearing the channels) and hoping no seal or fluelvalve would need an exchange and a resync to your motor (maybe checking mixture, too) and you will have a nice spare-carbset

The carbs came off a race bike that was basically stock. They are jetted and those knobs are for adjustment yes. They need a full cleaning yes[emoji23] as they look rough but I think after cleaning they should be good. I'd really like to just switch a diaphragm from that set and put it in my set for the one carb that seems to be shooting gas out the top and not functioning correctly and see if it fixes it

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[TomcatMJ]

Wasn´t it your 400 with the mixture of carbodies between 3BF and first gen. 1WG? If yes it might be easier to clean the carbs from the auction if you get them, change the jetting of the mainjets between the 2 carbsets and run them as they would be easier to get in sync...changing the mixtures screws is also a good idea if you have the tools for checking the proper mixture (colortune spark or CO-Tester) as its fu***ng narrow to reach the original mixturescrews for checking the mixturelevel in the 3BF during running the motor. It was even a fiddling work to get the synchronizer-screws with help of a pocket-mirror last week when i resynced the carbs of my 3BF..standardproblem with european glove-size 11 (would be 2xl in other countries if i´m remembering the size-translations correctly)...and the mixture screws have less space around the way for the screwdriver

[snydes]

Yes my bike is the one that has a 1wg engine and 3bf carbs. And trust me I know aha to adjust the mixture screws I just have been taking the carbs right off (but the adjustment doesn't seem to be making much difference to my bogging issue). My carbs and the other set are both jetted(amount for other ones is unknown) but I have a 110 main instead of original 87.5. I need them jetted since I have Pods(I may get a airbox later) and a custom exhaust.
What is the colour tune spark mean? It just shows colour of plug after running to show the mixture?

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[TomcatMJ]

I think mixing a 1WG engine with 3BF carbs should not be the real problem,i thought about mixing the carbbodies of a 3BF and a 1WG in the same carbbank (1 of the 1WG and 3 of the 3BF or so) which might make in hard to get them properly in sync due to the different amount of air coming in (based on the fact that a 1WG has one airjet more than a 3BF)...and bogging is often coming from not-synced carbs as i recognized after having resynced my carbs last week...it now takes the gas better, is reacting faster and no more sounding like a rusty ol´ farmers´ truck ...did you check the yamaha-racekit-manual for the 1wg/2tk available at litetek.co ? might help for finding optimized jettings and other performancetuning

A colortune is a special spark plug which allows to have a view to the combustionchamber and so to the flames color during(!) operation so that you can check if the flames are running in optimized range and get the most power out of the fuel or if your mixture is too rich or too lean... http://www.carbtune.co.uk/colortune.html
Its in my opinion a good way for do-it-yourself-mechanics as its way cheaper than a CO-Tester but helps you to get the best mixture for proper operation of the combustion maybe this concept is also adopted by other manufacturers of tools,but up to now i´ve only seen this manufacturer for this kind of adjustment-setup-sparkplugs...

P.S.:If my budget wouldn´t be so low i already would have got a set of them for optimizing my 3BFs, but as they´re now way rejetted but in default-setup (87,5 jets) i also use the default-setup for the mixture (3,5 turns of the mixturescrews out according to the service manual) up to now even when i know that the default-setup is usually only a starting point for optimizations....

[snydes]

I think mixing a 1WG engine with 3BF carbs should not be the real problem,i thought about mixing the carbbodies of a 3BF and a 1WG in the same carbbank (1 of the 1WG and 3 of the 3BF or so) which might make in hard to get them properly in sync due to the different amount of air coming in (based on the fact that a 1WG has one airjet more than a 3BF)...and bogging is often coming from not-synced carbs as i recognized after having resynced my carbs last week...it now takes the gas better, is reacting faster and no more sounding like a rusty ol´ farmers´ truck ...did you check the yamaha-racekit-manual for the 1wg/2tk available at litetek.co ? might help for finding optimized jettings and other performancetuning

A colortune is a special spark plug which allows to have a view to the combustionchamber and so to the flames color during(!) operation so that you can check if the flames are running in optimized range and get the most power out of the fuel or if your mixture is too rich or too lean... http://www.carbtune.co.uk/colortune.html
Its in my opinion a good way for do-it-yourself-mechanics as its way cheaper than a CO-Tester but helps you to get the best mixture for proper operation of the combustion maybe this concept is also adopted by other manufacturers of tools,but up to now i´ve only seen this manufacturer for this kind of adjustment-setup-sparkplugs...

Well I don't have any 1wg carbs though, as my set and the other are both 3bfs. My engine is only the one that's 1wg so I have no way of getting a 1wg carb as of right now. My carbs are not synced currently but I just have been having this massive bogging and just learned that the one diaphragm may be an issue as it take a solid .7s slower release than the others. I have not tried the bike however yet with the swapped diaphragms between 2 carbs on my set.

I will look into getting one of those testers but usually I just got by if it bogs or not with mixture screws[emoji23]

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[TomcatMJ]

I guess syncing the carbs properly would eliminate most of the bogging soon, mixture chek makes sense only after first syncing the carbs.

Check https://www.flickr.com/gp/tomcatmj/01E228 if you want to see how i build my sync-tester for around 50 €, but with a "bit" long hoses...i used 32 m of hose with 8mm inner diameter where usually 16 m would have been already enough ...would keep around 16€ to use only 16m instead of the 32...additional ther where 3 T-Hoseconnectors (Y-Connectors would have been better but weren´t actually available at the tools market), one meter of the 8mm diameter hose for the filling and emptying connection, a coupling and connector from compressors technique ("Pneumatic-Schnellkupplung" in german), an old oil-can for the oil (i used 20W40 as it has been sitting around in the cellar) and just an old 2m long, 40 cm wide board i already had (an 60 cm wide osb-wooden plate cutted to 40cm,used the rest for also building a fitting stand with some screws and 90° metal angles, but not neccesary)and which i painted with some old white paint, some cablestraps, 0,5 m hose with 6 mm inner diameter and 0,5 m 3,2 mm inner diameter hoses (due to the fact that there seem to be no adapters between 8mm and 4mm hoses directly) 4 adapters 8-6 mm and 4 adapters 6-4 mm (for the 3,2 mm hose)...the scale is 6,5 cm between each stage as this would give a scalestep of 20 kPa (or 200 mBar) per step...in the service manual of most yamahas the pressuredifference of the carbs should be not more than 1,33 kPa so the scaling works fine enough to evaluate if the carbs are good enough in sync after turning the screws...and its way cheaper to use that selfbuild thing than to buy a synchontester, even if its lager to store (thats why i made it refillable-on-demand instead of fille-once-and-leave-it)

[snydes]

I just brought my bike into a shop and they are going to look into the gas shooting issue and why its bogging, also they are going to do a carb sync so we will see how it runs when it gets back


UPDATE (May 6th):

Got bike back, turns out Cyl1 has no compression all of the sudden, did aleakdown test and valves are definitely out of spec as the intake is always open causing it to open at the wrong time so thats why gas is shooting out the carb and why its bogging im guessing. Will be fixing this upcoming week. Terrible news but its not too bad to fix.