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The 2-Stroke Garage => Turning Wrenches => Topic started by: rd400greenhorn on July 19, 2020, 07:23:33 AM

Title: Running tm34 on my rd400 problem
Post by: rd400greenhorn on July 19, 2020, 07:23:33 AM
So i got tank on just to start her up and go ride to test the gears

Its got the old oem fuel petcock on, fitted with industriel 6,4mm ( 1/4") fuel lines

Does it get fuel enough or is 1 liter of fuel in tank just not enough for consistent start?

Title: Re: Running tm34 on my rd400 problem
Post by: rd400greenhorn on July 19, 2020, 07:37:04 AM
I mange to get it to run so what with choke on,  plus the left carb is leaking underneath somehwere.. Cant seem to find the problem with that carb. Had it open 2 times now
Title: Re: Running tm34 on my rd400 problem
Post by: Czakky on July 19, 2020, 08:38:15 AM
Float height? Float needle?

Try to find where it's leaking from.
Title: Re: Running tm34 on my rd400 problem
Post by: rd400greenhorn on July 19, 2020, 09:01:03 AM
Yeah so iam not sure how and or where do adjust this, allthough the float sits on 1 metal rods, and they seem to slide easily
Title: Re: Running tm34 on my rd400 problem
Post by: ElFuegoBlanco on July 19, 2020, 10:00:43 AM
There should be a tang on the float that sits on the needle. Bend the tang up or down as necessary to get the proper float height.

The float height is important as it will stop the flow of fuel before it overflows out of the carb, but also allows enough fuel flow to not starve the motor.

I'm not familiar with the VM34, but it should look similar to this.
Title: Re: Running tm34 on my rd400 problem
Post by: rd400greenhorn on July 19, 2020, 10:02:57 AM
Awsome.
I Will look into it
Title: Re: Running tm34 on my rd400 problem
Post by: Seizer on July 19, 2020, 10:59:52 AM
When I upgraded to TM34s, I also got the Raptor 660 upgraded Petcock from Chuck. Also went to all 5/16 fuel lines.
Title: Re: Running tm34 on my rd400 problem
Post by: rd400greenhorn on July 19, 2020, 11:18:57 AM
Yeah so did I.
But when removing the fuel line from it I pulled out the one fuel connection ( brass?)
Not sure what do fix it i put a oem petcock on
Title: Re: Running tm34 on my rd400 problem
Post by: m in sc on July 19, 2020, 12:02:43 PM
at the end of the day, you need to size it for total area of needle seat(x2) vs total area of petcock opening. that's really what it all boils down to. 

sounds like you had debris behind the needle at the float valve.

as far as the petcock, you should be able to press the fitting back in.

:twocents:

Title: Re: Running tm34 on my rd400 problem
Post by: rd400greenhorn on July 19, 2020, 12:06:46 PM
Yeah, though Its just a bit to easy to put in or take out.. Might need some strong glue /locktite

Yeah gonna have to adress the total fuelling system on it
Title: Re: Running tm34 on my rd400 problem
Post by: rodneya on July 19, 2020, 12:25:48 PM
On of my carbs also did that. I scuffed up the end of the brass fitting and put it back with a little bit of JB weld.
Title: Re: Running tm34 on my rd400 problem
Post by: m in sc on July 19, 2020, 02:36:06 PM
yup. jb weld or green loctite.  :clap:
Title: Re: Running tm34 on my rd400 problem
Post by: SUPERTUNE on July 25, 2020, 12:15:50 AM
I adjust all the big TM carbs floats down some as with the big petcock conversion and the stock 3.3 needle valve size they don't need to be so high like in a wide open throttle dirt bike!
Chuck
Title: Re: Running tm34 on my rd400 problem
Post by: teazer on July 26, 2020, 11:57:16 AM
Float height is just a crude proxy for fuel level and that's what's important.  Ask Evans Ward if he has a fuel level adapter for your carbs and set fuel level initially 3mm below the gasket surface and work from there.

If not, get a float bowl bottom nut from a snowmobile with a water drain and use that.
Title: Re: Running tm34 on my rd400 problem
Post by: rd400greenhorn on August 02, 2020, 05:35:30 AM
So have both carbs hanging of the bike
Buttombis taken of, everything looks similar, flot height membran? The one you can adjust up and down is both equal flat?.
I think the one side thats leaking, the floater maybe dont love so freely.

:umm: :umm:
Title: Re: Running tm34 on my rd400 problem
Post by: rd400greenhorn on August 02, 2020, 05:56:59 AM
Not sure if you can anything but
First picture  is of the carbs thata been leaking fuel.
The 'tap' is Very slitly Bent down


Second picture

The carb has not been leaking
The tap is slitly upwards


So a first would be adjusting the tap on the leaking carb a little up?
Not sure if that small amount does anything?
Title: Re: Running tm34 on my rd400 problem
Post by: m in sc on August 02, 2020, 07:53:54 AM
well the fuel level on the bottom pic is higher so? if level was the issue that would be the one more likely to overflow.  might be something in behind the needle and seat causing it to seep past and leak.
Title: Re: Running tm34 on my rd400 problem
Post by: SUPERTUNE on August 03, 2020, 10:23:20 PM
In the 2nd pic... you went the wrong way. Should be below, not up as shown.
Remember TM 34's use 8mm fuel lines (not stock RD 6mm) and use 3.3 mm needle and set size. so at stock setting on the TM 34's they will leak,
When looking from the side in relationship to the float base gasket, the float arm needs to be at 9:30 or 10:00 o'clock.
(lower fuel level than stock)
Chuck
Title: Re: Running tm34 on my rd400 problem
Post by: rd400greenhorn on August 04, 2020, 12:54:27 AM
Chuck
Thank you, i Will have them Bent the other way and try that.
How much do I Bent it?

I Will also get some bigger lines on eventually

Not sure what the jetting is, but got a set from you i changed it to from stock

Title: Re: Running tm34 on my rd400 problem
Post by: teazer on August 04, 2020, 11:37:09 AM
Check the FUEL level with the carbs off the bike.

I know I keep saying that and it's because it makes a difference. With separate floats it's a crap shoot setting float levels. 

Modify a base nut to take some clear tube.  Evans sells the barbs for some carbs, or get a vacuum adapter and drill and tap the base nut for it or grab a base nut from a snowmobile.  They typically have a barb on the end so that water in the fuel drops into teh tube where it freezes.  You just use a longer tube bent up to measure fuel level.

I think these come from Evans Ward on this forum.

https://www.kzrider.com/forum/3-carburetor/601369-mikuni-vm-33-carbs?start=100#gallery-4
Title: Re: Running tm34 on my rd400 problem
Post by: 85RZwade on August 05, 2020, 10:22:57 AM
2nd that. I recently bought the above mentioned kit from Evans, and it showed that my meticulous float height setting resulted in a fuel height that was way wrong. Reset my floats to achieve the desired fuel level and my leaking carb stopped leaking and the RZ ran a bit better. Easy-peasy.
Title: Re: Running tm34 on my rd400 problem
Post by: motulman on August 05, 2020, 08:58:53 PM
Quote from: rd400greenhorn on July 19, 2020, 10:02:57 AM
Awsome.
I Will look into it
the two lil black floaties need to be level with each other also ok or the bent tang wont make a difference
Title: Re: Running tm34 on my rd400 problem
Post by: rd400greenhorn on August 09, 2020, 04:26:00 AM
Yeah so iam gonna try this, see if it changes anything