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The 2-Stroke Garage => Turning Wrenches => Topic started by: 350GUY on September 20, 2025, 07:23:11 PM

Title: Mikuni TMX34 carbs on RD350
Post by: 350GUY on September 20, 2025, 07:23:11 PM
Has anyone tried mounting the TMX34 (Skidoo) carbs on the RD350? Seems like the are quite tall in terms of height and I suspect that the float bowl might hit the engine case. Has anyone tried these?
TIA
Title: Re: Mikuni TMX34 carbs on RD350
Post by: 1976RD400C on September 21, 2025, 11:35:55 AM
Here's some pics of VM34s on my 400 to show how much room there is for them. Plenty of room for the bowls and maybe you can gauge how much taller the TMs are.
Title: Re: Mikuni TMX34 carbs on RD350
Post by: 350GUY on September 21, 2025, 01:18:11 PM
Quote from: 1976RD400C on September 21, 2025, 11:35:55 AMHere's some pics of VM34s on my 400 to show how much room there is for them. Plenty of room for the bowls and maybe you can gauge how much taller the TMs are.

A very many thanks, very helpful. Seems like the TM series are much taller. I've snagged this from e-bay.

https://ebay.us/m/ynO8Ly

Title: Re: Mikuni TMX34 carbs on RD350
Post by: 350GUY on September 21, 2025, 01:31:08 PM
Snagged this from Ebay
Title: Re: Mikuni TMX34 carbs on RD350
Post by: m in sc on September 21, 2025, 01:42:58 PM
going to be very tough to get air filters on , the 350 frame is narrower there.
Title: Re: Mikuni TMX34 carbs on RD350
Post by: 1976RD400C on September 21, 2025, 02:50:37 PM
Yes, the 400 has almost 6" between the frame rails so you can cram a pair of foam filters in there but the 350 only has 4".
Title: Re: Mikuni TMX34 carbs on RD350
Post by: 1976RD400C on September 21, 2025, 03:39:43 PM
BTW my cylinders have had lots of work done to the transfer ports and the reed cages are modified RZ sized with single petal reeds. That's why the big carbs.
Title: Re: Mikuni TMX34 carbs on RD350
Post by: rodneya on September 21, 2025, 09:07:44 PM
Billet Banshee intakes move the carbs back and up. Just make sure you buy from a reputable seller with genuine mikuni intake flanges and not chinese knockoff stuff. Thats not a place you want a leak.

I have a RZ motor in my 73 350 with TM34 carbs and I use a Ramair sock filter due to serious lack of space. I just stretch the openings over the carbs and it has stayed in place so far.

Screenshot 2025-09-21 at 18-03-38 2x Twin Inlet Motorcycle Carb Sock Foam Air Filter 72mm (2.8inch) - Ramair Filters Inc.png
Title: Re: Mikuni TMX34 carbs on RD350
Post by: m in sc on September 21, 2025, 09:41:23 PM
this is exactly why I had a custom y boot printed i designed.
Title: Re: Mikuni TMX34 carbs on RD350
Post by: 350GUY on September 28, 2025, 04:14:46 PM
Quote from: rodneya on September 21, 2025, 09:07:44 PMBillet Banshee intakes move the carbs back and up. Just make sure you buy from a reputable seller with genuine mikuni intake flanges and not chinese knockoff stuff. Thats not a place you want a leak.

I have a RZ motor in my 73 350 with TM34 carbs and I use a Ramair sock filter due to serious lack of space. I just stretch the openings over the carbs and it has stayed in place so far.

Screenshot 2025-09-21 at 18-03-38 2x Twin Inlet Motorcycle Carb Sock Foam Air Filter 72mm (2.8inch) - Ramair Filters Inc.png

Thanks Rodney, I might have to get these RAM air filters. I like Marks custom Y boot.
Title: Re: Mikuni TMX34 carbs on RD350
Post by: 350GUY on September 28, 2025, 04:21:17 PM
Quote from: m in sc on September 21, 2025, 09:41:23 PMthis is exactly why I had a custom y boot printed i designed.

Thanks Mark. This would be the solution. Will now need to figure out the specs of the Y-boot....
Title: Re: Mikuni TMX34 carbs on RD350
Post by: m in sc on September 28, 2025, 05:21:24 PM
steve burgess (3d unobtanium) out of the uk has the model and i ok'd him to sell them in my design. if the bellmouth is the same diameter as a TM34, it will work. its fuel proof and flexible enough to work.  0.02
Title: Re: Mikuni TMX34 carbs on RD350
Post by: irk_miller on September 28, 2025, 08:22:14 PM
I've been running a custom TPU 3d printed intake on my Honda Elsinore for well over a year. It goes through hare scramble hell and it works great.  I've also been using the Ramair filters with my TM34's and they also work great. The Ramair filter has more surface area than running a single filter through a wye and keeps everything inside the cradle, which is why I swapped to the Ramair. I've also printed an exe intake to run dual filters. I never properly flow tested anything, so can't say for certain if any setup is better than another. so went with the simplicity of the Ramair.     
Title: Re: Mikuni TMX34 carbs on RD350
Post by: m in sc on September 28, 2025, 10:23:58 PM
no motor on here here is going to ever going come close to outflowing a 75mm ID Y boot, w 56/58mm id runners. ever. It's not about area, its about smoothing & directing the air flow,  or i would have stuck with my all-foam unis i had on as well. it def runs better w the Y on there. IF there was room i would have just made 2 straight runners but that damn frame. lol.  However, the difference was not night and day  over all, the foam filters are really good. Yes, i even have an all foam ram air setup like that as well.
Title: Re: Mikuni TMX34 carbs on RD350
Post by: irk_miller on September 29, 2025, 06:41:23 AM
Quote from: m in sc on September 28, 2025, 10:23:58 PMno motor on here here is going to ever going come close to outflowing a 75mm ID Y boot, w 56/58mm id runners. ever. It's not about area, its about smoothing & directing the air flow,  or i would have stuck with my all-foam unis i had on as well. it def runs better w the Y on there. IF there was room i would have just made 2 straight runners but that damn frame. lol.  However, the difference was not night and day  over all, the foam filters are really good. Yes, i even have an all foam ram air setup like that as well.
When it comes to a filter, it's absolutely about surface area. That's a ridiculous statement.  Your wye works well because of it's large interior dimensions, not the shape or some flow it creates.  You want intake air to be pretty much ambient, unless you're creating a forced air situation like with a turbo.
Title: Re: Mikuni TMX34 carbs on RD350
Post by: m in sc on September 29, 2025, 07:18:23 AM
IM aware its about surface area.
I was talking about the Y boot. I made a huge y boot so i could run a huge filter AND get the benefit of directed air.

Put on a huge (6") pancake filter w the back 1" away from the bellmouth of a carb. its going to run like shit.

its not one OR the other, its about both.  The filter i have on the back is tremendous and none of it is restricted. . the 1st setup actually used a pleated cold air intake car filter.  smooth laminar flow intot he bellmouth is key , and yes, from a static ambient source.

So, its about BOTH. but my statement was why i ran the y boot. 
Title: Re: Mikuni TMX34 carbs on RD350
Post by: 350GUY on October 05, 2025, 11:07:39 AM
Quote from: m in sc on September 28, 2025, 05:21:24 PMsteve burgess (3d unobtanium) out of the uk has the model and i ok'd him to sell them in my design. if the bellmouth is the same diameter as a TM34, it will work. its fuel proof and flexible enough to work.  0.02

Had reached out to Steve Burges, he is no longer printing these......
Title: Re: Mikuni TMX34 carbs on RD350
Post by: 85RZwade on October 06, 2025, 03:20:35 PM
:'(  well that's too bad; I was thinking that I needed one as well.
Title: Re: Mikuni TMX34 carbs on RD350
Post by: 350GUY on October 07, 2025, 10:30:18 PM
Quote from: 85RZwade on October 06, 2025, 03:20:35 PM:'(  well that's too bad; I was thinking that I needed one as well.

Yep! I wonder what material was used....
Title: Re: Mikuni TMX34 carbs on RD350
Post by: m in sc on October 07, 2025, 10:42:07 PM
tpu will work