Rd350b throttle valve

[2t Fan]

Hello
Like to understand whether the  73 Rd350B throttle valve  (slide) is same for high top and low top carbs or there is a height difference ?  Where can I find a right throttle valve for a high top carb?
thanks

[Brad-Man]

First of all, a '73 is simply an RD350, a '74 is an TD350A and a '75 is an RD350B.

'73 and early '74 RD's had low top carbs and later '74's and '75's had high top carbs.

I have a '74 low top and a '75 and the slides are a bit different - the cutout is shaped differently.

The slides will interchange because the high tops utilize a "plug" to make up the difference on height from top of slide to cable.

Going from memory, so I may have this turned around, the low top had 2.0 slides and high tops had 2.5.  Or vice-versa.

This might be due to a difference in airboxes...

I don't think it makes much difference, but if I am wrong would certainly like to know it.

[m in sc]

actually, the 2.0 slides are for an r5.

they will fit in rd carbs, but they are not from an rd.  all 73-75 rd 250 and 350 stock carbs have a 2.5 slide cutout.

low top slides are heightwise different, by quite a bit and the cable retaining is slightly different between low tops and high tops.

you can, however, swap the slides AND  tops between the low and high top carbs,, but the lower cables will also need to be swapped. the change was late 73 model year from low to high top.

low tops have a simple straight adjuster on the tops. high tops have a 45 degree angled elbow retained with an e clip to the cap, with an adjuster at the top of the elbow.

the rd350s also followed this protocol.

there was a service bulletin released at the time explaining this change. they claimed it was to keep water out of the carbs, which also included a large rubber boot over the tops of the 'new and improved' high top carbs. both perform the same.

[2t Fan]

thanks a lot

[2t Fan]

one more question can we use throttle valve from banshee on RD high top carbs ?

[Dxrat]

I just looked, I used to have a set but I forgot I had them machined down to short slides. I have a set of 2.0 and a set of 2.7 short slides. I was experimenting a long time ago to get rid of an off idle stumble. Didn't help either direction by the way, was fun though 

[m in sc]

one more question can we use throttle valve from banshee on RD high top carbs ?

for multiple reasons, no. also banshee carbs are 26mm

[2t Fan]

thanks

[Kawtriplefreak]

I may have what you need. I will try and look today.

[bhh1989]

I also noticed that the R5/DS7 2.0 slides were chromed steel, whereas all RD 2.5 slides that I came across were greenish colored aluminum. I somehow found some 2.5, steel, R5-height slides at a swap and ran those, no idea what bike those came from. I preferred the throttle response of the steel slides, they had more weight to them and seemed to close with more "authority".