RD350 not returning to idle

[RadioDanNYC]

Heya fellerz,


I've got a 73' RD350 that I got running not that long ago. I've rebuilt the carbs and it runs, pulls...etc. I'm having an issue where it doesn't return to idle very well. I have to put it in first and slowly let out the clutch to calm it down. When warm, it'll stay where it's supposed to idle (1.5k) if not it shoots up kinda high (4-5K).

Sticky floats maybe ?

[TheSaint]

Can't remember whether those old beasties were rotary valve or the other type (reed valve??). Check them.

[Evans Ward]

'73 was first yr of reeds and first year for the RD350. The Torque Induction name on side cover is for the reeded engine. Doesn't sound like sticky floats to me but more like the throttle cable and/or the carb cabling routing issue. Check to make sure the routing is correct and that the cables have some slack in them and are not tight. If that doesn't cure it, I'd disassemble carbs for a thorough cleaning (I know you said you just did this though) and/or test for an air leak somewhere to include the intake rubbers, base cylinder gaskets, head gaskets.

[Cadman]

It takes air flow to raise the RPM. If there is a seal (like a crank seal) that is not holding when cold, well, there ya go. Too much fuel will slow it down due to the poor mixture.

[KillerKaw]

the number 1 cause of engines not returning to idle is unsync carbs .

[RadioDanNYC]

Seems that when the idle is brought down, it slowly creeps back up. Might be an air leak

Me thinks it might have to into the shop

[John T]

Wanna sell it?

[RadioDanNYC]

Wanna sell it?

Sure!....but seeing as how it was my late father's and it only has 4K on it...the pricetage is $50,000

Lotsa sentimental value. But I think if someone offered me that kind of paper and I didn't take it; my dad would ghost-slap the $h1t outa me

[djbinzo]

On an RD, I'd look at the intake boots or (more than likely) the crank seals.

[RixRex]

Sure!....but seeing as how it was my late father's and it only has 4K on it...the pricetage is $50,000

Lotsa sentimental value. But I think if someone offered me that kind of paper and I didn't take it; my dad would ghost-slap the $h1t outa me

[grandpaul]

Sounds like air leakage, probably the rubber intakes dry cracking...

[KillerKaw]

I was totaly thinking of another bike.....

[RadioDanNYC]

OK so I looked for an airleak on the surface and found nothing. Turns out the idle screws were imbalanced brother might have played with it last. The bike has had an issue with plug fouling as well. The bike never really ran GREAT...so I drained the 2-stroke oil tank and mixed Amsoil 100:1 synthetic in the fuel tank. After taking it for a blast the bike runs even and nice! Doesn't even want to shut off. Just idles at 1.5K nicely. Effin' finally. I'm betting that the ol' oil pump is fubarred. Must have been the reason my dad stopped riding it in 1976 in the first place. I remember him saying that something was screwy with that motor. Since I first started playing with it (2 years ago), I've had to get the cylinders bored out and new pistons installed.