IDA's popping back through carbs

[Chris V]

How much advance do you have at idle now?

You could probably find the camshaft model by pulling the oil pump...what kind of RPM are you running it out to anyway, 7k? Do you have the 'high' RPM points with the striped wire? http://vwparts.aircooled.net/Bosch-009- ... 01-030.htm

[type3]

How much advance do you have at idle now?

You could probably find the camshaft model by pulling the oil pump...what kind of RPM are you running it out to anyway, 7k? Do you have the 'high' RPM points with the striped wire? http://vwparts.aircooled.net/Bosch-009- ... 01-030.htm

While it's trying to idle it's moving around too much to be sure. I'll check again though.

Not sure what the top rpm is maxing out at, I'll get the rev counter hooked up. It starts screaming which is a bit loud for the neighbours! I hadn't heard of the high rpm points before! I'll get hold of some.

[type3]

Okay, been a bit busy recently but a friend popped over to help with this today. I also spoke to the guy I bought the longblock from and he says the cam is CB's equivalent of an FK87.

So I put in a different 009 but with a lumenition. Timed it at 32 degrees full advance. It seems possible to get it to idle at 18 degrees. However sometimes the idle speed drops and it becomes lumpy at 12~14. If it drops to 10 degrees it'll stall. If I put the snail on the carbs it wants run away with the revs climbing. Either they'll stay high and we have to cut the power, or they'll slowly drop down. The snail seems too restrictive. At stall it'll register 10ish otherwise it's around 20 on the snail.

I also removed the muffler as that could be a bit restrictive (I was trying to silence it for street use). I've got an A1 muffler on order.

[edit]: also when turning it over, it sometimes wants to run backwards until it catches and fires.

[Marc]

Your idle jets are for IDA, not DCOE, right? The latter look the same but have an extra bleed hole near the top. I don't think you're out of the woods yet as regards idle mixture...100% sure there're no induction leaks? If the carbs are out of synch mechanically you're pissin' into the wind, detach the linkage and ensure that both throttle plates are shut initially.

Can the snail be opened up to reduce its restriction? It's acting like a choke, causing the mixture to go richer...if that makes the engine speed up, it must be too lean to begin with.
18° initial is too much, you need to back that down (ideally widen the curve). You'll have real problems starting when hot; putting the ignition on a separate switch so you can get the engine cranking before hitting it with spark is a work-around.

[type3]

Your idle jets are for IDA, not DCOE, right? The latter look the same but have an extra bleed hole near the top. I don't think you're out of the woods yet as regards idle mixture...100% sure there're no induction leaks? If the carbs are out of synch mechanically you're pissin' into the wind, detach the linkage and ensure that both throttle plates are shut initially.

I'll double check the jets. Yep, pretty sure there's no induction leaks. I had the linkage off today, it just seems to not take much to get the revs to go up, or for it to drop down and stall.

Can the snail be opened up to reduce its restriction? It's acting like a choke, causing the mixture to go richer...if that makes the engine speed up, it must be too lean to begin with.
18° initial is too much, you need to back that down (ideally widen the curve). You'll have real problems starting when hot; putting the ignition on a separate switch so you can get the engine cranking before hitting it with spark is a work-around.

I did look closely at the snail today, but there doesn't seem to be a way to change the way it flows. With this dizzy I could knock the total back 28 max and see where it'll idle. I did try a Mallory in there but it really doesn't like it which is odd. I had that set to advance to 22 degrees (also tried 14 and 18 for the hell of it, but no joy). Interesting idea on the separate switch!

[rs58rag]

type3 you said you're using 170 main air and 200 main gas jets, that is way too rich...a good starting point would be 195 main air with 160 main gas jets or 200 main air with 165 main gas jets with 40 venturis. 60 idles. This is around sea level to 1200' elevation ...don't know your elevation..

[type3]

type3 you said you're using 170 main air and 200 main gas jets, that is way too rich...a good starting point would be 195 main air with 160 main gas jets or 200 main air with 165 main gas jets with 40 venturis. 60 idles. This is around sea level to 1200' elevation ...don't know your elevation..

Hey man, thanks for the pointers, much appreciated. I'll definitely check it out. I haven't touched the car for a while as it's been on a back burner. Have to move it soon though to another storage location.

Last time I worked on it, I freed off the seized clutch and drove it down a private road.

https://www.youtube.com/watch?v=zUVtlyUMbT4

You can hear the popping in the video. Thanks again.

[rs58rag]

Check and clean idle jets and put on good fuel and air filters. Also, check valve adjustment....if set too tight, valve may not seal completely when engine is at running temperature and spit out carbs. I'm using chromoly pushrods on 2175 and went with a .002 gap instead of loose zero and all is good ever since.

[type3]

Yeah, I've been over the basics a few times. Always good to check and recheck. I've ordered the 165 & 200 and I'll see how that goes. They only come into play off idle right? It's pulling more cleanly off idle now but probably still rich like you say.
I'm gonna put an A/F gauge on next, try those jets, then take it to the Test Station to get it legal and then onto a rolling road.

[Piledriver]

A 009 frequently needs the slop taken out of the springs, and the weight stops (goalposts) can be bent in to limit travel.

[type3]

A 009 frequently needs the slop taken out of the springs, and the weight stops (goalposts) can be bent in to limit travel.

Yeah it probably needs a strip down and a once over. Not sure how many miles it has on it.

[type3]

New jets fitted, battery was flat though. Will fire it up at the weekend.

[type3]

type3 you said you're using 170 main air and 200 main gas jets, that is way too rich...a good starting point would be 195 main air with 160 main gas jets or 200 main air with 165 main gas jets with 40 venturis. 60 idles. This is around sea level to 1200' elevation ...don't know your elevation..

Fired it up today with the new jets that you recommended and the idle mixture turned out one turn... and it almost wants to idle! Sweet as!!!

The idle speed needs to come up a touch as the alt light is flickering. I'll retime it over the weekend and then move onto the linkage.

Thanks again!

[type3]

This finally went on the rolling road and they went through it. It made 138.3rwhp.