Pwk jetting question

[Hunter]

Hehehe.

don't really like the song but shes kinda cute

 

[Nickt919]

My gosh, Damien has a YT link for any topic whatsoever. I'm impressed.

Among other topics..the man of vast musical knowledge.

I learned this fact a while back.

 

[DAMIEN1307]

My gosh, Damien has a YT link for any topic whatsoever. I'm impressed.

And I'm just here Watching The Wheels Go Round and Round, (I really love to watch them roll)...lol...lol.

 

[Pancho86]

Read this…it may help

http://www.keihincarbs.com/tips/gate.html

Thanks for that link I appreciate it, I was reading in there where they was talking about the different tapers on the needles. And I was actually thinking about bringing that up on a different thread, I was curious if anyone's ever heard of anyone basically creating their own taper on a needle? To modify the slopes and the changes in accordance with however their motor Acts. Now I understand that's like a super advanced thing there, and I have no intention of undertaking that task. But I was just curious if that was a thing if anybody did that

 

[Chainlube]

Thanks for that link I appreciate it, I was reading in there where they was talking about the different tapers on the needles. And I was actually thinking about bringing that up on a different thread, I was curious if anyone's ever heard of anyone basically creating their own taper on a needle? To modify the slopes and the changes in accordance with however their motor Acts. Now I understand that's like a super advanced thing there, and I have no intention of undertaking that task. But I was just curious if that was a thing if anybody did that

Yes, Des Hammil did a whole book on custom tappers for the SU carbs. All you have to do is chuck the needle in a drill press and hit it with some 400 grit sandpaper, 4 second burst takes it down .001 of an inch.

Even though they are British car carbs, the same will apply to other carbs.

You have to remember the tapper only controls the flow to the 3/4 throttle opening, then after that it's all jet.

 

[robe]

Okay everybody let's get back to mechanics. The verdict is in and here is what I have come up with. I'm running a 100 main and 32 pilot. The main is terrific all those problems I was having in the high end or gone but I'm still having problem in the low end still real smokey I got the air screw all the way open. It acts mushy for the first I don't know maybe quarter or eight throttle, but once you get it past that it takes right off. I probably am going to have to drop the clip a couple notches, at least one cuz I feel that it could still use a little more richness towards the top. But one way I found that I can get away with still being mushy on the low end is when I'm sitting idle if I rub it real hard a few times and burn up on that gas in there then you can take off and get it up into the higher range. I guess I'm going to need a smaller pilot which means I'm going to have to order something else again and wait even longer

Sounds like you have it running well enough. As the temperature changes the tune will change. You don't have to make major changes, just a tweak here and there. Also as it breaks in it will change considerably. Don't make the mistake of many others to run the bag off it when it isn't fully broken in. Take it easy for several tanks.

 

[Pancho86]

Sounds like you have it running well enough. As the temperature changes the tune will change. You don't have to make major changes, just a tweak here and there. Also as it breaks in it will change considerably. Don't make the mistake of many others to run the bag off it when it isn't fully broken in. Take it easy for several tanks.

Okay, I now have enough information that I feel confident enough to publish what you would call a final report, I guess. By dropping the main jet I was able to determine that I also have a small air leak somewhere that I'm about to try and pinpoint this weekend.

Sounds like you have it running well enough. As the temperature changes the tune will change. You don't have to make major changes, just a tweak here and there. Also as it breaks in it will change considerably. Don't make the mistake of many others to run the bag off it when it isn't fully broken in. Take it easy for several tanks.

I do admit that is a factor that I didn't really consider until now. The fact that it is a new piston and rings and if there is going to be some sort of break in with this, even though the motor itself is done been broke in long ago. But one thing I did have planned for the weekend I am going to just rip everything all the way apart again I'm going to put my last cylinder gasket on there and this time seal it all up with RTV sealant, and completely dismantle the Reed valve, and our TV all those gaskets as well. It makes me uncomfortable with the cylinder leaking oil from that one corner, even though it is a very small amount. I've tightened the motor studs down as tight as I'm comfortable doing them, so it's better to err on the side of caution and just go in and replace it and seal it up real good with gasket sealant

 

[Pancho86]

Okay I'm confident that I found the culprit of all my misfortunes. I made up my mind to take apart the Reed valve and seal up every gasket on there with RTV sealant. When I took the whole read valve intake setup off of the mounting block that is attached to the intake manifold of the cylinder I noticed that the gasket had deep indents from the hex screws that are recessed in the mounting block. That mounting block is one of those variable things where you can move it left or right as needed depending upon the spacing of the studs coming out of the manifold. And I know that not only did that weekend the gasket right there but gas is also coming through those recessed holes just because the way holes were cut and drilled in pieces and just the way things match up. But there is a fix to this take it all off clean it all up dry it all out remount it and make sure I get a nice healthy amount of that RTV sealant in those holes as well. And what I thought at one time to be a cylinder gasket leak on the bottom in fact turned out to be just gas that was running out from between the Reed valve in the mounting block and it was running down the motor gathering all kinds of dirt and muck and appeared to be as like a oily substance leaking out of the cylinder when it wasn't. So once all this is taken care of then I can really get down to business with the proper jetting and tuning.

 

[Nickt919]

….turned out to be just gas that was running out from between the Reed valve in the mounting block and it was running down the motor….

So if fuel was escaping from the reed block so was air… air leak.

Once you get it all sealed you’ll see better results.

Motoseal works well in this application.
Be sure what ever you use for sealant that the surfaces are completely oil free…clean and dry. Hands clean too during application. Let it dry.

 

[Pancho86]

So if fuel was escaping from the reed block so was air… air leak.

Once you get it all sealed you’ll see better results.

Motoseal works well in this application.
Be sure what ever you use for sealant that the surfaces are completely oil free…clean and dry. Hands clean too during application. Let it dry.

This is the setup now. I got a section of a good radiator hose to make the carb sit better and stay out of my way. I know this rubber won't hold up to the fuel for an extended period, but this is only a couple days temp fix until. I can get a reinforced vinyl hose the right diameter. I used ultra black permatex RTV gasket maker, oil resistant. It'll be cured by the the time I goto work in the morning, so I'll report then.