Redline on start

[bens4X4]

Hello all,
Recently got spark, etc and have been working on getting my Rat running. It's a 1970, had been sitting since the 80s in a dry dark garage. It has a "brand new" .030 piston with reed valve setup(came back from engine shop before being parked). So, I have tried to be careful with it as I am feeding it gas to ease this 40 year old new piston into use.
This is exactly what has not happened. First startup seemed alright, it ran for a second with ether and no gas. Second startup it revved sky high for a second with a little bit of gas. Realizing this may have been an air leak, I redid the gasket between carb and jug flange where I thought I could see a leak. Even put some gasket sealer around it for good measure.
Third startup, I accidentally overflowed the carb- no big deal, I shut fuel off and let it drain. However I kicked it once and the bike again shot up and redlined for a good 7 seconds before it ran out of gas from the carb.
Anyways, I am really not wanting to kick the bike again before solving this issue. An engine overhaul would be an unfortunate and costly expense I would rather not deal with. I am not sure exactly what the issue is, it may be an air leak but I also am suspicious of my carburetor. I will include as many pictures as possible to help you guys maybe clue in on what may be the issue here.



The carb slide should definitely be more closed than that on "idle" but that is not grounds for an air leak. I will check the floats also.

[Bullfrog]

None of your photos are visible to me. But your comment that the carb slide should be lower MAY (repeat MAY) be a very important observation.

1. Install a kill switch.
2. Look, listen and feel - does the carb slide "thunk" to the bottom when the twist grip is released from (say) half throttle? If not, you have a problem. Find the problem and fix it.
3. "Back out" the idle adjust screw. This screw simply stops the slide from "falling" all the way to the bottom. Screwing it "in" stops the slide at a higher spot - resulting in higher idle speed. If the screw is too far "in", it can be like holding one-eighth throttle . . . which will result in "run-away" engine RPM when in neutral.
4. Did I mention(?), install a kill switch(!)

Ed
PS: I am VERY uncomfortable with the comment about replacing an intake manifold gasket because you thought you could SEE a leak. Your engine MUST be airtight - and you can not "see" airtight. Your engine should (must?) be tested to be airtight before you run it again. Lots of engines have been "worked around" the pressure test . . . and lots of engines have died as a result of not doing a pressure test. Air leaks are baaaaaaaad.
PPS: Since it is a Wombat 03 with primary kick start and you don't seem to have a kill switch (I did mention that you should install one - right?) --- you could start it while in FIFTH gear. Then if you need to kill it, easing out the clutch with foot on brake should do it. (Um, put on your helmet and do this outside.) I did mention the need for a kill switch, right?
PPPS: Did I mention the need for pressure testing your engine?

[bens4X4]

Hopefully these ones are visible
Edit: I can see them on desktop but not my phone. Weird

[bens4X4]

I do have an original kill switch installed. It reads out as working on the ohm meter but I haven't been able to test it out while running of course.
Regarding the air leak, I should've included a picture.. it may have just looked strange. I may go back in and redo every gasket and have someone redo reed valve assembly. This bike belonged to my 14 year old uncle(at the time) who was very messy with the gasket sealer. It's possible the gaskets have not held up entirely.


I have a feeling the carb was dropped or abused for that to happen.
Edit: I also have a back brake that is disconnected(fixing that while the engine is on standby) and no chain on it to stop something like this from sending my bike through the wall into the kitchen.

[taber hodaka]

Not sure what your cylinder is to but it looks like someone tried to hook up a ace 90 or ace100 reed valve to a cylinder it doesn't fit. --- Clarence

[bens4X4]

Not a super rat cylinder, they are a four bolt not two as shown in the picture, ?? --- Clarence

Carb is from a Wombat, reed valve setup is not original either as is the piston. I'm not sure what a Super Rat is supposed to have

[taber hodaka]

I cannot share thoughts on this, as I look closer I don't think all the parts you have are going to work together. I don't see how the reed valve can hook up?? I would never use ether on a dry engine or anytime(no lube), But I would put a tablespoon of 2 cycle oil in the spark plug hole and kick the engine over a dozen times. I also have a screwdriver handy to lift the sparkplug cap off, never redline a new piston that's just me. ---------- clarence

[bens4X4]

I cannot share thoughts on this, as I look closer I don't think all the parts you have are going to work together. I don't see how the reed valve can hook up?? I would never use ether on a dry engine or anytime(no lube), But I would put a tablespoon of 2 cycle oil in the spark plug hole and kick the engine over a dozen times. I also have a screwdriver handy to lift the sparkplug cap off, never redline a new piston that's just me. ---------- clarence

The reed valve apex(in the pic) is on the jug side, the side you don't see is the side hooked to the carb. It looks like other reed valves I've seen online? The screws holes do look weird but I believe that's just bc it is a generic attachment made for various bikes.
I was concerned about the dry engine part, I did put a tablespoon of 2 stroke in there and crank it up and down 10 times to get it lubricated. Then I gave it a spray of ether. In the next few startups I had gas in the carb but not running to the carb continuously.

[Bullfrog]

Now that is really odd. I still can't see any photos. Not on my Windows computer OR on my Android smart phone. But Clarence can see 'em? Odd.
Ed

[taber hodaka]

I had 3 pictures now I have two. ----- Clarence

[bens4X4]

I can email you guys pictures if need be- I promise I'm not a corporate marketing info grabber

[taber hodaka]

Now I have none, don't have any, three less than two, zilch, zero, uno. --- Clarence

[bens4X4]

Weird, I haven't been removing them.. buggy site maybe.
I believe I found the leak... really big oops. Right along there with the guy who dropped his new cam shaft. There was a gasket just plain old missing, the one between intake manifold and jug. A few months ago I had it apart when a friend wanted to look at the piston, and in putting it back together(i assume temporarily) I forgot any type of sealant. Wow. My bad!!
Double check things!