Going case inducted too!!!

[Theon]

If you have reasonable 'head' from the tank, It doesn't seem to need the pulse tube in my experience, but I always put one in anyhow.
However on my dirt bike (Dual sus' Roo), I have been considering redirecting the pump bulb waste to the pulse pick up as a cold start, as my bike can be a little hard to start without a choke if not used in a while.
But have tried with and without pulse tube and bike runs fine.

 

[Flyman]

Well Dave you may just be right about the gravity feed deal.You must know I,m
from the kart racing crowd.We never used gravity feed & this bike thing is a little
new to me.

But I like pumpers & know them much better than the slides.When Yamaha first
came out with there rotary valve kart engines it had a slide carb & used a external pump.

I messed with it some & replaced it with a pumper as most of us did.Not that it
did not work, I just did not like changing jets.Lazy I guess (WINK)

Fly

 

[Davezilla]

Yup, that's a huge advantage for the floatless pumper carbs... the ability to change the air fuel mix without taking the carb apart. The other advantage is that they have a built in pump in case the fuel tank is bwloe the carb. Back in the early 80's we built a few ultralight aircraft that ran Cuyuna 440cc engines and the fuel tank was located above the engine but they used an external pulse pump with a rather large Mikuni slide carb. The gravity feed by it's self was enough to feed the carb but with any aircraft, you just don't take chances and the pulse pumps would keep a positive fuel flow.

One of my motorcycles also uses a pump in conjunction with the gravity feed to the carbs since the carbs are mounted rather high... like in the tank tunnel for the front carb and just below tank level for the rear so there's just not enough head for the gravity feed to be completely reliable.

For the pumper carbs on these engines and where the tank is above the carb, they'll work without the pulse line connected, but it's cheap insurance just to connect and use it.

 

[Ron344]

Yesterday I got the air cleaner done and fitting of the carb assembly so it will fit in the frame. Also put new bearings in the crankcase and glued the cups I made in the case. I trued the crank up in the lathe the other day. I hope to put the motor back together real soon and get this thing running.

 

[Davezilla]

Looks like your going really good with this project... I'm really liking the way the carb mounts and that air filter looks awesome... that engine should scream when done

 

[Ron344]

Thanks Davezilla, I'm glade your liking it. I think it should run pretty good. Today I did some more work on the carb linkage and I button up the case. I made some gaskets for the carb assembly. Its getting close. I can't wait till it's done.

 

[Ron344]

I finally got the motor to fire up, but not for long. I had a carburetor problem I have to fix. I will redo the linkage today and it should be ready.

 

[Davezilla]

Awesome... Then once you get the kinks worked out and get it to stay running it'll be time to start tuning it...

 

[Ron344]

I'm still having a carburetor problem it not getting gas thru the carburetor. I might have to rebuild the carburetor. It sounds real good if I inject some gas into the carburetor but it dies when it runs out. Back to the drawing board.

 

[Ron344]

I got the carburetor problem fix and it runs , BUT!!! I developed a vacuum leak in the reed block. I took the motor back out and fix the vacuum leak, I hope. I put it back together, but I'm too tired to finish it today. It seems like the last two days have been the most difficult so far. At least I know that it runs. When I get this thing sorted out I will take a video of it to show.

 

[Davezilla]

Sounds great... Was the carb just needing a cleaning or rebuild from sitting too long? I've had that happen a few times before on my other toys...
If you have a workbench or room for it in your shop, you could make a simple engine stand so you can start it before it goes in the bike... makes troubleshooting and basic tning real easy... Here's one I made up that holds the engine just fine for leaving on my countertop at the shop office, but when i need it for working or test running an engine, it just C clamps to a table corner or can be placed in a vise, then I just install a pull starter or a wider nut on the mag side and drill start it. For a fuel supply I got an old iv stand and just hang an old pocketbike tank with enough fuel for a short run, connect an exhaust to it, and it can be started and ran out of the bike, There are also some already made like the frame adapter for a china doll into a stingray frame that'll work the same way, I just had the metal and welded up this... It holds just fine for idle runs or even a few revs once clampped to a table.

 

[Ron344]

Hey Dave, The carburetor had a two gaskets in revers order. Got that all fixed and have it all back together except the chain. In morning I'll go back at it. I might have to helicoil the holes for the reed block. That would mean taking cases apart again.
I really like the engine mount that a good idea I'm going to make one of them. it would make it a lot easier to work on. I hated taking the motor out of the frame. Yesterday I spent half the day working on the rear wheel to get to chains the right tension. Also change the rear axle.
Hopefully tomorrow will be a better day.

 

[frank66]

helicoils are deep so it won help im afraid. a new motor and reed block is not expensive.

-rse has a nice 4 petal reed that matches your carb. wich reed block do you have now? was it custom or an arrow?

 

[Ron344]

Yea, I bought the reed block from arrow and I made the cylinder and case my way. I have one bolt that's good and one that's questionable. Yes case are expensive and now that I know that everything works I will probably get another cylinder and case to work on. Last night I thought of another way to connect the reed block so I might try that. I'm thinking a Dax lower end. I have very little money in this project so far my goal was to see how it all worked.

 

[Ron344]

I thought I post a picture of the bike and motor all together. I tried to post a video of it running but it wouldn't let me for some reason.

 

[Davezilla]

That's a really cool looking bike, I like the way you put the seat post into the top bar instead of coming up the original seat post tube... Is that the same expansion chamber you hydroformed a while back?

 

[Ron344]

I'm glad you you like it. The seat post looks like it's just aluminum but it has a steel bar inside the aluminum post. I thought that up and later someone on here said that one of the old board track racer was built like that. The expansion chamber is the same one that I hydro-formed awhile back well it's the only one I've made so far. It works great. The motor sounds real good. I'm going to see if my son can help me load the video.

 

[Ron344]

I finally got the video my son came over to help.




http://youtu.be/PvEIylQgXJg

 

[Davezilla]

Very Well Done!! Sounds great... can't wait to hear back on how it runs

 

[pak39]

Nice job on the reed valve conversion that thing sounds nice. I like how you did your air cleaner what are you using for a filter?