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Discussion Starter #1
Put the Blue Demon eng back in the Lucky 7 after whole new cases, and crank and the rework B/B top end.
Also put my second drag engine on the stand w/ a Polini exhaust just for fun.
 

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Nice Job EPR and good to hear/see alls going well with the Demon engine..............Keep up the good work...........
 

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Two Stroke Addiction
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You have very nice toys, EPR!...congrats

I can see most of You use Walbro carbs..Have you ever try tillotson HW racing carbs?
 

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Discussion Starter #5
I am trying, but having alot of bugs to work out. It starts w/ the throttle cable, to it won't start unless you open the throttle alittle. PMed Cam2 about notching the bottom of the butterfly plate to let more air thru when its close. The throttle arm is on the threads of the Idle screw which I had to mod, so its hard for me to say anything about that. Having trouble w/ all three eng that I put Walbro's on. My 2 fastest bike are the A2 and the A1, both have Sam's swirl bore, straight thru 14mm bore, with .70mm main jet and needle cilp 2 from the top. The A2 is my build the A1 is Sam's build, For months Not One Problem. Walbros so far a nightmare.
I am going to put my compression tester in the plug hole, to see what is. It has more compression than Sam's engines, had to grind the piston to clear the head. You have to tie the thing down to pull start it, or my 130lb son to sit on it and I sit on my but behing the bike, and try to rip the cord out of the starter cover.
 

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I am trying, but having alot of bugs to work out. It starts w/ the throttle cable, to it won't start unless you open the throttle alittle. PMed Cam2 about notching the bottom of the butterfly plate to let more air thru when its close. The throttle arm is on the threads of the Idle screw which I had to mod, so its hard for me to say anything about that. Having trouble w/ all three eng that I put Walbro's on. My 2 fastest bike are the A2 and the A1, both have Sam's swirl bore, straight thru 14mm bore, with .70mm main jet and needle cilp 2 from the top. The A2 is my build the A1 is Sam's build, For months Not One Problem. Walbros so far a nightmare.
I am going to put my compression tester in the plug hole, to see what is. It has more compression than Sam's engines, had to grind the piston to clear the head. You have to tie the thing down to pull start it, or my 130lb son to sit on it and I sit on my but behing the bike, and try to rip the cord out of the starter cover.
I dragged out an old scooter I had in the back of the shed to pull off the carb on that one to compare it to the wt-603 style rep carbs.....................The HDA is a way bigger carb with accelerator pump like the WT813 and after rebuilding it I plan on trying it out on my 5 port engine when I finish blueprinting it.........







 

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Discussion Starter #9
Wow, I saw the HDA on the carb. They are $66 bucks shipped from Daves, been looking for 1 or 2 on Daves sale of the week.
How big is the bore on the 48, I wanted to find a 19mm Walbro carb for the drag bike engines. Or anything bigger than a 16mm
 

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To run the HDA carb you either have to make a adapter plate for the pulse hole or modded the carb to be a purge carb and add a fitting to it and to the crankcase or to one of the transfer port in the cylinder.
 

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Wow, I saw the HDA on the carb. They are $66 bucks shipped from Daves, been looking for 1 or 2 on Daves sale of the week.
How big is the bore on the 48, I wanted to find a 19mm Walbro carb for the drag bike engines. Or anything bigger than a 16mm
The HDA is the same size bore as the WT813 ..............

The carb does require an adapter or manifold......It was removed from this engine and worked quite well when I used the scooter its mounted on as a pitbike...............




 

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Discussion Starter #12 (Edited)
Wow, I was riding the A1 today w/ Sam's first 3rd Stage engine, and the 10 bolt weighted flywheel, and his Swirl bored carb. Once you get that flywheel going mid to high you can fill the pull, and the engine does not vibration like a lite flywheel.
I sprayed the 603 Rep in all the holes, an drilled a 1/16" hole in the butterfly plate at the bottom an then cut a notch, cleaned it up, put it back on Sam's #2 engine w/ the Polini exhaust and it runs great. I took the crutch off the idle screw, it idles good, but still. needs alittle bigger notch, cause I still had to peg the spring, but it is so much better than before.
On the L7 I lost my second spring off the throttle cable spring, just alittle play and it slips out of the pivot for the end of the cable. Thought I just adj it. So, its back to Work.
I keep eyeballing the WT813 on my scooter for a Cag engine,lol.
 

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Thats good to hear EPR..Im glad youre making some headway on getting that WT603 rep carb dialed in.....Keep up the good work......
 

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GHETTO FABRICATOR
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Wow never realized you were having so much grief with the walbros.

I have them on 2 cags and the blata rep and I haven't had any issues.

If your throttle cable is slipping out of the throttle arm do what I did and add a spring in between the cable bracket and the throttle arm.



Keeps enough tension on the line to stop it from slipping out and also assists the return of the throttle as these carbs have much weaker springs that the stock carbs.

If ya wanna unload one of the walbro kits for the del rep



I will trade ya got one sitting in a box brand new. Goes for you to CAM.
 

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Discussion Starter #15
Thats the spring I keep loosing when I let off the throttle fast, just alittle to much play in the cable and it slips out. The engines still tight, so will keep fixing the stupid stuff till it works.
The V notch in the butteryfly valve helps alot, need to notch it alittle bigger on the next carb.
I have 3 of those 19mm already, one is on my C1. Will try 2 on my B/B drag engines when I can make some smaller main jets.
 

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Try putting a couple 1/4" stand-offs under the cable bracket to raise it with a couple longer screws to secure it to the carb body.............

 

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Discussion Starter #17
On the L7 have them standoffs for the throttle arm, Randy at SP4L sent it that way and it still hits and twists it alittle. Got a side mount holder I am putting on when I put the Alum Cag to Walbro Intake Manifold w/ boost fitting that I made today. Going to post them soon on a new thread. Now I can hook up the boost bottle tube.
 
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