j301

My Feedback: (12)

Thanks for the offer Speedy-G, I may take you up on one of those choices! I pulled the jug off and the liner did not look scored, the ring moves freely but also looks looser then most I've seen. Once compressed I dont thing the gap to be too bad, but given its age I think I will contact Bowman tonight and see if he has a ring for me. I dont want to give up yet, but I also cant spend too much more on it. If I could get it running half as good as the ones Speedy is selling I would be happy! I was lucky to find a JTEC pits for a decent price, but I guess the ying to that yang would be the bad carb. I'll keep you posted, thanks for all the help.

Speedy-Gonzales

My Feedback: (202)

No problem and whatever you decide. Since you pulled the jug off did you notice the bulk of the guts of this engine? The connecting rod is massive. You can't go wrong with a Bowman ring. I would first take the existing ring out very carefully slide it up into the top of the cylinder and check the ring gap with a feeler gage or shim stock. The gap should not be over .002" with the ring at the top of the bore. Make a special note as to which is the top and bottom side of the ring.

j301

My Feedback: (12)

Is this some info I will need to give to Frank? Do you think it may need an over sized ring?

Speedy-Gonzales

My Feedback: (202)

NOPE! Frank is the ring "guru" and he will know the exact size you need. He may however ask you to send him the jug for his own scrutiny.

SG

2walla

My Feedback: (10)

I would get the carb straightend out and make sure you have the timing correct before messing with the rings. I am pretty sure with a pro zinger and a can muffler that wasnt too restrictive that mine would turn 7100 with a zinger 18-10.. depending on now restrictive your muffler is you may not be that far off.. Are you sure some of the numbers guys are quoting are from running on glo?? They would turn 500-700RPM faster on glow than on gas.. Does your ignition advance the timing or is it fixed?

j301

My Feedback: (12)

The ignition unit is an older CH and I dont know if it is fixed or electronic advanced, I tried looking up the specs on it but couldnt find any info. I checked the timing and it is at just about 30deg. btc. The prop I am using is a zinger 18/10, the others were quoting APC's I think, which would be a thinner prop anyway. I changed out the muffler to a JTec pitts which should be less restrictive then the odd thing that was on it when I got it, but your right, I believe the carb is the biggest factor. Also though, people have told me that it should have a considerable amount of case pressure from the bottom of the piston, which it has some, but not what they are describing, thats why I want to try the ring as well.
Thanks for the info, its good to hear Im not out of the ballpark with this one.

tkg

My Feedback: (1)

A CH unit will have SS engraved on the back cover if its a computer unit. If not a fixed unit will only effect idle not WOT.

j301

My Feedback: (12)

That is good to know, thanks!

Speedy-Gonzales

My Feedback: (202)

Your advise on getting the carb and timing straightened out before dismantling the engine is good solid advise. Start from the outside and work your way in.

There is a big difference between an 18x10 and a 19x7 which is my benchmark prop. 3" in pitch difference is a lot. 10" of pitch is pretty hefty. All of the specs I have quoted are for 92 octane gas and Stihl HP Ultra mixed at 40:1. Most guys tend to overprop but again...it depends on the application. Using an 18x8 would be comparable to the 19x7 since the 3W 19x7 is almost impossible to find in any make/brand now days. Always seems like that "magic prop" is unavailable. I will do a test run with an 18x8 and post my results but it may be a week till I can get to it.

I have two Walbro carbs that I use. The WT-540 and the WT-542.

HEY!!....I see ValleyView has XOAR 19x7's in stock. I think I'll by a couple or maybe three. :>)

computermonkey

My Feedback: (90)

Here is my set up for a Rcexl ignition. Have to be really careful when drilling the holes for the pickup. I've been pleased with the set up.
I have switched the HDA 6a carb for a WT540. If I ever get around to it I would like to try the Bully TN carb and the Bully Dynamix carb.

j301

My Feedback: (12)

OK, so the new ring is in, put a velociy stack on the original carb, gave up on the new carb as Im sure its just bad, and cut a new base gasket for the jug as it looked as though the original was saturating with fuel and most likely leaking. Also put a G38 exhaust gasket on it. It idles happy down to 1300, and the top end with the zinger 18/10 is still around 6750 as long as throttle transition is slow (no stabbing the gas or it dies). Im at the point where I think it might just have to live relegated to more scale war bird duties. I'm on the fence about trying one of Speedy's carbs, kind of like the idea, kind of just want to be done with it.

Speedy-Gonzales

My Feedback: (202)

This is the great thing about the Walbro WT-540 and WT-542 carbs. They have a built in "accelerator pump" that squirts that little extra bit of gas to keep your engine from stumbling during transition. You should be able to bang your throttle stick up and down all day long without any hesitations.

I have seen a lot of hand made gaskets with a majority of them being questionable at the least.

PM me if you want a set of gaskets ( there are 2) and a carb. I will prove myself right and not just sit here at my keyboard bragging and seeming fat headed. Your choice on the carb. Only difference between the two is that the WT-542 has shorter needle valves which I find favorable since I shorten the needles on the WT-540 anyways.

They are the same internally and externally and have the exact same throat diameter of 13.49mm. Good for any engine from 30cc to 60cc and this can be attributed to the suberb air/fuel metering capability. The great secret to a good running engine is proper atomization of the fuel entering the combustion chamber, a good timed spark/burn, and then exhausting the spent gasses effeciently.

$25 shipped. You have the ball now! :>)

I wish you the best with your "Bully". I love them dearly...you will too once you get it right.

I almost forgot.....original carbs ( Delorto? )......I have a box of them. I never use them but am thinking about running one on a ST-3250 on glow since they are notorious for poor fuel delivery and the Delorto is a pump diaphram carb specific for methanol. I do not recommend them for gas apps. They are OK but there are much better choices if burning gasoline and oil.

Speedy

j301

My Feedback: (12)

OK Speedy, you talked me into one last shot at getting this thing running right! Everyone has the same opinion of the Bully, so I will stick with it just a bit longer. I'll send you a pm. Did you have a chance to check the rpm of the 18/8?

Speedy-Gonzales

My Feedback: (202)

Nope not yet. I have been busy for the last 2 weeks moving a 50 employee modern machine shop to a new location and it has been intense! My ***** is dragging but I still like to chat on the RC forums for a bit of R&R in the evenings.

I wanted to ask you what ignition setup you are using. If you are running the original module that is a true magic act since they are over 30 years old in technology. You will definitely need to upgrade to a modern ignition or you will never get your "Bully" to run right.

You need 2 things.

A new ignition setup and a new carburetor. She will rock with this double combination/upgrade.

No sense in a new carb if you do not upgrade the ignition.

Let me know what you want to do. It is an act of futility to install a new carb without the new ignition.

SPEEDY

j301

My Feedback: (12)

Thanks Speedy,
Life seems to always get in the way of living, does't it? I just PM'd you about the carb. The ignition is an older CH unit, but it seems to be working fine. I may one day decide to try a Rcexl unit, but not just yet, CH's are supposed to be good units too though. I have always felt the problem lies in the carb, and it just seems to be my luck that the one out of a bazillion WT series carbs that are bad from Walbro came my way! I know the HDA 48 that is on it now is missing some parts, and I want the pumped carb to fix the transition issue anyway. Let me know if you didnt get my pm.

tkg

My Feedback: (1)

If the CH unit is in a silver/aluminum box then it should be OK. If its in a brown box then its a paper weight.

j301

My Feedback: (12)

Well as luck would have it, it is one of the lovely brown units that is on mine. Isn't that just special.....

j301

My Feedback: (12)

After comparing your photo to my engine, mine looks more like yours then Speedy's; I don't have ribs on the prop shaft portion of the case either. I'm assuming they were milled off by CH, but if so they did a great job as it looks as though they were never there. How did you do your pickup? Just drill a small hole and epoxy in the magnet? Did you need any additional parts, like a collar for the prop shaft, or just drill into the existing part?

captinjohn

I prefer always to spin out a collar on my lathe. Slip it over prop hub and I use a small set screw to hold timing. Too re-set the timing its then easy....just rotate the collor.Get a small magnet at Radio shack. Capt,n

j301

My Feedback: (12)

Hey Captn, good to see you again. Unfortunately I dont have a lathe. I was thinking perhaps I could just use the 'rings' from the old ch unit but Im not sure the magnets would be correct. Any thoughts? Just ordered another carb from Speedy, great guy by the way. Im on the fence, still, again, as usual, (take your pick!) about swapping out the old ch which is functional, but apparently not great from what I am hearing. The only hang up is the plug type, 3/4 14mm (odd mix match of verbage there) with the BPMR6A plug thats in it, and the pickup situation. Hobby King sells a unit that would work, basically their version of the Rcexel, of which I have one that works great on a G20, but I am not sure if their 14mm boot would fit my plug, could be 5/8, could be 3/4??? And it still leaves me with engineering a pickup magnet. Do you know if the Rcexel units come with the hull sensor at all? Im figuring its would all have to be bought separately correct? Getting closer though to getting this 'great deal' of a motor going (kind of a 'stone soup' situation its turned out to be).

Speedy-Gonzales

My Feedback: (202)

This spark-plug reference code for their numbering designations is priceless.
They are all here including NGK. I drag raced much of my younger adult life and I will tell you all that once I started running NGK plugs I decided that would be all I would ever buy and nothing else.

See link below. Hope it comes up for you.

http://spark-plugs.co.uk/index.php/c...ntents.symbols

SPEEDY

j301

My Feedback: (12)

Yup, that one's goin' in the old bookmarks list.

Speedy-Gonzales

My Feedback: (202)

Yup............ It's great........ giving hex sizes, heat ratings, and electrode/thread depth, and thread sizes. You can pick any plug combination to fit any application. Getting the right plug electrode length/depth is something that is commonly overlooked. You need to get the correct spark delivered into the combustion chamber at the right location. Your engine will run without all this tech info but not like it should and this is the info that I have learned from racing and experience. It all carries over into all IC engine apps big and small. Once you learn it you will achieve "karma"! LMAO! Funny but true!

The true reward from all this is when someone compliments you on how well your engine runs.

SPEEDY G

tkg

My Feedback: (1)

Get one of the RCEXL testers and set the rpm for around 12,000. Take on old spark plug and cut the side electrode OFF. In open air a good ignition will fire the gap.

j301

My Feedback: (12)

To go with the Rcexl I will need to pull the old CH sensor and pick up 'rings', Speedy mentioned a puller, any advice on how to get the front end apart, or should I just cut them off?