Sorry,we didn't release the non pull-start version. I will think about it seriously. It will have another version for roto-starter later. Someone modified his STS.28 to non pull-start version on his Revo here. He use the D21B's back plate on his .28. But you need to do some modify to avoid the piston hit the rear plate at BDC.

having some trouble with the .28. when I try to lean it , it will take off but when it reaches its upper rpms it shuts down like it ran out of fuel but its blowing lots of smoke all the time like it way rich also is blubbery . if I just leave it rich and not try to lean it it wont shut down but it never reaches rpm and has no power. do you think it still needs more breakin time as there is still some resistance at the top with the plug out?

Yes,it still needs more breakin time. Too much rub against will cut off the engine. Just run it with rich setting for more tanks. And lead it step by step between each tank.Don't forget to remove some head shims after break in process.

I am using 20% nitro what shims should I leave in. there are two copper shims and one aluminum shim.

I also have an sts.21 dragon motor using the same fuel what shims should be in it?

Use 0.3mm (aluminum) with 20% fuel,both of D21B and 28.

I have a delema with the new motor. When i am running it it will just shut off when it starts to hit higher revs. I have lots of smoke coming out so i dont think I am too lean, I know I am rich on the bottom as it sputters when first accellerating, But it will make a few good passes then I will give it wot the motor will rev the truck will take off and then as it reaches I wouldnt say max rpms but pretty high rpms it will just shut off instantly. i have tried going richer. If I go way rich to where the motor wont rev high then it doesnt happen so i lean it down 1/16 turn at a time and just about the time I am getting good power and the motor will rev up without sputtering but still producing lots of smoke it will start the killing thing.

any ideas would be appreciated.

I do feel it is broken in now and I have removed the extra shims

Ryan,

It seens the problem is on the pipe or the back pressure. When you WOT the .28 need to suck a lot of fuel. But if the pipe is too small or the back pressure is too small,the fuel supply system can't supply enough fuel in time. Maybe that is the reasion to make the engine to be shut down. You can try to shorten the back pressure line if you can. What pipe are you using?

Also,if the engine does not finish the break-in process,it will happen too. How many fuel has through it already?

Another,Use the hottest plug that you can get when break-in.

Dino

I have 1/2 gallon thru it, I have tried different pipes I tried a tsias pipe that work killer with the .21 and then I tried a xtm 2 chamber tuned pipe ( stock mammoth pipe). I did have a hot plug in when I was beaking it in but switched to a meduim range plug to try and get a good tune on it. Is the #5 plug you recommend a hot, med, or cold plug. I will try shoteneing the pressure line right now its about 10 to 11 inches. I keep at it.

thanks for the tips

Standard Plug
#4 - HOT
#5 - MID
#6 - COLD

Turbo Plug on .12
#5 - HOT
#6 - MID
#7 - COLD

Turbo Plug on .21
#6 - HOT
#7 - MID
#8 - COLD

man I am still having trouble with .28 still has the stall problem when motor gets in the upper revs, carb started leaking also leaking from brass pinchers that hold the carb. so I sealed the carb and holders with some silicone. thought that may have been the problem. its very strange when motor leans out on its own at the very end of the tank it doesnt die when reved but if I try to lean it out with the needles it does. i am so lost. could the needles be bad if so where can i get some new needles and an oring for the carb. also what are the factory settings for the needles

Sorry for any inconvenience. I thought I knew where is the problem. You said it will die when you WOT? And somewhere leaking when you WOT? Try to use a CABLE TIES to tie the Dust Protection of the carburetor. Please see the attachment.

I just tried a .28 and recorded the needle setting.That is running setting not break-in setting.
High speed needle -- about 2 ~ 1 1/2 turns out
Low speed needle -- about 4 turns out
I'm using 0.4mm shims with 25% nitro,#5 plug.

Try it first. If you still have problem after testing,don't worry. Just send this engine to me. I will check it carefully. And let you know the result. But you know it will take some time.

This engine sounds wicked but I have no desire to tear up my gears. One of the great things about monster truck is the low maintenance on repairs. Guess I'll wait for the stronger transmission like Dino said.

I guess you could always just gear the baby up - less torque on the drive train + more speed..

Dear Ryan,

I went to test the .28 this afternoon and would like to find what trouble you have. As my experience when the engine still new,it do have the same situation that you have. It is not leaking problem. Please back to the rich setting. And run some tanks of fuel. Lean the main needle 1/8 turn between each tank till the high speed is enough. Another way is that you can add 0.1mm head shim to lower the compression.

How to check if the break-in process is finish? Take out the plug and pull the pull-start system. It should be very smooth after break-in.

Regards,
Dino