Re: need help with RB concepts engine

[treetoad]

Na...you're both on track.What I should have said was,I set the carb 2
turns out from closed.Initially we broke the engine in with Byrons 20%
race fuel. we always had good luck with this fuel,put a ton of laps in
with the rc10. the engines were nice and clean inside even after 5 or 6
gallons of fuel. I did away with the onboard connection to the glow
plug, opting for a seperate glow igniter. got a good battery in the
easy start,the glow plug is getting nice and bright/hot, and from all
appearances,has adequate compression, although nobody has been able to
give me a definitive test for compression. (even the guy from RB, who
by the way is like a freakin' scientist) I've had every screw, bolt pin
etc out of this engine,tore the carb down to nothin' every port etc is
open, the bore is shiny,etc. I've had a few people tell me to make sure
the one way is super clean and lubed but I don't know why this would
keep the engine from firing.I'm at a point where I need some divine
intervention.If I knew some one who was really familiar with these
things, I'd take the engine off the truck and mail it to them, and let
them figure it out. I KNOW these are good engines, but this one has me
baffled.

[\Doc\]

"treetoad" <dlowe34731@zoominternet.net> wrote in message
news:1133470780.996210.146200@g14g2000cwa.googlegr oups.com...
> Na...you're both on track.What I should have said was,I set the carb 2
> turns out from closed.Initially we broke the engine in with Byrons 20%
> race fuel. we always had good luck with this fuel,put a ton of laps in
> with the rc10. the engines were nice and clean inside even after 5 or 6
> gallons of fuel. I did away with the onboard connection to the glow
> plug, opting for a seperate glow igniter. got a good battery in the
> easy start,the glow plug is getting nice and bright/hot, and from all
> appearances,has adequate compression, although nobody has been able to
> give me a definitive test for compression. (even the guy from RB, who
> by the way is like a freakin' scientist) I've had every screw, bolt pin
> etc out of this engine,tore the carb down to nothin' every port etc is
> open, the bore is shiny,etc. I've had a few people tell me to make sure
> the one way is super clean and lubed but I don't know why this would
> keep the engine from firing.I'm at a point where I need some divine
> intervention.If I knew some one who was really familiar with these
> things, I'd take the engine off the truck and mail it to them, and let
> them figure it out. I KNOW these are good engines, but this one has me
> baffled.

Have you tried switching back to the Byrons fuel? You said this problem
started when you switched fuels?

Are you sure the sleeve is installed the right way?

Doc

[treetoad]

Yeah I went back to byrons,tried traxxas top fuel,tried to lean out
things, tried going back to original factory settings just to get it
started,but ut still won't fire. When you ask about sleeve being
installed the right way, I'm pretty sure RB dummy proofed it with an
indexing pin.How much do you know about compression testing ? If it was
a small block chevy or harley or lawn mower, I'd be a heck of a lot
more familiar with doing a compression test, but how do you know when
the compression you've got is enough?

[Tom B]

"treetoad" wrote:
> Yeah I went back to byrons,tried traxxas >top fuel,tried to lean out
> .......

Did you try a new glow plug? New like unused! I have had brand new-looking
plugs where the element has become contaminated and has lost its catalytic
properties. Such plugs glow brightly and appear to be fully functional;
they just don't work.

Tom B

[\Doc\]

"treetoad" <dlowe34731@zoominternet.net> wrote in message
news:1133660963.458077.29030@z14g2000cwz.googlegro ups.com...
> Yeah I went back to byrons,tried traxxas top fuel,tried to lean out
> things, tried going back to original factory settings just to get it
> started,but ut still won't fire. When you ask about sleeve being
> installed the right way, I'm pretty sure RB dummy proofed it with an
> indexing pin.How much do you know about compression testing ? If it was
> a small block chevy or harley or lawn mower, I'd be a heck of a lot
> more familiar with doing a compression test, but how do you know when
> the compression you've got is enough?

The specs vary from engine to engine, but anything over 30psi should light
right off. I've seen engines with virtually no compression light off as
well. They crap out pretty quick but will still light off relatively
easily. They make special compression testers for our little motors; they
run around $40. I tried to retrofit my automotive compression tester for my
nitros to no avail..........

Generally speaking, if you're getting a good "popping" noise as the engine
turns over using an electric starter you've got enough compression to
support a burn.

My method for lighting off a crapped out engine..................

1. Remove engine, pipe and fuel tank from vehicle and vice-mount.
2. With LSN flush and HSN all the way IN (yes, in!), start turning motor
using either handheld electric starter or an electric drill directly on the
one-way. Make sure carb is closed!
3. Slowly back off the HSN until it starts popping and farting and
eventually starts.

Starting with HSN all the way IN prevents flooding as you're trying to get
the needles to the point they will allow the engine to start. I also use a
bit of Marvel Mystery oil when doing this to make sure the engine is
properly lubed when it's spinning with little to no fuel flow.

Doc

[treetoad]

do you strat it without the pipe? i always heard that you could damage
a 2 stroke from cold ait rushing back into a hot engine( On chain saws
and weedwackers anyhow). I'll have to give the vice mount a shot.Thanks

[\Doc\]

"treetoad" <dlowe34731@zoominternet.net> wrote in message
news:1133692223.312929.65460@g44g2000cwa.googlegro ups.com...
> do you strat it without the pipe? i always heard that you could damage
> a 2 stroke from cold ait rushing back into a hot engine( On chain saws
> and weedwackers anyhow). I'll have to give the vice mount a shot.Thanks

The pipe MUST be attached!! It probably won't even start without at least
the header attached, and relies on the pipes' backpressure to keep the
engine working correctly. Without any backpressure 2-strokes have the
tendency to blow the intake charge right thru the cylinder and out the
exhaust ports!

Also, if you have a handheld, variable-speed electric drill and the right
size socket to fit directly on the one-way bearing, your handheld starter
will thank you if you remove it and turn the motor using the drill and the
one-way. While the backplate is off, check the one-way bearing to make sure
it's still good. This might sound ridiculous but I've seen several motors
that wouldn't start because the one-way was shot and locked to the starting
shaft.

Doc