Can't figure this sachs out

Matthew Andrade /

So it's been a long haul but I have it running all the airleaks are finally fixed but can't get this tuning down. So what I have is an amal 15mm with the stock 45 jet but a 2 in extension on the intake. New b6hs spark plug set to right gap and new points set to 17* before tdc at.16 gap. The bike turns over first kick with solid compression it idles then ramps up to a real high idle I drive it and kind of dies at prolonged stops I bring it back stand it and idles wild again. I try and adjust idle and then it seems to die real quick. Not sure how to adjust that in series with the fuel mixture screw what do adjust first. Also my plug looks like this when it runs for about 15min. Any thoughts?

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Re: Can't figure this sachs out

That's caused sometimes by loose carb or intake or cyl. jug base gasket bad.So are you sure they're all tight? don-ohio

Re: Can't figure this sachs out

Matthew Andrade /

Carb is tight and sealed, intake is tight and jug has new gasket as well as high temp Rtv high temp red pressure sealant. I spray it all with carb cleaner no rpm drops

Re: Can't figure this sachs out

Check that float bowl level is staying consistent.don-ohio

Re: Can't figure this sachs out

Matthew Andrade /

What do you mean by that make sure the carb is level coming off the intake? Could the vibration be messing with the carb?

Re: Can't figure this sachs out

Some carb body angle is fine... but check that the float in the bowl is level.

Re: Can't figure this sachs out

Right.....make sure the bowl isn't being filled too full by a collapsed(partially)float or float out of adjustment(or float sticking) is what I meant,like Wiz says.

If the float is brimming,spilling over,or conversely,starving the engine you'll get rpm changing symptoms. don-ohio

Re: Can't figure this sachs out

Matthew Andrade /

I will have to check that because now when I do think about it when I twist my air filter off I see a small puddle of gas sitting on the lip of the carb would that be due to the float overflowing?

Re: Can't figure this sachs out

♣Slew Foot♣ /

it may be the back scavenging isn't working right, the orig carb had a restrictive airbox to provide the slight pressure change between cycles to scavenge the charge back from the carb.

Re: Can't figure this sachs out

Matthew Andrade /

Can you put back scavenging into laymans terms? I'm not to sure of what that is.

Re: Can't figure this sachs out

Quote:`but a 2 in extension on the intake'.........

Okay,I just went back and read this again. Just how did you extend the intake two inches? Could be critical to the swirl of air/gas mixture entering the engine.

Is this extension the same size inside diameter? don-ohio

Re: Can't figure this sachs out

♣Slew Foot♣ /

most peds use loop scavenging 2 stroke engines, sachs uses a back scavenging system.

http://www.mopedarmy.com/wiki/Engine

http://en.wikipedia.org/wiki/Kadenacy_effect#Two-stroke_engines

Re: Can't figure this sachs out

Matthew Andrade /

Yes I used a small piece of metal pipe that had the same size inside diameter as my intake.

Re: Can't figure this sachs out

Okay,should be alright then. don-ohio (:^)

Re: Can't figure this sachs out

Matthew Andrade /

Should I be altering my jetting at all and generally what do you adjust first on the carb idle or fuel mix screw

Re: Can't figure this sachs out

Matthew Andrade /

So do you think I should partially obstruct the intake filter to give more of a back pressure?

Re: Can't figure this sachs out

Re: Can't figure this sachs out

Brent Bublitz /

Over thinking it. Your case seals are leaking. You have an air leak. You won't be able to test with spray on the case seals.

Re: Can't figure this sachs out

Matthew Andrade /

Where would I get a case seal? Also is there one on both clutch side and stator side?

Re: Can't figure this sachs out

Brent Bublitz /

Re: Can't figure this sachs out

Yeah,Brent may be right. But make sure the float level is right just the same. don-ohio

Re: Can't figure this sachs out

Matthew Andrade /

Would seals make it sound louder as well? I check the whole thing for airleaks and find none and I'm working on a 78 columbia with the same motor and just got that fired up with a dellorto carb and I can swear it sounds quieter. And with no adjustments it idles with good throttle. Also the 78s lighting is much brighter and than my 77 would that also be an indication of something?

Re: Can't figure this sachs out

♣Slew Foot♣ /

i put the electrical dia. in the other post, get the electrical bugs out first.

505's just had like yamabond as the case gasket.

decompressor pin fell down out of cage or is leaking at the base? that would make it a little louder.

the scavenging thing was just explaining why you had fuel backing out of the carb.

Re: Can't figure this sachs out

Matthew Andrade /

I removed the pin before and plugged it so that's not the issue. So with the wiring I cut back the 5 wires on my terminal block and made fresh connections and what do you know the horn works but come to find out the bottom bulb in the taillight is out would that be one of those points for major concern? If so has anyone had luck going somewhere local to get a bulb and what kind?

Re: Can't figure this sachs out

Taillight bulb can affect some usually they wont run.12 volt 1157 light bulb. two filaments. use for head light with regular and hi beam. or tail light with regular and brake light. From any auto store. (edited)

Re: Can't figure this sachs out

Downhill Harvey (OFMC) /

Matthew Andrade Wrote:

-------------------------------------------------------

> Can you put back scavenging into laymans terms?

> I'm not to sure of what that is.

Re: Can't figure this sachs out

Matthew Andrade /

Ok so if I have the back scavenging issue how would I correct it?

Re: Can't figure this sachs out

♣Slew Foot♣ /

nothin to worry about, the light bulb thing however look at the dia. see which stator you have wattage wise. there were 6v, 2w and 3w oshram bulbs for some models, i ended up bringing the voltages and wattages to an electrical supply co. they have huge catalogs that list resistance factor as well as watts, volts.

dollars to doughnuts the bulb is not letting it idle or top out.

the scavenging is through the hole on the bottom of the jug, some peeps just block the decomp with a bolt, i just use a bic pen spring threaded on the orig pin. i think when its fully blocked the scavenging changes to loop scavenging.

Re: Can't figure this sachs out

Matthew Andrade /

I have a punch e50 stator bosch with 5 wires I think it is a 6v would it show it on the flywheel?

Re: Can't figure this sachs out

Brent Bublitz /

If it's a Bosch E50 stator, it most certainly is 6v. Although there is no internal regulation or rectification, so it will put out anywhere from 2v to 20v depending on your engine speed, setup and other things. It's not uncommon for people to add a 6v regulator to stop blowing headlights on higher RPM engines.

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