Doesn't have the punch it should

[79 bronco]

Having your needle in the #5 bottom clip position makes it rich, and looking at the jets your running i would guess its running rich. But your plug chop dont look rich???

Read this, it talks about the needle clip position, diameter, taper and length. If you look at the little chart it will show you how much of a range the needle clip position effects. http://www.blasterforum.com/threads/jetting-the-keihin.46341/

 

[Larry's Shee]

So seemed great during breakin but not now? Does it seem different from before?
Never answered on condition of spark. What plug # ? Try another new plug, to rule that out.
You confirmed it's 170# comp?

 

[Larry's Shee]

As long as those plug chops above look good. I went up a size on the main from that picture with the 2 plugs

So you think the main chop in pic is lean?

 

[nick20555]

I would put the needle clip in the middle position and I would think the 50 pilot is way to big for that motor. You should be between a 42 and 45 with the air/fuel screw 1 and a half turns out. The black screw is the idle adjust screw.

I started with the clip in the middle position and chopped from there. I can re-post my plug chops I got from each position. But I was told that 50-52 pilot would be what I should expect. I'm not doubting you, just what I was told by another member, but you guys would know better than me. I'm on a 50 at 2 1/2 turns out. I can try again to set the air screw with a 48 because it looks like I need to drop it one anyway since I'm at 2 1/2 turns.

So seemed great during breakin but not now? Does it seem different from before?
Never answered on condition of spark. What plug # ? Try another new plug, to rule that out.
You confirmed it's 170# comp?

Well on break in I set the throttle stop screw to only open to 1/2 throttle so it wasn't too powerful. I did kinda think that it ran a little better at half throttle at the second to last clip position but I thought that was the false power of running lean. It was when I did my 2 full throttle plug chop pulls that it felt like I was being thrown off but like I said it may just have been the misconception from the fact that it was the first time I'd opened it up and had it screaming so it just seemed like I was flying. Sorry, I didn't get a chance to check my spark. Maybe I can later today and report back. I'm running the br8es. I can throw in a new plug after I run to the store to get more. I never checked my compression since KOR did it and I trusted that he does it right and that I didn't screw it up in the 2 tank break in I did. But I can run and get my dad's compression tester sometime as well and check that.

 

[nick20555]

Here are my plug chops...
Half throttle on middle clip position

Half throttle chop middle position

• nick20555
• Jul 1, 2015
• 2

Half throttle plug chop with clip on middle position of CEL needle

Half throttle on second to last position

Half throttle chop second to last position

• nick20555
• Jul 1, 2015

Half throttle plug chop with clip on second to last position of CEL needle

Half throttle on last position (right) and full throttle with 160 main (left)

half and full plug chops

• nick20555
• Jun 12, 2015

Half throttle plug chop on bottom clip position (right) full throttle plug chop with 160 main (left)

Full throttle with 162 main

full throttle plug chop 162

• nick20555
• Jun 13, 2015

Full throttle plug chop with 162 main jet

 

[Awk08]

according to those pics above of the 1/2 throttle chops, the top pic of the middle position seems to have the darkest smoke ring ?
followed by 2nd from bottom, and bottom clip being the lightest ?
thats strange or are my eyes decieving me ?

how long are you holding it at the desired throttle range for each plug chop run ?
20+ seconds is best, holding the brake if needed to make it work hard.

I'd leave the 50 pilot @ 2-1/2 turns if thats what the highest idle procedure told you, nothing wrong with 2-1/2 turns if the 48 was un-tuneable, or under 1/2 turn out for high idle.

double check your compression, compression is different at differing elevations and drops as elevation rises.
I've successfully run straight 93 octane sunoco @ 165 psi. compression.
this race fuel mix you're running may not be needed and very well could be part of the equation here.
if in fact you are @ 170psi. I'd be tempted to try a few runs with straight 93 octane @ 32:1 mix and listen very very closely for any pinging sounds of detonation, and read the plugs to look for any signs of black or silver specs on the plug, use a magnifying glass for better inspection.

read on detonation.....http://www.klemmvintage.com/deto.htm

I'd also switch to a straight b8es plug, no R needed.

 

[nick20555]

according to those pics above of the 1/2 throttle chops, the top pic of the middle position seems to have the darkest smoke ring ?
followed by 2nd from bottom, and bottom clip being the lightest ?
thats strange or are my eyes decieving me ?

how long are you holding it at the desired throttle range for each plug chop run ?
20+ seconds is best, holding the brake if needed to make it work hard.

I'd leave the 50 pilot @ 2-1/2 turns if thats what the highest idle procedure told you, nothing wrong with 2-1/2 turns if the 48 was un-tuneable, or under 1/2 turn out for high idle.

double check your compression, compression is different at differing elevations and drops as elevation rises.
I've successfully run straight 93 octane sunoco @ 165 psi. compression.
this race fuel mix you're running may not be needed and very well could be part of the equation here.
if in fact you are @ 170psi. I'd be tempted to try a few runs with straight 93 octane @ 32:1 mix and listen very very closely for any pinging sounds of detonation, and read the plugs to look for any signs of black or silver specs on the plug, use a magnifying glass for better inspection.

read on detonation.....http://www.klemmvintage.com/deto.htm

I'd also switch to a straight b8es plug, no R needed.

I agree that my middle clip position half throttle chop is unusually dark but the second to bottom one is the lightest. I'll see which ones I still have and try a side by side comparison. Might have the second to bottom one still but I know for sure I still have the bottom position ones and full throttle ones.

All my plug chops that are shown in the pictures in the last post are done doing a pull from 1st-6th gear just long enough to wind out at each gear and then kill it after it winds out in 6th gear. With how fast it accelerates I would say probably done in 6 seconds or less especially with the full throttle chops. The one half throttle chop that I did with the front brakes pulled came out pretty dark on the bottom clip position but it also was probably over within 7 seconds or less. I would think it would be very hard on the motor to wind it out for 10+ more seconds.

I can double check the compression sometime soon along with my spark. I'm at 400ft elevation and KOR did my head so I don't know the difference between our elevations but Ken told me to run half and half so thats what I did. I'll have to read on detonation because I'm not sure what "ping" I would be listening for.

And I thought the br8es and b8es would give the same results?

 

[nick20555]

@Awk08 @Larry's Shee @79 bronco @MURPH @jus_me @bansheedave @speedyslyder
thank you guys for all your help so far. I really appreciate it. Hopefully, together we can get this issue worked out and I can get it tuned in and ready to rip over the holiday weekend coming up so I can show those 4 strokes what real power looks like at the drags

 

[nick20555]

here is the pic of the plug chop I refered to above where I had the front brakes held in some the whole way. Still only took about 7 seconds or less to wind out all the way and kill it

half throttle plug chop

• nick20555
• May 31, 2015

Half throttle plug chop on bottom clip position

 

[jus_me]

Were all the chops done the same day, or realatively in the same conditions, temp, humidity, same altitude ?

 

[nick20555]

Were all the chops done the same day, or realatively in the same conditions, temp, humidity, same altitude ?

yeah. never more than 15 degrees different, always humid here and that never changes, exact same altitude

 

[MURPH]

the pinging noise is really hard to hear but once u hear it u know exactly what is sounds like. I just switched over to a 34pj carb over the winter and was jetting for my big bore motor (dealing with the same problems u r)and I could hear the pinging only while coasting in gear with the clutch pulled. I have a full body skid plate so it reflects the noise so I could hear it better. i heard it with the cel needle in the middle and second to last slot. with it in the middle it sounded like a 2 stroke 65 and the rpms would be high but I would barely move. I put it on the bottom slot and runs great now. did some chops and it was near perfect.

I am at 15ft above sea level

 

[bansheedave]

https://www.google.com/url?sa=t&sou...2BCTZYdFuNmxSzBJg&sig2=vZs5wPxJy5Dvw46tiCH1Cg

 

[Awk08]

With how fast it accelerates I would say probably done in 6 seconds or less

There's part of your problem, you must hold it wide open for longer than 6 seconds total for it to have enuf time to color the plug. upwards of 20+ seconds should produce good results

6 seconds isn't enuf time to color a baby wipe on a newborns dirty behind

 

[jus_me]

^^^ X2,, You want it to pull hard under a load and for a little bit..


Here is a link that I used and it always did me justice. Read closely as it says something about where the ring actually is. Also It says about 1-2 miles but imo you don't need to go that far but you do want it Wot for a little bit.
http://www.mopedarmy.com/wiki/Plug_chop

 

[pudvah]

“Plug Chop Plug Chop Plug Chop” I cry!
“Until you learn to feel me,
You’ll have to do it by eye.”

When it's dirty and black, it's got the sh*ts,
You have too much gas you are running rich.

When its hot and white, but looks pretty clean,
You're 'bout to blow your sh*t up; you're running lean.

Haha yessss

 

[nick20555]

^^^ X2,, You want it to pull hard under a load and for a little bit..


Here is a link that I used and it always did me justice. Read closely as it says something about where the ring actually is. Also It says about 1-2 miles but imo you don't need to go that far but you do want it Wot for a little bit.
http://www.mopedarmy.com/wiki/Plug_chop

There's part of your problem, you must hold it wide open for longer than 6 seconds total for it to have enuf time to color the plug. upwards of 20+ seconds should produce good results

6 seconds isn't enuf time to color a baby wipe on a newborns dirty behind

So how do I manage doing a WOT pull that lasts 20 seconds if it winds (pretty sure I'm spelling that wrong) out after just a few seconds? I've always been told to never hold it wide open for extended periods.

 

[Awk08]

I've always been told to never hold it wide open for extended periods

extended periods means minutes or miles, not 20-30 seconds

 

[nick20555]

extended periods means minutes or miles, not 20-30 seconds

A top speed run for 15+ seconds makes me a little worried but if you guys say it's safe then I'll give it a shot. Maybe that's why my dad's blaster is going on 28 years with only 3 rebuilds, because we don't go wide open for 20 second pulls lol but I'll take your word for it and post my results. I'll still check spark and compression when I can.

 

[jus_me]

Start safe (rich) and chop down.. Might take a few plugs but whats a couple bucks to be safe.