Need some advice --> 1981 Ironhead

[MFC]

Jim, in regards to the carb... what screw are you talking about ??? I think your saying to take the screw (9) and put it into (8)

[JBinNC]

I'm talking about plug #21.
Put it in position #8 in the upper pic.

Jim

[MFC]

how will I know that I am satisfied with the timing. no pinging noise at 2000 RPM???
Also, what do you mean if the bike doesn't pull cleanly through all the gears??

Sorry for all the questions, I am trying to cover my basis with the mechanical part of having an ironhead, I'm better with the fab stuff.

[JBinNC]

What I mean by pulling through the gears is just that. It should pull strongly from 1500rpm up to at least 6000rpm with no hesitation, missing, sputtering, etc. And an ironhead will pull rather strongly. It should not go flat until the valves start floating, and they have enough valve spring to turn 7000rpm. Looks like you have plenty of carb, a nice exhaust system (from appearance only) and you say you have an electronic ignition which should give consistent spark. Tuning should achieve this result.

Now, if there is something (or several somethings) mechanically wrong with the motor, no amount of tuning will fix that. That remains to be seen.

Jim

[Dragstews]

Valve timing too ...

Being that motor is a 81 it's most likely to have a world of miles on it ...
Bout the first thing that wears out is the lifter blocks ... The rocking back and forth throws off valve timing greatly ....

Easy to see if indeed this is the case by pulling the pushrods covers and lifting them up to eye-ball what the tappets are doing while spinning the motor over ...
At high lift you will see it jump from side to side ....

If you do need a set of blocks, I have these in stock...



Sell em cheap .... They are brand new ...

[MFC]

Valve timing too ...

Being that motor is a 81 it's most likely to have a world of miles on it ...
Bout the first thing that wears out is the lifter blocks ... The rocking back and forth throws off valve timing greatly ....

Easy to see if indeed this is the case by pulling the pushrods covers and lifting them up to eye-ball what the tappets are doing while spinning the motor over ...
At high lift you will see it jump from side

If you do need a set of blocks, I have these in stock...



Sell em cheap .... They are brand new ...

Thanks !! This will be another thing on the list I’ll check

[MFC]

So here is the update.

I set up the timing light and followed the directions on the vti PDF. I was only slightly advanced from 35* BTDC. Retarded about 5 degrees And jumped on the bike.

Like Jim said I pulled through all the gears and listened for a ping noise.. none, bike fired perfectly, sounded great. However the plateau issue still existed. So I adjusted my clutch cable first. Got back on and still I could feel the bike lag then catch. Adjusted my pressure plate and again the cable and BINGO the bike pulled through each gear beautifully!! Powerful and sounding best it has been in the time I have had it.

Question Jim, if I swap the plug like u suggested what will that do to the current tune?

[Tattooo]

So here is the update.
Adjusted my pressure plate and again the cable and BINGO the bike pulled through each gear beautifully!!

Awesome.....

[MFC]

Awesome.....

Thanks Tattoo ... turned out the clutch needed some adjustment to get it right! I appreciate the guidance!

[JBinNC]

So here is the update.

I set up the timing light and followed the directions on the vti PDF. I was only slightly advanced from 35* BTDC. Retarded about 5 degrees And jumped on the bike.

Like Jim said I pulled through all the gears and listened for a ping noise.. none, bike fired perfectly, sounded great. However the plateau issue still existed. So I adjusted my clutch cable first. Got back on and still I could feel the bike lag then catch. Adjusted my pressure plate and again the cable and BINGO the bike pulled through each gear beautifully!! Powerful and sounding best it has been in the time I have had it.

Question Jim, if I swap the plug like u suggested what will that do to the current tune?

If you swap the location of that plug, hopefully nothing. Drag racers discovered that with a velocity stack, a vacuum can be created at that point at high speed. That is why the plug is there to start with, to give you the optional vent point when not running the air filter box. You need to swap it.

Jim

[MFC]

If you swap the location of that plug, hopefully nothing. Drag racers discovered that with a velocity stack, a vacuum can be created at that point at high speed. That is why the plug is there to start with, to give you the optional vent point when not running the air filter box. You need to swap it.


Jim

Jim... I went to remove the bottom plug and realized the spot I’m supposed to put it in (location #8) is not threaded... does this mod require me to tap location 8?

[JBinNC]

Jim... I went to remove the bottom plug and realized the spot I’m supposed to put it in (location #8) is not threaded... does this mod require me to tap location 8?

Yes.

Jim

[MFC]

Yes.

Jim

Jim, I appreciate all the help sir!

[JBinNC]

You can just leave the bottom plug out, that will help, and tap and install at your leisure.

Jim