HPI ignition not charging and running issues

[rd400canuck]

Thats what I was wondering, too, Econo... I assumed max advance is where marks should line up then the module can calculate retard after it sees the mark.

I went in the garage to make a video to show you guys what I'm doing. Please check it out and let me know.

https://www.bitchute.com/video/AKV72n20SZ3m/

[Czakky]

The way I understand it is your static timing is where you want to be at mid/high RPMs, the rest is a compromise on a static system. So the HPI has no curve at 8-10k that is where you are setting your static.

[27 Cycles]

Canuck, it looks like you have done everything right, however, myself and most other people with this system have found that the initial setting using the dial gauge is only a good starting point.  You must check, verify and adjust with a light.  I had to advance my timing a lot using both adjustable plates to get it right.  My bike did not run properly either only using the dial gauge and the line to put on the rotor.

For the record, I used chucks dimensional measurements in his HPI thread to mark 24 degrees with a piece of welding rod bolted to the engine as a mark, then revved it to about 3500, where it then lined up with that mark.  With some RPM off of idle it will advance, to 24-25 degrees, what ever you choose, then it will begin to retard itself when revved really hard.

[m in sc]

thats just where the marks line up John, not nec where the trigger point is. ;)

[rd400canuck]

thanks guys,

I am using a timing gun after and the line is always showing at the line and never seem to sweep higher or lower whether is idling or revving. Also it runs like shit. With the points system it idled nice and smooth. Everything was smooth. This thing is jumping and chugging and wont settle into a normal idle. Plus the timing mark on the fly wheel is sketchy... it never shows up consistently even when the light flashes. Something triggers the light to flash but the mark is no where to be seen sometimes.

I'm still confused where to set the lines to line up... at 2mm (18.4 degrees) or 3.4mm (24.1 degrees) ?

[rd400canuck]

Ok... i noticed on the instructions it says set lines to match up at 2mm btdc and that's the max advance it'll see.

According to this chart 2mm is 18.4 degrees advance but their own ignition curve shows it at 25 degrees.

I dont get that.

[m in sc]

like i said. its a reference mark, not nec where it triggers. if you don't beleive it, mark tdc, use a dial back light, and rev the motor and watch the mark move. you can then use the timing light to verify its max advance. (thats kinda why they exist)

[rd400canuck]

I believe it:)   Just seems when i look at the numbers in that chart i posted and what the instructions say things dont make sense to me. That chart I posted says 2mm is 18.4 degrees yet the instructions have a a ignition curve that shows it goes to 25 degrees. If it's really advancing to 25 degree how is it doing that when 2mm is apparently 18.4 degrees?

Also.... dont kill me guys  but some how the left cylinder idle screw was screwed in so far it was probably running of the needle and soaking the plug. I noticed the exhaust pulse felt and sounded different so I thought I'd better check them and I found the left one needed multiple turns in to no longer be holding the slide up while the right took only 1 turn. I'm not sure who I manged that honestly... no clue.

So i set them both equally, set the timing to 2mm btdc and bam... it started up and idled more like normal... a little choppy but way better. Took it up the street and it ran way way better... lift the front wheel so its definitely running way better. I took it up the road a little up to 4th... seemed more aggressive but now it seems the 150's are too rich but more testing is needed before I start jetting.

It wont idle at 1300 rpm like it used to either... it just dies so either timing needs a tweak or the 27.5 needs checking along with the air screw. Its got a chunky idle and i need to keep it at 1500

I'll keep you all posted on the rest of the tuning and how the bike runs... so far the mid range is certainly more aggressive. feels nice.

Thanks for putting up with me and my mistakes LOL   

[1976RD400C]

After the rotor is mounted verify that the marks line up at 2.0 with the dial gauge. If not, loosen up the backing plate and rotate as needed to get them lined up with the dial gauge reading 2.0 btdc. Then the lines should line up with a timing light at 6500-7000 rpm (according to the HPI graph) Before 6500-7000 rpm it will be firing before the marks line up and over 6500-7000 it should drop right off and fire after the marks.

If static timing is 2.0 how does it advance beyond that for their curve?? I'm not familiar with this ignition.

That's a good question. I'll try. I guess the right term should be static set up and not timing. HPI wants you to align the mark on the rotor to mark on the backing plate so the magnet on the rotor is referenced to the charge/trigger coil mounted to the stationary plate. Then they want that aligned to the piston at 2.0. After installing the rotor you should check everything with a dial gauge and rotate the backing plate if needed to get it spot on. Without a electronic controller it is not going to fire at 2.0. Everything is in place to fire at max advance 25* or 3.65mm btdc on a RD400. They say that in the instructions. The 2.0 setting is just for getting everything in place. Now you start it and it immediately starts reading rpm. It takes the rpm reading, even if it is 50, and calculates the time it will delay the trigger coil signal to fire off the spark coil. It is very accurately reading the pulses from the charge/trigger coil and it can calculate the exact rpm. Knowing the rpm it can calculate the exact amount of time delay it puts into letting the coil fire to get the right ignition curve.  Making marks with a degree  wheel or using a dial gauge and find 25* or 3.65 btdc, at 4000 rpm and 15* or 1.33 btdc, 9000 rpm, you can check it at full advance and retard with a timing light.
After setting mine it was pretty close. Since you know the marks line up at 2.0, which is about 18.5* on a RD400, that should happen at just under 7000 rpm. I think that HPI figures people without a timing light can set it up and go, if you follow the instructions. I think you can but without checking with a timing light but you may have nightmares about holes in pistons.  Hope that helps people understand what is going on.

[m in sc]

exactly. just a reference mark. 

[rd400canuck]

ok... now it makes sense to me that its only a reference mark and is not indicative of max advance. I also now understand why rotating the base plate while it was running made no difference to if the marks alignment changed or not. And now I see why lining them up while piston is at 2mm btdc does not mean thats when it's firing.

To make sure it's actually firing at 2mm you'd have to have a pointer set to 2mm on a timing wheel and make sure that the 2mm is showing up at the pointer when the timing gun goes off. Just like I see in Chucks post on it.... I thought he was using a degree wheel just to be ultra accurate but you need to do that to verify it's firing at 2mm.

However I did notice that the markings lined up are the baseline and do not retard past it. It idles at 2mm and when i rev it i see it advance then drops back to lining up again to 2mm at idle. Anyone else notice that? seems like whatever mm you set it at is the minimum it sees.

I went for 10 minute hooligan ride. Will certainly take some fine tuning. Idle seems to be a little chunky and irregular than before. Once I print out a degree wheel and make 100% sure it's firing at 2mm btdc I'll see how it idles and if it doesnt improve then its pilot jet trying time.

I also notice that chuffing at steady speeds has returned and with the stock ignition the only way I got ride of the was to lean out the needle a little. So, it seems like its running a little rich on the needle now.. its in middle position... but.. it might be because those 150 mains ive been running that the stock ignition seemed to like the most.

It will not rev out like it used to, either.. It starts to weaken around 6500 and almost dies by 7200. I dont remember it being like that. Once on the hwy I could not get it passed 7000 rpm no matter how long l held it open. That mid range feels good though.

so... its degree wheel and verifying 2mm btdc first.

Thanks again everyone. I'll keep you all posted.

[rd400canuck]

I just realized something... the idle isnt smooth as it used to be because there isnt a heavy chunk of metal spinning on the end to smooth it out anymore.

[m in sc]

heres my sort of final suggestion.

take the plugs out, and cover off, and make a pointer with soem stiff wire.

find tdc, make a mark on the rotor and aim the pointer at it. mark it 't'.

then back up the rotor to 3.65mm btdc and make a nother mark there on the rotor.

start bike, warm up. rev to 3500 -4k and see if it lines up at the 2nd mark you made. if it does, youre good. If not, you need to adjust it.

this si basically how triples with cdi's are set, over 4k at max advance with a timing light.


just my .02

IF this is correct, you have it everywhere else. 

[rd400canuck]

awesome... will do that tomorrow!

I might order that fly wheel weight they off... it doesnt look too heavy and it'll smooth out the idle a bit which would be nice.

[m in sc]

it shouldn't affect it too much.  both csis I have idle smooth. . verify the timing first