hard start big red

[rx7turbo1]

Hello all, new to the club! I have been battling this hard start issue ever since I purchased my late 85 big red. I believe I have narrowed it down to electrical (weak spark). It progressively worsend and only 10-15 kick starts would barely start it. Now I can't start it at all. I have removed and cleaned the carb multiple times with zero results. However, anytime I'd clean the plug and it would respond better. I have tried new plugs, which actually made it worse. Grounding the plug to the block and kicking showed a faint spark. When using the electric start I saw little to no spark. Once started it runs okay, except when you get on the throttle quickly it will bog (sometimes stall). like it blows out the spark... High rpms will backfire.

I went straight to the source and removed the stator. I was planning to replace it with a used one, but they are hard to find! The first was in worse condition, the second was for an early 85 big red which wont fit. I started to clean the "teeth" of mine thinking they need to be exposed metal (is that true?) and did a continuity test between the output wires and the stator body, which looked fine. I am about to re-install it, but wonder if there are any other tests I can do? Re there common issues with the big red stators?

I also snipped the end of the spark plug wire to expose fresh wires. What are the odds this is a CDI or coil problem? And what are the odds I am going to beat my head against the wall until it hurts? wait..I already know the answer to that question :)

Thanks everyone!
-Brad
:TrikesOwn

[rx7turbo1]

Also, I remember seeing a guy who rebuilds and tests 250r stators here on the forum. You ship him the entire electrical system with $100 and he does his thing... Does anyone know who this is? I can't find him anywhere now. He looked like a real electrical guru!

once again
:TrikesOwn
hehe

[Hair Bear Bunch]

Hi Brad, Welcome to the club.
Have you got a manual? There is full test instructions ie not just continuity but resistance values as well for the stator, coil, controlbox ect.. If you're good with a multimeter then you can check most parameters and maybe confirm your suspicions.
I think there are manuals on the main page but I couldn't be sure if the 250es is there.
If you do have to part with some hard earned to get it going it's usually worth it.
Just get it going and enjoy, you won't regret it!
Rob.

[rx7turbo1]

thanks rob Ill take that advice. I don't think the 250es manual is published here. Ill look online.

and for the heck of it...Ill check the local honda dealer for a new stator. gulp

[Hair Bear Bunch]

Unfortunately I followed the instructions thinking I might have a fault and discovered the charging stator was stuffed and the charge controller was toast! Also had various pieces of broken starter gearing attached to the rotor. I'd replaced the starter and gears because some teeth were missing, but never expected to find them there. It still runs but I have to charge the battery regularly and all the time it works, well, I can't be bothered to fix it.
Probably shouldn't do it, but if you lay the trike on it's right side you can access the stator without draining the oil.
Rob.

[Hair Bear Bunch]

Just a silly thought, I've been sat here for an hour or so trying to work out why my BR won't start. Apart fron a couple of backfires there's been nothing.
Last time I had it home there was a weak spark, so I closed the plug gap a bit to get an easier jump and it's been fine. Took the plug out this evening and the centre electrode of the plug is all but missing, completely burned away. The gap was so big I could get half my feeler gauges in there at once. Gave it a clout with a wire brush to reduce the gap and it started first time! Obviously needs a new plug, but made me wonder about the gap on yours.
Rob.

[rx7turbo1]

I think the gap was correct. I am pretty sure I looked that up on here and double checked it, but you bring up a good point. The new plugs I tested were from an autoparts store and were made by autolite. Using them did worse than the old plug. I am thinking I will buy a new OEM plug (NGK) and try that. A lot of guys here talk about different plugs giving different results.

My stator is on the bench and my trike is in the barn. I need to get back on it this weekend. I just purchased a manual on CD from a guy on ebay. We shall see how it helps. I'd like to test the crap out of the stator before it goes back in...

Thanks!

[hublake]

I have an 85 BR and another Honda and there have been times when they have started fine and run good and the next time I go out to start one of them and they won't start. All I have done is changed the plug and away they go. I would get an NGK over an autolite.

[rally4x4racer]

autolite makes good plugs - but I always run NGK in my bikes.

be sure to post up the prognosis when you get it fixed, turbo

[rx7turbo1]

okay, I just received a pdf manual for (250es). If there is a place to upload this, I will be happy to. It includes the resistance values for the CDI, Ignition Coil, Exciter Coil, Pulse generator and plug wire w/ cap.

I will order a NGK DR8ES-L and check all my components. The manual mentions the CDI unit as "most probably cause" to check after a faulty spark plug which I found suprising since that is a solid state component.

I'll check it all and report the results. I have WAY more confidence with these specs and I do not mind sharing!

Thanks ya'll!

[rally4x4racer]

how big is the document, turbo?

[rx7turbo1]

the manual is 80 mb's..

I just picked up a new DR8ES-L and a hotter DR7ES NGK plug. I also priced up the electrical components.

The stator : $255.34 and on backorder (probably impossible to get)
CDI box: $151.39 (after talking to the parts guy, he seems to think this is the culprint)
Pulse generator: $58.27 (also a likely culprit)
Coil w/ plug wire: $59.30 (unlikely a problem)

[rally4x4racer]

don't buy any of that for those prices!!

[rx7turbo1]

Here are my resistance results.

Stator: 117ohm black/red wire to ground (good)
Pulse generator: 325 ohm between two blue/yellow and green/white (good)
CDI: my digital multimeter failed to test properly (no results)
Coil: I couldn't understand the results of this. between the two coil terminals I had near 0 resistance. Between the plug wire and either terminal I had no continuity AND the strangest parts was with the boot. I couldn't get any continuilty between the boot ends (spark plug side and plug wire side). How could this be??

[rally4x4racer]

im not sure what you mean when you say boot, rx7 - but if I hear you right you are saying your wire is no good? no continuity from one end of the plug wire to the other? (bad plug wire)

find you a parts lot of electricals on ebay for 10 bucks or so and start swapping things out...

[bigreddaddy]

I second that. Look at ebay first or here in the classifieds for some parts. Also, there is already a honda 250 big red manual on this site.

[Hair Bear Bunch]

I guess as it runs the Ht voltage is enough to ionise the breaks and make the connection but losing power as it does it. The ohmmeter is only low volts, so doesn't make the connection 'open circuit'. So, yes, start swapping things out but check the viability of parts first. If they're second hand, they've been removed for a reason!

[rally4x4racer]

the cost of the risk you take buying used parts is much less than the cost of new parts.

there are a few bad sellers out there, but average intelligence circumvents the majority of them

[rx7turbo1]

Welp, I finished re-assembling and it starts and idles great! My current symptoms are: it cannot start with electric start, it stalls when applying load and only revs if I feather the throttle ever so slightly.

I ruled out the stator and pulse generator. I'm pretty sure the CDI box is working properly, even though I cannot test it and I am putting money on the coil being bad. It fails my resistance checks and I see little to no spark. Primary voltage is 12v when running, 10.5v turned off. I cleaned the on/off switch with steel wool and it now has a solid neutral light! The good news is I am fixing all the little known issues, but the root problem is still a mystery.

I am looking for a replacement on ebay now. Will a 250r or 350x coil would work just as well? It seems a 12v coil would be rather universal and I could save a few bucks with a wider selection. The big red coils are going for about $30 shipped. Also, I'd be interested in a higher capacity coil if available.

Thanks again!

[rx7turbo1]

Man! after 6 months of dorkin' around with this thing... It turned out to be the CDI box! A $30 part and 30 seconds to replace.

I feel like I wasted way too much time on this problem, but at least I learned a few things a long the way. Lesson learned, the CDI box really is "mysterious" and can fail halfway. When it does, the symptoms are that of weak spark and lean fuel.

[rx7turbo1]

Also! start by replacing the easiest and cheapest parts!