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Mike Anhalt

HPI Ignitions

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I've pretty much abandoned getting a standard EI to work with my RB motor. They just can't rev out far enough and no matter what it goes to crap at 8000 RPM  (right at the peak of my power) have tried multiple stators, flywheels and coils in various combinations.

 

 

So I've run across this little gem

 

http://hpi.be/item.php?item=068K352-1CF

 

 

According to their website they make a FW that will work on the GP 5 deg taper crank.

 

Anyone ever used one before?

 

Race use only, no lights 

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Is this for street use? If so an led brake light will run on a stack of aaa batteries (or a 9v with a pair of aaa's) for a long time. Could also get a $60ish bicycle LED light with Lipo battery setup (be careful charging) for the headlight, it will be enough to be seen, but not enough to see above 25mph...

Have others had issues with ignition at rpm? I have only revved my rb twice (still tuning and breaking in) but didn't notice anything odd. BGM stator with AF flywheel.

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I haven't used one, or heard of it, but it certainly looks like a good set up. You haven't gotten any standard type set up to run well at 8k n above? I thought there's been quite a few ts1's running above that mark quite well. I think even the old Dave Webster book talks about hitting 10k with a points set up (of course, a modified set up) You're sure the trouble isn't coming from another source?

 

Separate conversation altogether, but what pipe are you running?

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I haven't used one, or heard of it, but it certainly looks like a good set up. You haven't gotten any standard type set up to run well at 8k n above? I thought there's been quite a few ts1's running above that mark quite well. I think even the old Dave Webster book talks about hitting 10k with a points set up (of course, a modified set up) You're sure the trouble isn't coming from another source?

 

Separate conversation altogether, but what pipe are you running?

Bullet exhaust. They say it peaks around 7-8k and should rev out past 10k

I've been chasing lots of little issues with this bike and it still hit 69mph in the 1/8th mile.

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Think you may have a problem in the parts Mike. Put an RB together with a AF flywheel and regular 'ol Indian stator and it revved right out. Had to shim up or lower the pick-up, can't remember which.

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Think you may have a problem in the parts Mike. Put an RB together with a AF flywheel and regular 'ol Indian stator and it revved right out. Had to shim up or lower the pick-up, can't remember which.

 

 

That's what I've been doing and I think it's an uncorrectable alignment issue between the stator and flywheel (Indian stator with BGM trigger w/spacers and LT coil, no light coils) AF light flywheel, no fins. Is the current set up.

 

Have also run with

 

BGM stator

AF flywheel

BGM flywheel 

Indian CDI

Ducati CDI

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That is interesting... And the wiring is good, there is a good ground connection, ht wire and cap?

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That is interesting... And the wiring is good, there is a good ground connection, ht wire and cap?

 

 

yes. All solid connections (ohmed out, soldered and clean bare metal grounds)

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Just a thought...

 

I assume you've got a tachometer on it? Have you done a 3rd gear run and revved it out? Does it stop dead at 8k then too, or rev out correctly? Generally, ignition problems like you're thinking should affect all gear ratios, not just 4th gear. The results might lead you toward the correct path.

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Just a thought...

 

I assume you've got a tachometer on it? Have you done a 3rd gear run and revved it out? Does it stop dead at 8k then too, or rev out correctly? Generally, ignition problems like you're thinking should affect all gear ratios, not just 4th gear. The results might lead you toward the correct path.

Yep, happens in all gears. Hit 7500/8000 rpm and gas just pukes out the pipe. I know it's jetted close because if I go too small on the main it starts to drop out around 1/2 throttle and backfires.

 

It's been a weird one.

 

running a mychron 4 multi tachometer with EGT and CHT

 

tried multiple carbs too, too eliminate any weird hardware issues. Currently it's got a TMX 35 on it and that's been the best one so far,.

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I hate to tie the topic up with extras, since this is actually about ignitions, but now I'm thinking about the problem!

 

The next test I personally would try is- try revving out in 2nd, or even 1st gear (on the stand even!?), but specifically with a very low throttle opening (very low gearing is the only time you can rev to 10k at 1/4 throttle!), not wide open. Even downhill if necessary. It seems odd that all the ignitions you've tried, that generally have no problems at those speeds, are causing the trouble. My thought is that maybe when the pipe starts coming on to the power, it's messing up carburation (pulling super hard suction waves, in turn running rich and dumping fuel into the engine). Perhaps the pipe/head/barrel/exhaust timing isn't coordinating? Low throttle opening will be lean inherently, so if it will rev out downhill in 2nd gear at 1/8 throttle, but dumps fuel in and dies out once you open it up to full throttle, it might be that. If 8k kills it dead no matter what you do, then you may have to get real picky in the ignition dept (check crank width vs mag flange vs ign pick up, etc).

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Hey Mike, what you are describing sounds like the old method companies like Spec II used to keep over run conditions from occurring like during a missed shift... The exhaust stalls the flow, causing intake to pulse thru the carb, drawing fuel in the multiple passes thru the carb causing the mix to be very rich. It may be some combination of exhaust port timing or shape and the pipe. You could try extending or shortening the stinger length...

Does the tachometer become erratic? An electronic tach will normally spaz out with bad ignition...

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Oh yeah, I'll post all about it. Being a wet year the salt beds should be really good for racing. That's been the big push to get this bike running right. We did some porting that I've never seen on a Lambretta before so hopefully it pays off with some big numbers. 

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Mike, are you using an AF light flywheel or an AFR light flywheel? The AF was made by Ducati and I've never had a problem with these. The AFR is made in India. I had one and it did the same thing you are describing. When I strobed it, the timing would become erratic above 7,000 RPM.

 

Since you need as light a flywheel as possible, you could go old school and find a Motoplat internal rotar ignition system, or use a dead loss system. I would think the one you linked to should work, too.

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One more thought, have you tried it without the tach? Not sure where you are picking up signal, but wondering if it might be causing something...

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The tach signal just clips to the ht wire. Interesting approach though.

It has an internal battery and only the rpm signal goes crazy when it starts missing. The tach it's self stays stable and keeps working (CHT/EGT stays active).

Mychron 4 they are used heavily with t2 cart racing, very trick.

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We've used the HPI on tons of mopeds, they work well.

 

 Arne. Maybe Andre Prager could help with high rpm ignitions. He's a engineering tech for Stihl and those things go up to 13,000.

 

I could give you his contact info Mike and you could see what he says. Super nice guy and super smart.

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Good article. Makes wish I would have known about HPI when I had my rd400.

Will be purchasing the HPI next month and see how it goes.

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Mike - any updates on the HPI or are you still having the same problems?

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