New to forum, mods for a dio

[Wheelman-111]

Greetings:

You don't need a new plug to evaluate yours, do you?

If your stock reeds lasted 25K Kms, get new stock ones. I didn't think they'd last nearly that long, but learnt something today. What weight rollers, and how tired is that Contra spring?

I'd just get another Honda shroud if you don't think it's your cylinder preventing closure. Tape whatcha got until it arrives.

[808BMW]

The reeds should seat firmly with no gaps, and the edges should be crisp with no cracks.

I have that same bore, and had to trim my shroud around the spark plug (on the back side towards the tire). The front fit together fine, but the back doesn't like to sit tight, so I have it zip tied for insurance.

I'm assuming you replaced the roller weights after that pic, yours look horrible
I'd grab a few plugs in different heat ranges (I run a #8), and test with/without your air filter. Is your exhaust clogged up? Maybe try finding someone with a dio and swap pipes to check.

[hughjass63]

Yes, rollers were replaced with variator kit. There doesn't appear to be any problem there.

I had another crack at the dio today, removed the reed block, and the reeds seems clean, seal well, and no cracks. I am guessing that they have been replaced at some stage. I did, just to be safe, put a thin film of gasket sealant on each of the carb flanges just to be sure they were not leaking.

I checked the plug and I have a NGK br6hsa. It is looking oily and black, but not with any carbon build up (that said, this is just a reading from having the bike revving for a few minutes on its stand).

I have experimented with raising and lowering the carb needle, putting on and taking off the air filter, but ultimately the response is mostly the same: It starts well from cold, but after just 10 seconds or so, it starts getting quite smoky, will eventually rev out but takes a while to get there. If I hold the throttle mid way, it does tend to pick up in revs okay when I put it to full throttle. But if I let it go back to idle and then put on full throttle it starts to load up and only after about 10 seconds of spluttering clears itself and gets to full revs. When hot, it will only start with full throttle and takes some time to clear and pick up.

Ironically, it was doing almost the same thing before I put on the big bore kit, so I don't think there is a problem with the carb being too small for the bore kit.

I have not yet tried to clear the pipe, and do not know of any other dio owners, so can't really experiment with other pipe.

Help!

[Wheelman-111]

Greetings:

Well, at least oily and black is safer than charred white! According to your spark plug, then the issue is either a very rich mixture or too much oil. How's that air filter again? And are you adding oil pre-mixed with your fuel?

(Prolly has somp'n ta do with buyin gas in them Litres instead o' what God and Honda-san intended... Gallons.)

It's probably not a bad idea to assess your exhaust for carbon impaction, based on your description of the plug. It's as simple as "puttin' another pipe on the barbie!". Cook, shake well, serve.

Sorry for not reading through again, but one other thought would be a failure of the enrichener (Bystarter) to close once the engine is warm. It'll run, but not very well. And that theory is consistent with your black oily plug, as well as no change between bores.

According to US manuals, the bystarter should show less than 10 Ohms static. If you hook up 12V DC across the terminals (polarity probably doesn't matter...) and wait 5 minutes, you should see a 5mm "erection" before/after. If not, your runnin' on the choke, mate.

Hope this helps.

[hughjass63]

Thanks for the tips wheelman. I will test the bystarter next time I am in the shed.

Today I had a friend over who is well versed in 2 strokes from the 70s and 80s. He had the thought that it seemed to be flooding, like too much petrol was pouring into the intake. Indeed, it does seem that there is petrol leaking out the exhaust manifold and around the autolube. So we measured the float level and it seemed to be set too high. Though the manual we have is for an af16 engine, we tried the 12.2mm space recommended and lowered the float level. It seemed to be a bit better, but the problem was still there. The float needled seemed to be fine.

I went to get a new spark plug but the correct one was not available so I will have to try somewhere else tomorrow. I am still thinking that perhaps, just perhaps, the plug might be breaking down under load.

Took the scoot out again after adjusting float level. It started well from cold and if just let to idle, it sounded great. But when revved it started the chugging again. On riding under 3/4 throttle the power it had was good, but was still chugging to get the to power revs. Then I also noticed that going up hills under power, after about 15 seconds it would cut out like someone had cut the ignition. But when I turned the scoot to be level and back down the hill and it would start perfectly, almost straight away.

I am thinking that you, Wheelman, might be on the right thing with the bystarter... except for one thing: why would I get quite good clean power once revving if the choke was still on? Wouldn't it be worse at high revs if the choke was on?

Is there any aftermarket carb I can get that still allows me to use the autolube?

Also, I am guessing that this problem is probably the reason the dio was on a rubbish pile!

[hughjass63]

I've been out to the shed again and did the 12v test on the bystarter. It moved, but only a couple of mms.

[Wheelman-111]

Greetings:

Quoth Hugh:

The float needled seemed to be fine.

They can look OK and not be OK. The test is to blow - er, I mean apply pressure with an EPA-approved pressure-generating device - into the fuel inlet as you lightly lift the float. Even if it seems to seal well in testing, it's a fussy, high-intolerance little device. Only a NEW Honda float needle and a light polish to the seat/bore fixed mine.

I went to get a new spark plug but the correct one was not available so I will have to try somewhere else tomorrow. I am still thinking that perhaps, just perhaps, the plug might be breaking down under load.

There have been countless occasions in my wrenching life when a new plug fixed my issue after I had tried almost everything else... Now I always start there.

Took the scoot out again after adjusting float level.

The US carbs are all-plastic and can't adjust. Yours is different?

I am thinking that you, Wheelman, might be on the right thing with the bystarter... except for one thing: why would I get quite good clean power once revving if the choke was still on? Wouldn't it be worse at high revs if the choke was on?

Quite right, mate. Maybe that's not the problem. But also consider the effect of your airbox mods. Maybe it's getting just enough air at higher revs, but the midrange alone is dodgy. (That's Oz-talk for f-ed up... )

Is there any aftermarket carb I can get that still allows me to use the autolube?

You can install a 1/8" barb at the manifold and inject your oil there. I have not identified an aftermarket carb that has an autolube port except for the Arreche-for-Honda at Scooter-Center.com.

I've been out to the shed again and did the 12v test on the bystarter. It moved, but only a couple of mms.

Take a caliper and measure the full travel precisely. If it's really only 2mm, it may not be closing completely, which would explain a lot of your symptoms, if not a completely satisfying answer. Maybe crush a Levitra tablet and sprinkle it in the tank? A new bystarter from Honda is pricey. The Chinese clones are tempting but not well-regarded by those who've bought them. Maybe source a known-good used one?

Also, I am guessing that this problem is probably the reason the dio was on a rubbish pile!

And you are very close to outsmarting the Previous Owner, who should be ashamed.

[808BMW]

Have you checked the gas tank + fuel petcock?

I had a lot of rust in my tank which kept clogging my petcock, and I would get weird symptoms all the time. It was extremely hard to diagnose because the fuel flow would be so erratic that the problem changes. It ended up clogging my petcock open, and gas would leak down the vacuum line into the manifold. That could lead to flooding for a few seconds while your motor runs through all the gas, and then it opens up to normal.

I've also spent 2 months down for a spark problem that ended up being a plug. My plug was new (less than 1 hour on it), so I insisted it must be good when everyone said to change my plug.
Unfortunately it was a brand new #6 (all I had) and I normally use a #8.

[hughjass63]

Thanks for the replies guys. I have not had time to do anything on dio except look at it briefly as i walk past.

Plan of action:
- New plug
- reset carb to previous float level
- measure bystarter
- will pull apart petcock (can't help giggling like a girl when I say that out loud) and give it a clean

My carb does seem different to the one in the Elite manual (don't have a dio manual anyone?) and there is a metal thingy holding the float needle up, I just bend it like the old mower ones.

Hey wheelman, what's a levitra tablet and what does it do?

I guess before I muck around too much with the standard carby, I need to ask the question: is it ever possible to get 50mm big bore working with standard carb? I notice that on ebay they have standard dio carby brand new quite cheap at the moment, so was thinking of buying one of them, but will not if I really need to upgrade.

I just want dio reliable, reasonable economy, and with the autolube working.

Thanks again for help.

[Wheelman-111]

Greetings:

My 49mm bore got to 58 MPH with the stock Elite carb, which I believe to be considerably smaller than your Dio's. What may be a limiting factor is the stock airbox. Consider a pod or K&N-style oiled cotton mesh and jet up to 96-ish with stock pipe or to 101 or more with a chamber.

That said, tuning an OKO or PW Keihin is said to be much easier. 24-28mm should be right.

The autolube can be retained, however additional oil for the added demands of 82cc is necessary. I use 75:1 in my tank. Your mileage may vary.

Levitra is an US brand of drug for uh... Erectile Dysfunction, hence therapeutic for sluggish bystarter performance. Just a little humor from The Land Up Over.

[hughjass63]

thanks for the advice.

have just come across carb rebuild kit on ebay for US$10 so I thought I might start my carb journey there.

we don't have levitra in australia. we use a piece of twine, a brick and an electric probe. works for me every time.

[Wheelman-111]

Greetings:

Quoth Hugh:

we don't have levitra in australia. we use a piece of twine, a brick and an electric probe. works for me every time

.
Ah, to be young again... Don't forget the whipped cream!

[hughjass63]

Just located a dio sk50 pdf manual on line at http://www3.telus.net/MyScoot/repair02.html (left a pm to noiseguy). Will review float level and carb adjustments accordingly. I think I may have wrongly adjusted float level to SA50 measurements.

I have also been having a bad feeling about the pipe (as others have previously noted). When I removed it it was awfully heavy for a little piece of metal. I spoke to a friend that said he would burn out the pipe on his two stroke enduro bike (yamaha it200) at least once every six months and would suffer significant performance loss if he didn't. I bet this '93 dio has never had its pipe cleaned. Only problem, I don't have oxy gas torch. But will try chemical clean as per other posts. Any thoughts?

Have just been getting over a pneumonia asthma thing, so I am getting a bit behind in dio development. Am feeling quite excited though because I can feel the little beasty raring to go under all the misfiring and smoke!

Mr Jass

PS - below is a similar dio to mine for sale on the Sunshine coast in Queensland Australia on ebay. he wants $500 and no one seems to be bidding, but looks a great scoot. We do have strange retro coloured dios in Australia

[sanjuro]

That Dio above looks to be in great shape cosmetically.

[Clivester]

It looks like in Ozz Honda added the brake light/flasher/rack unit to make the scoot street legal but left the JDM brake/flasher unit in place! In the States they replaced the whole factory-original light unit with the US-compliant one.

Hopefully, when the bike fell it was the Ozz-compliant light that took the damage. The scooter would look so much better put back to the JDM state.