I'm back, with a new toy... Honda Gyro X

[Raizer]

Can't say that's lean looking!

Tried a stock CDI and no improvement.
Have another coil I can try too.


tsimi it's a Chinese clone of a Keihin PB but in 19mm, swapped the stock Keihin PB 16mm back on earlier.

[Raizer]

Quick thought, is fuel supposed to just flow through the pump even when there's no vacuum?
Adding vacuum doesn't seem to have any effect on the flow either?
Wondering if the pump isn't working and gravity isn't keeping up with the engine?

[pitobread]

If it is like a Dio Pump, it's a pulse pump so its the rapid vacuum on/off that pulses the diaphragm and pushes fuel thru it.

Easy enough to make a fuel bottle and gravity feed the carb and see if the problem gets better or worse.

[tsimi]

Dec 7, 2017 22:14:34 GMT -5 Raizer said:

...it's a Chinese clone of a Keihin PB but in 19mm

There you have it, a clone! Those are hit and miss and not always 100% reliable.

Unless you get the same issue with the genuine stock carb.

[Raizer]

Problem stayed when I changed to the stock carb.

But I swapped the dead pump out for a known good spare, DRASTIC improvement!

Still runs out of fuel (which I thought was soft seize at first) after a while at WOT but not anywhere nearly as bad!

Think I now know why all the Japanese builds I see online have the bigger Dio fuel pump fitted...


So I think Dio pump is the next step.





Oh and although I'm gutted the Green Gyro isn't going to make the club ride this weekend, at least I've got "Plan B" together and ready to go!!


Damn I really need to tidy my yard!!

[Raizer]

Gyro pumps are little things like this


Dio pumps look to be way bigger

[190mech]

Mikuni/Briggs and Stratton vacuum pumps work well;
www.ebay.com/i/272699619533?chn=ps

They should be available at most small engine shops..

[Raizer]

Now that's an idea!

[Raizer]

32 seconds @ 32mph, full quarter mile haha!

[Raizer]

Moves a HUGE amount more gas than the stock one ever could!
Reinstalled the Chinese 19mm carb when I put the pump on, forgetting it still has something like a 110 main in it.
Took it for a ride and I'm fairly confident in saying the problem is solved!
But I couldn't get it much over 3/4 throttle with the main that's in there as it just 4 strokes, but either way I had it going at high enough RPM for long enough that it would have played up with the stock pump.

Going to drop down a few jet sizes and fit lighter rollers and see how it goes, as soon as the rain passes anyway.

[Raizer]

Fuel pump works!

I'm fairly confident I haven't hit the power band yet, it's running 6x6g rollers so I'll swap them out for something a bit lighter and see if that wakes it up!
Still just a touch rich I think, that's with a 95mj in there but I don't want to go leaner until after I get the RPM up.


Before I carry on tuning I am going to rework the headpipe on my exhaust, the Malossi cylinder puts the flange a little bit further forward and I'd made the exhaust around a stock cylinder so it was a super tight fit/struggle to get it on this engine!  Also it just fouls the trim panel that sits in front of the engine over bumps etc.
And the thin Chinese pipe flange bends before it seals so I'll cut a new one to suit out of some 5mm plate and zap it on.

[Raizer]

Also still thinking about going to a PWK carb, currently looking at either the Naraku V.2 21mm

Pretty sure it'll be a Chinese made carb with Naraku packaging, has a power jet on it but I can't find any reviews or anything on them.


Other option I'm looking at (and leaning towards) is going a bit bigger than 21mm and grabbing a Polini 24mm.
Have read on a couple sites that they are made by Keihin for Polini and are excellent, no powerjet or anything but look to be a decent carb by all accounts!



Should really upgrade to a proper exhaust at some stage too.

[Raizer]

Been running about town on Plan B all weekend, even after the abuse of the 1/4 mile drags last time it was used it still started first kick and ran fine.

Filthy pig gets a ton of attention around town, had Sandy ride it for a while while I hung back a little on her AZ and yeah the amount of heads it turns is crazy considering it's fairly stock and silent etc!




Had my Green one and everything outside today while attempting to yet again clean my little shed, ended up decidiing to try some lighter rollers then worry about the exhaust etc after.

Real pain in the ass to change rollers on these things!

Thinking of cutting one of my spare covers just behind the kickstart assembly, so then I don't need to jack it up and remove the hub and brakes etc to get to the CVT.

It turns out I was running 6x7g rollers not 6x6g as I'd thought.
Also when I ordered my CVT tuning kit I was still only planning a mild low RPM engine, the 3 lightest rollers were 5.5g so I have ended up using the 6 lightest rollers I had on hand, 3x6g and 3x5.5g.

They have brought the RPM on the flat up to about 8200rpm, still pushing to about 64k.
BUT on the way back home there was a stretch of road with a mild downhill gradient, the RPM gradually climbed until at one point the engine note changed and it started pulling, HARD!

Think I've found the power band, it starts up over 9000!


It was hitting 75k before I ran out of road.
So now I need to order rollers and maybe a clutch and carb etc...

Might have to bite the bullet and pay WAY to much for super cheap quality rollers here in NZ rather than wait ages for overseas shipping.

[benji]

You can drill holes in the clutch shoes too light them a little which will raise your take-off rpm. I bet you find with lighter rollers and stiffer clutch and torque driver springs you'll get moving alot faster haha. On most of my 70cc bikes with expansion Chambers have around 21-24g total weight in the vario.

[Raizer]

Yeah the clutch leaves a lot to be desired, it's a stock clutch with I think 1000rpm springs, they came with my variator.

Think I'm running either 27 or 28.5 total roller weight in my Suzuki, and this seems to want to rev higher than the Suzuki!