Throttle Balance adjustment

[smokey]

Originally Posted by otter

I'd be hesitant in doing that. My Canadian bike had a nice sticker beside the fuel cap: 91 Octane only, or "severe engine damage will result". Do our 1700s not have a knock sensor?

Been running regular 87 since day one, with no issues whatsoever.

[otter]

I probably live around the corner from you

The other reason I stay away from 87 is that pretty much everyone is blending 10% ethanol in their low and mid grade.

The only way to avoid ethanol around here is Ultramar super, Stinson super, Petro Canada 94.

I've always thought the slower burn of higher octane fuel results in a slightly cooler burn. But then, our bikes are soooo lean that it probably makes no difference at all.

[ponch]

Originally Posted by otter

I probably live around the corner from you

The other reason I stay away from 87 is that pretty much everyone is blending 10% ethanol in their low and mid grade.

The only way to avoid ethanol around here is Ultramar super, Stinson super, Petro Canada 94.

I've always thought the slower burn of higher octane fuel results in a slightly cooler burn. But then, our bikes are soooo lean that it probably makes no difference at all.

Considering they are such low compression engines, 94 or 91 octane would be a waste. I know on the Vulcan 800 I had, using higher octane was/is bad and leads to excess carbon on the piston which can actually build up enough to smack the valves. If the 1700 has a more modern engine management than the 1600 with an O2 sensor and knock sensor, 87 shouldn't be an issue.

[GodOfDirt]

recently switched to 89 with no issues for 3-4 tanks. My nomad does not have neither a knock sensor nor an O2 sensor.

Ordered spare Throttle body off ebay for more research.
Looks like there is a intake pressure sensor on the bike, however it is only hooked up to the rear intake port. with the imbalance found between my cylinders, I can see why the front was running lean. With MAP systems in cars, a drop in vacuum indicates an increase in airflow, requiring more fuel. What I did with adjusting the big brass screws(actually plastic I think) is drop the idle air pressure in the manifold while also balancing the front and rear port. as a result I have a much more balanced acceleration and better fuel economy than new.

The ultimate result is changing a bike I nearly regretted buying to one I'm really happy with.

[ponch]

Originally Posted by GodOfDirt

recently switched to 89 with no issues for 3-4 tanks. My nomad does not have neither a knock sensor nor an O2 sensor.

Ordered spare Throttle body off ebay for more research.
Looks like there is a intake pressure sensor on the bike, however it is only hooked up to the rear intake port. with the imbalance found between my cylinders, I can see why the front was running lean. With MAP systems in cars, a drop in vacuum indicates an increase in airflow, requiring more fuel. What I did with adjusting the big brass screws(actually plastic I think) is drop the idle air pressure in the manifold while also balancing the front and rear port. as a result I have a much more balanced acceleration and better fuel economy than new.

The ultimate result is changing a bike I nearly regretted buying to one I'm really happy with.

Or a the two can be balanced to a degree by a port or notch between the two runners.

[GodOfDirt]

20150919_125135.jpg

after my tuning, I plugged my vacuum port extensions together to help with the off idle imbalance.

[JoeOuts]

Originally Posted by RACNRAY

Although Kawi recommends 90 octane many of us have found the engines run better with 89. What we have down here is 87/89/93 and not only with the 1700's but many sportbikes (most with 12-1 c.r.) run better with 89 than with 93. The feedback I get from 1700 owners (from around the country) have positive results when they have switched from the higher octane to 89. Better performance, mpg and many report less decel popping on skoots with that occurring.

1700's with exhaust mods, a good BAK and proper FI tuning can run 87 with no problems. The 1700 is a mild engine, 9.5-1 c.r., a good spark plug design (although Kawi should of stayed with dual plug heads like on the 1500/1600).

In the first few thousand miles I experimented with octane, first runnin 93. On the first tank of 89 the engine ran noticeable smoother, a tiny bit better throttle response and about 4 tenths better mpg. Ran 89 for awhile then switched to 87. No pinging and no change in anything other than saving some $$$ at the pump.

RACNRAY

Is anyone using 89 Oct in the northeast with any success? Ray is down in Florida and i'm wondering if the climate makes a difference in engine performance with 93 vs 89 up in New England.

[Ken Vega]

Originally Posted by JoeOuts

Is anyone using 89 Oct in the northeast with any success? Ray is down in Florida and i'm wondering if the climate makes a difference in engine performance with 93 vs 89 up in New England.

Ray and I both use 87 octane with no issues. Even on rediculously hot days 87 has not caused any knocks or pings.

[ponch]

Originally Posted by GodOfDirt

Attachment 9957

after my tuning, I plugged my vacuum port extensions together to help with the off idle imbalance.

That might work

[redjay]

I never heard my Voyager ping or knock running 87 from day one.

[Hillhouse]

My Voyager has only knocked (W/87 fuel) while riding two up on a very hot day in York, PA.
My HD friends say that the bike was just being intimidated by all the Harleys being built there.

[gv550]

I think your differential manometer is indicating a serious intake manifold leak, rather than an out of adjustment throttle body. The manifold can leak air at the cylinder heads, injector ports and at the throttle body.
The manifold to cylinder joint is a bit cheesy, and I sealed mine with Hylomar on the aluminum surfaces, made a world of difference in how the bike runs. I also added sealant to the injectors and installed the Thunder gasket at the throttle body.
In theory you may be able to compensate for a manifold leak by adjusting the idle air screws, but the engine will still be pulling unfiltered air past the leak, and the leak gap may change with engine temperature.

[RACNRAY]

Originally Posted by gv550

I think your differential manometer is indicating a serious intake manifold leak, rather than an out of adjustment throttle body. The manifold can leak air at the cylinder heads, injector ports and at the throttle body.
The manifold to cylinder joint is a bit cheesy, and I sealed mine with Hylomar on the aluminum surfaces, made a world of difference in how the bike runs. I also added sealant to the injectors and installed the Thunder gasket at the throttle body.
In theory you may be able to compensate for a manifold leak by adjusting the idle air screws, but the engine will still be pulling unfiltered air past the leak, and the leak gap may change with engine temperature.

I agree Garry..It is such a well known fact of the intake leaks on the 1700's. God of dirt I thank you for startin this thread as it compelled me to do 2 things on my skoot.

First was to check the idle vacuum balance. Using my carb stix there was LESS than a 3 mm difference between the 2 cylinders. Adjusting these even made no discernible difference, but I as most have done have sealed my throttle body to intake manifold junction, and on top of that the junction of intake manifold to the heads, another prime source for vacuum leakage. Safe to say I have no vacuum leaks to have a negative affect.

Second I always knew but never gave it much thought that the MAP sensor is fed vacuum from just the rear cylinder, all of the 4 cylinder skoots have vacuum ports on each t/b that connect into a common hose that feeds into the MAP sensor. DUH ME!!! So last night I machined an extra vacuum nipple outa stainless steel, drilled out the throttle body and pressed it in. This extra nipple feeds into a hose which tees off to the rear t/b and both feed the MAP sensor. The one existing nipple on the front t/b bore can be used to accomplish this tie-in, but I wanted to make future checking of the idle air vacuum a bit simpler.

Idle seems a bit more stable so I will have to wait until I can ride the skoot to determine any on-road differences.

RACNRAY

[Scootergptx]

Originally Posted by GodOfDirt

Attachment 9957

after my tuning, I plugged my vacuum port extensions together to help with the off idle imbalance.

I think I'll look into this on mine. Just to be sure, do you mean plugged, or plugged together as in hooked up to each other?

[skullbagger]

Originally Posted by Hillhouse

My Voyager has only knocked (W/87 fuel) while riding two up on a very hot day in York, PA.
My HD friends say that the bike was just being intimidated by all the Harleys being built there.

I've toured that final assembly plant during my one and only visit to York bike week, very cool inside