Honda Motorcycles - FireBlades.org banner

1 - 3 of 3 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
I end up riding a lot in traffic and such and I'd like to make the bike more driveable at the lower revs. There are some real abrupt changes in engine behaviour in the rpm range around the first switch point for the HTEV. I'm thinking of removing the cables and locking the valve in the middle position (where each pipe has it's own hole through the valve).

I am guessing that the low rpm band would end up leaning out a bit because of this change while the high rpm band would run richer. Does anyone think this will cause any problems?

Thanks,

John
 

·
Registered
Joined
·
381 Posts
I think that the optimum mod would be to remove the second cable from the valve, replace that with some spring and limiter. This way the valve could be limited to only use 4-2-1 pipe for 0-7000 area, then 4-1-4-2-1 :) for the high end... this would eliminate the low 0-3000 area (90decree? if I remember correctly).

I was reading one car tuning book, and it came to me what the honda may be after with this 0-3000 setup. The valve shut downs the top two pipes and connects them to the lower ones. This creates backpressure and thus leaves more exhaust gas to the cylinders. this effect is very big, when engine is running aggressive cams.(like honda is). Exhaust gas in the cylinders is good for the NOx emissions, because it cools down the champer, because the mixture doesn't burn so fast. CARs even use EGR valves that circulate exhaust gasses to the intake. But that is probably too complicated to bikes.

of cource exhaust gas in the cylinders is not good for the power/fuel consumption or drivability.

jakeT.
 

·
Registered
Joined
·
3 Posts
Discussion Starter #3
The limiter is a very interesting idea.

I actually pulled the plastic off the bike testerday and I was about to un-hook the cables but decided not to. I think I'll order a power commander as I have seen a bunch of posts talking about how much better the engine runs when one is installed with the right map. I checked the PC site and they have a map for my Yosh 1/2 system.

Thanks for information.

John
 
1 - 3 of 3 Posts
Top