LocostUSA.com

I'm likely early with my concern on this, but I'm curious as to what's going on with my car's bike engine...

My motor is a 98 Honda VFR800, and it ran perfectly while in the bike- no issues whatsoever (it has a Powercommander III on it).. Now it's in my project car and is acting differently- probably because of my many changes to get it there... The biggest diffence is once I revv it up to say 5,6,7K, it is a bit slow to come back down to idle... I seem to remember on the bike it would rev quick and drop back down almost as quick, and now it revvs quick and takes 3 to 5 seconds to drop back to idle...

Surely I've caused this, but I'm not sure which mod is doing it (I'm still tweaking to bring it all together)..

-#1 My "new" exhaust has almost NO restriction (handmade headers and a 12" glass pack muffler) and is REALLY loud... I hate it, and it will be getting something MUCH quieter soon--- maybe the total lack of backpressure is to blame?

-#2- in my hurry to cobble it together and limp it around the block, it currently has no airbox lid (no hood clearance for the stock lid) Soon I'll make a much flatter built-to-fit lid... maybe changing this is my issue?

-#3- I took out the PAIR system at changeover.. did it by the book- capped the vacuum leads/PAIR valves, etc. Maybe slow deceleration is a side-effect to this mod?

My gut tells me it's the intake/exhaust and will sort of remedy itself once I put and airbox lid on and a 'real' muffler inline..

---It's so cool to have it under it's own power- even if it does currently piss off all of the nieghbors

... My wife has been cool with the many hours/weeks/months and (gulp) now years in the garage, but that good will has been wearing thin recently- nice that it's now running as a whole, and I'm finally down to the last 728 details to finish the build

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Dean

1972 Honda N600 Restomod "ccrunner's N600 VFR800 repower"

1963 Volvo P1800 Restomod
http://locostusa.com/forums/viewtopic.php?f=36&t=16309

1959 Berkeley SE492 Restomod...
viewtopic.php?f=36&t=19397

"ccrunner's 1960 MGA coupe Restomod" found on MGExp.com

If you have the exhaust flowing better and airbox open it's probably running way lean.

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Yep I got a build:

is there more restriction on the throttle cable?

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Fingers of butter and fists of ham.

My first thoughts would be to check for vacuum leaks and then make sure the tune is running correctly...But then again, I'm certainly not an engine tech.

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-Justin

"Orville Wright did not have a pilots license." - Gordon MacKenzie

Optimus- the throttle cable is 'free' and is not binding (although I had to remove the 2nd throttle cable that manually pulls the throttle closed)...

..I'm with you guys- this thing in it's current state is pretty much an unrestricted air pump, which I just wouldn't expect to run right until I get all of the pieces back together...

With all of that air, I agree it's got to be quite lean, even though I'm on the most agressive of the 3 tunes available.. once I'm truly running, I intend to get a custom map for it..

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Dean

1972 Honda N600 Restomod "ccrunner's N600 VFR800 repower"

1963 Volvo P1800 Restomod
http://locostusa.com/forums/viewtopic.php?f=36&t=16309

1959 Berkeley SE492 Restomod...
viewtopic.php?f=36&t=19397

"ccrunner's 1960 MGA coupe Restomod" found on MGExp.com

It was there for a reason.

I'd suggest either replacing that cable, or beefing up the throttle return springs.

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Fingers of butter and fists of ham.

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