In Conclusion: What is Possible with 477cc?

sam2019

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22. July 2021, 4:50
There are various threads now that hide this kind of information from all but the most notorious readers so I attempt to consolidate the information in this thread.
Here is a very interesting dyno chart from Dool that shows that up to 30 REAL HP (not BHP) are possible with various add-ons to the 477 upgrade: (for a bigger version right-click and open in new tab)
(Lately he went up to 31 REAL HP (on the wheel) by using the TEC camshaft - and that value may be top of the line for a 477)
 

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sam2019

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CARBY VS EFI

Our 3 carby 477 mods show a strong increase in power that lead an old hand (40 years RE tech) to call it a "rocket". So is there a difference if you use the 477 on carby vs. EFI? All the nice dyno charts we have exclusively for EFI.

Well, there is. If you go up where the air is thin (well above 2000m) you will have to change the jets or else you will loose a LOT of power due to a too rich mix. (in Ladakh way too rich, black sod coming out of the exhaust).

The EFI with its O2 sensor is better in that landscape and if you use a Powertronic you can easily switch mapping optimized for low or high elevation.

Other than that carby has the same power, it is a lot cheaper because a jet costs 10 bucks, a PT 300 AU$.
 

sam2019

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5. August 2021, 5:33
I am still getting questions regarding the dyno results that quote the Hima with stock 24.5 hp.
It seems clarification of the admittedly confusing use of the term Horse Power is in order:
If we use the term HP or hp on this forum we always talk about measurements at the rear wheel, some use the term RWHP for that reason but mostly only HP is used.
The RE factory on the other hand measures their horse powers at the naked crankshaft which is of course more than what reaches the wheel - with the gears and chains in between eating into the power that finaly reaches the rubber on the road. This is called brake horse power or BHP for short.
Baseline for the Hima is 24.5 BHP (as of the manual) whereas measured at the wheel are 20.5 HP only.
So if we state an otherwise unmodified 477 has 27 HP it is 6.5 more than the stock Hima. This can be further enhanced by carving out the head adding bigger valves or a modified camshaft that allows for better fuel flow. In both cases up to 30 and 31 HP respectively have been reached.
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sam2019

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Quote from Dool on 5. August 2021, 5:56
So my 31RWHP would equate to around 35BHP.
Manufacturers could do a Dyno run like I did, but why would they? , They get better Numbers than me!
Brake Horse Power always looks better to the uninitiated, people are like that! To say the Manufacturers are not telling the Truth would just be stating Fact.
not necessarily. 31RWHP are more like 36 or 37 BHP. the conversion also depends abviously on what is between a crank and the road. a shaft driven bike has more loss, nobby tyres more than slick etc.
 

sam2019

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Does the Carby tie in with the TPS or does that require changing ?

I have never touched the TPS. Maybe I just got lucky.
(TPS=Throttle position sensor)
 
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