Did you get these? I'd be interested to find out your results.

 

Is there really any reason to get a jet "kit" rather than just getting larger jets and shimming up the needle with washers? I jetted my suzuki GS 500 this way and had good results, while otheres who bought a kit had some problems.

 

The very first dyno run showed a huge lean out on acceleration so I had to rejet to get fuel.
These runs were on a dynojet dyno. as you can see i got a max of 70 rwhp after the exhaust and intakes were changed over. the last dyno run has nice smooth acceleration, good a/f mix and 100 rwhp.
I thought the figures in the w/shop manual are taken at the engine? I was taught that the "general" power loss from engine to rear wheel is approximatly 15 to 20 %.
It may be different on bikes as I work on trucks and we use this % as an average as a benchmark when we dyno engines. My workshop has the facilities to dyno a truck motor alone and we use another company to dyno it again when its fitted to the truck.

[IMG]local://upfiles/10571/967EA469FDFC432E9B5C8C976DDF0FD8.jpg[/IMG]

 

Yes it definitely looks lean on that graph.

The Hurricane should deliver 135 hp on the crank, i.e. about 115 rwhp in stock condition. The transmission loss on a motorcycle is more like 12 to 14 percent. The chain is effective compared to cars U-joints and rear axis differential gear.

The 70 rwhp reading, and also a little low 100 rwhp reading, could depend in a lot of things. It could be a dyno calibration issue, something wrong with the engine etc. The main jets are large already stock, and the adding of a 4-2-1 system and K/N filter only requires the main jets to increase a few numbers like to #125 jets maximum. Could there be something wrong with the A/F measuring equipment? Is there a PAIR function in the CBR 1000 F that adds fresh air to the exhaust ports, so the A/F measurement will indicate a leaner A/F ratio than it really is in the combustion chambers? I can't say right now what the reason is, but the power is far to low for the 145 jets. Other causes could be some trouble with the fuel delivery liked clogged carbs or a to low float level in carbs, which is masked to some extent by installing huge jets.

A Honda Blackbird has 142 jets on the outside and 145 jets on the mid carbs to produce 140 rwhp by Keihin carbs, as the Hurricane have.

The stock air box will provide more midrange power and a better throttle response than K/N pods that are known to cause a lean condition on engines with vacuum carbs. The airflow might be great, but the vacuum system in the carbs is designed to operate with an air box to get the correct fuel supply over the rpm range.

 

Took me ages to work that out! the reason i went with larger jets instead of the dynojet kit is causemany people told me of the problem with slides fluttering with the dynojet springs. I left the originals in, maybe thats a problem?Ive got good throttle response through the range now. there's no PAIR function on the bike, maybe a problem with the test gas pickup?
I know i have a problem with cam chain and tensioner but didnt think that would be so much of a problem as far as dynoing it. As for the hp reading, the compression isnt perfect and it uses a little oil so i guess, with out a motor strip, it could use a freshen up. for some reason i cant explain, i couldnt get a good a/f mix until i went to 145 jets. never really thought i had a problem but now youve got me thinking.

 

In case you have time and interest you could re-install the stock air box and jetting and compare the performance by the butt-dyno. My guess is that the bike will run better than with the K/N-pods and #145 jets, but I can very well be wrong and it would be interesting to learn more.

 

Nah, I cant go back to the stock airbox because of the SSSA mod. Thats how i got into the drama in the first place. Having said that, i havent quite finished the mods but am well happy with it so far.

[IMG]local://upfiles/10571/50B06C283AAA4BF893E9C9C2E8B0B752.jpg[/IMG]

 

a side view of my bike as it was a few weeks ago. I have since put a sealed GEL battery under the seat so the box behind the shock is no longer there.

 

That back wheel looks a bit deadly - (Cool..)