CBR400RR 1991. Possible?

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CBR400RR 1991. Possible?

Post by PARUS » Tue Jun 15, 2010 1:29 pm


Please, advise how to fit camshaft position sensor ? Really, there is only one question for now
I going to use
MS v2
GSR400 Throttle bodies + TPS + fuel jets
GSR400 Fuel pump
GSR400 air sensor
Car lamda sensor
Stock temperasture + stock cam sensor.

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Re: CBR400RR 1991. Possible?

Post by Tiberius » Tue Oct 25, 2011 2:20 am

I want to convert a Honda CB-1 with Microsquirt3, thats the same engine as in your CBR400RR. I'm very interested in your progress.
Do the GSR400 throttle bodies have the correct spacing for our engine?

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Re: CBR400RR 1991. Possible?

Post by EWflyer » Tue Oct 25, 2011 6:45 am

This might help:

He posted a picture with measurements of the GSR400 throttlebody over on the MSextra forum well over a year ago now. Don't know if he's made any progress since then: http://www.msextra.com/forums/viewtopic ... us#p255757

I don't know what Parus is up to lately, I can't remember reading any posts from him recently.

Also, If you look just a little further down the MSruns webpage you'll see what Tubular did to his GSF400 Bandit: viewtopic.php?f=93&t=23094 An interesting approach, using the "secondary" injector rail from a Honda CBR600RR which uses a Dual Stage Fuel Injection system (the CBR600RR has 8 injectors total, the secondary rail is housed in the bike's airbox). Apparently the injectors on the CBR600RR's secondary rail are the perfect size for a 400cc 4-cylinder bike.

We haven't heard from Tubular in a while. He lives in Athens, Greece which makes me worry for him. Greece seems like the place that history will note as "where the world first began to come apart"

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Re: CBR400RR 1991. Possible?

Post by tubular » Tue Oct 25, 2011 12:12 pm

EWflyer wrote:We haven't heard from Tubular in a while. He lives in Athens, Greece which makes me worry for him. Greece seems like the place that history will note as "where the world first began to come apart"
this is tubular speaking, I don't know about the rest of the world but things are coming apart here...
except that I am doing fine!

I do not have the slightest clue about CB engine intake spacing and whether the GSR400 TB will fit but, regarding CBR600RR injectors, both primary and secondary are rated somewhere at 175cc/min @ 3 bar. According to documentation these are a bit oversized for a 400 I4 engine (meaning 100cc each cylinder). Big injectors are said to cause issues in idling. Except injector size, also other injector characteristics (like spray angle and spray pattern) and injector positioning (how far from intake) and injector angle (maybe not so important depending from the throttle body) will affect engine behaviour. In fact I think that injector spray pattern and angle will affect more than injector flow rate, always speaking within reasonable limits. Don't expect a 50cc engine to run decently on a 330cc injector no matter what.

For example, in my case the GSF400 would require injectors of about 100cc/min. The CBR600RR injectors I used are rated at 175cc/min. Almost double the flow needed. However these injectors have 12 holes and spray fuel in a big cone. So flow rate may be big but fuel comes out in a fine mist instead of huge droplets which are not easy to atomize. Furthermore, injectors are placed upstream of the TB butterfly and this gives the fuel a good long path to mix with incoming air and atomize more efficiently before entering the combustion chamber. At least this is what my theory says. As a matter of fact I am about to move the injectors downstream from the TB butterfly and see what will happen.

Hope this helped a bit!

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