race nc29 still not revving above 7000rpm help

[rigsby]

hi there,

i have posted the same question about this damn bike before. Basically this bike was once in road trim and always reliable, and went well on trackdays. Me and me mate decided to get race liscence's and do a few races with the wirral. So the job was on to race prep his bike, one last track day was done before strip and the bike went fine. All unwanted parts were ditched lights alternator etc, a dynojet kit was fitted with filter and rear muffler. The first race was up and due to no pre testing it was firedup and wheeled onto the grid. With red lights out it trundelled of the line at a snails pace, it refused to rev out and not budging above 7000rpm, first wasted entry fee. Much messing was done new plugs, caps+leads took the dyno kit off and thoroughly cleaned carbs. Again with no real road test and still spluttering we went to oulton where it cut out just before practice and all was dead no lights on dash and with no time to fix it was yet another wasted entry fee(bloody dodgy battery wire). We are slowly loosing patience and although it now runs fine low down the rev range it still refuses to rev out even when stationary and reved in neutral. We have tried the obvious fixes but without any real success. We now think it must be electrical we have replaced the cdi and still no change. Because the loom has been butchered we think we may have disturbed the speed limiting circuit and engaged the speed limiter. Is this possible, if the cdi is thinking the bike is doing 50mph+ or wat ever the limit is could this cause the misfier when the bike is actualy stationary and been reved in neutral. If anyone can shed light on this limiting device and how it works so we can check and be sure it is not affecting the running of this soddin bike. Or any other electrical gremlins that can cause these symptoms.


cheers rigs

[CMSMJ1]

can you get a speedo and fit that - sounds like the limp home mode to me.

it is an easy enough fix - see the thread by chrisja2 and his wiring loom - check where you need to put the resistor to fool the CDI and you are rockin.

Also, a thread with pictures by LP showing the deal.. in the CBR section about speed restrictons

good luck!

[rigsby]

cheers mate,

just found link, gives us some thing to work on. Let you no how we get on.

rigs

[Cammo]

If anyone can shed light on this limiting device and how it works so we can check and be sure it is not affecting the running of this soddin bike. Or any other electrical gremlins that can cause these symptoms.

Yeah mate, when you remove the speedo electrical connection at the back it cuts spark to a couple of cylinders over 5000 rpm.

You can get around it by doing the resistor mod or buying a plug in derestrictor.

[greggo]

Or wiring the blue/orange wire from the CDI direct to the +ve battery terminal.

[leopard_pagan]

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0314992484" onclick="window.open(this.href);return false;
it also explains how the limiter works.

[matt69]

Or just bridging the two wires where you removed the speedo at the loom with a piece of 1mm thick wire and a bit of tape. Mine's run for 3 years now like that.

Matt