The International CBX Owners Association

Hi Guys
I have still got problems with CBX, story so far, Stripped the top end, honed, new rings, lapped valves, overhauled carbies, adjusted valve clearance - engine started idles OK but part throttle response is lousy, just wont pull, feels lean compression 90 psi - Stripped top end again, another set of good quality rings this time, wet tested valves, perfect, replaced long timing chain, checked valve clearance - remove idle jets and clean carbies again, started engine again idles good, same part throttle issue - Checked valve opening with a degree wheel at 1mm lift, exhaust and inlet cams are 5 degrees late i.e. exhaust should open 35 degrees BBDC but opens at 30 inlet 5 BTDC but opens at TDC, if I advance 1 tooth then opens 10 advanced ( not sure if 5 deg is enough to cause this problem) compression is 90 psi - If I put a vacuum gauge on a carby the needle moves rapidly between 0 and 20 inches, so fast that you can barely see the needle. My current plan is to ride the bike in hope that the problem is just the rings need to bed in - If it does not fix it then I will sell it and cut my loses, I see a spot in my garage for a VFR-1200 Lol.

I know you used a timing wheel. Have you tried the simple alternate method? Bottom of page 3-5 in the shop manual. Also does the spark advancer operate freely? You should be able to turn it by hand and spring back freely. There is allways a solution to everything and I hope it is a easy one for you. You have all ready paid your dues. Good luck

Some previous owner may have changed the cams. Different years had different timing. The 5° was exactly the difference. Take the cams out and check the rise on the lobes to make sure.

EMS wrote:Some previous owner may have changed the cams. Different years had different timing. The 5° was exactly the difference. Take the cams out and check the rise on the lobes to make sure.

Ooooh, good one.

Have checked the advancer and checked the timing with a light, all good, fired the engine last night again, once warmed up it idles perfectly and throttle response is very crisp without load, this weekend I will take it for a ride of at least 200 km and see what happens.

Very nice looking CBX Stevo, I sure do like a nekkid Prolink, very tasty. Hope it enjoys the 200 km run as much as you will.

Cheers....Tony

Update - the bike is running fine now it just needed a couple of good runs, it is a real pig when cold but once it warms up runs fine, I don't know how many miles the bike had done but there was no sign of any wear in the bores, assuming they are very hard, maybe it took a while for the rings to bed in? All good now.

GREAT!!!!

Great news!