hopefully nobody is annoyed at my constant posting in here - but I fint it helos to have everything written down somewhere for reference.

Got stuck into the clearances today. Most of them were fine, one exhaust on cylinder #1 was out, and on the intake side, both intakes on cyl #4, and one on cyl #3 were out. Cyl #4 were extremely tight - enough that when the engine is warm, the vale would damn near be open the whole time.

So that explains much of the issues we were having with our vacuum sync - #3 and #4 were sucking a whole lot more than 1 or 2, and was the main issue in us not getting anything to sync.

We also had a chance to check the plugs, - the new ones that has just been installed a few days ago - #1 - #3 were rich, and number #4 was lean, all very much so. Which again supports y theory if whats been going on.

Since today is a public holiday, nothing is open, so i will go to the bike shop tomorrow, and get some shims to sort out the wayward clearances i have, and I think I might grab a small selection of main jets as well.

My plan for tomorrow is get new shims, and jets. finish the clearances and reassemble, and recheck to make sure everything is right.

Install stock main jets in the carbs (have already bench sync'd them)

reassemble everything, including the air filter, and try a vacuum sync.

Then whip it round the block a few times to see how it goes.

Fingers crossed this is more or less the end of the saga!

 

Nothing wrong at all with the posts.
Keep us up to date on how things go.

 

Well, this bike is quickly turning into a ****ing nightmare.

Got all the shims and jets I needed today.
Finished the valve clearances, and got them all within spec.

Replaced the jets in the carb with stock sizes, reassembled the bike, got it fired up and it idled, but it hissed and spat, and missed something horrendous.

Still couldnt get carbs to sync.

Took a backwards step, and put the larger jest back in, ran a little better, but not by much.

tried running with and without air filter.

Im getting ready to give up and sell the ****ing thing.

 

Hi Tim, have you got ,or can you borrow a known good NC23 cdi to swap over and test , if the previous owner could let you know whats been done to the bike that could be a place to start.

 

Are you positive you don't have an air leak somewhere?

 

I could hunt for one, but Id have to buy it i think.
Previous owner bought it to do a street race, then realised you need a race licence, and previous race experience to do street races, none of which he had, so he only had it a short while, and never actually rode it.
So, short answer, not really. Ive been in contact with him asking for details of who he bought it off, he's looking to see if he still has that info anywhere, but im not holding my breath.

absolutely. Have emptied most of a can of spray into the various areas of the bike when running to see if there is the telltale rpm increase - definitely no leaks.

Its running slightly better this morning, but I have a mate coming over tonight to help out - I find when I get frustrated with something, sometimes you have one of those 'can't see the woods for the trees' moments, so hoping a fresh set of eyes, and a pair of hands that aren't frustrated enough to take a hammer to the bike might be more helpful than what I've done so far.

I think its probably still running better now than it was when I got it, but not well enough to race.

 

OK.

So more fiddling. Its running better now, but Im pedantic with these things and I want it perfect.

Ive tested the resistance as per the manual on the coils, and they are within range, so that rules that out as a contributor to any issues.

It does seem to run much better after its warmed up a bit, but still not perfectly. I think at this stage I need to go to a track and run it flat out for a while and see how it goes, bit hard testing a racebike out around home. cold, slick tyres on our roads arent ideal, and last nights brief test ride around the block resulted in an unexpected powerslide courtesy of cold slicks . . .

The thing I am finding now is that cylinder 1-3 are rich, and cyl 4 is lean.
Im going to clean the plugs before a hard session at the track and check them after.

 

Hi Tim , did you put the nc23 jets back in

 

CaBaRet, its back on the ones it came with - 138's.

I have however, been doing some sleuthing, and today discovered the owner who owned the bike before the guy I got it from.

I am hopefull that this will result in getting some more info about the bike, to confirm what else its had done to it previously. For all I know its got a thinner headgasket, port work, or bigger pistons in it, IF someone went to the effort of removing stuff to turn it into a total loss machne, who knows what other efforts they went to to get some extra gains.

Im currently doing up a spreadsheet on all the race meetings that are coming up near me, so I can get to the track and try this thing out.

Hopefully armed with a bit more info on it than I currently have!