Compression test part 2 - results not good!

[The Novice]

wouldnt you just adjust the same screws you adjust if your balancing it with a vacum gauge?....

[oldgreyandslow]

wouldnt you just adjust the same screws you adjust if your balancing it with a vacum gauge?....

No doubt, but I'm here at work and my Haynes is in the garage, I'm trying to get a head start! Also being bloody lazy You can never have too much information.

[viper61]

Is that drill bit method done by putting the bit between the inlet body and the butterfly of the carb? So that they are all set the same? That'll get you close I suppose but each cylinder will still run slightly differently, especially if you have 8bar compression on 3 cylinders and 7.5bar on one.

Each cylinder will always run slightly differently (very slight) from the next, hence the reason to sync the carbs so that they are all sucking equal amounts of air/fuel in.

Just my thoughts.

edit: for info on balancing best to download the Workshop manual pdf from the main site, under the document library section. It's 8mb but has all the info you need for working on your bike in there. It's a god send if you ask me! :-)

[oldgreyandslow]

Is that drill bit method done by putting the bit between the inlet body and the butterfly of the carb? So that they are all set the same? That'll get you close I suppose but each cylinder will still run slightly differently, especially if you have 8bar compression on 3 cylinders and 7.5bar on one.

Each cylinder will always run slightly differently (very slight) from the next, hence the reason to sync the carbs so that they are all sucking equal amounts of air/fuel in.

Just my thoughts.

edit: for info on balancing best to download the Workshop manual pdf from the main site, under the document library section. It's 8mb but has all the info you need for working on your bike in there. It's a god send if you ask me! :-)

They're all pretty much 8 bar cold, the 7.5 bar was the one I was concerned about with the washer being knackered hence trying with no washer and getting 8 bar (well one was about 7.9). I do take your point regarding different compressions making a difference though.

I've got the NC30 manual downloaded on the PC at home, between that and Haynes I guess you can probably find everything you need, understanding it however is slightly different!

[viper61]

Haha yeah true, haynes and user manual has pretty much everything, then the forum can fill the gaps. Although 9 times out of 10 there's usually more reliable and real world information on the forum :-).

If you get stuck mate just shout on here and someone will help. If you get really stuck I do have a carbtune if you need to borrow it, although I am in the process of doing my valve clearances and will be balancing mine any day (week / month) now! Hopefully.

[oldgreyandslow]

Haha yeah true, haynes and user manual has pretty much everything, then the forum can fill the gaps. Although 9 times out of 10 there's usually more reliable and real world information on the forum :-).

If you get stuck mate just shout on here and someone will help. If you get really stuck I do have a carbtune if you need to borrow it, although I am in the process of doing my valve clearances and will be balancing mine any day (week / month) now! Hopefully.

Cheers, appreciate the offer, I'm going to try the drill bit method, get the thing running as best it can, enjoy it and then wait for the winter months to get it spot on, no doubt spending far too much money on things I can't afford!

[VFR400+]

Did you ever sort out the smoking? Mine is smoking like a trooper. Going to get it dyno tested tomorrow to see if/how far out the fueling is.

[oldgreyandslow]

Did you ever sort out the smoking? Mine is smoking like a trooper. Going to get it dyno tested tomorrow to see if/how far out the fueling is.

Yep, it was just in need of a damn good run to clear the condenstaion out. If it stands for a few days it smokes on start up, after a good warm up and a reasonable run it seems to be fine. I think it was just a case of it being stood for a relatively long time. The carbs were also pretty mucky