Fractious Fettling (GPz900R Project)

[Petertp]

Folks

Greetings

I've just recently joined .... seperate introduce myself eMail done

Bought an old GPz900R (C-Reg) phew, 6 years ago), cleaned the usual stuff/fluids/pertol carbs out then), and it sits in the garage/shed at the moment

Last year I rolled the sleeves up to try and get it going, but it's in the huff ..... Any suggestions folks ? Do I tap someone local on the shoulder ? Is there a garage in West Cornwall that could oblige without stipping my already bare pocket ? Read on ........

Background : I've stripped the carbs a few times, and set up the carbs last year (with pointers from a GPz900 owners forum). Fitted new rubber tip valves to the carbs, float height set using digital calipers, diagphrams are okay - no pin holes, cleaned using areosol carb cleaner and soaked the jets in some nasty degreasing chemical from a former place of work, all turns set to what they should be. Didn't tinker with the needle heights or jets, but settings matched the info on the Gpz site and checked with Haynes. New fuel, New Air Filter (freshly oiled too). New carb rubbers (carb/air box ones), New Plugs. Tappet cleanances set and checked. Compression on the low end of "fair"

Current Situation : Bike would only start with air filter out and easy start squirted in and when it started it took bit for the engine revs to "settle down". Getting a decent (slow) idle speed is near impossible . Seems to fluctuate of it's own accord. GPz site suggested air getting in between carb/head rubbers - recommended trying spraying WD40 at them when running to see if engine speed increased to indicate a suck leak of the WD40 onto the chamber...but no reaction from the bike when I scooshed

Tried to balance the cards too using borrowed guages (the tube type (not round guages)). Lots of flutter on the tube guage and the little 'stent' type nylon tubes inside the rubber tubes to act as buffers seems to make no difference (in our out) to the fluctuations, so tried leaning the guages over backwards (top away from me) which helped, but trying to balance the carbs seemed to end up in pissing off the idle speed which got higher, then I used the idle screw to bring it back, tried then to carry on balancing things, then I just got frustrated going round and round

Should I buy/borrow round gauges and see if these are any easier ?

Should I take the carbs back out and re-clean / check settings ? (Carbs were drained before the bike was last parked up and garaged, albeit the bike has never seen many miles from me at all....more time laid up .... No real "gum" in the carbs to talk of, they look pretty clean

I also got a loaner pair of ignition coils just in case, no difference, elec cons healthy and correct, all the plug leads are new lead and caps and are all on the right way (checked and treble checked)

I'm not sure if I hand the bike over to someone, any recommendations ?? and ask them to have a go ?

Compression was poor, but I'm not searching out top performance ..... Perhaps the value guide seals are knackered ? Mmmmm....I've not had the engine sripped beyond having the rocker over off

I was going to try the compression check with some oil in the cylinder (measure it before and after) to see if it makes a difference ....... Or I split the head and check the value condition / vale seal condition .... Mmmmmmm. Trouble is the boss i(Mrs Petertp) is looking for DIY on the house to progress as her sister is coming for Easter

I'm just looking to get the bike rideable for the odd sunday ride out, but have a tight budget and don't want to throw good money after bad .... plus the bike's not worth spending too much money on it

What do you reckon.....any suggestions ? Other than burn it ?

[Mel64]

Cut your losses and sell to me for a couple of hundred quid

[Captinblood]

Borrow a spare set of carbs from somebody,!!

[badgerKDD]

I found balancing carbs a bit difficult to get them to balance out, it took a few hours one evening but with perserverence it finally 'clicked' and worked out. If the carbs are cleaned and set up then maybe you are looking at valve seals?

If you haven't done the compression test with oil, then I would suggest thats also a way to go. It will give a fair idea of whether its down to rings and pistons or valve seals. If you want to get the valve seats done proffesionally I can reccommend a good engine specialist in the area, who i'm told will charge a reasonable rate ( around £40 -£50). I will have to get the name of the guy because I don't have it to hand and only know of valve work on car heads but its all much the same so he should be able to do it.

I am happy to come up and have a look when I'm not busy, I'm no pro but I've worked on my own bike for a good few years now, so I might be able to shed a bit of light on your problems? I don't know if I'll be popular with your other half though, I might be accused of keeping you away from your home DIY! ;)

As for local bike mechanics, Anton Pariss,Suzuki specialist, Camborne is good or you can try Spike up at Chiverton Cross. They won't be cheap, but thats a given really.

[dan90210]

You may have totally unbalanced the carbs now. Apart from that it seems you are on the right path to be honest.

If it runs with easi-start then timing and spark should be okay.

I'd balance the carbs then go from there.

When balancing a bank of 4 carbs you really do need a steady needle on the gauge. The hoses to each gauge must be almost clamped tight, there should be a screw arrangement in the kit. Set a fast idle before you start. Idle will fluctuate, finish the balance then reset the idle. Balance carbs 1 to 2, then 3 to 4, then 1+2 to 3+4.

Here, check this out..

http://www.youtube.com/watch?v=Hr6_Qu348is" onclick="window.open(this.href);return false;