Z650 restoration

[kz900B1]

Well Done Nice looking job CB and Ralph.Another Z re invented

[mothra]

Thats awesome. I was just wondering the other day what a 650 in black and silver would look like (Thinking about a second paintset) - now I know, and it looks great, but I need to come upwith something original now!

[Big John]

Well done Ralph and congratulations CB, thats a real nice Z650.

[stephen parr]

That's lovely Ralph/CB. Would like to get one of those for karen, but she thinks it may be a bit high for her . Would like to see it at the rally but don't think I'll be able to get the Saturday off.

[CB]

That's lovely Ralph/CB. Would like to get one of those for karen, but she thinks it may be a bit high for her . Would like to see it at the rally but don't think I'll be able to get the Saturday off.

Thanks for the kind comments from all of you. Stephen - you could always pull a sickie and then you can come to the rally and Karen can try out the bike

[RALPHARAMA]

Those of you at the SW rally this year will remember that CB's 650 was pretty enough, but a tad unwell.

Yesterday was the first chance I have had to look at it and it wasn't good I had accepted that it would need a set of guides and we had resigned ourselves to that. When I dragged the barrels off and de-ringed the pistons I realised I could get Gordon Brown's head between the pistons and the barrel

There was evidence that the head had been removed not many miles ago and the valve stem seals looked pretty fresh. The rings also seemed pretty springy which I suspect was a previous owners attempt to sort the engine with minimal expense. This did partially mask the under lying cancer for a short time.

The pistons are first oversize, but the only pistons I can seem to be able source for this bike are Wiseco 700cc big bore. I am reluctant to fit a big bore kit as it raises the compression ratio which will doubtless cause pinking as it does on the Old Gurl despite retarding the timing and running soooper doooper fuel.

Naturally the guides were proper shagged, but Z-Power do a set for £90 and they won't cost a mint to get fitted.

CB's a bit down in the dumps about her Zed as all she seems to do is spend money on it

[Ginger Bear]

Ralph,
Might be more cost effective to source another set of barrels & re-bore 'em to suit your pistons, or failing that have 'em re-sleeved.
Tell CB not to get too down about it......... Hopefully we'll see it at the Ace in April.

[chrisu]

Those of you at the SW rally this year will remember that CB's 650 was pretty enough, but a tad unwell.

Yesterday was the first chance I have had to look at it and it wasn't good I had accepted that it would need a set of guides and we had resigned ourselves to that. When I dragged the barrels off and de-ringed the pistons I realised I could get Gordon Brown's head between the pistons and the barrel

There was evidence that the head had been removed not many miles ago and the valve stem seals looked pretty fresh. The rings also seemed pretty springy which I suspect was a previous owners attempt to sort the engine with minimal expense. This did partially mask the under lying cancer for a short time.

The pistons are first oversize, but the only pistons I can seem to be able source for this bike are Wiseco 700cc big bore. I am reluctant to fit a big bore kit as it raises the compression ratio which will doubtless cause pinking as it does on the Old Gurl despite retarding the timing and running soooper doooper fuel.

Naturally the guides were proper shagged, but Z-Power do a set for £90 and they won't cost a mint to get fitted.

CB's a bit down in the dumps about her Zed as all she seems to do is spend money on it

Ralph,

Why are you so certain it'll pink with a big bore kit. The 1075 Wiseco kit I put in my Z1R was much higher compression than standard but certainly did NOT pink.

you may however know something specific about Z650s that I don't..

[RALPHARAMA]

Hi Chris

The Old Gurl pinks despite my best efforts with retarding the ignition and running higher octane fuel. It only tends to happen at lower revs under load. Jak has always had the same problems with high comp pistons. I have even put the Old gurl on a dyno to ensure good carburation. I have tried everything I can think of short of putting a shim gasket under the barrels to lower the compression. I think my kit is 1045 or there abouts. It was only fitted by a previous owner as Wiseco pistons tend to be cheaper and more readily available that genuine oversize standard pistons.

Seems that that Zedrider may have a set of pistons and barrels for us - fingers are firmly crossed

[kev edwards]

Hi CB & Ralph,my brother has a standard set of barrels with one small break on a fin,and stainless inserts in the front and back 6mm bolt holes ,in a previous life they had been tapped to 8mm,but i had the inserts kicking around and put them in,and they are in line,he also has a pair of crankcases with very little damage all the threads have been cleaned,no broken bolts,i even removed the studs and chased the threads and gave the studs a little clean.If you are interested send me your email and i will send you pics.cases are kickstart ones.
He won'want a kings ransom for them.

Regards Kev.

[mick znone]

i like that, cracking looking machine, well done

[irhobotolo]

Thats a great story. Keep the faith with the bike. The engines are easy to work on and straightforward and when the top ends sorted it should give many more years of trouble free use.
The comments earlier on about 650 engines not being as bulletproof as the 900/1000 engine are a new one to me ! The engine in your bike is the same one as in my 650 and is very over engineered. Its only making about 60 bhp and as long as oil is changed regularly and its not thrashed from cold it should last forever. The same basic engine was used in the 750 turbo making 100bhp.
Good luck with sorting it and it seems that you may be suffering from a previous owners neglect or bodging which is unfortunate but at least you will know its right when its sorted.

[RALPHARAMA]

Trouble with the 650's is that they were bought by the folk who really wanted a thou but couldn't afford one and in fairness couldn't afford to maintain 'em either, but desperately tried to keep up with their more well healed mates

Rode up to see Zedrider today who furnished me with a set of low mileage +20thou (+0.5mm) hepolite pistons and plenty of tea.

I sent CB back to her house to collect the barrels from her first engine and whilst they were knackered they had never been bored so I'll get them bored to fit Ian's pistons. I'll order a set of valve guides from Z-Power on Monday and hopefully we'll have the 650 mill turning soon Many thanks Ian

[RALPHARAMA]

The saga continues

Got the barrels bored. Had the valve guides replaced, only to find one of the bloody valves was bent! Not the end of the world as I had spares in the other head

Rebuilt the engine and fired her up. Got the Dyna S spot on with the timing light and guess what ... she's missing like a b*****d on no 1. It's at low revs/throttle opening and does start to fire with more throttle but with a freshly rebuilt engine I don't want to be revving it too much - still very tight. I have tried everything. In desperation I have even cleaned up another carb and exchanged the no 1 carb. Tried changing coils, plugs, carb slides, pilot jets, but nothing really works. I did a dynamic vacuum test which isn't a million miles out but there is a vague suggestion that there might be an issue with the inlet stub, so I guess that's the next to try I spose. And yes I have checked the fuel level in the float bowl. Put the colour tune on it and it's sparking away like a good'un - nice and blue - only with increasing the throttle do we get any sign of burn which is then an on and off yellow flame. Compression is OK.

I'll have another go at it later