Time to get the K2 out of the naughty corner

[park3164]

Hi Joe,
The CM atomisers cost me $9 US plus postage - I'd suggest get them if he still has them and see how they go before you do more hair pulling out?. I found Herdan's phone number on my original manual - USA 610-562 3155.
Cheers,
Fiona

[penman]

Thanks for that Fiona, I'll follow it up.

I am now pretty well convinced that the corrosion in the central tube of the carburetter body is the root cause of my problem. If I put all my jets and atomiser into George's carbs, the bike runs really well, just a very minor and liveable-with flat spot, which might well be cured by changing to a CM atomiser. A bit of research has given me two options:

1. A pair of 1973 VHBZ 25 BS carbs from Paddy Ducatti for £185 plus post. These are cleaned and serviced, but of course they are over 40 years old and may not be perfect. These should work fine if they have no faults - and they'd be dead easy to fit.

2. A pair of brand new Mikuni VM26 carbs from Motocarb, £117 each including a selection of jets for fine tuning. There would be some hassle involved in fitting these, but they are new and should work.

Any views? What would you folks go for?

I have not managed to track down any "HS" type Dellortos and so far, just the one set of the earlier "BS" carbs.

Regards,

Joe.

[MickeyMoto]

Get the soldering iron out and design a fuel injection system?

[AntietamClassicCycle]

NLM doesn't have any good used VHBs?

If I were "in your shoes", replacement Dellortos would be at the top of my shopping list. PHBH 26s are £89.25:
http://www.dellorto.co.uk/shop/dellorto ... phbh-26bs/

FWIW: my '86 K2 had PHBH 28s from the factory.

[penman]

NLM doesn't have any good used VHBs?

If I were "in your shoes", replacement Dellortos would be at the top of my shopping list. PHBH 26s are £89.25:
http://www.dellorto.co.uk/shop/dellorto ... phbh-26bs/

FWIW: my '86 K2 had PHBH 28s from the factory.

Thanks for this information. I didn't speak to NLM today, closed on Mondays, and I couldn't make sense of their spares list, but you're right, I'll try them tomorrow.

I am showing my ignorance of Dellorto here, so please bear with me. Is the PHBH a replacement for the VHBZ? It looks similar, but I couldn't find a dimensioned diagram on the Eurocarb website. The attraction of the Mikuni is that it is very similar in size, except for the diameter of the intake side - but really, that's the only attraction and I'm not generally a Mikuni fan. It looks a bit as if the PHBH has the same issue. The inlet side is threaded 42mm but the inlet stub on the VHBZ is 38mm, so again, a bit of adaptation would be necessary. At about £107 inc VAT, the PHBH is a bit cheaper than the Mik.

You say your 1986 K2 was fitted with PHBH 28 carbs, do you have a photo of how it mounts? Mine look like this:


If you have the same airbox, the rubber adaptors must be available and you may be able to tell me the jetting.

Once again, thanks for the information!

Joe.

[72degrees]

PHBH 28s are often used on 'tuned' 350s (I have a pair on mine) As you are aware, there are different versions. For a start you need a 4T version. Then you probably want the type that are :
42mm Plain air intake connection.
36mm rubber sleeve type engine connection.

I assume the K2 uses the same screw in steel intake stubs in to the head and rubber elbows as the other late 350s. I had a K2 but never fiddled with it much. Didn't realise they came with PHBH28s as standard but they should fit and work with the connections to the air box OK.

The downside is that in the experience of some (including me) they can be tricky to tune on the earlier 350s as they are really too great a diameter for sweet running throughout the range. Having said that, mine also has an L5 cam, pod filters and 2:1 exhaust so too many variables to blame the 28s alone.

I must get round to ordering a new pair for the 'project'.

[penman]

I found the following table among the many things I've downloaded from the web:



It does show PHBH 26 and 28 carburetters used in the 1980s, but only on 500 models. It shows VHBZ 25 HS carbs used on all 350 models up to 1988, and on the 400 Dart. The 1986 K2 with PHBH 28 carbs sounds like a bit of an oddity - perhaps there was a shortage of the VHBZs, or perhaps Morini made some late changes to this model before discontinuing it. I would be interested to know what the jets, needles, atomiser and so on are.

The PHBH 26 still looks interesting, though the scary price of Dellorto parts is a bit off-putting if it takes a bit of experimenting to get the jetting right.

I'll give all this a bit more thought and I'll give NLM a call tomorrow and see what they've got.

Regards,

Joe.

[72degrees]

It does show PHBH 26 and 28 carburetters used in the 1980s, but only on 500 models. It shows VHBZ 25 HS carbs used on all 350 models up to 1988, and on the 400 Dart. The 1986 K2 with PHBH 28 carbs sounds like a bit of an oddity - perhaps there was a shortage of the VHBZs, or perhaps Morini made some late changes to this model before discontinuing it. I would be interested to know what the jets, needles, atomiser and so on are.

The PHBH 26 still looks interesting, though the scary price of Dellorto parts is a bit off-putting if it takes a bit of experimenting to get the jetting right.

That was a USA market 1986 K2 I think? Perhaps that's why it had PHBH28s - though I'd think big carbs wouldn't fit the usual US emissions mods reasons.

Ha! You should try getting the jetting right on a KTM 2T MX bike if it has been tweaked a bit, though to be fair Keihin stuff is much cheaper. If it wasn't for keeping the project Forgotten Era eligible I might try to graft some Kehin flat slides on to it.

[penman]

"That was a USA market 1986 K2 I think? Perhaps that's why it had PHBH28s - though I'd think big carbs wouldn't fit the usual US emissions mods reasons."

Mine is a 1985 US model K2 and Fiona's is a 1986 US model - both of these were fitted with the VHBZ 25 HS carbs, so I don't think the PHBH 28 was common on the K2 in any market. I agree with you on the emissions front. All the engine breathers are taken into the airbox via a separate collector box and the jetting is generally leaner. I am told the cam is different as well, though I haven't seen that confirmed.

When I fitted George's carbs the other day, I had a taste of the bike working properly for the first time and despite a few distractions towards PHBH and Mikunis today, I think the line of least resistance will be to find a decent pair of VHBZs - either the BS or ideally the HS variants, either will do though. I know they fit and I know they work! If I can also track down a pair of CM atomisers, that should put the icing on the cake. (Hopefully!) I shall phone NLM tomorrow with fingers crossed and if that doesn't work, I'll probably order the carbs from "Paddy Ducatti".

Regards,

Joe.

[Steve Brown]

I'd agree the Dellorto option will be less problematic. I did fit a pair of Mikunis to my 350 a couple of years ago when I could only find worn out Dellortos. I have now reverted to a pair of Dellortos from a Kanguro and the bike is running better than it has in years.
I got the Mikunis fairly close but never quite good enough. It was only when I read in a Mikuni publication somewhere that they will only tolerate a limited amount of downdraught, 17 degrees I think whereas the original take much more of a tilt before they play up. On my bike at least, one carb is more like 25/30 degrees.

Before anyone asks the Mikunis are now being trialled on a friends bike so not available, sorry!

[72degrees]

I have a couple of 25mm carb bodies in the "never throw anything away" shed. Off an early 350, so probably VHBZ BS. Very furry with oxide by now, so possibly no help (though I do have an ultrasonic cleaner). I can dig them out tomorrow and have a look if NLM haven't got anything.

It's a amazing what Morinis will at least start and run on in a fashion when experimenting. I had a 350 with 'sportyish/L5' cam and Sport pistons running on 22mm carbs from a 250 the other day just to prove it ran. It started surprisingly easily.

[penman]

Thanks for the offer! I'll phone NLM later this morning and see what that produces, but I may be back to you.

Thanks again,

Joe

[72degrees]

Thanks for the offer! I'll phone NLM later this morning and see what that produces, but I may be back to you.

Thanks again,

Joe

Well I found them. VHB 25 BS. So early, that they still had the clamps for fitting to the early cast alloy intake elbows. They can be used with rubber manifolds with the clamps remove. By the way, if anyone is going for total originality on an early 350 I have a pair of said alloy intakes in useable condition.

The bad news is that the first carb I started to disassemble to put in the ultrasonic cleaner went swimmingly with all the jets coming out easily - except the starter jet (choke) plunger. Budged it a bit but it won't come out. I have it soaking in Plusgas but the brass plunger must be corroded to the body.
A pity, because the slide didn't look too worn at all and the bore isn't hugely furry. They are probably the original set I took off when I first equipped the original hill climb '76 350 with PHBH28s in 1981 !

The starter jet plunger has already been robbed from the other one (as have the float needles from bot carbs and the floats from one) so could probably be cleaned up OK.

I'll leave it overnight and have another go, but the starter plunger bore may be too far gone even if the plunger can be extracted. Anyone got any bright ideas on how to persuade it out?

[72degrees]

In fact, with plenty of Plusgas, a little perseverance and a modicum of brute strength it finally started to twist, move a little and then came out. The plunger bore looks not too bad. The body has come up quite nicely after an ultrasonic session. What sort of play is acceptable between the slide and the body? This has a little but the slide doesn't look very worn.

I'll put a photo up once I've finished the clean up in case anyone else might find them useful (I'm assuming the other one will be in a similar state).

[72degrees]

IMGP6449.JPG (227.11 KiB) Viewed 13794 times

IMGP6464.JPG (203.08 KiB) Viewed 13794 times

IMGP6458.JPG (205.28 KiB) Viewed 13794 times

I'll put a photo up once I've finished the clean up in case anyone else might find them useful (I'm assuming the other one will be in a similar state).