1052 rebuild

[downtheshed]

What carbs are a good match for these engines as I'm getting one rebuilt and getting the head etc done. What can I realistically expect this engine to put out, with head/carbs/cams upgraded?

 

Thanks

[canamant]

If you want to keep the airbox then the 34mm standard carbs would be a good start.  The 36mm ones from later models might go.  If the airbox is going then perhaps 36 or 38mm RS Mikunis but they might be a bit of a handful if you are not racing but using it on the road.  As for power, who knows.  Depends on the cam profile, the cam timing, and most of all what you want to use it for.  For road use I'd go for a good flat torque curve and perhaps squander some potential top end that you could only actually use when you'd gone beyond the point where they throw the key away if you get caught.  You know my 860 only had the standard 750 slabby cams and bored to 33mm VM29s on it plus I very lightlly cleanerd up the ports.  It was making 108bhp at 10,400rpm and 58lbft at 8,400with over 55lbft from 6500 to 10500. Then I made a change to the cam timing and immediately knocked 1.25 seconds off my best lap time (1:04.25 to 1:03.0) so I'd guess it ended up at maybe 110 to 112 bhp.  Who knows what the 1052 will make maybe 135 - 140bhp and 70 to 75lbft.  But don't get tied up on the numbers, see what it feels like.  I know a lad that builds very successful GSXR race bikes who has never had them anywhere near a dynamometer.  He just goes by feel.

 

Edited July 19, 2015 by canamant

[kokolis]

With matching inlet boots, you can use 36,38 carbs without airbox.

The vm29ss bored out to 33mm work  on the 1052 really well and you can keep the airbox.

[Ben Slabby]

Another one for the VM's bored to 33mm. Very good and none of the potential issues with CV carbs running pods. 

[downtheshed]

I will have a spare set of 29's , is it just a case of getting the (outlets to head) bored to 33mm.?? 

[canamant]

No.  The bodies are OK.  Take the face plates off the carbs and get them turned in a lathe to make the hole 33mm.  he new hole will be concentric with the bellmouth so the lathe will remove 4mm from the top and nothing from the bottom.  Trust me it works perfectly.  You will need anti-tamper 6 point torques/star driver to get the face plates off.  Float bowl off, accelerator pump nozzles out, carb tops off and throttle shaft /slide screws removed to get face plate off.  Take you an hour or so.

 

Ant

[downtheshed]

Thanks Ant, for info.

[Ben Slabby]

Speak to Simon Francis,  he did mine. Top service. 

[downtheshed]

Thanks, will do. What's his name on here?

[Ben Slabby]

Dunno offhand. Google "Simon Francis Services"   

[clivegto]

What main jets needle height and air screw settings are some of you using on vm 33"s on a 1052 motor ?

[Funkymonkracing]

I`ve got standard carbs,Micron full system and ramair filters on my 1052 racebike and it pulls like a train .

 

[kokolis]

With k&n filter replacement, 130 DJ mains, I reckon it would be something like 122,5 mikuni

[canamant]

Is that the original 34mm CVs or original 1127 CVs Mark ?

[kokolis]

Vm29ss bored out  to 33 mm, on a slabby 1100

[kokolis]

Is that the original 34mm CVs or original 1127 CVs Mark ?

The original cv s (BST34SS) have 130 mains mikuni ( main Europe)