Carb jet sizes help would be much appreciated

In the Shed
1

Hello fellow VF1000 enthusiasts.

I’m helping a friend who has bought a project bike for complete resto. It’s a 1985 “B” reg in UK. VF1000F. Engine number SC15E-2005182. Non runner. Kph speedo. My initial research suggests it’s German one.

Question is re carbs - which I am stripping and cleaning and rebuilding. I like carb jobs and have done a few sets for my old FJ1200 which I completely restored. But gosh these V4 ones are complex just in terms of linkages and how they connect together! Lots of video and photos have been taken on disassembly to assist on reassembly!

carbs are stamped as 85EAYG Keihins

jets all seem to be original Keihin ones with the Keihin star stamp on them

Pilot jets are marked 38 and float valve seat 2.4 and those both seem to accord with specs I see in workshop manual

my confusion is re main jets. What is fitted is 110 Keihin mains in all 4 carbs.

research is confusing me. Workshop manual says 150 front and 145 rear. And in brackets (for different counties I presume - 138/135). Looking at Keyster kit for these carbs on NRP website they say kit contains as standard 145 and 115 mains and if you have an FF 1986 model then it’s 145 and 150 mains.

I’m confused!

Oh and to answer the question you might be asking - exhaust seems to be a replica of standard one - not sure the make - but not any fancy 4:1 race one or anything

Would really appreciate if anyone can shed any light on what model this bike really is and what jets are right for these carbs

many thanks

Michael (in Scotland)

2

Ah a fellow Scot,welcome.

The German carbs are restricted thus the 110 mains.

Out of interest,do the carbs vent into the alloy plenum or do they vent to atmosphere?

Best regards Bif

3

Ah ha! Thanks so much. That makes sense. Let me check tomorrow on the venting. Meantime much appreciate the quick and helpful response! Michael

4

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5

Do these photos help to establish if the carbs on our bike do vent into the plenum chamber?

6

These carbs vent to atmosphere.

7

Thanks Don. Appreciate the input.

8

wht size of mains would you chaps recommend when I rebuild them? Don’t want to keep them as restricted! I’m planning on using Keyster rebuild kits. But do I get the 145/150 version or the 145/115 kit?

9

I fitted a Factory Pro kit to mine, 145’s front and rear….but the kit had different needles too. If you find it running a tad lean in the higher rpms, you can fit small shims under the needles to lift them slightly. I’m very close to sea level where I am…if you’re at a decent altitude, you may want to use smaller mains.