Yamaha RD200 Cafe Racer Build - Carb Blues

[duraacemike]

I've been working on my Yamaha RD200 Cafe Racer.

Stage 2-3 Porting, widened exhaust & transfers,
Larger reed cages & racing reeds
Raised compression 0.2mm shaved off heads
Larger Mikuni VM 22mm carbs
Micron expansion chambers
RS250 exhausts.
Pod filters

Heres a few pics.

I got a few problems with the carbs that I've installed.
I'm having problems getting the cables to work with both the carbs and the oil pump.

The sliders on the Mikuni carbs are about 10mm longer than the old TK's. It shouldn't be too hard to get the cables on the sliders to work, but if I accommodate the extra travel required for the mikuni sliders then the oil pump is either fully on, way too early, or worse stops the sliders in the carbs from opening fully.

How do I get the cable to operate both the carbs and the oil pump with the 10mm difference?

Any suggestions?

[bogan]

That's cool man, is the oil pump rotated to go more or slid? If it rotates you could just get a bigger rotomicator to match. Though, if you got more air going in through them new carbs, perhaps the oil should come on a bit earlier anyway? Dunno, all my 2t have been premixed.

[duraacemike]

The old carbs where TK 20mm. The new are Mikuni 22mm. So the difference between the cable pull on the carbs and cable pull the oil pump should only be 2mm?
I just measure the difference on the two carbs and it measure a bit less, about 1.7mm.

So either I put 2mm slack on the oil pump so both the oil pump and the carbs are fully open at the same time.

or,

there is no slack on the pump cable, but then I risk the carbs never being fully open.

Any thoughts?

[Yamahardman]

id just go premix mate, my rd400's oil pump shat itself suddenly one day, and as a result lost a big end and a piston.
Should hopefully have it going again this weekend, and it'll run on premix.

The oil injection is nothing fancy, like that of a suzuki gt, and only mixes it in the carbs, whereas i believe the gt's automixed in the crankcase, and a scavenger pump, took the excess out and lubed the bore.

Juist o long stretches of deceleration, and itll be algood on premix.

[gjm]

I used VM28s (30mm) on my RD400 - with pre-mix. I was racing and wouldn't trust the pump.

[JimO]

i had a rd200 electric

[98tls]

Cant help re the carbs but love your project,nice work.

[Yow Ling]

make a new cable inner from the splitter to the pump, premix is ok but you use heaps more oil, my rd350 uses 650mls in 20 litres on premix

[Karitane pete]

How about fitting a RD350 or 400 pump?