Mikuni RS 36 set up for 79 1200 with 4 C cams?

[Paul LeClair]

Hi all

over a decade ago I spent a considerable amount of time trying to set up a set of Mikuni RS 36 on my heavily modified 84 RGS with 1200 barrels, high comp pistons, ported head, big bore exhaust, etc. https://laverdaforum.com/xf/threads/82652/

The rack of three Mikuni RS 36 carbs I started with had originally been set up by Tophams in Germany, then I bought the set used from a seller in the UK through eBay. While I was trying to make them work on the modified RGS engine, Red was a great help, and supplied two additional RS 36 carb bodies and various other bits.

I eventually gave up. The carbs and bits and bobs got tossed into storage.

I recently tripped over the Mikuni RS 36's while hunting through my storage bins for a brand-new old stock wiring harness I bought from Wolfgang many years ago for my 79 1200, which I have been procrastinating over replacing the wiring but can't put off any longer as the original hacked up wiring harness is falling to bits....

Many of the issues I previously had with the RS 36 seemed float related, so I just bought 3 new floats from Sudco. I also dug out from storage some other bits like an early version of Red's angled manifolds and got out my selection of jets and the spare needles. Also found the K & N pod filters I was previously using. See photo.

so, for a 79 1200, 4 C cams, now vintage John Wilson IIS TA 120 ignition, does anyone have knowledge or suggestions on starting setup jetting/needles for installation on the 79 1200? Anyone, please?

 

[redax5]

Pilot jets 17.5, Main jets 127.5, Mixture screws 3/4 turn out, Needles set on middle slot

You will need to remove the lower 7mm studs from the inlet flange and replace them with 7mm bolts, the studs stop the rubber coupling from seating all the way home when using our 10 degree angled manifolds

 

[Paul LeClair]

thanks so much, Red!!!

I am still digging in my storage boxes for the three rubber couplings, and a dual cable push/pull throttle and cables, other than that I am ready to go through the RS 36's, give them a run through my ultrasonic, then jet them per your post.

 

[Paul LeClair]

can't find carb rubber couplings from my storage, will have to order new.

I did finish stripping the RGS 36 carbs this evening and dumped them into the 30 liter ultrasonic tank.

I am hoping I might have identified my prior Mikuni "float " problem, flooding and running over with fuel, which problem was the reason why I recently ordered three brand new floats. When I removed the float needle assemblies, which are each held in by a screw holding down their lip, two of the three fell out as their O ring seals were perished and shrunken and not sealing. I am guessing fuel has been flowing right past them even when the floats were holding the float needle closed. Bloody fire hazard.....

If perished seals on the body of the float needle assembly installed in the carb body has been the "flaot" problem all along, I have wasted many hours fiddlingwith float height adjustments when the carbs were on my RGS and then finally ripping the carbs off the bike and throwing them in a storage bin for years in frustration. Bloody hell. Live and learn.

 

[Vince]

If you're having trouble finding inlet rubber manifolds I ended up using these that suit 40mm Dels on Guzzis, they have a clear through run. The 36mm ones have an internal lip that blocks flow a but. There would be a Guzzi place in your hemisphere probably.

Bike Spares - Motociclo

motociclo.com.au

 

[1200 JOTA]

Pilot jets 17.5, Main jets 127.5, Mixture screws 3/4 turn out, Needles set on middle slot

You will need to remove the lower 7mm studs from the inlet flange and replace them with 7mm bolts, the studs stop the rubber coupling from seating all the way home when using our 10 degree angled manifolds

that's the right answer ... I did find that 3/4 out on the screws was a good start and some minor variation between carbs improved things (e.g. my centre carb runs best 'barely open') (that could be the rubber seat)

 

[iis_iis]

If you're having trouble finding inlet rubber manifolds I ended up using these that suit 40mm Dels on Guzzis, they have a clear through run. The 36mm ones have an internal lip that blocks flow a but. There would be a Guzzi place in your hemisphere probably.

Bike Spares - Motociclo

motociclo.com.au

Hoping Jonny V is still the man at Motocicolo, tah Vince for the jogging of memory here..j

 

[BakerOW31]

Pilot jets 17.5, Main jets 127.5, Mixture screws 3/4 turn out, Needles set on middle slot

You will need to remove the lower 7mm studs from the inlet flange and replace them with 7mm bolts, the studs stop the rubber coupling from seating all the way home when using our 10 degree angled manifolds

Hi Red,

Would these carb jet sizes + mixture settings be the same for my S2 180 Mikuni's. I have your angled inlet flanges installed with Ramair foam inlet pods in place.

Cylinder heat distribution appears to be uneven, blueing of nearside downpipe evident compared to the centre + offside pipes.

Any advice greatly appreciated, thanks.

Best regards,

Vic.