Conflicting information in owners manual.

[beemeerr11]

In the process of having to use an easy out to get one of the pilot jets out of one carburetor, I started compairing jet sizes to the manual, my biks is a 1981RH.
The Manual supposedly covers 1978 to 1981 models, and the bike on the cover is the same as the home page here.

The Manual states the following:

Mikuni BS 34-11-2700
Pilot Jet No. 42.5
Air Jet Main No. 140
Air Jet Pilot No. 180

What I have is the following:

Mikuni 5K7 00 111 is the only marks on the Carby (obviously different)
Pilot Jet No. 40
Air Jet Main No. 110
Air Jet Pilot No. 185

Now Pilot Jet No. 40 is the Jet just in front of the main jet, and Air Jet Pilot No. 185 is the jet at the rear of the carbies where the air filter rubbers go on, hope that bit is clear!!

The manual also says that fork oil replacement (as I am changing the seals) is 10W and 212cc, but I have read somewhere here that it should be 10W and 225cc, maybe even 250cc.

Any thoughts/Advise?

Cheers

Lou 81RH

[CatatonicBug]

Remember that the RH is a unique beast. It has parts and pieces from several models, and some that are only found on the RH. It would not surprise me in the least to find that things are not the same on the RH as they are on the other models.

According to the benefiscal site, the pilot jet on the RH is #400, and the Main jet is either #1050, 1100, or 1150.

The Air pilot jet for the RH is not listed with a measurement, but the Part number is 2A2-14172-00-00. However, on the SF, it's listed as a #180, with a part number of 2A2-14172-36-00.

[DGXSER]

Hey Lou,

The 80-81 model year carbs were jetted differently than the early models due to a change in the carbs. On the early model carbs, the hole where the pilot jet goes in gets plugged so the pilot jet has to pull its fuel through the main jet. Therefore, the main jets were bigger to let the extra fuel through.

Here in the US, the stock SH ( the similar model to your RH) came with 42.5 pilot jets, 110 main jets across the board (at least on mine they did, yeah, some early ones they mixed sizes betwen inner and outer carbs, but everything I have seen or read says they gave that up before to long.). The pilot air jets were 185 stock. So seems like only your pilot jets are different.

As to fork oil, I know the Special models (where the front wheel axle is in front of the fork tubes) used different amounts than the Standards (where the axle mounts at the bottom of the fork tubes). Perhaps that is the difference your seeing.

[Crazcnuk]

I suspect that the Aussie machines used a different setup to compensate for running upside down! (That and the whole toilet vortex going the wrong way....)

Sounds like an interesting setup, wonder what the reasoning was. As I understand it going smaller on air jet will richen the system, except they went larger on the jets?

The only carbs we see that use the 140 main have the tunnel between the main and pilot towers and use a plug over the pilot...

[Lamric]

Lou, the 5K7 carb specs are here (along with all the other models). Yours look absolutely standard.

[Lamric]

And here are the specs for the RH / 5K7 forks, this is from the Yamaha XS1100RH Supplementary Service Manual.