High Speed Jetting/Tuning for WR426

[wattsy]

Wanting to know if i should adjust jetting or tuning for constant/high speed running from stock for an upcoming trip.

[GCannon]

The answer is yes but you need to give more information if you need specific help what has been done to the bike? where(elevation ,temperture) are you riding? how is it performing now? , are you capable of this work technically?

[Matty05]

Wanting to know if i should adjust jetting or tuning for constant/high speed running from stock for an upcoming trip.

Just put in a fatter main than normal, helps keep things cool.

Hows your jetting anyway now that it is winter?

[wattsy]

Thanks Matty.

As far as current jetting goes as far as i know it hasn't been touched from new. Just bought the bike from a mate who bought it brand new. I'll be looking at the jetting today as i have to clean the carby out as the bike has been sitting idle for about a year or more and last time he rode it he said it started missing and carring on at about 1/3 throttle.The reason i posted the thread is that im heading up to Cape York on a trip later in the year and needed advice on tunning/jetting as the bike will be running at constant higher RPM for some time as you would have guessed. Also looking for fuel effeciancy as well but to keep the motor cool but i guess you can't have both.

Regards Wattsy

[Matty05]

Missing is rich, drop the needle a clip to clean it up. This will save you fuel too!!!

I'm up the top of the Territory, in Gove. It has been constant 26*c - 27*c lately.

When is your trip? I'll get my neighbour's 426 jetting specs if you like.

You might have to play around with your jetting a bit more when you head north.

Where you living now?

[Numskull]

I didnt know Austrailia had winter But thats right, you guys are on the other side of the equator.

I just ordered the JD kit too and will be installing it this weekend. I was wondering Matty how every one says if its missing it means its rich. My bike misses at constant throttle and has all the ity bitty stock jets, with yz timming- cam and ignition, plus open exaust and air box.

How can you tell when the bike is lean then?

[Matty05]

I didnt know Austrailia had winter But thats right, you guys are on the other side of the equator.

Were I live we only call it winter, but it is not cold. It is 27*c (80*f) here now! The humidity has dropped off to a cool 70% at the moment! Riding all year round!!!!!

I just ordered the JD kit too and will be installing it this weekend. I was wondering Matty how every one says if its missing it means its rich. My bike misses at constant throttle and has all the ity bitty stock jets, with yz timming- cam and ignition, plus open exaust and air box.

if missing at constant throttle, try lowering the needle and you will see the difference. I would wait till you get the JD kit though! His needles seem to run good the whole range.

Running rich can feel like the bike is cutting in and out, stuttering.

How can you tell when the bike is lean then?

It will run real ashmatic, be lethargic, won't pick up speed real easy, run a lot hotter than normal.

When you get the JD kit, you are going to have to do some experimenting. It is a pain in the ass, but what other way are you going to learn to jet your bike? Everyone skips this part and they will be very lucky to get spot on jetting the first time. Use Indy's chart as a starting point, it would be close to start with. To tell what lean and rich will do to your bike, why not play around with the main jet? If you are using a 165, put in a 160 to feel lean then a 170 to feel rich? And also, take note of your jetting. Once you get right, you can change back to that setting the next year.

[Numskull]

Thanks Matty

[wattsy]

Thanks again Matty05

I'll try that and see how it goes. I'm in Casino, N.S.W. Bout 16 degrees here at the moment. The WR motors can obviously handle high speed running with a little jetting change here or there with people running them in the Australian Safari and the Finke Desert Race with little or no problems. Do you have a long range tank on yours or do you know of anyone running an 18 litre tank or so and approx how many Km's they get out of it. Living up there in the top end you would be THE person to ask i guess about the best way to seal these bikes up for deep river crossings.

Regards Wattsy

[Matty05]

ok, for crossings, depending on how deep and long they are, I just ride straight through, and check airbox on the other side. I have been through water nearly over the bars before, no probs. If I were worried about it, I would tape up the airbox with gaffer tape.

Still haven't got a long range tank yet, but planning on getting one of those 15.5L safari tanks from Yamaha. They are $450, but I think you could talk them down. I get about 100 kms out of the stock 8L tank, so that is 12.5km/L. using this, 15.5L = 195kms. I have a mate that has a safari 28L supertanker that you see in the safari's and finke, he has never used it all up, but could get ~315kms out of it flat nacker!

I seriously need a larger tank, but just brought 2nd house. I'm broke.

I have been using 2L coke bottles for extra range, I take 2 out and drop them off on the way out, and use them up on the way back. They don't leak, which is good, but I still don't recommend it for your cape trip! You will pop in and say hi to my parents in Weipa, won't you!

[wattsy]

Thanks Matty

Those 15.5's sound like the go. Anyway thanks for your info so far better go and make some money to pay for these things.

Wattsy