Altitude Sick Transalp

**Simon Harby** · #1 3 Jun 2004

My wifes transalp is sick.

We are above 3500m and have recently crossed a pass at 5600m.... but since these heady days her bike has started playing up.

We have done the following:

Reduced the carb pilot screws a quarter turn each.

Cleaned the sparks

opened the air filter (which is pretty dirty).

Checked the carb slow jet and main for clogging - they're clean

So can anyone out there help us??

The current syptoms are loss of power at 4500RPM in any gear.

And for reference this transalp is a 2002 model with all the electrical complications Honda have thought up...

Thanks in advance from the Himalayas

Simon

**Grant Johnson** · #2 4 Jun 2004

I'm no Transalp expert, but the symptoms are definitely altitude sickness - no air, so it's too rich.

Search the HUBB on:

carb pilot slide needle

and you'll get a number of good threads.

Note:

Pilot screw you adjusted is only the first 1/4 throttle. Don't waste your energy on it.

Mid range is controlled by the slide cutaway and the needle and needle-jet.

LOWER the needle in the slide to lean it out.

3/4 to Full throttle is controlled by the main jet - SMALLER to lean it out.

Usually dropping the needle a notch is the best you can do without a full set of jets and bits and a lot of knowledge.

Make sure the air cleaner is VERY clean, even remove it if you're not in dusty conditions.

------------------
Grant Johnson

Seek, and ye shall find.
------------------------

One world, Two wheels.
www.HorizonsUnlimited.com

**Simon Kennedy** · #3 8 Jun 2004

Yeah, mine suffered at these altitudes too. Others have been fine though, so it seems luck of the draw.

The slide needles on early Transalps are not adjustable unfortunately. I suspect this is the case on yours too, but I am not sure about this.

You can change the jets though. At 5,000 metres plus, look to reduce the size by 10 to 15 per cent. Just make sure that you change back to stock as you come down. They are real small, so cost nothing in shipping. This will help a bit.

I am assuming you have done everything to free up the airflow into the filter yeah? Drilling holes is an option. You can tape them up later.

Good luck.

Simon

**Pedro Rocha** · #4 11 Jan 2005

So is it safe to assume that a stock Transalp isn´t going to have altitude problems below 3500m or 4000m ?

**davidmc** · #5 12 Jan 2005

I have had my Transalp up to 10,000 feet with no problems at all. I couldn't really tell a difference in performance. Haven't gone higher than that though...

-Dave

**Simon Harby** · #6 12 Jan 2005

My wife Transalp was OK upto 4400 metres then the problems started. One thing on the T/A that can casue an additional problem is the sleeve linking the carbs to the cylinders. It needs tightening from time to time, other wise you get secondary air in to the carbs and this, plus the altitude will cause a large loss of power.... just tightening it makes a huge difference..

Quote:

Originally posted by Pedro Rocha:
So is it safe to assume that a stock Transalp isn´t going to have altitude problems below 3500m or 4000m ?

**Simon Kennedy** · #7 22 Jan 2005

I recently found out that my altitude problems were due to the spark plugs not being firmly enough tightened. I was loosing compression.

Most people I have spoken to with TAs have very few problems at altitude.

And let's face it, how much time does anyone spend at 4,500 metres plus? In the grand scheme of overlanding, it is not an issue.

**Simon Harby** · #8 26 Jan 2005

I can assure you this problem is a major limiting factor if your in the Himalayas! I guess that "in the big scheme of overlanding" depends on how adventurous you are.. we spent six weeks between 3500m and 5300m so, to find a solution was necessary. The journey was magnificent and well worth the trouble and effort.

Quote:

Originally posted by Simon Kennedy:
I recently found out that my altitude problems were due to the spark plugs not being firmly enough tightened. I was loosing compression.

Most people I have spoken to with TAs have very few problems at altitude.

And let's face it, how much time does anyone spend at 4,500 metres plus? In the grand scheme of overlanding, it is not an issue.