2002 Gasgas 280 Pro Maintenance/setup

[dylanewilliams]

I am a new trials rider in San Diego, CA. I have ridden large adventure bikes extensively and decided to get a trials bike to really learn the fundamentals. I was fortunate enough to come across a 2002 Gasgas TXTpro from a member of a local riding group. As a new owner, I want to make sure I am doing the maintenance and set up for the bike properly. Possibly there is an existing thread I could be pointed towards, but I could not find one. Here is what I am looking to find out:

1. What are the common pitfalls of this year and model that I should look at and remedy if necessary, and what are the remedies?
2. What are the recommended service intervals and fluids specs? I would like to go through everything at first as I don't know how long the bike has been since being serviced. What should I change?
3. What gas and premix should I use?
4. I am 6'5" and weigh 250#. What is my best bet to raise the handlebars? Risers, or a new bar? will the cables reach? If not, how to change them?
5. Also, due to my weight and size, what should I do about suspension adjustment/replacement?
6. Any other questions I should ask or things I should know?

Thank you in advance!

[lineaway]

This was probably the worst bike from gas gas. What you need to know is what the previous owner fixed.

Change the tranny fluid monthly and clean the air filter often.

synthetic oil at 70-80:1

You bend your legs to ride trials or by a Harley.

A heavier rear spring might be needed, the front fork springs can be adjusted with pvc spacers. The stock springs would sag after a year.

Welcome to trials, ride often is what you need. One of the best videos is By Ryan Young. Best book was by Bernie Shrieber on basics.

[copemech]

Best bike ever, ride it like you stole it!

I hope you did!

Edited December 13, 2014 by copemech

[eddie1]

I have one of these - It is my first trials bike bough cheap with several problems..

If it is running well just put fuel in it and enjoy.

I softened mine with a flywheel weight and head spacer.

Main issues I have had are with the clutch and waterpump but these are common to all Pro models.

Jim Snells, how to fix videos, are great should you have any issues.

Keep an eye on the gearbox oil level as there is less than 400cc in there and it lubes the main bearings as well.

I use ATF and pre mix at 70:1 with good quality fully synthetic oil but know some who use 50:1 and others 100:1 so...

[lineaway]

For a complete waste of time read this http://www.trialscentral.com/forums/topic/53282-reliability/. For the best info on your bike look here http://www.trialspartsusa.com/. You will notice there is no parts book for a 2002 pro,use the 2003 for parts. That is how bad the 2002 was, most engine parts were upgraded. 2003 suspension was all the same.

Edited January 1, 2015 by lineaway

[peterb]

These bikes were not so bad once the gearbox and clutch issues were addressed.

As far as I am aware the transmission oil did and still does lubricate both main bearings.

There is a 2002 parts book, the 2003 parts book would show an incorrect crankcase gasket for the 2002 model, the 02 is different.

There were a number of improvements made over the years to the Pro motor after it's initial release, like other manufacturers would make. The 02 clutch case would flex when the clutch was used, accentuating the clutch drag and parts of the gearbox were altered over time.

The 02 airbox was a bad design, always letting in water just crossing a stream, may have been replaced by now on your bike.

I would have thought that a bike this old, may have had much or all of the needed changes made as a matter of course. In this case, the bike could be a good buy.

We always used 450ml oil, any more usually finds it's way out the vent. Used ATF Dex III since 2002 (and on the earlier GG) and never had a problem. Some of the UK guys use synthetic, according to my UK GG guru friend, it tends to cling to the main bearings and better prevents them from rusting up when the motor takes in water into the clutch case, which could be often up north in the UK where there are plenty of proper stream sections.

The Kokusan electronics are different to the later models, and are pretty rare at the best of times.

I produced a tech sheet for basic things to do with a new GG bike that is somewhere in/on the web which may be of help to you, I think Jim at trials parts usa would still have this, was about a full A4 sheet size. Contact him for all things GG, he is really brilliant.

I always ran my GG's at 50:1 with a mineral 2T oil, but I have been told that 70 to 80:1 synthetic has worked well too.

The water pumps tend to wear the shaft and seal, which can be replaced. Biggest problem is water getting into the gearbox as this can swell the clutch fibres and this then increases the clutch pull on the lever, generally needing a new clutch pack.

Bye, Peter B

[lineaway]

You are right about the mains lubrication Peter, I was thinking of the upgraded mains w/seals. Jim never listed the 2002 parts in the USA. The main difference was the mag cases and the oil quantity was less on the `02 as with the gasket size. The worst thing with the `02 was the shift drum would crack. Then it was clutch plate swelling and shifting problems. This could of all been upgraded if you are lucky.

[scoobytoo]

Clutch problems where remedied in 05 with new clutch material--this clutch did and does not to this day require different thickness steel plates--- main 2 mods where the air box fixings(more screws holding the two halfs together in 03 onwards) and the clutch cover-- this had a gallery on the inside shaped like a half moon which allowed oil to get trapped and run onto the clutch enabling better cooling and therefore stopping so much swelling of the clutch plates--there where many other minor mods also, head was less compression-- the 02 was the most powerful 280 we had!

[lineaway]

If you want the clutch perfect (And know what you are doing) You still either change the steel plates or mess with the friction plates to keep the proper finger height.