motomerlin

see my trials bike buyer's guide - aimed at Ebayer's but still usefull. Cheers, Mike

Usually the piston slightly siezes & smears alloy over piston rings, trapping them in place. To check remove exhaust pipe & shine torch up ex port. If lucky a stip & clean up will cure. If unlucky it's ripped the barrel coating and a replate & piston is needed.

Well worth re-packing. Do it regularly! Here's a guide I posted about the GG Pro middle silencer. The principles the same. Silencer repack the easy way!

Brief buyer's guide here: Trials Bike Buyers Guide

Shown as same part number as older Pros ....so it's a 6004 2RS.

Fronts are 6905 2RS ...cheap ones from guess where! Shock rose bearing is an odd size & so far only at premium price.

Ignore the drilling. See diagram here: Beta Carb Mod. Just alter float arms/tangs, that does it.

The forks will loosen up. But I found my 09 GG forks needed some work: I went to 2.5 w oil. And trimmed the plastic spacer (on top of springs) by 5mm. Also tried a different make of fork seal. Now they're pretty good. I tried a Raga & 2011 and the forks seemed fine. But bikes can vary....

I've got a couple left from current batch....call me tomorrow if you want one, Cheers, Mike

GG 2011 in action

I tend to use 450cc. ATF is fine. No dipstick, use the sight glass.

Chances are it's smeared the alloy of the piston trapping the rings - so low compression. Remove exhaust pipe & you can prob see this. Iff really lucky a clean up of piston would get it going. If not, plated bore may be damaged, so a piston & re-plate would be needed.

If it appears to change gear better going up the box than down, or vice versa, then the adjuster behind the clutch could need a tweak. GG USA have a video on youtube showing this. It's a fiddy proceedure, but should cure it.

Vic, Pistions are available here in the UK. However, you'd almost certainly need to re-plate the bore as well, after 11 years... Normally they re-plate to the new piston spec, and the letter is no longer an issue. Putting a nice new piston into a tired boke can be a false economy. Mike

6004 in the rear hub.

The 09 forks always felt too firm to me. First ones had 7.5 w oil, changed that to 5wt - much better. I head the some type of fork seals were causing friction, so I striped mine but couldn't feel this, but removed dust scraper spring to help. Finally, cut 3mm off spacer tube & went to 2.5 w oil. Feels like I've got there.....testing in France at Easter. Jokerr.....I assume you're releasing the built up air via the bleed screws?

Late model Pamps arrived with two exhausts - one was much heavier & has emmision junk attached. The original 02 model part number gives you that

GG flywheel pullers I sell for about 9 quid....... The 270K is the needle jet. The float valve, is the "orofice" the float needle locates in. It's unlikely to be wrong, but check (it unscrews). It was an issue on the VHST Dellortos, bit you don't have that carb , as std.

A "top tip" given to me was: Treat the SSDT like a 6 day enduro - that some kind fellow has bunged a few sections in the way...... That way you might stay on time.

I've had 5 Beta's & now 3 Gasser Pros. All gripped well One thing you need to know, GG have the most tuneable engines out there. A Raga is top spec, top tune. One for the real experts....(not me!). You can tune it up or "down"! So, try IRC rear tyre, slow throttle. Dellorto carb (if it has Kehin). I would check squish clearence & keep it fairly std, but fit an intake spacer & flywheel. Too much squish gap will lead to spluttery carburation.

I've added the Gas Gas SSDT set-up to the Motomerlin downloads page see here. Also the Beta SSDT guide that has some useful tips for riders too. Mike

33 or 34 is more usual. But before changing try pilot screw 2.5 - 3 turns out. Really, you need to set screw to where engine runs happiest (!)... and if thats many turns out try a bgger pilot.

The rim band fits into a groove n the inside rim edge. To cure leakage almost certainly someone has used silicon sealer or similar under the band. Best to remove band, clean rim & re-fit with silicon or bead sealer under the band. You may need a new rim band - the newer types have the valve bonded in & they're the better bet.

Pampera tyres? Anything that's black & round.... IRC trials tyres will wear fast on the tarmac, so try anything else really. It probably depoends on how many trials or LDTs you intend riding. And how much you like changing tyres! Pretty much all the events demand a trials rear, some a trials front too. Oddly enough, the IRC rears sharpen the trailing edge on road work. I seem to remember the Pamps originally came with some michelin all rounder fitted.

Fast throttle, Boyesen reeds & a Keihin carb will wake the beast...