under powered EC200

[geoff g]

just had my 2007 EC200 on the dyno and guess what ?....only 27hp ( should be 38hp ) this bike has been under powered from the first ride in July 2008 and was purchased new, the jetting is spot on, squish is 2mm, compression is spot on, any idea where the other 11hp may be ?
Cheers

[GMP]

Assuming everything is in order, check the pipe. The newer 200s have a different pipe than the 250/300s. There was a test done by one of the UK mags that flamed the 200 for being weak, and they discovered that the bike had been shipped with a 250 pipe, the correct pipe cured it. BTW, 2mm squish is sloppy for a 200.

[2 strokes 4 life]

Yes the pipe could be your main problem for sure. I am sure you could find a pipe on here in the for sale section at a good price.

[stay_upright]

I guess that 38hp is quoted by GG? You would need to compare to other dyno'd GG 200's. 27 may not be an unreasonable rear wheel horse power for claimed 38hp at the crank.

Is it noticeably slower than other GG 200's in a straight line?

The KTM200 probably makes more power but mime was very on/off, For tractability you have to trade ultimate power which I believe the GG does and KTM does not.

Also the UK magazine TBM ran a test and said while the bike felt slow it was faster than both a MX250 and a KTM400 around a special test (surprisingly since it felt much slower to ride) and much less tiring to ride.

As I remember when TBM dyno's bikes say the current crop of 250 4t's which claim 35hp+ (I think - check this) the power on a dyno is around the 30hp mark. I think a knobblie tyre costs about 5hp over a slick alone.

Other factors - O ring chains use power

Manufacturers will test at optimum conditions so usually a cold day when the air is more dense but regardless they have probably claimed BHP so without an engine dyno the best you can do it to try and match other known good GG test test results to see if your bike is down on HP.

Did you check if the bike was revving high enough and who was doing the jetting - how do you know it was set up spot on for max power.

I've been told 2t oil mixture affects power and something like 16:1 gives max power because of better ring sealing and increased compression - you would be better speaking to 2t kart tuners or possibly MX tuners to confirm this though Enduro tuners aren't too bothered about max HP. I don't know if manufacturers do this for their dyno runs but obviously you would have to re-jet for this and then it's only to produce a number from a machine.

Have you checked the basic compression on you bike - how many hours do the rings have on them - this can make a big difference and even aftermarket pistons may change the compression ratio and timing.

If I remember I'll try and look through my TBM mags to see the GG 200 dyno result - PM me if you haven't heard anything for a bit (I may forget) if you really want this.

[widebear]

Yes The media's job is to keep you unhappy , insecure and to keep you buying their pay masters products , never ending chain of short term gratification.Like upright says, 27 whp not bad, its a 200 what'd you expect?

[geoff g]

Hi Glenn, the pipe was the first thing to be checked back in July and I was assured that it was correct, I also read the mag test TMX about the 200 and they said the correct pipe made a difference, however gasgas australia tell me that the pipes are all the same, the squish was set at 2.6mm from new and the optimum is 1.6mm but without machining the head I was able to get that to 2mm by setting the barrell height which also lined up the ports spot on at bdc.
Cheers

[geoff g]

Hi, a road bike tyre was fitted for the dyno and I would not think that you would lose that much HP through to the rear wheel on a bike. how worn is the engine ? .....this has been under powered since day one, compression is good, jetting is finally right after going to a 172 main ( which resulted in 2HP gain...25HP - 27HP ) thanks for your interest.
Cheers

[cattledog]

This should be a Mythbusters show. I am fairly sceptical about the power of GG two strokes that you sometimes see quoted. I suspect they are exagerated or misinterpreted ie crank V rear wheel. It would be interesting to see some dyno chart comparisons for GG and other like bikes.

I agree, my bet your bike is fine and the other 11 hp is in a brochure somewhere.

[GMP]

I didn't consider the numbers, just the comment that he felt the bike was slow.

[gasgasman]

There was some talk at one of the National Enduros about GG changing the porting on the '07 200s.
A dealer mentioned that owners of earlier models were saying how much faster their older bikes were.
Food for thought.