G1 Bravo/Enticer port maps?

[1989Marathon]

Originally Posted by TheGDFP

The fixed timing I think the 2 strokes have, isn't really ideal.
Cheap and easy HEI module doesn't change that.
But, the 5-pin has a pin that when grounded, retards 5 degrees of trigger timing. I'll advance the base timing, and run a wire to the carb with contacts at full-throttle, to reduce melt-down

Have you tried the 5-pin before?

[TheGDFP]

Originally Posted by 1989Marathon

Have you tried the 5-pin before?

Just on a turbocharged inliner.

[1989Marathon]

I have tried it with the 5-pin(HEI/EMR) module with no success.

[slonomo]

I appreciate what you are doing here. Maybe you'll have some better success than others. Most have tried to hot rod the G1 engine but they don't follow up and post the results, probably because they failed. The setup I ran did pretty good. As good as a golf cart could be. It was a high rpm screamer, I never did find the top. The carb I had ran out of fuel before I topped it out. The mid range power was killer. It scooted pretty good. However.....the bottom end was near nothing. It was fine if you were on level ground. If you hit a hill, it would not accelerate at all. The clutching would allow it to climb hills, but it would do so slowly at a high rpm. If you tried to pull anything or do any work with it, it would not like it and would stall out.

So this little engine is going to like rpm. It will be loud with a pipe, as you already expect. And it might have some pretty good power, but not below 3000 rpm. The primary clutch will need to have a decently high engagement, which will make takeoffs on gravel a lot of fun. If you have weight in the back, it might even pull the front tires. I had mine engage at around 2600 rpm, for one day.....it was crazy. I backed it down some and it worked ok. But again, trying to do anything practical with it just didn't work.

I'm anxious to see your twist on this engine. I believe it can work, it just has to have the right combo of mods to get the most out of it. Not sure exactly what you have planned, but the ET250 is a direct swap out for the top end of the G1. The ports are huge comparatively and the combustion chamber/head design is much more aggressive. You wouldn't have to mod the ports to get good power. The Enticer 250 was a lower rpm cruiser sled compared to the 340 and 440. I decided to cut my losses on mine and run a Vtwin Vanguard. But I'll be watching this thread.

[TheGDFP]

Originally Posted by 1989Marathon

I have tried it with the 5-pin(HEI/EMR) module with no success.

Didn't run?

[TheGDFP]

Originally Posted by slonomo

I appreciate what you are doing here. Maybe you'll have some better success than others. Most have tried to hot rod the G1 engine but they don't follow up and post the results, probably because they failed. The setup I ran did pretty good. As good as a golf cart could be. It was a high rpm screamer, I never did find the top. The carb I had ran out of fuel before I topped it out. The mid range power was killer. It scooted pretty good. However.....the bottom end was near nothing. It was fine if you were on level ground. If you hit a hill, it would not accelerate at all. The clutching would allow it to climb hills, but it would do so slowly at a high rpm. If you tried to pull anything or do any work with it, it would not like it and would stall out.

So this little engine is going to like rpm. It will be loud with a pipe, as you already expect. And it might have some pretty good power, but not below 3000 rpm. The primary clutch will need to have a decently high engagement, which will make takeoffs on gravel a lot of fun. If you have weight in the back, it might even pull the front tires. I had mine engage at around 2600 rpm, for one day.....it was crazy. I backed it down some and it worked ok. But again, trying to do anything practical with it just didn't work.

I'm anxious to see your twist on this engine. I believe it can work, it just has to have the right combo of mods to get the most out of it. Not sure exactly what you have planned, but the ET250 is a direct swap out for the top end of the G1. The ports are huge comparatively and the combustion chamber/head design is much more aggressive. You wouldn't have to mod the ports to get good power. The Enticer 250 was a lower rpm cruiser sled compared to the 340 and 440. I decided to cut my losses on mine and run a Vtwin Vanguard. But I'll be watching this thread.

The ET port timing is still too aggressive for non-reed low end, I'm guessing.
I was wanting to see what the porting was, as a "too far" number.

The trouble with the wilder sled jug, milling the base to lower the ports also increases intake timing, unless a long-skirt slug is found. Reed jugs leave the intake port open 360 degrees and draw-on-demand, so exhaust height and blow-down can be tuned without harming intake tuning.

Observed trials bikes did fine as P/P, with mild specs, and my commercial mowers are P/P while residential ones are reed.

There is plenty of material in the G1 for mild porting, without hurting any torque any where.

The extra 4-5mm bore that the G1 jug will accept, will add some torque, too.

I'll pay attention to squish distance and angle, along with compression, and likely end up with a curved ignition.

ANd, I need to emphasize, I'm not discrediting any prior work, but Wilbur & Orville didn't build the BEST plane

[slonomo]

Roger that. I can tell already that you are more of a 2 stroke guy than me. The lack of reeds on the ET250 explains its lack of low end. Never really thought of it that way. Low end just isnt needed on sleds because of the way the track works in the snow, right?

1989marathon did a G1 long ago and claims it had pretty good power and speed. I'm betting he did similar to what you are planning. The G1 engine is also a low compression engine so maybe use an ET250 head? I have some good photos on my Enticer build thread. I dont know what the cc's are, but it looks more aggressive in design.

[TheGDFP]

Originally Posted by slonomo

Roger that. I can tell already that you are more of a 2 stroke guy than me. The lack of reeds on the ET250 explains its lack of low end. Never really thought of it that way. Low end just isnt needed on sleds because of the way the track works in the snow, right?

1989marathon did a G1 long ago and claims it had pretty good power and speed. I'm betting he did similar to what you are planning. The G1 engine is also a low compression engine so maybe use an ET250 head? I have some good photos on my Enticer build thread. I dont know what the cc's are, but it looks more aggressive in design.

The CVT and need for peak power, team up to make the sleds a little lame down low, as well as the compression/heat/meltdown matrix. Traction is ample and they have a fair bit of drag to overcome.

I read your thread a couple of times (nice write-up)and saw the head. The ET has a wider squish band, and I like to keep the 50% area, 1.5mm distance, and it may be easier to open the ET bowl than excessively cut and/or weld the G1.

[TheGDFP]

And a pipe doesn't have to add a ton of noise to be better than the 4-stroke type stock tube/can job.

[slonomo]

I have a ET250 pipe if you need. I paid $50 plus ship. Be willing to deal, its just sitting here.