I bought boost bottle before I read many bad saying about it. So I've installed it on my bike but never connected it to the intake. I was thinking it would just making my CG 2 stroke engine run worse.
After about 7 months of letting the boost bottle for decoration, I could not help to find out myself how bad it will effect the engine.
The first run with the boost bottle, the idle was high, adjusted it down and went for a ride. I could immediately notice the different sound the engine made at idle, it was choppy higher pitch (and I like that much).
Acceleration was worse, top speed was the same as before but in longer time to reach. (55 km/h).
The acceleration decrease (about 20%) made me wanna take the bb out immediately. And then I thought of learning a bit more on the net about this bb thing.
In a snow mobile forum somewhere somebody mentioned one can't expect gain with bb w/o tuning the carb and even w/ tuning someone may not gain at all.
Second run, I set the clip on the carb needle one step higher for leaner mix (from 3rd notch to 2nd notch from above). The run was worse so I knew I was going to the wrong direction.
Third run, put clip to lowest 5th notch. Idle sound was even better, choppier, it was at best. Acceleration was as bad at low end but a bit better in the mid and hi.
Fourth run, clip on 4th notch. Acceleration is clearly better than w/o bb (about 10% gain) and top speed is now 60+ km/h and it is reached sooner and easier.
Idle sound was less choppy with same hi pitch, still it is great.
My engine is:
> 69cc Flying Horse from BB (not the real FH China)
> balanced crank
> cns carb, standard jet, 4th notch neddle clip
> double boost bottles kit from BIS
> MM hi comp head the ashtray old model
> MM boost intake
> standard port timing
> standard exhaust with removed inside baffle
> jackshaft with Shimano Nexus 3 speed
> self made cdi (using plan from this forum) adjusted to 3 degrees retard + CR80 coil
I hope this can be informative for someone in similar situation (regretting a bb purchase).
For others, go buy expansion chamber exhaust instead, you will have more gain with that than boost bottle.
Not a good piping work but it works:
The bottles, one on each side:
After about 7 months of letting the boost bottle for decoration, I could not help to find out myself how bad it will effect the engine.
The first run with the boost bottle, the idle was high, adjusted it down and went for a ride. I could immediately notice the different sound the engine made at idle, it was choppy higher pitch (and I like that much).
Acceleration was worse, top speed was the same as before but in longer time to reach. (55 km/h).
The acceleration decrease (about 20%) made me wanna take the bb out immediately. And then I thought of learning a bit more on the net about this bb thing.
In a snow mobile forum somewhere somebody mentioned one can't expect gain with bb w/o tuning the carb and even w/ tuning someone may not gain at all.
Second run, I set the clip on the carb needle one step higher for leaner mix (from 3rd notch to 2nd notch from above). The run was worse so I knew I was going to the wrong direction.
Third run, put clip to lowest 5th notch. Idle sound was even better, choppier, it was at best. Acceleration was as bad at low end but a bit better in the mid and hi.
Fourth run, clip on 4th notch. Acceleration is clearly better than w/o bb (about 10% gain) and top speed is now 60+ km/h and it is reached sooner and easier.
Idle sound was less choppy with same hi pitch, still it is great.
My engine is:
> 69cc Flying Horse from BB (not the real FH China)
> balanced crank
> cns carb, standard jet, 4th notch neddle clip
> double boost bottles kit from BIS
> MM hi comp head the ashtray old model
> MM boost intake
> standard port timing
> standard exhaust with removed inside baffle
> jackshaft with Shimano Nexus 3 speed
> self made cdi (using plan from this forum) adjusted to 3 degrees retard + CR80 coil
I hope this can be informative for someone in similar situation (regretting a bb purchase).
For others, go buy expansion chamber exhaust instead, you will have more gain with that than boost bottle.
Not a good piping work but it works:
The bottles, one on each side:
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