awesome

GoldenMotor.com

2door

Moderator
Staff member
Sep 15, 2008
16,302
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Littleton, Colorado
Lots of good information here. But it seems focused.

One thing to keep in mind guys, and he covers this in his text.

Unless you're racing and looking for absolute top performance, the modifications he suggests won't really give you a reliable, daily driver engine. Yes, there is no doubt that if you follow his instructions and do as he says that your engine might make more power. But even he goes on to say that you need to be prepared to make frequent parts replacements due to the stress imposed on the stock components.

Racing and sport/daily riding are two totally different conditions. Give serious thought to what you want from your motorized bicycle before making major changes to a little engine designed and made for a fun hobby or sport.

Building an engine that has one specific task, that being producing the best performance in a race environment might not be the way to go on a bicycle that is used primarily to make a run to the corner store or take you on a pleasant ride down a country road at 25 mph.

In spite of what you might read or hear, there is really no such animal as a 'dual purpose machine'. Racing and reliable street riding are in fact worlds apart...and don't mix.

That said, thanks for posting this. I'm sure there will be those who will find it beneficial.

Tom
 

scotto-

Custom 4-Stroke Bike Builder
Jun 3, 2010
6,505
24
38
Ridin' inSane Diego, CA.
Lots of good information here. But it seems focused.

Racing and sport/daily riding are two totally different conditions. Give serious thought to what you want from your motorized bicycle before making major changes to a little engine designed and made for a fun hobby or sport.

In spite of what you might read or hear, there is really no such animal as a 'dual purpose machine'. Racing and reliable street riding are in fact worlds apart...and don't mix.

Tom
For the most part, I'd say this is true Tom, on the other hand I've built a bike that is a reliable daily cruiser and it also does quite well on the race track. It only puts out about 6.25 HP, but it's a heck of fun bike to ride (or race)!





Cheers! dnut
 

mech_engineer

New Member
Mar 3, 2014
175
0
0
Puerto Rico
This book and the other tuner guide are great. I am using the formulas for porting and port duration. I use the parameters for cycle to get the area i need for now i need to go case inducted for the the area required. I need to stuff the crank with teflon plates in case of failure teflon have the lowest friction coefficient and It will not harm any engine parts. Lower weight is also a benefit. For 8k rpm the mean area needed 3.667cm^2 with the duration of 135 but if i go case inducted i only need 2.75cm^2 mean area with duration 180 using reed valves.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
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63
Littleton, Colorado
For the most part, I'd say this is true Tom, on the other hand I've built a bike that is a reliable daily cruiser and it also does quite well on the race track. It only puts out about 6.25 HP, but it's a heck of fun bike to ride (or race)!


Cheers! dnut
True, to a point, Scotto.
Yes you can build a machine/vehicle that might serve two purposes. The little sedan seen in my avatar is capable of a 12 second quarter mile, yet, it is fully streetable and has been driven cross country several times. However, If I was to get serious about drag racing and had a desire to win at it, I'd have to make changes to the car that would make it less than desirable to drive on the street or highway. Lower rear gears, higher lift/longer duration cam, less than tolerable exhaust noise, etc, etc. No thanks. The car was built to be driven and enjoyed on the street, not the drag strip.

My concern is that the new and inexperienced motorized bicycle builder, who usually wants more performance from his bike than a stock engine will provide, will see and read the high performance/race suggestions and either successfully, or not, apply them only to discover that his mild mannered little bike will only now satisfy him at or near WOT conditions. Riding a bike at those power settings and speed isn't practical for most people.

In some places speed limits imposed on a motor assisted bike will make it illegal. If your bike will only run smoothly and reliably at 30+ mph, think how undesirable it would be to take a quiet liesurely ride around the trails or neighborhood. And let's face it. That's how the majority of these bikes are ridden. Sure, everyone wants their bike to run good, start easily and propel them around at reasonable speeds but to suggest major modifications aimed primarily at the racer seems inconsistant with the hobby as it applies to the majority or bike builders.

I have no doubt that your bike will ride and race but you are not a new or inexperienced builder. This is my point. This forum was established for the purpose of helping new builders successfully assemble and enjoy a motorized bicycle. They are the ones who need good solid help and advice. I simply want them to understand the ramifications of building a high performance engine verses just making what they have reliable and fun. There will be a time later when they can apply some performance enhancments but lets get them on the road and let them enjoy their bike a little before sending them to the race track. Is that asking too much?

Tom
 
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Theon

New Member
Jan 20, 2014
1,440
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0
FNQ Australia
I think this forum is serving both, to a degree.
There are obviously quite a few 'experienced' builders here, with more than one bike.
And I doubt that many of the noobies have the tools or understanding to pull of a 'race motor'.
I think the book adequately explains the point that full tilt mods are for race bikes, and these little motors do respond favorably to a bit of work.
Seems the book is not really aimed at being a Ht 'Bible', but does go a long way towards helping those with a little understanding gain a little more.
Those with very little understanding, will likely learn from 'mistakes'. Or be just confused by reading this.
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
I think this forum is serving both, to a degree.
There are obviously quite a few 'experienced' builders here, with more than one bike.
And I doubt that many of the noobies have the tools or understanding to pull of a 'race motor'.
I think the book adequately explains the point that full tilt mods are for race bikes, and these little motors do respond favorably to a bit of work.
Seems the book is not really aimed at being a Ht 'Bible', but does go a long way towards helping those with a little understanding gain a little more.
Those with very little understanding, will likely learn from 'mistakes'. Or be just confused by reading this.
No argument from me, Theon. Thanks.

Tom