79cc, 97.7cc, 99cc, gx120, or the gc160…decisions, decisions!

KeithSeymour

KeithSeymour

Active Member
Hi Guys,

I've come a long way since I first started doing my research on what motor to use for my BTR tribute bike. If you haven't read any of my other posts, Here's my scenario:

  • This is my first build even though I have done major work on cars over the years and am a good problem solver.
  • I'm building a BTR tribute and using a 1952 road master frame
  • I've been told I need to fabricate mounts because there is so much space so may as well go without a kit.
  • I'm a big guy and the legal limit for the state I live in is 35mph but have hills near where I'll be riding.

With these being established, I'm looking into selecting a motor but have some questions for you guys about the following scenarios:

Scenario 1- 79cc predator ($75 from HF with coupon) w/agk jackshaft and 2 stroke carb- Plus- Seems to be the most popular on here so there should be a lot of support along the way. Negative- lowest displacement

Scenario 2- 99cc Predator ($140 plus shipping from forum member) w/ agk jackshaft and 2 stroke carb. Plus- a lot of aftermarket support and popular on here. Negative- Can't buy it new and it is more expensive

Scenario 3- 97.7cc Lifan from Home Depot ($119) with ago 160 honda carb (thanks MotoMagz) Jackshaft- Will the agk "Doodlebug" Jackshaft work? if not, where can I get one?
Plus- good displacement, looks, negative- not as popular of a build and may have trouble finding jackshaft/aftermarket parts

Scenario 4- GC160 Honda ($75 from a local guy on CL)- CCC has recommended this numerous times on here but have no idea what to use for a Jackshaft and if the AGK GX parts work. I haven't heard back from AGK or CCC about this.
Plus- great displacement, good cost (used), honda reliability, vintage look. Negative- not sure of compatibility of gx parts or jackshaft
***Update- Culver City Classic recommends using this CVT:http://gokartsusa.com/Gokart_Torque_...mpatible_.aspx

Scenario 5- GX120 Honda ($100 from local guy on CL)- I see AGK has gx120 parts but I wasn't clear on the jackshaft I should use. Thoughts?
Plus- honda reliability, good displacement, good cost (used) Negative- Jackshaft, not seen many people on here use them, not sure of vintage looks

I'm drawn to the hondas for the reliability and the upright stance. Cost/budget is an issue but understand waiting/saving to pay for quality. What are your recommendations for what I should go with? I don't really like the thought of building something then upgrading shortly after (I like the idea of a 212 but don't trust the strength of my 61 year old frame). Thanks for all of you who have helped me thus far and thanks in advance for your replies.

Keith
 
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Culver City Classic just got back to me and he recommends the GC160 with a CVT not a Jackshaft. He also recommended buying it new which may eliminate this option coming in at around $220 (a quick google search). Just putting this up here for future reference of anyone considering these options.
 
Just a heads up on the compatibility.....the GX performance parts will not work on the GC series Honda engines.

All of the engines that you're choosing from are fine engines for powering a bicycle. I'm using a 99cc Pred for my daily rider and a 212cc Pred at the race track.
 
Scenario 1- 79cc predator ($75 from HF with coupon) w/agk jackshaft and 2 stroke carb- Plus- Seems to be the most popular on here so there should be a lot of support along the way. Negative- lowest displacement
Click to expand...

I am using the 79cc with the AKG jackshaft and stock predator carb and it will run 40 MPH.
 
KeithSeymour said:
Does this work with the Lifan 97.7cc? This says it's for the 79cc and 99cc predator and I haven't heard back from AGK if that's compatible.
Click to expand...

If you click on "select engine" it shows 79cc blue harbor freight, 79cc predator, 99cc predator, 97cc Lifan flat head
 
Here is the lifan flat head with the AKG.The flat head is being replaced by epa ohv...which I am installing on my next build.Great little engine.Hondas are the best for aftermarket parts
 

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I still think the GC160 is a better option since the OP is on a limited budget. He can pick up a used motor for a good price and a new CVT for the same price as the jackshaft. If going with a jackshaft he will need to purchase a good clutch so it does not chatter (another 200.00)

He will be pleased with the power and performance of this combo. I have run both and think the CVT for a street bike is the only way to fly.
 
Keith,
I just uploaded my current daily driver "Raven" in the album "from Barry's Shop". It's a 79 Preditor (modified to a 49cc, I'll send you the new photo shopped decal if you like). It has a lot of low end power but, seems to vibrate a bit while accelerating and mid-range throttle settings. It does well for an old fat fart (see seat).
 
birdmannn101 said:
Affordable Go Carts is where I bought my linkage kit for $12. http://www.affordablegokarts.com/mm...e_Code=A&Product_Code=2900&Category_Code=99cc They sell the linkage for the stock Harbor Freight carb.

Here is a You Tube video on it http://www.youtube.com/watch?v=Or_-Avn_zfo
Click to expand...

Very helpful to know!

Anyone have any experience running the stock gc160 carb with a motorbike application?

I think I've landed on my decision. I'm really leaning toward the gc160 for several reasons:
Upright stance similar to vintage btrs
Honda reliability
Higher displacement for my fat butt
Cvt instead of jack shaft and chattering clutch

I know the 79, 98 nd 99cc engines would probably do the trick but feel like I'd regret not going with my first choice up front.

Going to check out a used gc160 tomorrow locally. Any tips I should be aware of besides having him start it up, etc?
 
You know you need more room for the Gc160.So ...if you do have the means to get a drop loop put into the frame you should go with the Gc160.If you can't or are not going to modify the frame then go with one of the others that will fit the stock frame.As for tips on engine look for obvious wear..if it looks beat it probly is.
 
MotoMagz said:
You know you need more room for the Gc160.So ...if you do have the means to get a drop loop put into the frame you should go with the Gc160.If you can't or are not going to modify the frame then go with one of the others that will fit the stock frame.As for tips on engine look for obvious wear..if it looks beat it probly is.
Click to expand...

Good point. CCC said it was 12.5 inches tall in another post. I originally measured my road master frame and thought I had adequate space. Your post reminded me that I hadn't measured for it since installing the chainring and crank. I just ran down to the garage and from sprocket to my straight bar, I measured 10.5". The only way I got over 12.5" was if I leaned the motor toward the front which I don't think it would fit. I would like to think that I would've realized this before purchasing the gc tomorrow but I am so excited to buy a motor that I probably would've overlooked it. Thanks for pointing that out and saving me some $. :)
 
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