97cc engine ?'s

A

apekd

New Member
#1
#1
I am picking up a doodlebug with a 97CC engine on it. and I have a few questions about them

1) My old co-workers use these engines on theirs and with a few mods they are flying around and keeping up with the 6.5 hp motor my old boss has. besides taking the governor off, what else can increase the top speed besides gearing?

2) I work in a machine shop, and I was thinking of milling the head a bit, and doing some work on the valves as well. How much milling should be done, and if needed, what kind of carb should be thrown on? also, can 3 angle valve jobs be done on these engines?

3) I know some people have installed lights on their own DB's and I am wanting to do the same, just a head light, tail light and 2 turn signals for the front and back (all LED cept for the head light, HID) did anyone who did this just use a motorcycle battery or something else?

thanks guys. I have been browsing for a while, and figure that since i am picking mine up next week for 150, that I should register at last. :scooter:
 
minibikedude

minibikedude

Active Member
#2
#2
Sell the engine on ebay and get a 6.5 clone engine and new 3/4 inch clutch is the best way to go if your an adult thats going to be riding it. The stock engine is not that good and way under powered. Your time and money would be better spent going with the 6.5.
 
8

845mx5

New Member
#3
#3
There isnt anything you can do to that engine to make it equal to the 6.5. I mean, you could re re-engineer the whole engine, but thats not practical. Taking the governor off will not helo you. The stock engine is underpowered. I weigh 130 pounds and i had to push off even on pavement. When i went on the grass and stopped, it wouldnt go again unless i pushed it all the way back to pavement. Like minibikedude said, sell it on ebay, grab a 6.5 and maybe a mounting plate from ctjmini here on this site. 3 of the stock engines wouldnt equal one 6.5. A valve job wont add enough power to matter. Nor will milling the head.
 
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apekd

New Member
#4
#4
k so a 6.5 sounds like the only route? i go to harbor freight a lot and was wondering if the 6.5 they sell would be worth it? 160$ brand new. I can get clutches from a local shop. We have a 97cc that pushes around me and my friend. both of us weigh about 190 each. it has been milled and decked, and has some other things done to it. so I think till I get 160, ill just keep the 97cc for a while. Working at a gas station sucks haha.
 
A

apekd

New Member
#6
#6
I was actually looking around and saw that people used the 11/13 hp engines. So I think for 300 I can spend a paycheck on it for a 11hp with electric start.

yeah I get the coupons ALL the time haha thanks for that too man. when I get it ill tinker with the 97cc for a few weeks till I get the 11hp w/elec start.
 
Strigoi

Strigoi

#7
#7
have you seen those in person? they're huge and fitting one on a DB isn't going to leave much space.

mods are also 2-3 times more expensive than those for a 6.5.

i've got a coupon for a 6.5 for $109.99 that i could send you. it's valid until 11-30.
 
TT

TT

#8
#8
apekd,

Welcome to the Forum. I see a few things were not mentioned. I do agree at 190 lbs. the only way to go is Harbor Freight 6.5 HP with a Max Torque 3/4" 12 tooth # 35 chain clutch. You will need a chain breaker. Also, Harbor Freight sometimes sells the motors for $99.00 with the coupon. Be sure to look for a gas cap that is slim. Not 2 1/2" thick. It will not fit. Then or/ contact CJTMINI and he can supply the motor if you cannot find the one that has the smaller gas tank and cap. It is very important to get the right motor. Manufactures Supply under the search engine (mini bike) you can buy chain, breakers and clutch. Pay Chris (cjtmini) and it is all sent to your door. I would not bother with the 2.8 HP unless you have a small 12 year old child riding this machine. Again!! Welcome and good luck and have some fun. We are here to help you if you have additional questions....

Hundreds of upgrades have been done, it's easy it has a video too...

TT out! :doah:
 
A

apekd

New Member
#9
#9
yeah I actually scrapped the 11/13 hp idea about 30 minutes after i saw it. I saw the mods for the 6.5 and all the things you can do them and said screw the bigger ones haha

thanks for that info

anyone happen to know about the tail light/brake light idea?
 
A

apekd

New Member
#11
#11
haha thanks. Yeah ill be going to HF in december to get the 6.5. I plan on doing the header, new jet, and air filter. Since I work part time in a machine shop, I am gonna have my co worker make a small shield for the air filter to keep SOME of the dirt off of it as it will be messed with on the dirt more than driving it to and from places during summer. as soon as I get the bike I plan on starting a build thread on here. maybe by May (my birthday) I should have started building the 6.5. I plan on getting it ready for 9-10 hp as my old coworker and I plan on using an old 2.9L airpump as a supercharger. so it should be entertaining
 
milo raptors

milo raptors

New Member
#13
#13
yea with just a good header rejet and filter you might get just 1 or 2 horses outa that since you work in a machine shop you could prolly port an polish it an mill the head for more horsy easyily thes litle motors are a boat load of potentinal but once you hit 15 to 20 horse power it isnt very wise to use the clone block oh an try not to rev its guts out to bad
 
8

845mx5

New Member
#14
#14
Im glad you scrapped the 11 or 13 hp idea. With that you also need a battery to start it. The 6.5 will offer plenty of power right out of the box. You may get it and decide you dont even need to mod it. Im not sure what kind of filter you will put on it but dirt shouldnt be a problem. Meaning dont bother with the shield. If you have an aftermarket filter you can get a clotch sleeve for it that works great. As for the supercharger, dont bother. You need power to make power. A supercharger has to be drivern off of the engine, like the crank/pto. For about 300 bucks you can get parts that will get you to 8hp. ACTUALLY, I think NR-racing ahs a prebuilt engine that has 8.5 hp when you get it. I think they just add a jet, filter and header. Thats about 230 bucks.
 
awkwardkitten

awkwardkitten

New Member
#15
#15
Wow you guys are all reading my mind because that's exactly my plan when I get my 6.5, Cjtminis header, jet, a UNI air filter from AGK, and some 18 pound valve springs. And maybe governor removal. Since I'm only 13, I don't think Ill be needing much more.
 
milo raptors

milo raptors

New Member
#16
#16
awkwardkitten said:
Wow you guys are all reading my mind because that's exactly my plan when I get my 6.5, Cjtminis header, jet, a UNI air filter from AGK, and some 18 pound valve springs. And maybe governor removal. Since I'm only 13, I don't think Ill be needing much more.
Click to expand...
yea youll need a billet rod if you ditch you gov
 
awkwardkitten

awkwardkitten

New Member
#17
#17
Yea I was thinking about that. First off, i dont think ill be going anywhere past 6000 rpms, and I know it still is a good idea. plus Im not sure I would be able to install one. Ive looked at the AGK guide, but maybe I just havn't had enough experience yet.
 
Strigoi

Strigoi

#18
#18
swapping the rod isn't hard. you need an inch pounds torque wrench, 12pt 1/4" socket and a ring compressor. actually, you don't need the ring compressor, it just makes it easier.

you also need feeler gauges for setting the valve lash since you'll have the head off.

if you aren't ready to buy/install the supporting mods for removing the governor, don't mess with it.
 
A

apekd

New Member
#19
#19
Yeah I was looking into removing it at well. Since I will have the money, time, and others who know more about the motors than I do I have support for if I have questions.

supercharger idea ACTUALLY got scrapped this afternoon after my friend called and said that he might be able to get his hands on some good SMALL diesel turbos that just need a rebuild. being as he rebuilds larger turbos a lot, we are gonna try to get some and use them. my coworker at the shop is gonna help make the manifold, after turbo exhaust, and aluminum piping to the carb. also gonna make the turbo inlet too. Talk about a swell guy ;)

oh yeah. Im thinking of getting a jack shaft kit. I saw a video on youtube, but no website for it. I was really impressed as the guy was 220 and it pulled him uphill on the 97cc with just a filter, jet and header. :wink:
 
awkwardkitten

awkwardkitten

New Member
#20
#20
Strigoi said:
swapping the rod isn't hard. you need an inch pounds torque wrench, 12pt 1/4" socket and a ring compressor. actually, you don't need the ring compressor, it just makes it easier.

you also need feeler gauges for setting the valve lash since you'll have the head off.

if you aren't ready to buy/install the supporting mods for removing the governor, don't mess with it.
Click to expand...
I have the tools I need, and I guess spending an extra 60 dollars for a rod and pretty much having the ability to go much faster without worrying about the engine blowing up would be well worth it. Plus I know a guy that could help me with it If I ran into any real trouble.
 
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