Frame Too Small!!!!!

awsuman123

New Member
Dec 22, 2008
11
0
0
San Antonio
I just bought a new engine for my new mountain bike and when I went to put in the engine in, the down pipe was too big so i learned that ill have to drill but I was going to dry fit to find out where to drill so then I put on the Carb. and the adaptor for the front mount now the engine doesn't fit at all the Carb. is way to tight and i dont know what to do i have no money and i need this bike to work.

PLEASE HELP!!

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NunyaBidness

Active Member
Jun 29, 2008
1,062
1
38
memphis tn
There is no need to drill the frame and it should be avoided. The carb will need a 45 or 90 degree angle on the intake to give it the room it will need.

Search around and you will find many posts on both subjects. Someone else may come in with links to those posts and if I had time I'd find 'em for ya. It will all work out just fine, these problems you're having have been solved already.
 

spad4me

New Member
Jan 20, 2008
472
0
0
Arizona Bullhead
I just bought a new engine for my new mountain bike and when I went to put in the engine in, the down pipe was too big so i learned that ill have to drill but I was going to dry fit to find out where to drill so then I put on the Carb. and the adaptor for the front mount now the engine doesn't fit at all the Carb. is way to tight and i dont know what to do i have no money and i need this bike to work.

PLEASE HELP!!

:-||:-||
First You need to measure.
Carefully remove the spark plug and the studs front and rear from the motor.
Place the motor where it will go.
Does it fit Be truthful with yourself .
Is your bike made of Steel or Aluminum.
Make a pattern of the frame exactly where the front motor mount will bolt on out of cardboard.
Trim until it fits good around the frame.
Is your bike made of Steel or Aluminum.
Please reply ?
 

cachehiker

New Member
Jul 9, 2008
35
0
0
Hyde Park / Logan, UT
The frame I'll be putting my kit into is pretty small too. Sucks that they laid off the Tig welding wizard here. I was planning on having half of a 1.5" diameter tube about 6" long welded to the top of my down tube. Two adapter plates on either side and two U-bolts would hopefully finish it off with no drilling and maximum utilization of the available space. I'm thinking I'll need every last bit of it.
 

Cabinfever1977

New Member
Mar 23, 2009
2,290
1
0
Upstate,NY
remove the airfilter and rubber band or tie the foam over the end of carb.it will work ok.
do not cut frame or drill hole if you dont have too,you can buy a u-clamp for front mount.or if you have too use a diffrent bike,it will be easier in the long run.It took me a week to modifiy my bike to get mine to fit,if i had the money i could have got a new larger bike for$100 and it wood have only took me 3-4hours.
 
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toytime

New Member
Mar 20, 2008
550
0
0
Ontario
One thing I found is that the motor can be shifted around quite a bit and the smallest move can make a huge difference. What I did one time is to drill a hole through the centre of the bracket that we use on the old thin tubed bikes. This hole gets a bolt put through it and I then installed the bracket the opposite way you normally would. You have to drill the frame but using this bracket, instead of that thicker flat one gives you a little more room to play with,
I know that was hard to follow. Take your mount off and dry fit the motor. If it fits, my way will not change anything and if need be, I could try to explain it better.
 

2door

Moderator
Staff member
Sep 15, 2008
16,326
124
63
Littleton, Colorado
if its steel,cut notches in frame and drill,mine holds up good.but dont cut more than half way threw frame poles.and remove the airfilter and rubber band or tie the foam over the end of carb.it will work fine.
only cut notches in frame if you have oversize tubing not small pipe frame.
Cut notches in the frame? NOT a good idea. There are much better, and safer ways to go about it. Spend a little time here searching through the threads on mounting before you slice into your bike's frame. It just isn't necessary and could be down right dangerous.
Tom
 

Cabinfever1977

New Member
Mar 23, 2009
2,290
1
0
Upstate,NY
you can slant the engine forward to clear the spark plug and put the carb off to the side,that should give you clearance to mount everything.make sure your chain and sprocket lines up.
 
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