A forum for owners of Yamaha TTR250 trail and enduro bikes!

Members Login
Username 
 
Password 
    Remember Me  
The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> intake questions
Post Info TOPIC: intake questions
commanderjjones


Member

Status: Offline
Posts: 5
Date:
intake questions
Permalink  
 

Hey guys. I just picked up an '05 TTR 250 this past Wednesday (so I haven't had a chance to get a manual yet) and have a few questions. I was hoping to ride it tomorrow, but ran across a couple of issues when I started servicing it last night.

 

When I started to clean the air filter, I noticed a couple of hoses and nipples that weren't connected to anything, but looked like they definitely SHOULD be connected to something or plugged. I've attached pic's with descriptions below.

 

This is the first one thing caught my attention. I had to remove the seat to confirm, but just as I suspected, that fitting (circled in red) goes directly into the intake tube. So it has been sucking unfiltered air facepalm.gif ......NOT good. Other than these minor intake issues below (which I unfortunately didn't notice BEFORE I bought it), the bike appeared to be in good shape, does not smoke, and compression is good, so all I can do is hope no damage has been done. Since I don't have a manual yet (but will be correcting that immediately), I looked up the parts fiche and discovered there is a small chamber that is supposed to be there. The fiche calls it an "air chamber"......Yamaha part # 4GY-13591-00-00.  Although the drawing is poor, it appears to have 2 holes......so I assume there would be another hose hooked to that chamber. Can someone confirm if that is correct and, if so, where does the other hose go to? Also, can this chamber just be eliminated (by plugging the hole in the intake) or will removing it affect performance?

20160128_202005_zpswuzlwppx.jpg

 

20160128_202049_zpstruojahd.jpg

 

So here are the other problems. Just below the intake is what Yamaha calls a "breather assembly". It has one hose presently attached, but has a fitting on top with nothing attached to it (center red dot at 12 o'clock position). There is a hose that comes from the carb (left red dot at 9 o'clock position) that isn't attached to anything.....it has a one-way check valve on the end, but unless there is another section of hose missing, it doesn't appear that it's supposed to attach to the breather or to the air box. Is that hose supposed to attach to the missing air chamber? Also, there is a nipple on the air box (right red dot at 3 o'clock position) that doesn't have a hose hooked to it.

 

Can somebody help me with the hose details? I have a ride planned tomorrow and was REALLY wanting to ride this thing, but it isn't looking good so far.

 



__________________
Moo


Senior Member

Status: Offline
Posts: 389
Date:
Permalink  
 

Left red dot and 9o clock is the carb overflow, so fuel can come out of that.

The black chamber in the bottom picture is the emulsifier pot and will fill with emulsified oil occasionally, so can need checking sometimes. If memory serves me right it connects to the airbox and the engine crankcase breather.

__________________
commanderjjones


Member

Status: Offline
Posts: 5
Date:
Permalink  
 

I've found some pic's online and confirmed that the line from the breather does connect to the airbox, as stated above.

So is the carb overflow line supposed to attach to the missing "air chamber". And if so, are there any negative effects by eliminating that chamber, or do I need to replace it?

__________________
Moo


Senior Member

Status: Offline
Posts: 389
Date:
Permalink  
 

Nope, the carb overflow just hangs free downwards

__________________
Cubber


Super Guru

Status: Offline
Posts: 2610
Date:
Permalink  
 

Will these illustrations show you where and what are attached? confuse

These are the carb pipes

Carb.jpg

 

AND here are the filter box fittings

Filter.jpg

Martyn



__________________

You're never too old to learn something stupid

East Budleigh. Devon
mossproof


Super Guru

Status: Offline
Posts: 1436
Date:
Permalink  
 

The cut off pipe on top of the air inlet hose can be blanked off/plugged with no discernable affect. There was a thread a while ago about what the "air chamber", part 21, actually does - sort of balances out the resonance and backwash of airflow through the 4 stroke cycle, IIRC. (Sounds good hey, but I don't really have a clue what I mean Part 22 is a cyclone filter that removes oil from the air coming down the tube from the crankcase beather before it enters the airbox. It MUST NOT be blanked off. Side inlet from crankcase/engine top cam cover depending on age of bike, top outlet goes to airbox (upper of the 2 small tubes), bottom outlet goes to a short collector which, as Moo states, needs emptying from time to time.
Enjoy the ride, and welcome to the world's friendliest forum!
Simon.

__________________
TTRfan


Super Guru

Status: Offline
Posts: 8607
Date:
Permalink  
 

Trying to find some helpful photos:

Emulsifier 1.jpg

 

Emulsifier on airbox.jpg

 

Air chamber.jpg



__________________

Exeter, Devon, UK

http://www.ttr250.com  - The one and only dedicated TTR250 FAQ!  

TIP: For easy viewing bookmark the "Recent Posts" view - http://ttr250.activeboard.com/p/recent/ 
commanderjjones


Member

Status: Offline
Posts: 5
Date:
Permalink  
 

Moo wrote:

Nope, the carb overflow just hangs free downwards

 OK, thanks. It just struck me as needing to be attached to something. I have worked on A LOT of bikes over the years but have never seen a check valve attached to the end of an overflow tube. Is that valve really supposed to be there??? I'm not seeing it on the parts fiche anywhere. Looks like part 34 and 47, but their description just says "pipe". Maybe the description is wrong.



__________________
TTRfan


Super Guru

Status: Offline
Posts: 8607
Date:
Permalink  
 

Both of the carb breather pipes are open at the top where they bolt to the airbox and have one-way valves at the bottom of their run.

Carb pipes with one-way valves.jpg

The petrol overflow pipe from the carb float bowl attaches to the underside of the carb float bowl.

Carb overflow pipe.jpg



__________________

Exeter, Devon, UK

http://www.ttr250.com  - The one and only dedicated TTR250 FAQ!  

TIP: For easy viewing bookmark the "Recent Posts" view - http://ttr250.activeboard.com/p/recent/ 
commanderjjones


Member

Status: Offline
Posts: 5
Date:
Permalink  
 

You guys are great. Thanks for the welcome.

I'm gonna plug the intake port where the air chamber "should" be and run it like that for a few rides and see how it runs. If there are no running issues, I'll make the plug a permanent fix.

I can't wait to go ride this thing. I've owned NUMEROUS Yamahas since I was a kid, even a few Yami 4 strokes, but this is my first TTR. Looking forward to something with more manageable power than my previous YZF.

__________________
commanderjjones


Member

Status: Offline
Posts: 5
Date:
Permalink  
 

TTRfan wrote:

Both of the carb breather pipes are open at the top where they bolt to the airbox and have one-way valves at the bottom of their run.

Carb pipes with one-way valves.jpg

The petrol overflow pipe from the carb float bowl attaches to the underside of the carb float bowl.

Carb overflow pipe.jpg

 Excellent. Thanks for the confirmation. I feel better now.



__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.
The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> intake questions


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard