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

Members Login
Post Info TOPIC: I stripped my carb today


Veteran Member

Status: Offline
Posts: 54
Date:
I stripped my carb today
Permalink  
 


I stripped the carb today.  Good news, I didn't break the float pin post.  Bad news, the diaphragm is toast.  Weird news, the pumper wouldn't have worked anyway.  In stead of 2 o-rings, the in and out jets were blocked off by solid rubber rings.  I wonder if it was disabled from the factory or whether someone McGuyver'd the carb when the diaphragm wore out.  I see some ponies circling...  Unfortunately the damn diaphragm is almost £35   :'(

The trick with the float pin is pull the pin in the direction of the arrow.  It WILL break if you try to push against the arrow, that hole is smaller.  I also rotated the pin as I pulled.  It was still hair raising none the less.

I found a leak on the boost bottle / intake rubber mount.  Sent a pic to my friend who purchased a TTR recently as well and his showed the same.  Fixed it with some gasket maker - I hope.

The choke seems adjustable, is it?

Lastly, the agents supplied the wrong o-ring on the side of the carb.  This usually happens when a part shows as superseded.  Anyone experience the same?



Attachments
__________________


Guru

Status: Offline
Posts: 501
Date:
Permalink  
 

why do you bother with other suppliers get in touch with steve at totally ttrs good service good prices trained by our ttr god brian what more can i say

__________________


Veteran Member

Status: Offline
Posts: 54
Date:
Permalink  
 

Whoa there Johnboy. I am in darkest Africa. The postal service is a lottery and the Rand/£ exchange rate is a joke.

Added to that, I cancelled my credit card a while back. Makes buying on line a wee bit difficult. ;)

If I could, I would though.

__________________


Super Guru

Status: Offline
Posts: 6629
Date:
Permalink  
 

I am very grateful for the endorsement John wink

The arrow on the float post is confusing so thanks for the clarification. Take the pin out in the direction of the arrow and replace it in the reverse direction.

Once the diaphragm is holed then it opens up a connection into the top of the carb for petrol/air hence why the PO bodged it with the "solid" O rings cry

You will find the TTR a lot more responsive once you have sorted out the diaphragm smile

The factory used some sort of silicone seal for the resonator chamber but use anything that will make it airtight so that it doesn't draw in "dirty" air at that point. You want all the air to go through the filter.

I noticed the other day that the choke can be adjusted by moving the E-clip - similar to how the carb needle is adjusted. I can't think why it would need changing from the factory setting though. 

The O ring on the side of the carb is a special one and is square in section, I doubt if anything other than the genuine part will cut the mustard.

We are lucky in the UK to have Steve who can supply most parts (next day if required) with sensible shipping costs. I can understand the frustration of sourcing TTR parts in other parts of the world - especially where their Post Office is unreliable or downright dishonest such that parcels never arrive no

Brian

 



__________________

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/ 



Veteran Member

Status: Offline
Posts: 54
Date:
Permalink  
 

I ordered the correct oring again.  If they can't supply again I will contact the TTR shop.  And buy a lottery ticket on the same day...  ;)



__________________


Veteran Member

Status: Offline
Posts: 54
Date:
Permalink  
 

I serviced the rear suspension and assembled the carb. The 13 tooth front sprocket made the bike more lively. :)

There is a bit of advice that says not to change too many items at the same time, I changed a lot.

I cut the snorkel as explained somewhere in the forum and decided to cut out the center section to increase the volume - I wanted extra flow and to still maintain some water protection to the airbox. It finished off nicely using a dremel. I do not know if this is causing a surge on low rev, small throttle openings, but I now have a stumble on part throttle. Changing the fuel screw doesn't seem to affect anything. Any suggestions?

__________________


Super Guru

Status: Offline
Posts: 6629
Date:
Permalink  
 

What size pilot jet? I cured a low speed stumble recently by swapping out the 48 pilot for a 50. I did the airbox cover test which suggested a weak mixture....



__________________

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/ 



Veteran Member

Status: Offline
Posts: 54
Date:
Permalink  
 

You are a legend man.  Been reading old threads the whole afternoon and the help you give has made many a happy owner.

I already have a 50.  It seems South African bikes came stock 50/147.  I am happy that the carb is squeaky clean.  The only doubt I have is that my McGuyver of two small o rings on the fuel screw is working.  The old one was brittle and the o ring is only available with a new fuel screw.  I had the correct size, but slightly more than half the width, thus two narrower ones in the same groove.

That aside.  The only change I had made extra was hollowing out the airbox rubber and shortening it.  Prior it ran well, just very low on power.  I have just drilled the extra hole in the exhaust to complement the 'airbox mod'.  This will be the only mods I make.  I suspected that the needle needs to be a bit richer, for the overlap between needle and pilot.  Just came back from a test ride.  It is seriously worse.  That only leaves one conclusion.  Either the needle or the needle jet is worn.  I will try a leaner - 1 above stock - needle position tomorrow for interest.  I read somewhere that that worked even though it is counter intuitive when increasing the airflow...

Thanks again for taking the time to respond to this thread.

 



__________________


Veteran Member

Status: Offline
Posts: 54
Date:
Permalink  
 

Just some feedback. Went leaner on the needle and all is well now. Weird, but as long as the stutter is gone.

__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard