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 -> Does your petrol cap breather breathe properly? The question nobody is interested in :)
Post Info TOPIC: Does your petrol cap breather breathe properly? The question nobody is interested in :)
barra8


Guru

Status: Offline
Posts: 932
Date:
Does your petrol cap breather breathe properly? The question nobody is interested in :)
Permalink  
 

Hey all,

            This may be one for Brian or someone that has larger than standard jets installed. My question is as the topic suggests.....on a blue plastic tanked model TTR, does your breather breath properly as mine does not seem to even though i have made sure it is right. Yes i have taken the three screws out....yes it's working properly but no it does'nt breath properly.

I only noticed this from my muddy episode recently when the mud had got into the breather pipe i have fitted. It does not have the one way breather as the billet one i bought on ebay blocked almost instantly. Still trying to find the genuine part (i have it here somewhere). Anyhow this is not my problem now. My problem is that even if i do not use the breather pipe.... the fuel does not flow fast enough. I only relized by taking the lid off as i'm riding along & it went a ''fair'' bit better. I'd say about 10% more power.

So does your breather breath properly?

This problem may be only for people with larger jets installed.

I might add that i have a fuel filter but this i don't think is the problem as it is always full.....when it can breathe.

Thanks in advance.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

barra8


Guru

Status: Offline
Posts: 932
Date:
The question nobody is interested in :)
Permalink  
 

Well since nobody replied i'm guessing ........Brian has a standard Main jet #147 with #52 pilot. I'm not sure how or why but it seems this is the case. Maybe elevation/climate has alot to do with that. One thing i do know though is my bike would not run on a standard main jet #147 or it's way too lean.



I'm still interested to see if anyone is having the same problem as me (described above) but what i am even more interested in is...........If anyone has done mods & changed their main jet & pilot does your standard fuel cap breathe enough,because mine does not seem to.


Also if anyone knows of a decent replacement for the fuel cap ie. high flow please let me know.


Your help on this one would be appreciated as i don't want to gamble with buying a new fuel cap.

I'm pretty sure it is the cap now but i have no idea where to find a decent one. I'm thinking ......Moose racing? Tusk? GYT-R? Still have no clue where to find these & whether or not they would work though hmm


Thanks in advance (if anyone even replys)

 

.................
Jarrah.





-- Edited by barra8 on Friday 25th of January 2013 02:16:34 AM

__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

brindabella wrote:

I don't much fancy riding around flat out without a fuel cap on!

But yeah, a blocked cap breather can (after quite a while) cause a partial vacuum in the tank which reduces fuel flow to the point where the float bowl does not refill properly. But if you stopped and removed and replaced the cap to let air back in and allow fuel flow to the bowl, then start riding again, the performance should be better for at least several km of high speed running. If not, the problem surely lies elsewhere. If you have another bike, try riding with it deliberately blocked to see how long it takes for any effect to be noticed.

 Lol you don't have to ride around without a fuel cap...........All you have to do is ride for about 3 klms or 2 on dirt & loosen it until it lets air in.

I know it is the problem now & have checked my cap as mentioned & it's working how Mr Yamaha intended.

The question was more to see if other people have this problem ......or is it just me using the #150 main & #52.5 pilot?

More to help other people & find out if anyone has had this problem.

............................................

Jarrah.





-- Edited by barra8 on Friday 25th of January 2013 07:14:03 AM

__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

noeyedear wrote:

I have the same problem on a Honda year ago, after fitting a dyno jet kit. have you.tried a different cap? Worked for me.

 Well that explains it...I was still leaving the fuel filter as a culprit but now i'm fully convinced. What fuel cap did you buy for it & did it last?

I edited to say thanks for replying & fix a few spelling mistakessmile

..............................

Jarrah.



-- Edited by barra8 on Friday 25th of January 2013 07:21:57 AM

__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

BM Steve


Guru

Status: Offline
Posts: 691
Date:
Permalink  
 

I guess your talking about the fuel tank cap and so this may sound a bit obvious but can't you drill a hole in the cap somewhere and make it breath better ?

Haven't tried mine without the cap, so will be interesting to try it out.



__________________

2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.

 
barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

BM Steve wrote:

I guess your talking about the fuel tank cap and so this may sound a bit obvious but can't you drill a hole in the cap somewhere and make it breath better ?

Haven't tried mine without the cap, so will be interesting to try it out.

 Wahoooeeee a reply

Yeah Steve the fuel cap wink

Can't wait to see what your findings are aww

..........

Jarrah.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

brindabella


Senior Member

Status: Offline
Posts: 168
Date:
Permalink  
 

I don't much fancy riding around flat out without a fuel cap on!

But yeah, a blocked cap breather can (after quite a while) cause a partial vacuum in the tank which reduces fuel flow to the point where the float bowl does not refill properly. But if you stopped and removed and replaced the cap to let air back in and allow fuel flow to the bowl, then start riding again, the performance should be better for at least several km of high speed running. If not, the problem surely lies elsewhere. If you have another bike, try riding with it deliberately blocked to see how long it takes for any effect to be noticed.

__________________
noeyedear


Senior Member

Status: Offline
Posts: 199
Date:
Permalink  
 

I have the same problem on a Honda year ago, after fitting a dyno jet kit. have you.tried a different cap? Worked for me.

__________________
barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

Let me make this easier for everyone.....What would you prefer.....the outlaw ones on ebay (very worried :worried: ) These piranha  ones (look okay) or these tusk   ones or a GYT-R (yet to find)

Hopefully Steve is still game enough to open his fuel cap up & try what i decribed though (just out of interest)

..................................

Jarrah.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

TTRfan


Super Guru

Status: Offline
Posts: 8565
Date:
RE: Does your petrol cap breather breathe properly? The question nobody is interested in :)
Permalink  
 

I only ever had breather problems once Jarrah and that was caused by the mechanism in the cap catching a bit of rust and jamming and not allowing air in.

Otherwise my blue TTRs have been fine.

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/ 
noeyedear


Senior Member

Status: Offline
Posts: 199
Date:
Permalink  
 

I changed the cap for another standard Honda fuel cap. looked identical just new, not sure what's inside the cap that can go wrong ?¿? but only had issues after rejetting and mechanic suggested the fuel cap. sorry can't be of.more help. Adrian

__________________
barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

Oh okay.........Thanks for the info.

Brian.......This problem is not noticable unless you take your tank cap off after riding about 3klms.

Well looks like this problem is unique to my bike as the fuel cap looks really good (apart from the screws that i had to replace & now a little rusty).

If i cannot modify it in some way (have'nt checked yet) than i guess i'll have to gamble my money away on ebay no Hope i get a decent one.

Thanks all for replying.

...............................



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

BM Steve


Guru

Status: Offline
Posts: 691
Date:
Permalink  
 

I have devised a method to check the fuel cap

1. Remove Cap

2. Stick tube in mouth

3. Blow

biggrin



__________________

2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.

 
barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

For all you picture junkies biggrinbiggrinbiggrin

I must find some alloy screws for the fuel cap though. It only took a mth for these to rust. no

What i did was took it apart  & drilled out the 4 holes....then the top hole...Job done......(very technical i know) wink

It looks as though it's cracked at the screw hole but it's just the pic. Must be plastic from drilling or such.

014.jpg004.jpg

....................................

Jarrah.




-- Edited by barra8 on Saturday 26th of January 2013 12:15:24 PM

__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

Lol......Your one way breather is either stuffed or not attached while doing this i guess smile

It is not the fact that my cap does not breathe....AS DESCRIBED IT WORKS PERFECT! lol. It is the fact it does'nt breathe enough.

Still wondering which cap i should gamble on but i'll let yaz know when i find a decent one.

 

...............................

Thanks for the help everyone.

Jarrah.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

Actually ........i took it off (for the third time) & this time i took it apart (again) to see if i could modify it. Turns out it's an easy job but not sure if its the ball not letting enough in yet or the tiny hole. I'm guessing tiny hole so we will see. smile

Oh once again YES it works like Mr Yamaha intended. (Just to satisfy the unsatisfied people :)

.............................

Thanks all.

Jarrah.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

Just to finish this tread off.....I drilled it out now & instead of it being like trying to blow up a balloon now it blows through easy.....Using BM Steve test (very technical :)

............................................

Cheers all

Jarrah.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

Cubber


Super Guru

Status: Offline
Posts: 2608
Date:
Permalink  
 

I'm surprised that you are having so much trouble with a fuel cap, Jarrah. bleh

Australian petrol must be a different product from our brew in the UK which is 5% ethanol.

This is a shot of my 13 year old TTR petrol cap for comparison:-

Cap.jpg

As you can see there is no corrosion at all. disbeliefsmileno

I can vouch for its effectiveness too - not a drop spilled when the bike was on its side for a few minutes the last time (of many) it toppled on a trail.

Martyn



-- Edited by Cubber on Saturday 26th of January 2013 12:53:19 PM

__________________

You're never too old to learn something stupid

East Budleigh. Devon
BM Steve


Guru

Status: Offline
Posts: 691
Date:
Permalink  
 

Happy Australia Day to all you Aussies

Just came back from stuffing myself, Prawn, Chicken, Salad, Pavlova, Fruit and of course BEER wink

Hey Jarrah, Only 30 more posts to hit the magic "1000" posts

Quite an effort



__________________

2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.

 
barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

BM Steve wrote:

Happy Australia Day to all you Aussies

Just came back from stuffing myself, Prawn, Chicken, Salad, Pavlova, Fruit and of course BEER wink

Hey Jarrah, Only 30 more posts to hit the magic "1000" posts

Quite an effort

 Same to you Steve & HAPPY AUSSIE DAY TO ALL.

Make that only 29 posts now wink

Well back to drinking BEER

Cheers to everyone

..................................

Jarrah.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

TTRfan


Super Guru

Status: Offline
Posts: 8565
Date:
Permalink  
 

I took some time out of rebuilding my 325 engine to have a look at some spare caps. Using a short length of clear pipe I was able to easily blow down through all 3. There was no feeling of restriction and I could get a lot more air through than even a big jet could pass petrol.

I honestly can't see why it would be necessary to drill the cap as the other two holes will still be smaller confuse But I am happy to be persuaded wink

Brian

Blue petrol cap dismantled 001.jpg

Blue petrol cap dismantled 002.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/ 
barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

While we are still (kinda) on the subject it seems that all Australian fuel must be labeled E10 if it is Ethanol fuel ect. to be sold. It suits me though as that stuff is HORRIBLE!


As a fuel

Energy content of some fuels compared with ethanol:[57]
Fuel typeMJ/LMJ/kgResearch
octane
number
Dry wood (20% moisture) ~19.5 
Methanol17.919.9108.7[58]
Ethanol21.2[59]26.8[59]108.6[58]
E85
(85% ethanol, 15% gasoline)		25.233.2105
Liquefied natural gas25.3~55 
Autogas (LPG)
(60% propane + 40% butane)		26.850. 
Aviation gasoline
(high-octane gasoline, not jet fuel)		33.546.8100/130 (lean/rich)
Gasohol
(90% gasoline + 10% ethanol)		33.747.193/94
Regular gasoline/petrol34.844.4[60]min. 91
Premium gasoline/petrol  max. 104
Diesel38.645.425
Charcoal, extruded5023 
Main article: Ethanol fuel

The largest single use of ethanol is as a motor fuel and fuel additive. More than any other major country, Brazil relies on ethanol as a motor fuel. Gasoline sold in Brazil contains at least 25% anhydrous ethanol. Hydrous ethanol (about 95% ethanol and 5% water) can be used as fuel in more than 90% of new cars sold in the country. Brazilian ethanol is produced from sugar cane and noted for high carbon sequestration.[61] The US uses Gasohol (max 10% ethanol) and E85 (85% ethanol) ethanol/gasoline mixtures.

USP grade ethanol for laboratory use.

Ethanol may also be utilized as a rocket fuel, and is currently in lightweight rocket-powered racing aircraft.[62]

Australian law limits of the use of pure ethanol sourced from sugarcane waste to up to 10% in automobiles. It has been recommended that older cars (and vintage cars designed to use a slower burning fuel) have their valves upgraded or replaced.[63]


.................

Of course there is quite a bit of evidence to suggest that ethanol raises the octane level. But if it's already a cr@p standard then it would'nt help much. Especially not with valves smile

Also not so sure about running mine on 5% water & 10% sugar cane.

I only run premium 98 in my bike &......I'd prefer my bolts going rusty than using the bad word ie. ETHANOL wink

 

Enhanced Petrol and Engine Performance

Premium 98 is a high performance fuel with an octane rating of 98, compared with standard unleaded petrol which has an octane rating of 91. The high octane rating gives you optimum engine, cleaner burning and higher engine performance. Premium 98 will give your car more zip!

Premium 98 Benefits

Engines fitted with knock-sensors can take advantage of the higher octane level. It allows the engine to be more efficient and have better fuel consumption due to cleaner and more complete burning of fuels. This will allow your vehicle to travel a greater distance compared to standard unleaded petrol.

Benefits of Premium 98:

  • Better fuel economy 
  • Better engine performance 
  • Cleaner burning of fuel 
  • Higher performance fuel

I was running BP ultimate in my car awhile ago but i can't seem to find it. Guess it's off the market but there similar brands available in Austraila & of course Ethanol.

Awesome article i found....

...........................................................................................................................................................................................................................................................................

Conclusion

Frankly, the results of our test were a bit confounding. We consulted the chemists at Super 104+ and our pal Tim Wusz at 76 to help figure out what had happened. Heres what we learned:

First, the octane booster did work. However, we saw that octane alone does not deliver horsepower; it only allows more complete utilization of the hard parts in the engine. Wusz said, An engine does not know what the octane rating of the fuel is, unless it is too low; note that we made less power by adding booster to 91-octane fuel. The lower the octane of the base fuel, the more benefit youll get from octane booster.

Also, the Edelbrock heads on our test motor have high-efficiency combustion chambers that are very tolerant of low octane levels, and their aluminum construction helps, too. Older chamber designs may not be as efficient and may succumb to abnormal combustion more easily.

But most of all, we discovered that our presumption that higher-octane fuels burn slower than lower-octane fuels (and therefore require more ignition lead) is largely incorrect. There are too many other fuel-formulation issues at work to assign a general rule about octane. Race fuel tends to have a more powerful formulation than pump gas, regardless of octane rating, because it is denser and can release more power and heat. (Note that we made the best power with 114 octane with the least ignition lead, indicating it had the fastest burn time.) California pump gas is blended with methyl tertiary-butyl ether (MTBE), alcohol, and other ingredients damaging to performance. Knowing what we know now, well always experiment with ignition timingboth higher and lower settingswhen we change fuels rather than presuming that more power can be made with more octane due to more timing.


I'm no scientist when it comes to all this but i think it would make your bike go SLOWER & wear the engine more. gadget.gifThat's gotta suck! :p   :ride: lol biggrin

.....................................

Don't take it to heart all my UK friends .... I'll ride slower just for you biggrin

Jarrah.





-- Edited by barra8 on Saturday 26th of January 2013 09:37:50 PM

__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

TTRfan wrote:

I took some time out of rebuilding my 325 engine to have a look at some spare caps. Using a short length of clear pipe I was able to easily blow down through all 3. There was no feeling of restriction and I could get a lot more air through than even a big jet could pass petrol.

I honestly can't see why it would be necessary to drill the cap as the other two holes will still be smaller confuse But I am happy to be persuaded wink

Brian

Blue petrol cap dismantled 001.jpg

Blue petrol cap dismantled 002.jpg

 By the looks of Brians pic one of my balls is missing....The smallest one on the left side biggrinbiggrinbiggrin Well no more making kids for me hahaha biggrin

Also that filter looks flash. Mine did'nt have that. It is working much better now with larger holes.

I know it's hard to believe & why i started this thread to confirm it. It still has'nt i guess but im a believer atleast wink

..................................

Jarrah.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

Cubber wrote:

I'm surprised that you are having so much trouble with a fuel cap, Jarrah. bleh

Australian petrol must be a different product from our brew in the UK which is 5% ethanol.

This is a shot of my 13 year old TTR petrol cap for comparison:-

Cap.jpg

As you can see there is no corrosion at all. disbeliefsmileno

I can vouch for its effectiveness too - not a drop spilled when the bike was on its side for a few minutes the last time (of many) it toppled on a trail.

Martyn



-- Edited by Cubber on Saturday 26th of January 2013 12:53:19 PM

 Wow Martyn looks new aww The problem i don't think is the fuel but this could be contributing to the rust. It's more the fact that my screws are zinc-plated (i think) & yours would be stainless or alloy. wink

Not sure about our current fuel supply but it is usually ethenol free.

................................................

Jarrah.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

barra8


Guru

Status: Offline
Posts: 932
Date:
Permalink  
 

Hey Brian,guess what........I found my missing left ball. I had it tucked away for ''safe'' keeping biggrinbiggrinbiggrinbiggrin

Blue petrol cap dismantled 001.jpg

 

005.jpg

It does go MUCH better now that i drilled it out awwawwawwaww

...............................

Jarrah.




Attachments
__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

Nomada_Firefox


Veteran Member

Status: Offline
Posts: 64
Date:
Permalink  
 

Never I had a problem with this but I know how by example when you live at a site higher than the sea level, you can suffer carburation problems, I have seen it at more of 1000 meters, it is not a big problem but the engine does not go well. But it happens with more motorcycles.

__________________
barra8


Guru

Status: Offline
Posts: 932
Date:
RE: Does your petrol cap breather breathe properly? The question everyone is now interested in :)
Permalink  
 

Nomada_Firefox wrote:

Never I had a problem with this but I know how by example when you live at a site higher than the sea level, you can suffer carburation problems, I have seen it at more of 1000 meters, it is not a big problem but the engine does not go well. But it happens with more motorcycles.

Yeah i had thought of the elevation but did not think it would affect it much. Still unsure why nobody else is having the problem but i guess nobody has checked how i have. Maybe i'm the lucky one & get the all the breather problems wink

It's all good now,thanks all for replying.

Had to change the topic lol as it did'nt suit anymore hahahahaha biggrinbiggrinbiggrin

...........................

Jarrrah.



__________________

YAMAHA ROCKS!!!!!!

TTR250ACTIVE''BORED'' ADDICT!

Favourite quote: To be old & wise first you must be young & dumb!

My own: Your never too young to learn an old trick! :)

Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.
The TTR250 FAQ web pages -> TTR250 -> Repairs and maintenance -> Does your petrol cap breather breathe properly? The question nobody is interested in :)


Create your own FREE Forum
Report Abuse 		Powered by ActiveBoard