carb boots question #312 / Ordered Boots!

ok, I know replacing these boots is a really good idea when they're old & cracked(which mine are).
I'm ordering a new set tonight.

I wanted to ask though, about these symptoms:
The bike seems to start up when it's warm outside(75+), although a quick throttle snap always bogs it(warmed up or not)

If it's cold at all, she needs coaxing via gas thru the carbs to get it going...
And when she's warmed up, as I said, it restarts with no problems.

I'm wondering if the probability is really high that new boots will fix this issue, cause I've already cleaned out the carbs, and would hate to spend 100+ if it's not gonna fix this debilitating problem..

well, thanks lads,
Rich

 

Re: carb boots question #312

If the boots are not cracked to the eye then I would save my money. Cleaning the carbs in only the first step. Second is to colortune and third is to sync with a manometer.
Bogging down with a throttle movement is usually indicative of a lean mixture. This could be from the pilot screws not providing enough fuel, to the boots leaking and providing too much air. Boots being the airbox or intake boots. An airfilter not in place can do this also. One of Yamaha's design flaws in the airbox. The airfilter is held in place via the airbox top. Too easy to have the top of the filter not engage the top and have air leak by. Check these and get back with your findings.
You mention that she needs coaxing vai gas through thecarbs when cold to get going. Do you mean gas via the choke? It is normal for these engines to need choke when cold. IF you have to add fuel by pouring it in yourself then I would suspect the carbs are not clean, the float is too low or the starter jets in the bottom of the float bowls are clogged.

 

Re: carb boots question #312

Wow, are you saying that not having the air filter properly installed could cause this particular situation?
Interesting..
But, I'm not an engineer either..

I should mention that once the bikes warmed up, it goes just fine: actually has tons of power etc.
It's just wen you shut her off & she cools down.

As far as the choke/gas question, it will not start even with full choke: then I'll need to manually mist some gas into the rear of one of the the carbs.

So, I guess the big question is: given that it starts fine when warm, AND that once running it's fine, does that help you in your remote diagnosis at all?

Rich

PS.
I've been looking on the forums, but cannot find what COLORTUNE is.

 

Re: carb boots question #312

Well, I just submitted my order for a nice new shiny set of Carb Holders for the 81' XJ650.

'Joint, Carburetor' to use Yamaha ease...

Also, petcock rebuild kit & oil filter.

All through : https://www.partsnmore.com/


My boots are so cracked, there's consensus amongst the riders here, that I'll never have it right until I change them: and I agree.
Rich

 

Here's a link to a Colortune.

http://www.eastwoodco.com/jump.jsp?item ... pe=PRODUCT

Well worth the money!

 

indeed, I'm sure it is: unfortunately, I'm going to have to see what difference the boots make: money's getting really tight(common story huh?)
If she still doesn't start right, then I'm going to look into that method, as I'm betting the mixture screws haven't been touched since......


Rich

 

Keep an eye on eBay too. Sometimes the colortunes go up for cheap!

 

mmmm ebay......

 

Re: carb boots question #312

No not by itself, but yes if the carbs are a bit lean to begin with.

Yes it sounds like the starter jets are clogged, the mixture is lean at idle as set by the pilot mixture screws or maybe the valves need setting.

 

WOW that site has the carb rebuild kits cheap i paid $20 a piece thats a good site going to have to save that to the favs...
GL