Raptor Forum banner

41 - 60 of 95 Posts

·
Registered
Joined
·
42 Posts
Discussion Starter #41
ok, well it was definately 170 and 175 then, I thought there was a point between them but I could have been mistaken because I looked at the pilots first and they definately were 22.5. I will get him to take a picture of the main jets so you can see for yourself because the 7 on them did look kinda weird.

So is QM right? should I be looking to drop down in size to 155/160 or 160/165? thanks. Bearing in mind I live in the UK and its a little colder here generally, I don't know if that makes a difference.
 

·
Registered
Joined
·
42 Posts
Discussion Starter #42
The guy that took the carb apart also informed me that the starter jet was blocked and that he has cleaned it, could this cause the problem? thanks again
 

·
Master of the Electron
Joined
·
14,827 Posts
Starter jet only affects operation of the choke.

Has this bike ALWAYS exhibited this issue, since you got it, or did it just pop up over time? I ask because it is possible (with those huge jets) that this, itself, is the issue. If it's always done this, drop down to the 160 area and it may just go away.

The reason I can't be absolute is because every bike/carb is different - although 170/175 seems huge, that may be what was necessary to get your bike to run properly... although (as Willy stated earlier about having to be below sea level for them to work) we doubt it!

Either the main jets were dirty enough to cause the bike to lean out and run poorly at high throttle position, or the jetting is way to high causing the bike to be way too rich at high throttle position, making it run poorly. Without some beforehand testing to determine whether it was too lean or too rich, it's now just a guessing game that will be resolved once the carbs are back together. But, from general principle, I'd reduce the main jet size.
 

·
Registered
Joined
·
42 Posts
Discussion Starter #44
Yes QM the quad has done it since the very first time I rode it, shall I try 155/160 or 160/165 thanks for all your help.
 

·
Master of the Electron
Joined
·
14,827 Posts
With the holes in the airbox, and with just the Yoshi slip on, I'd start mains at 155L/160R with 25 pilots and DJ or GYTR needles with clips at center, fuel screws at 2 turns.

Let's see if Willy agrees.
 

·
Registered
Joined
·
42 Posts
Discussion Starter #46
Thanks mate will try to get hold of them from a local yamaha dealer tomorrow and take them down for my friend to put in, thanks.
 

·
Registered
Joined
·
42 Posts
Discussion Starter #47
and if willy could just confirm that this would be the correct course of action also that would be great.
 

·
I am unique
Joined
·
22,621 Posts
and if willy could just confirm that this would be the correct course of action also that would be great.
Like I said those jets, if they are 170 and 175 should be run with no air box and some porting with a stage 2 cam at least, and even then, it may be too big.................unless you live below sea level about 500 feet...............
 

·
I am unique
Joined
·
22,621 Posts
ok, well it was definately 170 and 175 then, I thought there was a point between them but I could have been mistaken because I looked at the pilots first and they definately were 22.5. I will get him to take a picture of the main jets so you can see for yourself because the 7 on them did look kinda weird.

So is QM right? should I be looking to drop down in size to 155/160 or 160/165? thanks. Bearing in mind I live in the UK and its a little colder here generally, I don't know if that makes a difference.
It cant be as cold as here, presently it is -13*C............
 

·
Registered
Joined
·
42 Posts
Discussion Starter #51
So willykiller do you think 155/160 sounds about right to begin with then or even lower? what would you recommend starting with?
 

·
I am unique
Joined
·
22,621 Posts
Ok here we go for a full run down of what I know,

1. The quad has a yoshimura slip on end can
2. It has a K&N air filter inside the airbox
3. The top of the airbox has been drilled to leave holes, around 10 to 15 holes are present. The filter was filthy and I have ordered a new one from ebay.
4. The pilot jets on both carbs are 22.5
5. The main jet on one carb is 17.5
6. The main jet on the other carb (The one with an idle air bypass so I'm told) is 17. He said the jets seemed a little dirty but not dirty enough to cause such a major problem.

Could you guys let me know what I want to be running that would be great, I will be getting the 25 pilot jets you have been talking about so really just looking for advice on main jetting thanks.
You have 10 or 15 holes in the airbox, how many exactly, and how big are they............IF you have 10, 1/8 inch holes or 15, 1 inch holes, there is a big difference in jetting between the two of them..............
 

·
Registered
Joined
·
42 Posts
Discussion Starter #53
There are 17 holes that are around 5.5mm each in diameter drilled in the top of the airbox randomly Willy so what do you reckon to jet size?
 

·
Master of the Electron
Joined
·
14,827 Posts
Lotsa big holes - I stand by my estimate. Willy?
 

·
Registered
Joined
·
42 Posts
Discussion Starter #55 (Edited)
Had a quick look around the net also for info on gytr needle and found a couple of pages about jetting. Most people seem to be around between 140 - 160, 150/155 seems to be a good average that someone mentions in one of them. Just waiting for a response from you Willy before I go ahead and start buying stuff thanks.

Some poeople even talk about going as low as 135/140 so I'm kind of confused as to where to go as the range seems rather large?

I have attached a crude picture of the lid for you to see
 

Attachments

·
Master of the Electron
Joined
·
14,827 Posts
If you just order the Vito's kit you'll get all the jet sizes you'll need, + the 22.5's, + aftermarket needles, + extended fuel screws that you can adjust with the carbs mounted... it's a win/win.
 

·
Registered
Joined
·
42 Posts
Discussion Starter #58
ah I've found it its $50 which seems reasonable and it comes with the 25 pilots which is what I think you ment QM, I will wait for Willys input and then probably go for this I think.
 

·
I am unique
Joined
·
22,621 Posts
So I would imagine that the snorkel has been removed if you have those holes in the air box lid, if so, you have about the size hole in the air box lid as the snorkel plus the snorkel being removed, if it is, the 17 holes is equivalent to about 6 square inches and I would imagine that the snorkel hole is about the same..................
I would start at #25 pilots, aftermarket needles half way up with mikuni mains around 155 to 160...............
 

·
Master of the Electron
Joined
·
14,827 Posts
ah I've found it its $50 which seems reasonable and it comes with the 25 pilots which is what I think you ment QM, I will wait for Willys input and then probably go for this I think.

Yes, sorry, I meant 25's.
 
41 - 60 of 95 Posts
Top