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Old 08-18-2011, 07:02 PM   #2506
BrownMike
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Joined: May 2011
Oddometer: 9
Ok so my bike has been running pretty decent since I did all the carb work, but a couple issues have surfaced.

1. high rpm surge: at cruising speed ~60 mph it tends to bog hard and randomly surge, almost like its not getting enough fuel, but the float height is set at the high end of the spec. if i crack the throttle a little more or back off it picks back up and runs fine, its just at the point where it doesnt accelerate anymore per given throttle amount. thinking maybe secondary needs adjusting? the bike seems to be running rich via black sooted rear fender.

2. the hot idle seems lean, it idles higher then when hot, but starts popping more. however if I richen it it anymore I cant get the rpm to drop into a respectable rpm with the throttle stop. if I lean it out it pops more and dies. idles cold/warm 2k

130 main, stock secondary, drilled pilot, no air leaks to be found, good intake boots.

any insight would be great!
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Old 08-18-2011, 07:46 PM   #2507
Tenstrike
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Thanks Z

I figured alot of the problems talked about here are related to tank and carb issues. I'm still struggling with the carb on my 550, no power in the higher gears. I've tried everything i can think of and the stuff offered in the 550 thread. I'm ready to take it to a guy to play with it.
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Old 08-19-2011, 09:25 AM   #2508
Brypoint
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Joined: Jul 2011
Location: Las Vegas
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Quote:
Originally Posted by BrownMike View Post
Ok so my bike has been running pretty decent since I did all the carb work, but a couple issues have surfaced.

1. high rpm surge: at cruising speed ~60 mph it tends to bog hard and randomly surge, almost like its not getting enough fuel, but the float height is set at the high end of the spec. if i crack the throttle a little more or back off it picks back up and runs fine, its just at the point where it doesnt accelerate anymore per given throttle amount. thinking maybe secondary needs adjusting? the bike seems to be running rich via black sooted rear fender.

2. the hot idle seems lean, it idles higher then when hot, but starts popping more. however if I richen it it anymore I cant get the rpm to drop into a respectable rpm with the throttle stop. if I lean it out it pops more and dies. idles cold/warm 2k

130 main, stock secondary, drilled pilot, no air leaks to be found, good intake boots.

any insight would be great!
Hey Mike, I got mine running pretty darn good. I'm on 140 main 2 shim's on the main needle and a mikuni 17.5 pilot jet, exactly 2 turns out on the screw . I also went with a 120 secoundary jet and 1 shim. I synched the carbs to open at the same time. I have stock exhaust without the spark arestor and a drilled out air filter cover with a UNI filter.
The bike starts cold 1-2 kicks and idles perfectly about 1400-1500 rpms. On hot restarts it starts with half a kick from a sitting positon. ( this is also for the guy above me wondering whether to buy that bike or not)
I had the same high speed bog as you did so I pulled the air box cover and it's gone (I'm trying to figure a good way to drill out my cover more without messing with the integrity of it and I would like to figure out a secondary filter to cover those holes.)
I'm thinking you need to get the Mikuni pilot jet to iron out your idle issues, cause it was like night and day when I changed mine out. (lemme know if you want the order info or Part# on that. It's a bit longer then the stock one but screws right in nice)
Lemme know what the status is with your exhaust and air box and we can go from their. Sounds to me like not enough air if your running rich and popping.
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Old 08-19-2011, 09:40 AM   #2509
Brypoint
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Location: Las Vegas
Oddometer: 75
Quote:
Originally Posted by Tenstrike View Post
I figured alot of the problems talked about here are related to tank and carb issues. I'm still struggling with the carb on my 550, no power in the higher gears. I've tried everything i can think of and the stuff offered in the 550 thread. I'm ready to take it to a guy to play with it.
How is your compression? When you use the engine too slow down does that do what it's supposed too? Mine will actually skid out if I downshift too fast when slowing down so I know I have really good compression. Also kickstarting mine is tough todo if I kick it without the decompressor. (i think the 550 is electric start so this may not be an indicator for you) It seems to work fine in the lower gears? When on a lower gear does it pull through the gears well with plenty of power, and tach out?
Is the fuel line to the carb nice and clean? (pet cock and any in-line filters) How about your air filter, are you running too much oil on it? It's hard to diagnose if it works ok on the lower gears but craps out on top. Keep in mind the engine does not know the speed of the bike only the RPM's. Maybe something here will give you an idea what to look for. If not give me some more to work with and I'll try to help.
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Old 08-19-2011, 06:30 PM   #2510
Tenstrike
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Brypoint-PM sent.
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Old 08-20-2011, 09:09 AM   #2511
yzergod
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Joined: Mar 2010
Location: Durango, CO
Oddometer: 61
Decided to thin the heard. So, sad to say, my XT is up for sale...

I am selling my 1989 Yamaha XT350 Enduro. It is registered and titled in Colorado, and the tags are good until 5/12.

Good Dunlop tires, jet kit with 3 other size jets to fool around with, digital copies of the owner's manual, shop manual, parts list, and Clymer manual.

Good running bike that needs nothing except a rear brake light bulb. All other lights work, as do both gauges. I replaced the turn signals with some new smaller ones.

$1200. Do NOT need anything for trade, thanks.

Located outside of Durango, Colorado in the Four Corners area.



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Old 08-20-2011, 07:24 PM   #2512
chef larry
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Joined: Jun 2011
Location: Northwest Indiana
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Quote:
Originally Posted by Brypoint View Post
Got the bike pretty much the way I want it to look now, not too bad I guess.
Loks great to me, where did you get the hand guards? See you have chrome pipes from the head to the muffler, as mine are black and in need of a new coat of paint. I enjoy the looks I get when I get off the XT and take off my helmet (that old guy is riding a dirt bike, just under the big 60) and even the ones I work with and my kids say I should be on a Gold Wing. Tell them it's still fun to play in the dirt.
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Old 08-20-2011, 09:13 PM   #2513
Brypoint
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Location: Las Vegas
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Quote:
Originally Posted by chef larry View Post
Loks great to me, where did you get the hand guards? See you have chrome pipes from the head to the muffler, as mine are black and in need of a new coat of paint. I enjoy the looks I get when I get off the XT and take off my helmet (that old guy is riding a dirt bike, just under the big 60) and even the ones I work with and my kids say I should be on a Gold Wing. Tell them it's still fun to play in the dirt.
Thanks I think it looks good too! The hand guards I got on E-bay for $35 shipped. I'm not really happy with them though, the stock levers rub and I have to leave the guards sticking out a little to work so not a snug finish (trying to find some inexpensive shorty levers so the whole thing will work better). Also I seen some name brand name guards in the back of a dirt bike magizine for around the same price, so now I'm really unhappy.
I needed to do the same thing with my pipes as they were brown and rusty looking. (turns out to be baked on dirt instead of rust) I started cleaning them with a wire brush and everything started coming off, paint and dirt. Well under all that I found what looks to be stainless steel so I went ahead and wire brushed and sanded the whole pipe. I probably wouldn't recommend doing this if you live in a humid climate as they may rust fast. For me they look a whole lot better and if I have to take them off for a sanding once a year I won't be mad.
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Old 08-20-2011, 09:17 PM   #2514
Brypoint
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Joined: Jul 2011
Location: Las Vegas
Oddometer: 75
Quote:
Originally Posted by yzergod View Post
Decided to thin the heard. So, sad to say, my XT is up for sale...

I am selling my 1989 Yamaha XT350 Enduro. It is registered and titled in Colorado, and the tags are good until 5/12.

Good Dunlop tires, jet kit with 3 other size jets to fool around with, digital copies of the owner's manual, shop manual, parts list, and Clymer manual.

Good running bike that needs nothing except a rear brake light bulb. All other lights work, as do both gauges. I replaced the turn signals with some new smaller ones.

$1200. Do NOT need anything for trade, thanks.
Good looking bike, I don't think you'd have too much trouble getting rid of it. I would buy it if I lived closer and didn't have one already, good price too.
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Old 08-20-2011, 11:45 PM   #2515
George 99
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Location: Kingman, Arizona
Oddometer: 770
Just added...

...an ADV sticker.

Guess I'm gonna keep here since her replacement was stolen with nothing new to report. :(
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Old 08-21-2011, 05:57 AM   #2516
LanaTheGreat
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Joined: Aug 2011
Location: Durban, South Africa
Oddometer: 23
XT350 Wiring Diagram

Hi there, been busy this weekend creating a wiring diagram for the 1996-2000 XT350 in full color. Here is a screenshot of the diagram I created using Powerpoint. I can email it to whoever wants to have the .ppt file so it can be editable. I still need to do the wiring diagram for the 1986-1995 models. Not sure if there are much difference between them. I used the Clymer manual wiring diagram to create this one.

Hope some of you find this useful, it surely will help me a lot more.
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Old 08-21-2011, 06:54 PM   #2517
SkidMarx
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Location: Ortonville, MI
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Quote:
Originally Posted by LanaTheGreat View Post
Hi there, been busy this weekend creating a wiring diagram for the 1996-2000 XT350 in full color. Here is a screenshot of the diagram I created using Powerpoint. I can email it to whoever wants to have the .ppt file so it can be editable. I still need to do the wiring diagram for the 1986-1995 models. Not sure if there are much difference between them. I used the Clymer manual wiring diagram to create this one.

Hope some of you find this useful, it surely will help me a lot more.
That has got to be one of the best first posts ever.
Welcome!
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Old 08-21-2011, 07:02 PM   #2518
BrownMike
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Joined: May 2011
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Quote:
Originally Posted by Brypoint View Post
Hey Mike, I got mine running pretty darn good. I'm on 140 main 2 shim's on the main needle and a mikuni 17.5 pilot jet, exactly 2 turns out on the screw . I also went with a 120 secoundary jet and 1 shim. I synched the carbs to open at the same time. I have stock exhaust without the spark arestor and a drilled out air filter cover with a UNI filter.
The bike starts cold 1-2 kicks and idles perfectly about 1400-1500 rpms. On hot restarts it starts with half a kick from a sitting positon. ( this is also for the guy above me wondering whether to buy that bike or not)
I had the same high speed bog as you did so I pulled the air box cover and it's gone (I'm trying to figure a good way to drill out my cover more without messing with the integrity of it and I would like to figure out a secondary filter to cover those holes.)
I'm thinking you need to get the Mikuni pilot jet to iron out your idle issues, cause it was like night and day when I changed mine out. (lemme know if you want the order info or Part# on that. It's a bit longer then the stock one but screws right in nice)
Lemme know what the status is with your exhaust and air box and we can go from their. Sounds to me like not enough air if your running rich and popping.
The airbox should still be stock (cant loo at the moment) and stock exhaust without the end cap as well. I drilled out the pilot to a #77 bit and it helped alot from where it was, but a real jet would prob be better anyway.
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Old 08-21-2011, 08:37 PM   #2519
Brypoint
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Joined: Jul 2011
Location: Las Vegas
Oddometer: 75
Quote:
Originally Posted by SkidMarx View Post
That has got to be one of the best first posts ever.
Welcome!
Agreed, very good diagram much easier to see what connects to what. Now if we could only sticky posts here we would have a central database...
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Old 08-21-2011, 08:59 PM   #2520
Brypoint
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Joined: Jul 2011
Location: Las Vegas
Oddometer: 75
Quote:
Originally Posted by BrownMike View Post
The airbox should still be stock (cant loo at the moment) and stock exhaust without the end cap as well. I drilled out the pilot to a #77 bit and it helped alot from where it was, but a real jet would prob be better anyway.
Well Mike pull that air box cover and I can almost be sure your troubles will go away. (must find a solution to this though cause I'm also running without a cover and this isn't exactly a safe way to run) I don't know what size a #77 bit is compared to jet sizes but hey if its idling good and off idle is responsive then that's good to go. (Keep in mind that each part of the carb is seperate and doesn't effect the other ex. choke circuit, idle circuit, high speed circuit. They only effect each other a little but tune each indivisually).
You usually wanna work from the top down. So WOT first get a 140 main in their and pull the airbox cover. Next is the main needle, I have 2 brass washers under mine. (You may or may not wanna mess with the secondary carb, I have 1 shim under the needle and I went up to a 120 jet and made both carbs open at the same time.) Last is the pilot jet in which case I have a 17.5 Mikuni pilot and I'm at 2 turns out on the fuel screw, which is exactly where a perfectly tuned bike should be.
You wanna get each circuit running perfect before going down to the next one, so tune your top end first and so on.
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