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Discussion Starter #1
So i bought a '97 VN750 last night for 1300.
in great shape, and I met the shop owner who rebuilt it in San Marcos, TX.

After riding, I notices the throttle acts a bit weird...
It seems to rev up pretty quickly, then do nothing at all.
This makes it incredibly hard to roll out of a stop going uphill without stalling.

Additionally, the bike wouldn't go over 70 on the ride home, nor did it have ANY pickup over 45mph.

My first guess is the battery or the carbs? The previous owner said the bike had been sitting since January before he got the drive shaft replaced, and the mechanic told me i needed to replace the battery soon.

Could these issues simply be side-effects of a dying battery, or to I need to pull the tank off and have a mechanic tinker around before i take her out?
 

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It sounds like air/fuel mix issues. That's pretty broad, but I would start with trying to do a good ride once the bike is warmed up and then pulling the plugs and getting a good look. If they're wet and black, then the mixture is rich with fuel. (too rich) If they are white (ish) then the mix is too lean (not enough fuel). That's a good place to start. I'm leaning (no pun intended) to the lean mix side on this one, maybe with vacuum leaks or air filters missing or not correctly oiled. These things can be caused by poor fitting of the carb boots or cracked vacuum lines, etc. Start with the plugs and see if it points to anything and check back with the forum... You can pull them and check them cold too, which probably isn't a bad idea, then if they look normal, try the ride and kill the engine with the kill switch so you get a good read on the plugs.

One caution, if it is running lean, it can burn the valves pretty quickly so I wouldn't keep riding it until we figure it out.
 

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Old Twistie Sticks Rider
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First-I agree with Fergy, it sounds like air/fuel mixture issues... but---
So you need a new battery why not go ahead and get a new MF battery (don't think that will cure it but) then give the gas a good dose of SeaFoam... Do the warmed up ride as Fergy suggests, and as much as you feel comfortable with...
If that don't help, then exactly as Fergy says above... That way all adjustments will be done with cleaned up carbs and more than likely be final, adjustments done on varnished up carbs will usually have to be repeated and sometimes several times as the carbs clean up...
Have a good one...Old Dog...
 

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Discussion Starter #4
Is SeaFoam an octane booster?
Sorry for sounding like the newb I am. I'm not a skilled mechanic by any means, and I've only been riding a little over 2 years, so I may not be too familiar with some terminology.

And MF battery? Maintenence free? And can I find one at auto zone?
 

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I sometimes forget to mention Seafoam since I use it all the time, ha! But definitely get you a couple cans and after the initial quarter can dose or even more in a full tank, use about 3 oz at a fill up per month for preventive maintenance. Seafoam is a cleaner, fuel stabilizer. It really can clean out a lot of gum and varnish, and can attach its self to water and get it burned through.

The reason I was leaning to the lean side was the high revs and weak power, together a sign of an air leak. If your battery is not a maintenance free you need to replace it with one as soon as possible. You don't have to check water levels which is a big plus considering the pain it is to remove the seat, and they have more cold cranking amps than the same sized wet cell so it is a win-win, and they last longer too, and don't lose as much charge sitting in the bike when you're not riding it...

Thanks Old Dog for the reminder! :smiley_th
 

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Discussion Starter #6
Awesome, So can i pick up a battery and SeaFoam at Autozone or any similar auto parts store?
 

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I've never bought a battery at autozone, but you can definitely buy seafoam there. The last battery I ordered from the net, was a big crank I believe that someone posted a link to here somewhere. Just take the old battery with you so you can match size and cable orientation and you should be good, if they have them.
 

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After riding, I notices the throttle acts a bit weird...
It seems to rev up pretty quickly, then do nothing at all.
This makes it incredibly hard to roll out of a stop going uphill without stalling.

Additionally, the bike wouldn't go over 70 on the ride home, nor did it have ANY pickup over 45mph.
Being more of a conspiracy theorist, if seafoam and mix adjustments don't cure it, you might want to consider whether the spark is getting advanced by the ignitir IC. I wish I knew how to test that ... :(

Good hunting.
 

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Deka and I think Big Crank (may be Westco) batteries are made by East Penn battery company here in the US and are good quality. If I wasn't lazy, I'd get the number off my battery and give you the ebay link for Deka. Beware Chinese made batteries!
 

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Awesome, So can i pick up a battery and SeaFoam at Autozone or any similar auto parts store?
you can get both at walmart.. just get the right size MF battery.. they have 2 differnt sizes that I have seen.
Also as stated above... check all of your hoses and boots for leaks...try useing WD40 sprayed around them if the engine stubels or reves then you know you got a leak there... what is your idle setting at on the Tac? does it bounce around at idle?.. look at the carbs next to the vent nipples on the sides.. is the plug still in the air/fuel mix hole?.. if not then take a small screw driver and turn them all the way in then back them out 2.5 turns...
 

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Discussion Starter #11
Awesome, thanks again for all the great feedback guys!
I want to try and get to walmart after work, and before the automotive dept closes, so i dont have time to pull the battery...
Anyone know a specific battery model number I'm looking for?
 

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I don't know if they sell a MF battery at Walmart for a motorcycle. Just remember it needs the positive on the left, with the terminals facing you. (+||||-) You might have to pick one up and just see if it fits...
 

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Linkmeister Supreme
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This is the battery our late, great, lance328 recommended:
http://cgi.ebay.com/ebaymotors/Deka-ETX15L-Powersports-AGM-Battery-100-NEW-/270282472155?cmd=ViewItem&pt=Other_Vehicle_Parts&hash=item3eee173adb

This part # is a direct replacement for the following part #'s:
Yuasa YTX14AHL-BS, YB14L-A2, YB14L-B2
12N14-3A
GNB 14L-A2, 14L-B2
Deka ETX15L
Delco MC1406
Interstate YTX14AHL-BS, YB14L-A2, YB14L-B2
GS-Ztong Yee CB14L-A2, CB14L-B2
GS-JSB GM14Z-3A, GM14Z-3B
Motocross M62H4L, M3214Y, M2214B
Napa 740-1851, 740-1828
Sears 44005, 44364, 44059
Wal-Mart ES14L-A2
Yacht CB14L-A2, CB14L-B2

Deka ETX15L Powersport AGM Battery

Sealed, Maintenance Free, AGM (Absorbed Glass Mat) Battery

For Motorcycles, Scooters, Personal Watercraft, Snowmobiles, ATV's, and more


List Price - $114.95

CCA 190
Amp Hour 14
Weight 11.0lbs.
Length 5 1/4 in.
Width 3 1/2 in.
Height 6 9/16 in
.
If you buy a MF-AGM battery locally check the case dimensions against these specs from the above link.
(The first battery I tried was from from NAPA and it was too long.)

Seafoam review from Web Bike World.
http://www.webbikeworld.com/sea-foam/
 

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Discussion Starter #14
When I called Auto Zone, they searched their internal database, and found one for this year and model. Ill fill u guys in on the results!
 

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Discussion Starter #15
Sorry for such a late reply, Ive had a busy weekend.

I didnt worry about a MF battery, and just picked up a regular one at autozone. No difference in performance since that really.

The seafoam appeared to open the throttle up a bit, but i still have nowhere NEAR the pickup i used to have on my 82 honda GL500.
Especially at the moment, where i have no throttle at all.

I figure the seafoam dislodged soem large sediment form the tank or a line, and after choking out on the highway, then chugging and jolting at 20mph for about 10 minutes, it died completely climbing the long winding hill up to my office. Joy.

So yeah, the bike is sitting on the side of the highway where my frined will help me load it up and take it home tonight. This is the point where i could REALLY use some guidance...


Like i mentioned before, the bike has been sitting since january before i bought it, so the carbs may need some attention, and i have no idea where to start in tracking down IF/where the blockage is.


Any ideas?
 

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Sorry for such a late reply, Ive had a busy weekend.

I didnt worry about a MF battery, and just picked up a regular one at autozone. No difference in performance since that really.

The seafoam appeared to open the throttle up a bit, but i still have nowhere NEAR the pickup i used to have on my 82 honda GL500.
Especially at the moment, where i have no throttle at all.

I figure the seafoam dislodged soem large sediment form the tank or a line, and after choking out on the highway, then chugging and jolting at 20mph for about 10 minutes, it died completely climbing the long winding hill up to my office. Joy.

So yeah, the bike is sitting on the side of the highway where my frined will help me load it up and take it home tonight. This is the point where i could REALLY use some guidance...


Like i mentioned before, the bike has been sitting since january before i bought it, so the carbs may need some attention, and i have no idea where to start in tracking down IF/where the blockage is.


Any ideas?
Did you ever pull the plugs and read them for rich/lean condition? We got off onto a battery discussion here, but the battery was not a solution for the trouble you were describing, at least in my opinion. If you are running lean, you could be damaging the pistons/valves by running the bike. It still sounds like an issue with air/fuel mix, or vacuum leaks, something like that. I don't believe it is an electrical issue...
 

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Discussion Starter #17
When I pulled the plugs i did not see a considerable abount of white carbon or oil. It seems like the current problem is a fuel blockage, and thats what im trying to figure out right now...
 

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If the fuel was fresh when it was parked, I doubt that leaving the bike sit for only 2 months before you bought it is the cause of any problems. Previously present sediment or varnish in the tank or carbs could be a problem though.
Try turning the petcock to REServe to see if the problem persists. Maybe the main ON position pickup tube is plugged.

I wonder if the lack of power is due to partially plugged jets??

Try turning out the carb drain screws and see if any crud comes out the nipples.
Then fill a big syringe (often available at veterinarians office) with gas and squirt it back in the drain nipples to back flush the jets. Let it drain and check for dirt again.

Go for a test ride. If it still falters, drain the carbs again and use the syringe to fill the carb jets and float bowls with Seafoam and let it sit and soak for a day or two.

While the carb is soaking pull the fuel hoses off the carbs and apply vacuum to the petcock to see if fuel flows freely through both hoses into a clear bottle with the petcock in both ON and REServe position.
 

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Discussion Starter #19
If the fuel was fresh when it was parked, I doubt that leaving the bike sit for only 2 months before you bought it is the cause of any problems. Previously present sediment or varnish in the tank or carbs could be a problem though.
Try turning the petcock to REServe to see if the problem persists. Maybe the main ON position pickup tube is plugged.

I wonder if the lack of power is due to partially plugged jets??

Try turning out the carb drain screws and see if any crud comes out the nipples.
Then fill a big syringe (often available at veterinarians office) with gas and squirt it back in the drain nipples to back flush the jets. Let it drain and check for dirt again.

Go for a test ride. If it still falters, drain the carbs again and use the syringe to fill the carb jets and float bowls with Seafoam and let it sit and soak for a day or two.

While the carb is soaking pull the fuel hoses off the carbs and apply vacuum to the petcock to see if fuel flows freely through both hoses into a clear bottle with the petcock in both ON and REServe position.

Awesome, thanks for all of that useful info. I'll get on that as soon as i can get the bike home.

What did u mean by 'apply vacuum'?
And i know what screw ur talking about on the carb, but where is the 'nipple' u speak of? Just where the screw is?
Also, the petcock was on reserve when this happened, and the problem persisted when i switched it to ON.



Could an issue like this could be caused by filling up my tank with 93 octane fuel with a bit of lower octane left in the tank? I doubt it, but i just want to cover all my bases...
 

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Discussion Starter #20
Haha i guess u mean to manually siphon the fuel out, huh?
 
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