Suzuki SV650 Riders Forum banner

1 - 20 of 28 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter · #1 ·
So my bike has ran rough since the day i bought it, but its recently gotten much worse, now when i start the engine if i run it at about 1500 rpms for about a minute the exhaust will turn cherry red at the pipe coming out of the cylinder head. The bike will start, idles ok if the choke is set to about half, and if i ride for about 4 miles i can barely break 60 mph. I think its running lean, i have checked the vacuum valve on the tank, and the fuel pump seems to be working ok. I cleaned the carbs, that didnt seem to fix ne thing so ive now had it in 2 different shops, they have no clue, also i think my engine has excessive blowby, at least it seems excessive to me. Can anyone help? Does anyone live in orlando?


Sent from my iPad using MO Free
 

·
Registered
Joined
·
51 Posts
Lean alone isn't going to turn the exhaust cherry red. Really late timing, burnt valve or possible timing chain problem.

Matt
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #3 ·
I just picked up a compression gauge, and feeler gauge to check the valves and condition of the engine, does anyone have any experience on this, where should i start? I do have some tools, i have downloaded a repair manual as well but it is of quality. Where should i begin?


Sent from my iPad using MO Free
 

·
Registered
Joined
·
1,269 Posts
Do a compression test, take the time to do the "drop of oil" secondary test to verify the health of components, not just their existence.

If you don't get great compression the first time, but only see marginal improvement by adding a couple drops of oil, you may have a burned valve or other issues.

As for the cherry red headers, check your carbs. You may have a float that is starting to stick and allow excessive amounts of fuel into the bowl, and then into the motor. It can't all burn during the power cycle like it should, so the reminder burns in the header as a massive flame. If this the direction things head, an oil change may also be a good idea since there will be oil dilution. Though, if its been going on a long time... and the compression sucks, you could easily have for all intensive purposes euthanized the cylinders and exhaust valves.
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #6 ·
Ill do the compression test tomorrow and post my findings, for some reason i just dont have a good feeling bout this thing, this is my 1st bike, i was hoping for a better experience : / the help is really appreciated


Sent from my iPad using MO Free
 

·
Registered
Joined
·
17,602 Posts
I just picked up a compression gauge, and feeler gauge to check the valves and condition of the engine, does anyone have any experience on this, where should i start? I do have some tools, i have downloaded a repair manual as well but it is of quality. Where should i begin?


Sent from my iPad using MO Free

The search tool up on the right.
 

·
Registered
Joined
·
381 Posts
Nothing helpful here...but is it actually easier to replace the any with ne_ in anything? I couldn't finish reading the post because of this nonsense.
 

·
Registered
Joined
·
6,834 Posts
Especially if you don't know the mileage on the engine.....check the valve clearances first. The fact that it barely runs explains the pipe turning red. They WILL turn red in the dark if you hold a high idle for a few minutes, so just going by red pipe doesn't mean much. You've got something MAJOR wrong if it won't start and idle cleanly after a minute or so without the choke.

After checking the valves it might be interesting to do the compression test. But remember that tight valves will hurt the compression....so valves out of spec will make the compression test not tell you what you want it to about the rings.

Come on back with your valve clearances and the group will help you plan your next move. This forum has cleared up just about every problem that has showed up as we've got quite a brain-trust in the members here.:)
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #10 ·
Ive managed to pull the valve covers off, according to the manual i have, the intake should b .004-.008 and exhaust should b .008-.012 my valves are

Front cyl intake .006
Front cyl exhaust .007

Rear cyl intake .005
Rear cyl exhaust .008

I think this should be ok, also the pipes were turning red in broad daylight. Ive left the valve cover and mag covers off for now, is there nething else i should do before i replace them? Maybe check the timing or timing chains? I havent done a compression check yet either tho but i did buy the gauge. Also is there a link to download a good service manual?


Sent from my iPad using MO Free
 

·
Registered
Joined
·
3,572 Posts
you should have 4 clearances per head not just 2

you can likely rent a compression tester
 

·
Registered
Joined
·
6,834 Posts
What you posted says you need to adjust your valves. 'Should be Ok'.....NOT. You are at the tight limit AND below. Time to adjust things, and I'd suggest you aim for the loose side of the tolerances to give you maximum time before needing to do it again. Actually, once things have broken in they really are stable valve trains...but most street bikes run best when set wide as it reduces the overlap period.

Excessive overlap can cause some of your symptoms. No way to tell if this is everything. Problem solving on a machine works like this: Check something. Good or Bad. If Bad (yours) you MUST correct before continuing. Thinking 'yes, they are out..but they can't be causing the problem' will likely have you chasing your tail. Fix everything you find wrong when you find it and the troubleshooting will be much easier.
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #14 ·
The clearances were the same, so both intake valves and exhaust valves were the same on each of the camshafts, in each of the haeds so i guess i should have put

Front cyl intake .006
Front cyl intake .006
Front cyl exhaust .007
Front cyl exhaust .007

Rear cyl intake .005
Rear cyl intake .005
Rear cyl exhaust .008
Rear cyl exhaust .008

Anyway, even tho the front cyl. Exhaust is a little tight its not enough to cause the sort of problems im having, i think we can probably rule out valve clearances as the culprit here. I did in fact buy a compression gauge, the one that was available for rent didnt have the adapters i needed, jus as well have one neway, its a cool tool to have. Im actually kind of shocked at how good of shape the valves and camshafts appear to be in, seems as tho they are barely worn at all, especially for a bike as old and beat up as this one. I guess the next step is to do the compression check or check the timing, im not certain which one to do first.


Sent from my iPad using MO Free
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #15 ·
What you posted says you need to adjust your valves. 'Should be Ok'.....NOT. You are at the tight limit AND below. Time to adjust things, and I'd suggest you aim for the loose side of the tolerances to give you maximum time before needing to do it again. Actually, once things have broken in they really are stable valve trains...but most street bikes run best when set wide as it reduces the overlap period.

Excessive overlap can cause some of your symptoms. No way to tell if this is everything. Problem solving on a machine works like this: Check something. Good or Bad. If Bad (yours) you MUST correct before continuing. Thinking 'yes, they are out..but they can't be causing the problem' will likely have you chasing your tail. Fix everything you find wrong when you find it and the troubleshooting will be much easier.
So i need to adjust the front cylinder exhaust valves then, everything else is within limits according to the book i have. As i dont have the shims for the valves ill prolly hold off on that for a little while, maybe move on to searching for something more catastrophic. Now how and where do i go about getting parts, on cars this is easy, jus be-bop on down to the old parts store n tell em what kina car you have, this is a different animal tho, do i go to an online supplier? Dealer? Is there the equivalent of an advance auto parts for bikes? I wouldn't mind ordering a carb kit just to be done with that. I dont even really know exactly what kind of bike i have, i do know its a suzuki sv 650, possibly an "S" tho im not even sure when and where that matters. I really appreciate your patience, i really know very little about bikes. I'm just working with what i have for now.
 

·
Hall Monitor
Joined
·
2,739 Posts
So i need to adjust the front cylinder exhaust valves then, everything else is within limits according to the book i have... i really know very little about bikes. I'm just working with what i have for now.
Then you need to borrow a trailer or pickup truck and haul the bike down to a good mechanic and have them do the valves, because tackling a valve adjustment is NOT something you want to do unless you really know what you're doing. It is way too easy to get the valve timing set incorrectly, and if you're just one tooth off you end up smacking pistons into valves and end up with an expensive paperweight where your engine used to be. And you wouldn't be the first person on this forum to do so. Well worth the money (particularly since you've already done a good chunk of the teardown work) to have it done right.
 

·
Registered
Joined
·
6,834 Posts
Anyway, even tho the front cyl. Exhaust is a little tight its not enough to cause the sort of problems im having, i think we can probably rule out valve clearances as the culprit here.
Sent from my iPad using MO Free
I agree the valve clearances are not ALL of your issues, but is some of it. You're going to be getting into the carbs to fix it right because it sounds like the pilot jets are clogged up. Might as well bump them up a little while in there as even a stock engine likes additional idle circuit fuel.

I've found it easiest to get parts mostly online. Let your mouse do the shopping.:) And, rather than trying to find one shim or three, I bought the set so I can do the valves anytime and not have to worry about finding this shim or that. Was about $75 IIRC and well worth the lack of hassle trying to get them locally.

Your tight valves aren't catastrophic at the moment, but there is a very good reason they called the clearances that they did. I'd adjust them all to the high side and enjoy the excellence of the engine running.:)
 

·
Registered
Joined
·
272 Posts
Sounds like your bike is running lean to me. This would explain the excessive heat, and needing to keep the choke open.
 

·
Registered
Joined
·
14 Posts
Discussion Starter · #19 ·
Sounds like your bike is running lean to me. This would explain the excessive heat, and needing to keep the choke open.
Thats the conclusion im coming to, i havent gotten around to the compression test yet, might try a do it tonight. Im going to try and find a link to get carb rebuild kits, but i havent had the time to look and am afraid of ordering the wrong parts. The fuel flow out of the tank is good, and the fuel pump is strong enough, any idea how i know which kit to order? Is there a preferred place to get these parts? Maybe a link
 
1 - 20 of 28 Posts
Top