knucks
XS650 Enthusiast
And by run I mean, troubleshoot points and backfiring...I know mufflers create backpressure..
-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
Backfiring out of right cylinder
- Thread starter knucks
- Start date
knucks
XS650 Enthusiast
Any suggestions on jetting? Currently 27.5 idle, 135 main.
Running pods. My guess is that's too lean on both (where do I get jets?)
Running pods. My guess is that's too lean on both (where do I get jets?)
lightfall
XS650 Addict
Pods and open exhaust a tried and true starting place is +1 pilot and +2 mains. jetsrus stocks mikuni jets, mikesxs has jets. Get a few sizes. Fine tune later, unless someone has better advice.
knucks
XS650 Enthusiast
Thanks.
Yeah, I wanted to order a few things from MikesXS..but that shipping and I've heard bad things regarding shipping times too..no thank you :/
Yeah, I wanted to order a few things from MikesXS..but that shipping and I've heard bad things regarding shipping times too..no thank you :/
knucks
XS650 Enthusiast
Cool got some jets from JetsRUs. Hopefully the correct ones hehe 
I am awaiting my PAMCO, coil, wires..will report back when i get those ;/
I am awaiting my PAMCO, coil, wires..will report back when i get those ;/
On jets most any independent bike shop that works on dirt bikes, atv's, snowmobiles PWC, often have a selection of gently used jets from rejetting other machines. If you ask nice they might sell you a selection of jets to try and buy back the ones you don't use.
Most of these places often stock a wide range of new Mikuni jets for about the same price Mike's sells the Chinese stuff.
Compression, with the carb off holding them open makes no difference. 90 lbs. is low. A lot of auto parts stores have loaner tools, some rent cheap. Try another gauge. The book calls for on a fresh top end 145lbs. as minimum. It can be higher. On a good running engine with a few miles anything above 135 is ok.
Often times if the bike has set for a long time the compression will be low. A thin layer of rust can form on the rings, cylinder walls as well as valves and valve seats. This rust prevents things from sealing as well as they should. It wears off and lets the rings and valves seal better. After a few hundred miles the compression will improve.
I often loosen the valve adjustment a bit for compression tests. Say .010 intake and .012 exhaust, This ensures the valves are closing. Once testing is done reset to .003 intake and .006 exhaust.
You gauge may read low but are they even side to side. Even indicates your ok. Not great but ok. Testing with another gauge won't be a bad idea.
Exhaust, the stock headpipes are a dual pipe. The inner carries the exhaust, the outer stays a nice chrome color. When cut off as most do, the part that seals the inner to the outer pipe gets cut off. You can't just slap a muffler on the outer pipe. Exhaust will leak back out between the pipes and come out at the head. You need to hook the mufflers to the inner pipe. The adapter does this.
Condensers, yes the ones from a car will work just fine.
Leo
Most of these places often stock a wide range of new Mikuni jets for about the same price Mike's sells the Chinese stuff.
Compression, with the carb off holding them open makes no difference. 90 lbs. is low. A lot of auto parts stores have loaner tools, some rent cheap. Try another gauge. The book calls for on a fresh top end 145lbs. as minimum. It can be higher. On a good running engine with a few miles anything above 135 is ok.
Often times if the bike has set for a long time the compression will be low. A thin layer of rust can form on the rings, cylinder walls as well as valves and valve seats. This rust prevents things from sealing as well as they should. It wears off and lets the rings and valves seal better. After a few hundred miles the compression will improve.
I often loosen the valve adjustment a bit for compression tests. Say .010 intake and .012 exhaust, This ensures the valves are closing. Once testing is done reset to .003 intake and .006 exhaust.
You gauge may read low but are they even side to side. Even indicates your ok. Not great but ok. Testing with another gauge won't be a bad idea.
Exhaust, the stock headpipes are a dual pipe. The inner carries the exhaust, the outer stays a nice chrome color. When cut off as most do, the part that seals the inner to the outer pipe gets cut off. You can't just slap a muffler on the outer pipe. Exhaust will leak back out between the pipes and come out at the head. You need to hook the mufflers to the inner pipe. The adapter does this.
Condensers, yes the ones from a car will work just fine.
Leo
Last edited:
I think you need to do the basics first and identify and correct the problems you have before you start ading new parts .
You don't need anything expensive or complicated to do an adequate compression test . This $5 dollar used tester will do the job just fine.
http://www.ebay.com/itm/Used-RAC-Compression-Tester-Tool-0-300-PSI-0-21-kg-cm2-Gauge-/141097792747?pt=Motors_Automotive_Tools&hash=item20da1574eb&vxp=mtr
Any auto accessory shop will have something suitable for under $15 .
Untill you do a proper compression test you won't be able to eliminate a leaking head gasket or valves .
Plenty of youtube videos to show you how it is done
You don't need anything expensive or complicated to do an adequate compression test . This $5 dollar used tester will do the job just fine.
http://www.ebay.com/itm/Used-RAC-Compression-Tester-Tool-0-300-PSI-0-21-kg-cm2-Gauge-/141097792747?pt=Motors_Automotive_Tools&hash=item20da1574eb&vxp=mtr
Any auto accessory shop will have something suitable for under $15 .
Untill you do a proper compression test you won't be able to eliminate a leaking head gasket or valves .
Plenty of youtube videos to show you how it is done
knucks
XS650 Enthusiast
Peanut, yes, you are right, but I decided that an electric ignition would be a good upgrade regardless.
I installed it all today, bike fired up, still backfiring out the right, so that rules out the points/condenser/coil being an issue before.
I shot my timing light at the stator and saw it sorta hovering around the "F" but not exact on it, is that okay..?
I need to re-check my valves but now the engine is hot and I cannot..
I installed it all today, bike fired up, still backfiring out the right, so that rules out the points/condenser/coil being an issue before.
I shot my timing light at the stator and saw it sorta hovering around the "F" but not exact on it, is that okay..?
I need to re-check my valves but now the engine is hot and I cannot..
knucks
XS650 Enthusiast
I do not have my electric starter hooked up, how many kicks to check compression? 4-5 should do it, yes?
Also, I tried to sync my carbs but the gauges were all over the place...i guess leaks ??
Also, I tried to sync my carbs but the gauges were all over the place...i guess leaks ??
knucks
XS650 Enthusiast
10 kicks and it gets to like maybe 90PSI and doesnt get much higher. I went and tested the gauge on a moped I own that runs well, that registers 30PSI no matter how much I pedal..I want to believe my gauge is not right
knucks
XS650 Enthusiast
Perhaps I resolved it..in the brief I had it running earlier today, I did not notice any backfiring..
What is this part in the top left? The brass pipe circled in red
I poked through that with a small wire and perhaps that did it?
What is this part in the top left? The brass pipe circled in red
I poked through that with a small wire and perhaps that did it?
NONclow
Confirmed Laquer Breather
knucks
XS650 Enthusiast
I really hope that was it
Is there a way to pull that tube out entirely? Is it simply a connection between the hole down the center to the hole in the bottom of the tube and then I don't need to bother further?
Hopefully after my jets arrive I will be getting a lot closer to having this at least running for some riding before winter..Though I need some mufflers now..
Is there a way to pull that tube out entirely? Is it simply a connection between the hole down the center to the hole in the bottom of the tube and then I don't need to bother further?
Hopefully after my jets arrive I will be getting a lot closer to having this at least running for some riding before winter..Though I need some mufflers now..
NONclow
Confirmed Laquer Breather
The tube is pressed in. If it were just a transfer tube it wouldn't be so small. It is a metered orifice for a specific amount of fuel for startup. I would thoroughly clean the carbs by soaking them in carb cleaner solvent (or ultrasonic cleaner), then blow each hole/tube/orifice out both ways a number of times (hopefully with compressed air, the canned stuff works, but there is no comparing it to a compressor w/100+ psi). But by all means leave it in!
BTW just poking a wire into it might move the blockage elsewhere. Remove the enrichener and break out the blow gun!
BTW just poking a wire into it might move the blockage elsewhere. Remove the enrichener and break out the blow gun!
Do an introductory thread with as much bike info as you can i.e. model, year, stock or altered etc. and mebbe your skills along with the problem.......we don't bite much until we know you well.
Pics, show some pics, pics of yer bike not yer girlfriend.....unless she's on the bike.
I'll chalk this reply up to post full moon mania.
Welcome aboard!
