Introduction, maintenance and backfiring problem

[bakeLit]

Hello there, guys (and girls, perhaps?),

First of all, I might use this post as a way of introducing myself to the community, as I've bought an '81 SOHC XS to play with for the summer (with no side covers, yes, I know).

I've already ridden about 800 kilometers and thought I would never had to go deeper and actually get to know all the parts of the bike (the fuel system, that is, for the time being), but there was this problem with the bike taking it at least 5 sweaty minutes to start and stabilize. Once it would get hot, it would work like a charm - but then again, who would want to kickstart the damn thing fifty times each morning? Also, the left muffler was backfiring from time to time, and therefore I decided to get my hands dirty a bit.

I watched the carb videos: I did the recommended maintenance (complete cleaning, diaphragms check - glad they're OK, checked and set float height to 26 mm), I managed to build the carb synchronizing tool and balance them and then I went on to play with the mixture screws. Whatever I tried, it just wouldn't work correctly. The bike starts more easily (thanks to richer mixture, I suppose) but the left muffler pops like crazy. Now, one filter's foam was completely falling apart so I'm expecting a new one soon, but I tried to change them, as it was the left one that was falling apart, but even with the healthier one, the left muffler still pops. I might have messed with the spark plug gaps and saw a minor change for the worse - I'm expecting the recommended NGK BP7ES's when I get home from college this weekend. I still have valve clearances on my to-do-list, so that might be the issue as well. If you have any further advice I could use when I get back home, I'll be glad to learn anything.

Along with this post I'd like to ask about those cheap POD filters. Are they actually rideable? Does any one have any experience with them? I've read a post about them blocking some of the intake passages. (this kind of filters or the similar ones sold on MikesXS)

Thank you very much and keep rollin'!

 

[xschris]

Welcome to the forum. If you go with pods get uni's. They work better on cv type carbs than the pleated ones. Also being a oiled filter they will keep a lot more dirt out.

 

[DARKMIDKNIGHTWARRIOR]

Welcome to the forum!

 

[willem]

welcome ! the bike looks like it's in great shape. About the girls, don't get your hopes up about there being any here

If you mount the pods onto the original intake H-piece you'll have no problems with the inner lip.

I'm not surprised the bike's not running well and backfiring if your air filter is in that bad shape. The stock air filters are quite restrictive to the air flow, so if they disintegrate the flow of air becomes bigger and your mixture will run leaner and leaner, resulting in these issues. I'd expect it to be a whole lot better if you get new stock filters on. Aftermarket air filters or pods are usually less restrictive than the stock version, so they will require re-jetting of the carbs. If you're going that way do make sure you adjust your valves and sync the carbs first, and make sure your exhaust doesn't leak. You don't want to re-jet and find different issues later, and then have to re-jet again.

 

[bakeLit]

Thank you, willem, that's the exact procedure that awaits me!

//Just a question - would the PODs fit when put onto the H-frame? As the battery case is quite wide.

 

[bcware]

I thought I saw someone do this on here in the past, but I can't find it. You could also try something like this with your filters:

http://jaredsgarage.blogspot.com/2009/05/custom-uni-foam-motorcycle-air-filter.html

Sometimes lawnmower air filter foam comes in strips locally that are about the right size.

 

[bakeLit]

So I've got to the point of ordering a new filter and I've found this one to be slightly cheaper. According to the description, this one is meant for the 80-82 SE version, but, in fact, does it really matter? Are they interchangeable with the one with foam? If they were, I'd get two of these.

 

[LuckyEight]

Nazdar. Pěknej kousek. Mám stejnou ale už v trochu pokročilejším stádiu úprav. Co se týče filtrů, hodně se tu píše o těch levnějších, který mají uvnitř takovej gumovej lem a v případě, že je dáš rovnou na karbce, tak ti můžou zlobit. Pokud je dáš na tu gumovou H-trubku co vede ke starejm filtrům, neměl by bejt problém i s těma levnějšíma. Teda takhle, řada lidí tady je používá a nemaj problém. Ale jak píše Chris, lepší jsou pěnový UNI filtry. Pokud je patřičně naolejuješ, možná bys ani nemusel moc tunit karbce a sahat na trysky apod. Bohužel UNI filtry u nás a snad ani v EU neseženeš. Jedině ebay