850 loses power at high speed after heated up.

[kdo58]

are you using stock fuel line that is thin walled, or car type fuel line?

[redfenix]

Definitely not stock. It's thick-walled grey tubing.

[kdo58]

i had a similar problem, but it happen with the thin stock fuel line, with a fuel filter it would get a kink in the fuel line, and acted like it was running out of gas.
change to thicker fuel line never happen again.

[Missile99]

Hi Kevin,

I think what you said about the way it runs seems accurate considering what you drained out. There is a likelihood of some junk coming from the drain bolt/gasket but yours looks like sediment from higher up. Glad to hear the tank looks good. When you do your carb cleaning, take the gas cap and sending unit apart and clean them up good. Flush the tank and install a new fuel line. This only takes an extra couple of hours. I'm with kdo58 on the automotive fuel line since the gas is horrible nowadays.

What are your plans? Ride it until winter or tear it apart now?

[redfenix]

I plan on adjusting valves and rebuilding carbs fairly soon. I need to be able to trust a bike to ride it much, and I just can't trust this one with its periodic tantrums. So, I'll plan on doing this in the next few weeks when funds become available to get started.

Also on the agenda is to get some other mufflers, since some cheap rusty ones came with the bike when I bought it. I'll probably make that purchase before I rebuild the carbs. I'd like to consider a 4-in-1 system, but it may be an investment I'm not ready to make just yet.

[redfenix]

One more question, for anyone who might know. Until I'm able to bite the bullet and crack open the carbs, would it be worth trying out some Sea Foam or other such fuel additive to clear out the carbs a bit? Do you think it would help with my situation?

[Dogma]

One more question, for anyone who might know. Until I'm able to bite the bullet and crack open the carbs, would it be worth trying out some Sea Foam or other such fuel additive to clear out the carbs a bit? Do you think it would help with my situation?

Sea Foam won't hurt, but it might help a little. It's not a substitute for a rebuild though.

Don't worry about the exhaust until you have everything else working. Changing to a 4-1 will require rejetting to run correctly, which means the carbs will have to be cleaned anyway.

For reliability, you should also give your charging system some attention (before worrying about the exhaust). Even if it's charging now, some preventative maintenance and routine checks are in order. Dirty connections in the stock charging system can destroy the stator before you know anything is wrong.

[redfenix]

Okay, so an update here. As soon as the finances started flowing, I started ordering parts.

Long story short, I've got several tasks to perform on the bike before it escapes my garage once more.

1. Carbs: Obtained cycleorings kit, and am going through them right now. The bowls had some dried fuel residue inside them, and the soapy water I was using after the carb dip had some particles in the bottom of it. Also, a couple of the vacuum seals at the top weren't seated 100% correctly. Getting ready to put them back together now. Oh, and the intake boots had been on there for 30 years, and the o-rings were useless on them. Good thing I have replacements.

2. Valve Shims/Cover: I ordered gaskets for the valve cover and blower from real gaskets, and got a thin shim from Z1. I will check clearances, shuffle around shims, and see if I need any new ones.

3. Charging circuit: I tested this, and the stator is fine, but the r/r was only working in one direction. I've ordered a replacement from electro-sport. I'll install it and go through the wiring hookups at the same time. Oh, and while I was testing, I found the 2-wire plug for the signal generator was just about destroyed either from heat or battery acid, not quite sure which. It was all yellow and crumbly, so I took it out of the circuit.

4. Fuel Petcock: I ordered the 3/8 NPT adapter plate from Z1 and will use a "normal" petcock. I'm used to turning on and off the fuel, so this will work best for me. I also ordered clear fuel line and new inline filters from Z1 too.

5. Fuel Tank: I ordered the Kreem kit to line the tank, even though it's not bad right now. I'll clean out the sending unit and cap while I'm at this.

And that's pretty much it. A good week or two of work here (in the evenings, of course) and hopefully she'll be running MUCH better.

[Dogma]

It sounds like you're on your way, though I don't understand what you mean when you say the regulator was only working one way. No matter, you're aware of the charging system now and dealing with it.

Be extremely thorough preparing the tank for the Kreem. Almost every Kreem story I've ever heard was someone having to clean it out of carbs because they or a PO didn't get the installation right.

Ordinarily I'd reiterate that the in-line filter should not be necessary and is more likely to cause problems than prevent any. In the case of freshly applied Kreem, I'd say keep it to protect the freshly-cleaned carbs. Oh, and you're replacing the petcock, so that filter screen is going away. You will actually need the in-line filter. Carry on.

[redfenix]

Thanks, Dogma. In light of your comments, I've decided to delay the Kreem for now until the rest is working. One less variable, right?

[Missile99]

Not a bad idea to wait on lining the tank if it's not too bad. Maybe a good cleaning will do for now and winter for the Kreem. You have a few good projects on the your list and it should run like a champ now. Keep us posted.

[redfenix]

Got an update...my 850 is running great!

I cleaned out the carbs, replaced the o-rings in them. The intake boots had never been taken off before, the o-rings on them were flat and came out in pieces! I sealed up the airbox as best as I could and put that all back together. Then I also checked my tappet shims. I really could use 4 new shims, slightly thinner, but I shuffled them around as best I could for now, until I could procure some shims. I also installed a "real gasket" for the valve cover and the breather. And finally, I scored a set of stock exhaust to replace the ill-fitting mac muffler set I had before, so I got some new exhaust gaskets and installed the stock exhaust too. I've still got the inline fuel cutoff, but I put in clear fuel line and a new clear inline filter.

Bottom line, she's running really well.

I still have a couple of things to take care of, I picked up some shims from the local cycle shop here, so I need to change those out, and then I also need to replace my little "fix" for the fuel petcock with the pingel conversion plate and the 3/8" NPT petcock I picked up from the local place too.

Thanks so much for the help!

[Missile99]

Good news redfenix. Now hopefully you can work on things one at a time as miles accrue since you've done this big chunk of repairs to get rolling. Enjoy the good running bike. Maybe your heat wave will eventually lift and you can ride comfortably all day unlike me here.

[redfenix]

Well, I replaced 4 of the 8 shims, now I have extra clearance on the exhaust and the intake is all right in spec. I also replaced the fuel valve with a standard 3/8" npt petcock and am happy with that. I also noticed over a 1V drop to the coils, so just last night I did the coil relay mod.

I also installed a new tail-light and led turn signals. I ended up replacing the turn signal relay with one that supports leds. It all works now, except that I had to clip the wires to the turn signal dash indicator as it was causing all turn signals to blink at the same time!

I'll have to start a new thread and take some pics.

[redfenix]

Oh, I think it's worth noting that I've ridden my 850 to work and back for 3 days in a row now. It's a 30 mile trip one-way. I've been getting a little over 30mpg, but I'm looking for ways to increase that now. The coil mod was the first step to this.