Some 850 T5 questions

[shabba]

I just picked up a very, very nice '84 T5 last weekend and I have some questions. I'm having a time finding any info on this bike and searching has been difficult.

The bike is in very nice shape. It has a Dyna III added on as the only modification to the bike. When I ride, it seems to have a miss...it's not too bad, but just enough that I notice it. I changed the plugs on Saturday and that helped immensely. However, after I've been riding for 15-20 minutes, it begins to lose power. As it loses power, it will rev momentarily as if it's finding power again only to fall flat on it's face again. My guess is there is a clogged jet in one of the carbs or some other need for a cleaning. The bike was riden fairly regularly by the guy I purchased it from, but it was only city riding. He never revved it and I would think never got it much over about 50 mph through town. I'm simply looking for suggestions as to what might cause this as I'm fairly certain it's a fueling issue.

The other question is about an oil leak. It appears as though there is oil leaking from the tachometer cable. The spot where the cable hooks into the timing cover (is that what it is?) is oily...I noticed this when I rode the bike home as it was leaking hot oil onto my boots...not much, but enough for me to notice as I rode...a dime size drop every so often. Would hot oil be coming from that area?

Thanks for any and all advice guys. I come from a BMW background, have been riding all my life and I'm no dummy, so let me have it straight (especially if I AM indeed a dummy).

 

[Rafael]

Hi Shabba,

Welcome.

I think the shop manual for this bike was probably a supplement to other manuals. Tons of paper and e files on-line.

Sound like you have junk in the gas tank. The petcocks have a vertical screen that prevents getting clogged but when the gunk covers the screen from top to bottom is starves the carbs. Then the junk falls to the bottom when stopped.

The banjos on the carbs have a small screen in them, check those too. These usually don't clogg but if you find a little dirt there's probably more in the tank.

 

[Trout]

Welcome to Guzzi World! They become addictive and they all need a little sorting out so please don't get discouraged.

Try This: http://www.thisoldtractor.com/gtbender/ ... -t5_it.pdf

Or This: http://www.thisoldtractor.com/gtbender/ ... s_diagrams

Actually just about any Tonti frame 850 Guzzi manual will do as the basic engine / trans / rear is almost unchanged from about 74 to 2011 other than some electrical changes for different models. If the links above don't work email me at chambers8000@gmail.com I have PDF files for parts & workshop manuals for them.

Sounds like you may have fuel line / carb trash going on. Guzzi tanks can rust on the inside. You may want to drain the fuel & use a flashlight to look inside. Petcocks can get fouled with trash, plastic filters under the carb banjos get partially clogged, vent in the fuel cap can be clogged, so check all the basic stuff first then explore the carbs. If you get into the carbs you will at least need new bowl gaskets so check out http://www.mgcycle.com good people to do business with.
The carbs tend to get stuck on the manifold so if you pull them then loosen the clamp and soak the connection good with WD40. Watch out for the spring on the choke slide & the carb slide they like to fly & hide. Can't think of anything else at the moment.

I did look at the shop & parts manual for a view of the tach adapter that's leaking but they don't show an exploded view. It's been awhile since I pulled one off but I have timing covers sittin at the house so if you need me to I can open one up to see if there is an o-ring or metal clad seal in there, I'm betting on an o-ring.

Post again if you need help. Trout

 

[shabba]

Wow! That was fast help...thank you guys loads. I'll pull the petcocks and tank tonight to do some exploring. On my R60, I had a fuel filter that was directly under the tank and right before the petcock to prevent any junk from doing this. I hope that's all it is and it sounds like it might be. I had a bear of a time with my old '85 RX-7 a year ago...changed the fuel lines and the pump, new tank, new injectors...couldn't figure out what was wrong unti l looked closer at the filter on the end of the new fuel pump...it was clogged with fine sediment. A new mesh filter and the car was like new. Simple stuff yes...

 

[shabba]

Welcome to Guzzi World! They become addictive and they all need a little sorting out so please don't get discouraged.

Try This: http://www.thisoldtractor.com/gtbender/ ... -t5_it.pdf

Or This: http://www.thisoldtractor.com/gtbender/ ... s_diagrams

Actually just about any Tonti frame 850 Guzzi manual will do as the basic engine / trans / rear is almost unchanged from about 74 to 2011 other than some electrical changes for different models. If the links above don't work email me at chambers8000@gmail.com I have PDF files for parts & workshop manuals for them.

Sounds like you may have fuel line / carb trash going on. Guzzi tanks can rust on the inside. You may want to drain the fuel & use a flashlight to look inside. Petcocks can get fouled with trash, plastic filters under the carb banjos get partially clogged, vent in the fuel cap can be clogged, so check all the basic stuff first then explore the carbs. If you get into the carbs you will at least need new bowl gaskets so check out http://www.mgcycle.com good people to do business with.
The carbs tend to get stuck on the manifold so if you pull them then loosen the clamp and soak the connection good with WD40. Watch out for the spring on the choke slide & the carb slide they like to fly & hide. Can't think of anything else at the moment.

I did look at the shop & parts manual for a view of the tach adapter that's leaking but they don't show an exploded view. It's been awhile since I pulled one off but I have timing covers sittin at the house so if you need me to I can open one up to see if there is an o-ring or metal clad seal in there, I'm betting on an o-ring.

Post again if you need help. Trout

I don't get discouraged easily. Riding an older bike is an exercise in futility at times and I''m ready for that. I like to learn and part of learning is failure/frustration. That a new to me bike is already running poorly is frustrating, yes, but it's also an opportunity.

I'll report back on what I find tonight. The temperature should be sub-100 tonight so I can actually get out and work. :laugh:

 

[Trout]

Well with that kind of an attitude you are gonna love this Guzzi!

 

[shabba]

Well with that kind of an attitude you are gonna love this Guzzi!

Ominous. :laugh:

I think I'll be ok. If I don't know a vehicle, I like to learn by doing. I am guessing I'll be doing a lot of "doing".

 

[shabba]

Update: I pulled the tank off, drained it and removed the petcocks. There was so much garbage and junk it was unbelievable. I was able to look in the tank and, sure enough, there is some surface rust and particles floating around in the left over gas. I also noticed the rubber arms coming out of the airbox will not attach fully to the carbs.

I guess I have some work ahead of me.

 

[john zibell]

Update: I pulled the tank off, drained it and removed the petcocks. There was so much garbage and junk it was unbelievable. I was able to look in the tank and, sure enough, there is some surface rust and particles floating around in the left over gas. I also noticed the rubber arms coming out of the airbox will not attach fully to the carbs.

I guess I have some work ahead of me.

Looks like you need to treat the tank. Look here http://www.caswellplating.com/restorati ... ealer.html

 

[shabba]

Update: I pulled the tank off, drained it and removed the petcocks. There was so much garbage and junk it was unbelievable. I was able to look in the tank and, sure enough, there is some surface rust and particles floating around in the left over gas. I also noticed the rubber arms coming out of the airbox will not attach fully to the carbs.

I guess I have some work ahead of me.

Looks like you need to treat the tank. Look here http://www.caswellplating.com/restorati ... ealer.html

Any experience with this? I've used Kreem in the past and I've had good experiences with POR-15 on my cars. I've also considered cleaning the tank properly and not using a liner. Is that possible?

It's a camera phone picture, but you can see the junk on the filters. I pulled the petcocks apart completely and cleaned them well.

This is a better image (or closer at least) showing how much stuff was on the petcock. I imagine as I'm driving, this stuff was slowly working it's way up the filter and choking out the fuel to the carbs.

 

[john zibell]

Colin,

It appears you have experience with fuel tanks. I just suggested what I thought to be a good option. It is your call on what you do with the information.

 

[shabba]

Colin,

It appears you have experience with fuel tanks. I just suggested what I thought to be a good option. It is your call on what you do with the information.

I'm all ears. Have you used the product before? I relined a tank back in the 90's with KREEM but I sold the bike months later...I can't speak to it's longevity. The item you suggested looks promising and I think I might give it a whirl. I'm going to call a couple of the local bike shops to see if anyone has any available.

 

[Trout]

I've also considered cleaning the tank properly and not using a liner. Is that possible?

I've done it. Especially with a new project. There may be other things lurking around that require time or money. Just remember it will get worse and I've had tanks leak thru pin holes & drip on hot cylinders.

Clean everything up, put it back together & see how it runs. You can leave the carb boots off for a short test run.
Probably going to have to clean carbs & pull the boots off again anyway.

 

[Chris R]

I have heard some failures with KREEM. POR-15 do a tank liner that seems to have good press. I used a Novolac Epoxy:
http://www.caswellplating.com/restorati ... ealer.html.

It seems good stuff - time will tell. It definitely isn't affected by alcohol.

Whatever you use if you don't get rid of the underlying rust the product will fail. KREEM is probably fine as long as the rust is neutralized. I suspect that the liners that don't fail are just a bit more flexible. In any case If you have a super duper liner and rust, the rust will simply work the other way around and rust out the outside!

First step is to fill the tank with gravel and solvent and give it a good shake until you get no more rust flakes in the solvent. if you can put it on a rotisserie and let it spin for an hour all the better.

The second step is to remove the surface rust and chemically neutralize it - you can do this with phosphoric acid (also known as Milkstone remover at the local farm store if you can find one - the dairy industry use it to clean the lines). You can also uses molasses. You can also do it electrolytically (See Greg Bender's very excellent site: http://thisoldtractor.com/gtbender/moto ... nd_coating)

I really like a product called Evaporust - it is a bit expensive but can be recycled for a long long time and is the best way to deal with thin metal that won't stand sand blasting. I'd buy a couple of gallons and have to. This is the easiest way of dealing with rust.

http://www.evaporust.com/

It really gets rid of rust and leaves it with protective coating. I would still coat it.

 

[shabba]

Update: I have taken everyone's advice and worked on the tank. I bought the KREEM kit as it was the only one available here locally. As I had posted before, the petcocks were pretty full of junk. I pulled them apart and cleaned them so they were flowing well. I looked in the tank and saw very little rust which was surprising. There were flakes and specks of junk, but it was mainly red (like paint?) and round so I used some drywall screws and cleaned all of that out. I used the etch that came in the kit and left it in overnight with a tank full of water. The next morning, the etcher had done it's work. I looked at it and decided to not use the KREEM and instead fill it with fresh gas (once it was dried out of course). Once that was complete, I put it all back together and took it out for a ride. 5 miles in, the bike died completely. Before I did this, it would run very badly, but it would not die on me. I was able to get it running again and make it home. Once there, I pulled the gas line off the carbs on each side and cleaned the screen on the carbs. Both of them were junky looking, but not horrible. While I did that, I turned the petcocks on and drained some gas from both sides. Nice and clean looking so no more trash. I hooked it all back up and started the bike. It ran ok, but it would not idle and eventually died even with me feathering the throttle.

I sprayed some carb in the carbs and left it to soak overnight. I'm fairly certain now that I am getting fuel to the carbs. When I get home, I guess I'll see how it is on the road if it will go.

 

[Chris R]

I looked at it and decided to not use the KREEM and instead fill it with fresh gas (once it was dried out of course)

If you don't go the liner route - and there are some good reasons not to -one trick is to run a bit of two stroke oil in the gas from time to time as well as keeping the tank topped up.

Otherwise it sounds like you got lots of junk in the system and just have to give everything a really good clean.

 

[shabba]

I looked at it and decided to not use the KREEM and instead fill it with fresh gas (once it was dried out of course)

If you don't go the liner route - and there are some good reasons not to -one trick is to run a bit of two stroke oil in the gas from time to time as well as keeping the tank topped up.

Otherwise it sounds like you got lots of junk in the system and just have to give everything a really good clean.

That's what I'm thinking too. I'd never heard of the 2-stroke oil idea, but I'll try that. As far as filling the tank up, that I did because I didn't want to get any more rust in the tank and do it all over again. I read that you can actually take naval jelly, mix it with water and put it in the tank producing the same results, better in some cases.

 

[shabba]

Update: I got home and fired the bike up to see if it ran. It did, so I took it for a 5 mile ride from my house and back being careful to not go too far. Sure enough, it started to lose power again, but this time, it was manageable like before meaning I was able to get it home. I decided to pull the carbs and clean them, especially the right side as it is the one I have suspected of having issues. The carb was pretty clean for the most part, but I cleaned it all anyway. I put it back on, fired the bike up and it ran really well. I was surprised as the airbox boots on both carbs just dont fit so there is a small air leak on both sides at all times. I got a little confidence and pulled the left side carb to clean it too. That turned out to be a bad idea. The left side carb was dirty inside...not bad, but definitely worse than the right. When I started to put it back together, the spring came loose in the cap and I had to get the cable and needle right. That took forever holding the spring while threading the cable end through the piston... During that process, the cable came loose in the throttle grip so I had to fix that.

I finally got it all working and, as it sits now, the bike is running on one cylinder. I pulled the plugs. The right side plug was a little moist from gas and the left side plug was incredibly hot. So I'm rich on one side and lean on the other?

 

[Trout]

Basically yes. Do you have a good motorcycle mechanic in your area? The carbs really need to be done correctly. Stripped, dipped, new gaskets/seals, needle valves & floats with the float height set properly. Spend the money, do it right, do it once.
When the carbs are properly set up and you re-install them you will have to adjust the cables to synchronize the slide action. If one slide rises quicker than the other you will be feeding more fuel to one cylinder and this causes an imbalance. You will be amazed how well these bikes run when done properly. Syncing can be done without special tools but it does take time. Once the carbs are done we can go thru the sync steps.

Please don't make the mistake that so many people make, which is now to start fiddling with points/timing/ignition and adjusting valves. Fix the fuel problems first then move on from there.
Trout

 

[davidguzzi]

I lined my tank with some poly syuff 17 years ago and haven't had a problem since. Can't remember the name of the stuff it was that long ago but it worked