The XT350 thread

[SkidMarx]

Originally Posted by FTL

I found a used head on ebay for $200 and went ahead and got it. Hopefully, it will be in as good of shape as the seller says it is in.

A question: When I was removing the head, the block pulled loose from the pan. It did not tear the gasket. I am thinking that I can just clean the sealing surfaces and bolt it back up. Any thoughts?

Should be OK if you really need to watch the $$$. There is a big o-ring at cylinder base so even if the base gasket isn't perfect it shouldn't blow out. A little Gasket sealer wouldn't hurt. My current base gasket is garbage and I still only gave a little seepage (It was a temp fix that now has a few thousand miles on it ).
But,
Spend the extra money on an OEM head gasket though. I know the Vesrah one I got was not very good, other brands may be better. I bought a gasket kit and ended up raplacing the head gasket with OEM. A visual comparison will tell you if the aftermarket one is any good. It was pretty obvoius. The kit will include a base gasket and exhaust gaskets which you will also need plus a bunch of others you may need. The head gasket it the only one of questionable quality.
I know it's very tempting to go as cheap as possible, but it will likely come back and bite you (BTDT). Since you don't know the history of the head, at the minimum, lap the valves and replace the valve seals. I took mine into my dealer (who I trust) and had it done. I sent the cams along and had them do the adjustment. It saved me having to buy shims. They just put the correct ones in and kept my old ones for the 'shim bin'. The price was reasonable since they didn't have to deal with removal or instalation on the bike.
While you have the head off, check the piston rings and cylinder for wear. It may be a good time to get a hone and rings.
The leaky exhaust was likely making the bike run lean, but I would seriously consider replacing the intake boots.
You can end up with a partially rebuilt engine that may have issues in a few years or a mostly rebuilt engine that will last many thousand miles.
Your choice.

[jegrmajstr]

Originally Posted by jegrmajstr

I remember that one of you used home made PowerNow inserts, but the webpage that originaly had plans with dimensions on doesn't work anymore. So has anyone an AutoCad image or anything useful so I can make them myself?

Thanks, Tom

No one?

[The Full Monty]

No one?

jegrmajstr--wish I could help! But I don't even know what Powernow Inserts are!

Should be OK if you really need to watch the $$$. There is a big o-ring at cylinder base so even if the base gasket isn't perfect it shouldn't blow out. A little Gasket sealer wouldn't hurt. My current base gasket is garbage and I still only gave a little seepage (It was a temp fix that now has a few thousand miles on it ).
But,
Spend the extra money on an OEM head gasket though. I know the Vesrah one I got was not very good, other brands may be better. I bought a gasket kit and ended up raplacing the head gasket with OEM. A visual comparison will tell you if the aftermarket one is any good. It was pretty obvoius. The kit will include a base gasket and exhaust gaskets which you will also need plus a bunch of others you may need. The head gasket it the only one of questionable quality.
I know it's very tempting to go as cheap as possible, but it will likely come back and bite you (BTDT). Since you don't know the history of the head, at the minimum, lap the valves and replace the valve seals. I took mine into my dealer (who I trust) and had it done. I sent the cams along and had them do the adjustment. It saved me having to buy shims. They just put the correct ones in and kept my old ones for the 'shim bin'. The price was reasonable since they didn't have to deal with removal or instalation on the bike.
While you have the head off, check the piston rings and cylinder for wear. It may be a good time to get a hone and rings.
The leaky exhaust was likely making the bike run lean, but I would seriously consider replacing the intake boots.
You can end up with a partially rebuilt engine that may have issues in a few years or a mostly rebuilt engine that will last many thousand miles.
Your choice.

SkidMarx--that is some excellent advice. I had not thought of having my dealer lap the valves and check clearances….that is an excellent idea. I have been purchasing most of the new parts (OEM) from http://www.babbittsonline.com/pages/parts/viewbybrand/default.aspx . This includes new head gasket and exhaust gaskets, I have already replaced the boots.

As far as the lower base gasket, it was not the money so much as another order and waiting for it to arrive, I will check it close. I will look at the rings and cylinder as well.

Now the only question is, should I go ahead and pull the whole engine off and blast/coat the frame!

[SkidMarx]

Originally Posted by FTL

jegrmajstr--wish I could help! But I don't even know what Powernow Inserts are!


SkidMarx--that is some excellent advice. I had not thought of having my dealer lap the valves and check clearances….that is an excellent idea. I have been purchasing most of the new parts (OEM) from http://www.babbittsonline.com/pages/parts/viewbybrand/default.aspx . This includes new head gasket and exhaust gaskets, I have already replaced the boots.

As far as the lower base gasket, it was not the money so much as another order and waiting for it to arrive, I will check it close. I will look at the rings and cylinder as well.

Now the only question is, should I go ahead and pull the whole engine off and blast/coat the frame!

I did.
It also gave me a chance to inspect and lube the suspension, stearing head and wheel bearings.
Plus I like taking things apart.
Once the engine is out, you don't have much farther to go.

If the base gasket is in good shape, I'd reuse it. Mine was on and off 2 or 3 times and it never leaked until now.

Originally Posted by [COLOR=#ffffff

jegrmajstr[/color]]I remember that one of you used home made PowerNow inserts, but the webpage that originaly had plans with dimensions on doesn't work anymore. So has anyone an AutoCad image or anything useful so I can make them myself?

I'm the one with the home made PowerNow inserts. Honestly, I don't know if it was worth the hastle, but it was winter and I was bored.
I did get the template from the website, but I wasn't able to get the scale perfectly. I used some flashing from Home Depot and did a lot of trial and error got it to work. I'll see if I can find one of the templates pages I printed. It will at least give you the general shape.
Did they help?
I don't know. I did so much stuff it's hard to tell what made the most differance. The bike does run cleanly now through the entire throttle range so something worked. I think I lost a little on the bottom, but I gained it on the top. I do not have that annoying surge/hickup around 4500rpm like I used to.
My bike needs a bore/piston/rings so it's kind of hard to know what the true benefits were.

[jegrmajstr]

Originally Posted by SkidMarx

I did.
I'm the one with the home made PowerNow inserts. Honestly, I don't know if it was worth the hastle, but it was winter and I was bored.
I did get the template from the website, but I wasn't able to get the scale perfectly. I used some flashing from Home Depot and did a lot of trial and error got it to work. I'll see if I can find one of the templates pages I printed. It will at least give you the general shape.
Did they help?
I don't know. I did so much stuff it's hard to tell what made the most differance. The bike does run cleanly now through the entire throttle range so something worked. I think I lost a little on the bottom, but I gained it on the top. I do not have that annoying surge/hickup around 4500rpm like I used to.
My bike needs a bore/piston/rings so it's kind of hard to know what the true benefits were.

Thanks for the answer, it'll be great if you can find those templates. I know that most likely there won't be any major difference at all, but like you said, winter and boredom (well, except that the winter won't be here for 2 months ). I'll be taking the carb apart anyway because of the rejetting (130/120 + airbox mod) so while I'm there I'll do all the stuff intended for the carb.
I just got the bike back from the dealers because of the valve clearance checks, and the valves are still within the stock clearance at 25 000 miles Gotta love this little tank :)

[The Full Monty]

Found something interesting on the old head that I am going to replace. Under the valve lifters, but above the valve spring retainers there are flat washers. I don’t see these flat washers listed anywhere on the part breakdown and think they were added as shims. Has anyone else seen something like this? It really does not matter, because I am changing the head, but I am curious.

[seriousracer]

above the vlave springs? as in it was between the follower and the retainer?

[SkidMarx]

There is a washer between the spring and the head so the spring doesn't grind away at the Aluminium. It's called the valve spring seat on the parts diagrams. Maybe it was put together wrong.
There shouldnt be anything between the bucket and the spring except for the retainer.

[The Full Monty]

above the vlave springs? as in it was between the follower and the retainer?

Yes, above the retainer.

There is a washer between the spring and the head so the spring doesn't grind away at the Aluminium. It's called the valve spring seat on the parts diagrams. Maybe it was put together wrong.
There shouldnt be anything between the bucket and the spring except for the retainer.

Have not removed the valves, but these washers do not look like the valve spring seat. It just looks wrong to me......

[jegrmajstr]

I have a question...
How drastic is the change in fuel consumption after rejetting (130/120, pilot screw adjustment and an 1'' wide hole in the airbox)? I'm asking just for info, because the bike is due for uncorking anyway.

[SkidMarx]

I'm going to guess -5mpg. It may also have something to do with the way I ride it with a little extra juce.

[jegrmajstr]

Great, that's minimal I know it's an educated guess, but if it's under 10mpg it's nothing. We'll see if the bike can reach 90 mph or even more, with proper longer gearing ofcorse

[nails1]

Does anyone happen to know the p/n for the rubber diaphram on the secondary carb throttle valve? This doesn't appear on the fiche, and it's too hard to talk to a real parts person these days.

[nails1]

Originally Posted by jegrmajstr

Great, that's minimal I know it's an educated guess, but if it's under 10mpg it's nothing. We'll see if the bike can reach 90 mph or even more, with proper longer gearing ofcorse

I expect an increase in mileage with proper jetting. Of course, that gets balanced against the fun factor effects of having a bike that actually runs right.

I got 85mph (indicated) even with a nasty high-speed miss. I get up to 75mpg riding mellow (twin-track or country roads), but down to about 50mpg on the freeway (ie. wringing it's neck).

After further jet testing this weekend, I think my miss is really a bad condensor. For the carbs, I'm looking at 124/112 main jets, which is consistent with what you flatlanders are reporting (my house is 7500 ft, where there's about 6% less air in the air).

[SkidMarx]

Originally Posted by jegrmajstr

Great, that's minimal I know it's an educated guess, but if it's under 10mpg it's nothing. We'll see if the bike can reach 90 mph or even more, with proper longer gearing ofcorse

Honestly, I don't pay that much attention to what mpg I'm getting anymore.
I can ride to work all month on $60 which is 1/4 the cost of driving my Jeep.
-5 mpg = about $1 per fill up. No big deal.
I could likely gain some of that back by taking it easy, but for a dollar, I can ride it like I stole it.