Looked at a 93 DR350 yesterday

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It won't hurt anything to try a thread chaser.. Although if you've pulled threads, it wont' help. Did you see little rings of aluminum when the bolt came out? Does it not tighten? If so, a thread chaser won't help..

 
dcarver said:
It won't hurt anything to try a thread chaser.. Although if you've pulled threads, it wont' help. Did you see little rings of aluminum when the bolt came out? Does it not tighten? If so, a thread chaser won't help..
Click to expand...
No little rings, the bolt threads looked bad for the first 3 or 4 turns. The rings could have stayed in the hole though. I didn't try putting it back in. I have the bolts and rocker cover from the other motor, I can try the bolt from it and see if it starts.

 
Another trick is to try a SLIGHTLY longer bolt to catch some virgin threads. Check it with a wire to make sure it's not a through-hole and will bottom before effecting anything mechanically.

 
Hmmmm, is that a helicoil backing out of that hole?

IMG_1352.jpg


Now what? Remove it and try putting a new one in?

 
Yep, it was and I went to Napa and got a Helicoil kit. Cleaned out the hole, carefully retapped it, cleaned it out again and installed a new one. Buttoned everything back up and it held nicely. Checked the valve clearances and they were right where I set them. No more leak from the cam cover! Yea!

But...now I noticed a slight weep around the base gasket. Crimeny! I might as well put a big bore kit in this winter. I'm gonna ride it for a while and keep an eye on the oil level.

 
Good to see another inmate like me who just can't stay away from the wrenches.. . ;)

Look at all you've learned in the last 4 weeks!

 
That wasn't exactly the plan! At first I thought I'd be replacing a kickstarter assembly, but it's been one thing after another. I definately have learned quite a bit!

If I ever look at another bike with a locked up motor, I'm bringing tools to pull the spark plug...you can tell a LOT from looking at it. I'll post a pic of what was in the original motor later.

 
Ok, here's the plug that was in the original motor.

IMG_1355.jpg


I've made a few changes...here's Thumper.

IMG_1356.jpg


Now I've got to dial in the carb. Pulled the plug last night and it was pretty black and it backfires and farts if I roll off the throttle quickly. I turned in the fuel screw about half a turn and it's better, but not quite right. I think another quarter turn might do it.

 
Arrrrrrrrrggg! I rode it to work last Friday and on the way home I gave it a few full throttle blasts since it was running so good and then a few blocks from home it started running a little rough. I pulled into the garage and pulled the clutch in and it started knocking pretty bad. I killed the motor and let it cool down and tried the kickstarter with the decomp lever pulled in. It was smooth through part of the stroke as usual but then got harder to push and I could feel something kind of binding up. I think a bearing is going out on the crank. Dammit! I was looking forward to some trail riding this fall. Now it looks like another teardown or find another motor. At least I did sell the other frame and parts for more than I paid for them.

 
Ok, since I have the bottom end of the original motor that dropped a valve, I split the cases to check it out. There was a little bit of crap in there from the piston so I sprayed the hell out of it with WD40 and all the bearings seem ok. Now I just have to get the tranny back in the way it was and seal it back up. Last night I pulled the top end off the knocker and hmmm, that piston looks bigger than the other one that got demolished. Hey, it's 86mm and stock is only 79. The piston hardly has any carbon on the crown and the rings are clean as can be. Evidently someone put a big bore kit in it and then it probably sheared the rotor key and they let it sit. Guess I don't need a new piston/rings set after all. The bore looked really good too, I'll just hit it with a hone

 
Got to give you some serious props, you now know more than you every thought you would about a DR350 and your still working on it. Very cool, very cool indeed. :clapping:

Thanks for taking us along.

Now I'm just waiting for the video of you ripping down a single track trail.

 
Thanks guys! But....you're not gonna believe this. I just came in from the garage, got bored and thought of something I wanted to check out. After pulling the top end off the other day, I rotated the crank around and the rod bearing was nice and smooth. Hmmm, I've heard that it's really rare for a crank case bearing to go out...what else could it be? I decided to pull the stator cover off and check it to make sure the key wasn't shearing again...ah sh..! The nut holding the rotor on had backed out just enough to let the rotor wobble a little bit! I took it off and cleaned the threads with carb cleaner and put some locktite on and reassembled everything. Turned it over several times with the kickstarter and it's smooth as butter again! Dayum, I took the top end off for nothing! Well, at least I know it's got a big bore kit now, so it wasn't a total waste. Now all I have to do is put the top end back on. The worst part is I could have fixed this in a half hour a month ago and been riding it! :rolleyes:

Of course the weather is turning to crap this weekend after having 4 or 5 days in the 70's and 80's... :angry:

 
Anybody have any tips for getting the rings compressed to get the piston back in the bore?

IMG_1423.jpg


I've never done this before!

It looks like this thing hasn't seen much action.

IMG_1422.jpg


 
Back in the day I rebuilt an RD350, and iirc we used large hose clamps to compress the rings. However, I think a 4-stroke engine may need a bit more finesse.

I'd probably follow this guide if I were doing a 4-stroke rebuild

Excellent thread, BTW. I enjoy wrenching, and last year restored an '82 Maxim that had been sadly abused by the HFM PO. Luckily it didn't need piston work.

This winter I'll be bringing an '81 XS11 back to life

Good luck with your ongoing project

:)

 

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