1984 Honda XR350R, Winter Project

[mcma111]

Perhaps this will help:

http://www.justxr.com/jaw/gearbox.html

[Pablo83]

Originally Posted by Big_John

We have to get down into the tranny. The bike shifts from 2nd to 4th and we have to figure that out.

I have a spare 6-speed NX250 tranny in the shop (I tried to see if it would fit in the 650, it won't). I wouldn't be surprised if it were the same as your tranny. It's yours if you want it.

Also, you might not have to split the cases for this. There is a plate outside of the cases that prevents the shift pawl from moving too far (and shifting past the intended gear). I would check that mechanism first.

gear counts and ratios for the 88 NX250:

13 37 0.35
18 32 0.56
21 28 0.75
24 25 0.96
26 23 1.13
28 22 1.27

[Big_John]

Originally Posted by mcma111

Perhaps this will help:

http://www.justxr.com/jaw/gearbox.html

This is frickin awesome.....thanks!!!!!

Originally Posted by pablo83

I have a spare 6-speed NX250 tranny in the shop (I tried to see if it would fit in the 650, it won't). I wouldn't be surprised if it were the same as your tranny. It's yours if you want it.

Also, you might not have to split the cases for this. There is a plate outside of the cases that prevents the shift pawl from moving too far (and shifting past the intended gear). I would check that mechanism first.

gear counts and ratios for the 88 NX250:

13 37 0.35
18 32 0.56
21 28 0.75
24 25 0.96
26 23 1.13
28 22 1.27

Awesome as well. I'll let you know.


.....

[Big_John]

Originally Posted by pablo83

Are you going to blast the frame? If so, do you do it yourself, or send it out?

o





Not sure yet......

I only paid $300 for this bike and honestly don't want to spend a ton of money on it.

Would love to have a 'smokin' bike for $600 total.

We will think it over and post as we go.....



......

[Big_John]

blbiker56 and I spent the evening looking at pics and wondering about our colors for this bike.....

Thinking of heritage colors.








On the other hand....We have the blue shock boots.....so maybe this color......

[creaky]

Hi John......I have owned quite a few XRs over the years and am familiar with their pros and cons. 1st of all, ditch the K&N filter, it doesn't seal well on the XR airbox and as you have seen, will allow dust and dirt particles to pass. UNI and Twinair are good choices. The '84 RFVC twin carb engines tend to run hot in the top end and cam and rocker failures are not uncommon. Jetting just on the rich side will help keep things cooler. Third gear is also a problem with the 350s and 600s, it is weak and if it lets loose major damage can result. These bikes are a blast to ride, I had two '85s and had plenty of fun with them. Good luck with the resto.

[Big_John]

Originally Posted by creaky

Hi John......I have owned quite a few XRs over the years and am familiar with their pros and cons. 1st of all, ditch the K&N filter, it doesn't seal well on the XR airbox and as you have seen, will allow dust and dirt particles to pass. UNI and Twinair are good choices. The '84 RFVC twin carb engines tend to run hot in the top end and cam and rocker failures are not uncommon. Jetting just on the rich side will help keep things cooler. Third gear is also a problem with the 350s and 600s, it is weak and if it lets loose major damage can result. These bikes are a blast to ride, I had two '85s and had plenty of fun with them. Good luck with the resto.

Yeah, very good information. This is our 5th Honda in the last 5 years.....and we have torn down and rebuilt all 5.

The top end of this one was complete rebuilt by a bike shop 2 years ago....and we hope it is still in good shape.

This coming week, we will pull off the top end and split the lower in half to check out the tranny. Pics coming on that.

[blbiker56]

Well i spent a couple of hours tearing apart the suspension linkage. The whole linkage is metal bushings, which is awesome, because all i had to do was clean, polish, and throw some grease on the thing and its good to go. And the bearings inside of the rear suspension arm were in great shape, so i just cleaned those up. Also i decided to make the linkage look pretty and went ahead and polished it all up.

[motomike14]

The roost boost was not only for 2 strokes; as a matter of fact, if I recall, it was made for several years specifically for the XR models (common on the 250s too). It added an additional pulse of electricity, kind of giving it a "pre-spark" if you will. Kind of like a turbo charger for your coil. They did add some power, around 2-3hp in the peak range. Noticeable? Eh, probably not. But, I think it will make starting a little easier in some situations.

[mikesova]

why strip the frame? The paint looks like it's in pretty decent shape.

[Big_John]

Originally Posted by mikesova

why strip the frame? The paint looks like it's in pretty decent shape.

The paint looks good in the pics, because the previous owner gave it a rattle can job.....on both metal and plastics. We are going to strip down and redo as it should have been and we are going with a different paint scheme.

The frame and some plastics will be white. The shock boots and the seat will stay the blue color. The tank will stay red.

[Ghost_Mutant]

Originally Posted by motomike14

The roost boost was not only for 2 strokes; as a matter of fact, if I recall, it was made for several years specifically for the XR models (common on the 250s too). It added an additional pulse of electricity, kind of giving it a "pre-spark" if you will. Kind of like a turbo charger for your coil. They did add some power, around 2-3hp in the peak range. Noticeable? Eh, probably not. But, I think it will make starting a little easier in some situations.

Hmmmmm, sounds like analog circuit voodoo to me

A capacitor on the AC CDI input probably has some frequency dependencies I would think. If it had to be tuned, its probably for the high end so that Answer could claim a larger HP gain. But if it was tunable, I would want it for the low end. It would be nice to see a circuit diagram of the Roost Boost and internal CDI components. If it worked back in the day, it should still work today

Since football is over, I spent an hour looking at my parts XL350 bottom end last Sunday. The 85 XL350 is the dual carb, wet sump setup versus the 85 XR350 which is the dry sump single year wonder. Other than the neutral switch and possibly the split/spring loaded balance drive gear, I think this is the same bottom end as in the 84 XR350. Need to study the parts fiche closely to see any differences.

I kept this bottom end to learn about splitting Honda cases. I last split a Yamaha case over 20 years ago. The job went relatively well getting things apart. I didn't have a flywheel/rotor puller so that stayed on the crank which is still in the left side case.

Piston had a hole in the top. Chucks of piston pieces were in the bottom of the case. Whatever happened to this engine was pretty catastrophic. My 5mm hex adapter rounded over on the 2nd to last case bolt. I ended up having to use the impact driver on the last two bolts after making a slot with the dremel.

Good news, transmission looks OK with only surface rust on the output shaft. The clutch protected the input shaft. It shifted through all six gears. I checked this after removing the clutch and primary drive components.

Some of the other parts may still be usable. I didn't spend any additional time cleaning up these parts, I had used enough propane to heat the garage and wanted to save some in the tank for other jobs later

Photos:

[Big_John]

Bryce worked a ton today.....


Well.....the news isn't as good as we had hoped.... "Houston, we have some problems."

This appears to be a 'weld'.




There appears to be some scaring on these parts.....





Some more pics of the engine......

[Big_John]

some more pics.....

[Ghost_Mutant]

Did you guys check the cam chain for stretch before removing? There was only one supplier of a new cam chain that I could find when I did my XR5 engine rebuilds. The piston pin to rod clearance is something else to check.

Other than the marks on the crank, those parts look good to me. No hole in the piston