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Discussion Starter #1
Okay well following on my other thread I figured I'd whip the head off this arvo for a bit of a look. Except I can't figure out how to get the ******* off! I've followed the directions in the manual, and removed all the (8mm head) bolts I can find, as well as the valve caps, the hanger plates, disconnected the carb, etc. I've also lined up the flywheel so the T mark is in line on the compression stroke. But I still can't get the head to move!

The manual says to slide it in the direction of the inlet valves (i.e to the back of the bike right?) but I can't see how it'd do that as the top of the adjuster nuts on the exhaust rockers look like they'd foul.

I gave it a couple of good taps with a rubber mallet but no change at all. Any suggestions or hidden bolts?
 

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Okay well following on my other thread I figured I'd whip the head off this arvo for a bit of a look. Except I can't figure out how to get the ******* off! I've followed the directions in the manual, and removed all the (8mm head) bolts I can find, as well as the valve caps, the hanger plates, disconnected the carb, etc. I've also lined up the flywheel so the T mark is in line on the compression stroke. But I still can't get the head to move!

The manual says to slide it in the direction of the inlet valves (i.e to the back of the bike right?) but I can't see how it'd do that as the top of the adjuster nuts on the exhaust rockers look like they'd foul.

I gave it a couple of good taps with a rubber mallet but no change at all. Any suggestions or hidden bolts?

if memory serves there a big bolt in the middle holding it all down ...

to be honest i dont think youll be able to get the rocker cover off without loosening the engine in the frame ( its a bitch i know):hitler:
 

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dead central are some bigger bolts, IIRC, and when I removed mine, I just fiddled it any which way and it came off :)
 

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Discussion Starter #5
Thanks for that info. I'll have another look around tomorrow. And snap's exactly what I DON'T want to hear - I managed to crack two big chunks off one of the valve caps but thankfully got it out without any drama.
 

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Discussion Starter #7
Thanks. Also I'm going to buy a cheap valve spring compressor to aid in the job, but have no idea what style is best? Either the G-clamp style or the one with the jaws. I guess with the g-clamp ones the head needs to be off, with the jaws style can you do the valve seats with the head in place?
 

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Thanks. Also I'm going to buy a cheap valve spring compressor to aid in the job, but have no idea what style is best? Either the G-clamp style or the one with the jaws. I guess with the g-clamp ones the head needs to be off, with the jaws style can you do the valve seats with the head in place?
i used the G clamp style which cost me 20 quid

dont think youll be able to do the valve seats without the head comming off

but you may be able to do the valve seals with the other type compressor but itll be tricky stopping the valve from dropping unless you have an airline and the tool some mechanics use

personally id whip the head off give it all a good clean and de-coke and when you put it back together you know its going to be happy days!
 

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Discussion Starter #9
Thanks for that info. I found that bolt I was looking for, cover's off, gonna put a couple of solid hours in on Sunday when I get some time. Stems still haven't turned up so I'm not getting her running this weekend unfortunately.
 

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I made up a valve spring compressor out of a peice of old handle bar with a section cut out for the removal/replacement of the collets,it worked very well indeed:cool:
 

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Discussion Starter #11
Orrighty oracle I need a bit more help please. Got the head cover off no drama, gave it a bit of an inspection. The rocker arms look okay, the left hand bearing is pretty crook, has a bit of play between the inner and outer races.The cam lobes look alright too. But what's more concerning is the decompression cam setup - what the manual refers to as the 'decompressor cam' and the 'reverse decompressor cam' are sort of sitting there loose, and can move up and down the cam a good 5mm or so. Is this normal or otherwise? It did sound like it had a bit of a rattle in the top end, this is entirely possible that it's the cause. I'll get a video tomorrow of it.

I also cocked up hard, and ****ed the cam chain tensioner shaft bolt. It was so tight that I rounded the head on it (internal 5mm hex bolt), then somewhat mangled the ******* trying to undo it. I'm going to bite the bullet and give it to the local thread repair dude to get out for me before I stuff the head. But what worries me is how tight that bolt is - is there a trick to getting it undone?

Sorry for all the questions, I'm attacking this fairly blind without any help and it's the first time I've pulled any engine apart.
 

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Orrighty oracle I need a bit more help please. Got the head cover off no drama, gave it a bit of an inspection. The rocker arms look okay, the left hand bearing is pretty crook, has a bit of play between the inner and outer races.The cam lobes look alright too. But what's more concerning is the decompression cam setup - what the manual refers to as the 'decompressor cam' and the 'reverse decompressor cam' are sort of sitting there loose, and can move up and down the cam a good 5mm or so. Is this normal or otherwise? It did sound like it had a bit of a rattle in the top end, this is entirely possible that it's the cause. I'll get a video tomorrow of it.

I also cocked up hard, and ****ed the cam chain tensioner shaft bolt. It was so tight that I rounded the head on it (internal 5mm hex bolt), then somewhat mangled the ******* trying to undo it. I'm going to bite the bullet and give it to the local thread repair dude to get out for me before I stuff the head. But what worries me is how tight that bolt is - is there a trick to getting it undone?

Sorry for all the questions, I'm attacking this fairly blind without any help and it's the first time I've pulled any engine apart.
if you mean the decompressor rotates round the shaft then yes thats normal, however if its moving up and down the cam ..than i may be wrong but i think thats a problem

as for the cam chain tensioner bolt ......search me ... mine came out like a normal bolt perhaps the last person to work on it fluffed it up for ya :confused:

if you look on ebay there are haynes manuals for xr650's this covers the same engine as the dommy and was considerable help when i rebuilt my engine just a couple weeks ago ...i cant stress enough how help full it is because if you dont understand whats in text theres nice pics to help you out which i found particulaly usefull when timing the engine whilst putting it back together!:happy2:
 

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Do you have an exploded parts diagram for the head? One that shows the camshafts, rockers etc? If not, then type your VIN (chassis number) into this website - ZSF - and you should be able to find the correct diagram no problem.

It looks to me as if there is a spring, or some such, missing that would "take up the slack" shown in your video.

i couldnt get this to work with my chassis number but i use Welcome to OEM Motorparts, Original parts for Aeon, Aprilia, BMW, Buell, Cagiva, Dinli, Derbi, Ducati, Gilera, Harley davidson, Honda, Kawasaki, KTM, Moto Guzzi, Peugeot, Piaggio, Suzuki, Sym, Tomos, Vespa and Yamaha motorcycles, mopeds and scooters. it has all the manufacturers exploded diagrams

:happy10:
 

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Discussion Starter #18
Thanks for the link. Doesn't really help though, it looks like I'm not missing anything, that it's just worn.

I did find this link;
XR650L decompression system, how does it work? on 4Strokes.com Forums

seems that the end float is its normal operation, but it doesn't account for the actual play/wear in the decomp cams internal bore. On those sites a new decomp setup is about 300 euro (!) so I'm wondering if I could just fit one of these and be done with it?

NEW HONDA XR650 XR650L HOTCAM HOT CAMS STAGE 1 CAM: eBay Motors (item 230478352285 end time Jun-21-10 18:42:53 PDT)
 
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