I just did the water pump impeller shaft seal, which requires the removal of both the intake and exhaust cams in order to remove the water pump body, which runs off the upper cam chain gear. Before taking it apart, I have put the bike to TDC by rocking the wheel (forward only) in 6th gear, and removed the clutch side over in order to line up the lower timing marks, which then perfectly aligned the upper timing gear to the notch in the cam support casting. But this then showed the intake/exhaust camshaft gears as being misaligned by almost a full tooth in either directions. I marked the tooth with a paint pen and took pictures so that I put it back in the exact same position as before disassembly because the bike good prior to taking it apart. I have finished the job and put it back into the same "misaligned" position and the bike still runs as good as before. FYI, removing the chain tensioner has no affect on the upper timing, this discrepancy is between the upper chain driven gear and the camshaft gears which are not affected by chain slop. My questions is, what the heck is going on here. Are the factory stamping marks off on the camshaft gears, or was my bike assembled out of time from the factory? If both the exhaust and intake cams were installed originally off by one tooth in either direction (which I think sould equate to about 10* degrees), would the bike still run OK? I was too nervous about trying to correct it and put it one tooth back in either direction to see what happens. For reference by bike runs great, tho I do notice that while there is great amount of power on the low RPM's, it kind of falls flat after about 5k RPM's, is this how y'all's bike are as well?
Here you can see the intake/exhaust cam gears are off by almost a full tooth in opposing directions, even though both the bottom timing mark and top timing gear mark are perfectly aligned.
here you can see the upper chain driven gear is perfectly aligned to the cam support casting timing mark. If I move the intake/exhaust gears to be perfectly aligned to the machined valve cover surface, then this timing mark moves about 2/3rd of a tooth to the right, no longer lining up to it's mark.
Sounds like your cam chain is worn out and needs to be replaced. The chain can be worn enough to effect the timing and yet not be seen. Paw Paw
The cam chain is fine, bike has 1200 miles on it. Like I mentioned in my above post, the fact that the top chain gear and camshaft gears seem to be out of line has absolutely no affect on chain stretch. A stretched chain can only affect the alignment of the bottom crankshaft timing mark and the top chain gear timing mark, which for me are perfectly aligned. The misalignment is between the upper chain gear and the camshaft gears, which are physically meshed together and unaffected by chain length. EDIT: since I too am a visual learner, I think this might better explain my point.
There are also marks inboard on the cam gears that must mesh with the mark on the timing gear. These are hard to see unless the cam journals are removed. Illustrated on page 196 of repair manual.
Its not the ole Yamaha trick of convert a yz450 to a wr450 my moving the exhaust cam one tooth is it ?
ah! I did not see this! I guess next valve job I'll check it out the inner side of the camshaft gears and see if there are dots there that align.
yes I do, that's what i followed, I did not see the inner camshaft gear timing marks because the picture in the shop manual had white paint marks over it. But now I know and will look for it next valve check. Anyways, I have put a total of 60 miles on the bike this week, it run great and ZERO coolant loss going into the oiling system! So the issues was the water pump seal, and not head gasket or any other more serious issues. Before I did the seal change, I would get about 300cc's of coolant going into the oil over the course of the 30 miles I put on it earlier this year. Luckily I'm really on top of this stuff and caught it almost immediately as the seal went. See photo below of how much water went into the oil, the oil only had 30 miles on it. It's the Motul 300V 15w60 Factory Line, which is green in color, as is the coolant, but you can still see where the water and oil separation line is. If I can give advice to anyone doing this job, heat the pump housing to 75*C and freeze the new water pump seal because it's a very, very tight interference fit and you will destroy it otherwise trying to force it in. Also, using sand paper, sand down the pitting and the groove that the old seal left in the impeller shaft (I put the shaft into a drill and spun it holding 500 grit sandpaper). This groove is what mostly likely caused such a massive leak. Also, you will need Loctite 542 and 648, so buy some ahead of time. Lastly, your pump impeller retaining nut will most probably be corroded to a point where it's impossible to get the 8mm socket to stay on and take it off with just hand tools, it will crumble. What I did was; spray the crap out of it with penetrating fluid, clamped the shaft in a soft jaw vice, pressed a 7mm socket onto the rusted 8mm nut, and used an electric impact to buzz it off quickly before the nut had a chance to round off or crumble again. Husky no longer sells this impeller retaining nut, but you can just use any galvanized M5-0.8 nut, so long as you use the appropriate Loctite 648 on it. This is the 3rd 630 that I have seen with this same coolant oil mixing issues. My friend's bike was exhibiting the exact same issue prior to my bike, though he sold it rather than fix it. Another 630 I saw up in the canyons also had milkshake on the oil sight glass. This seems to be a somewhat common issue, and is probably the cause of many premature engine failures, all because of a tiny $4.25 seal (part number 800053339). Check your radiators, if you're missing coolant, replace the seal asap.
Just to confirm for anyone who might be interested, my bike looks exactly the same: the dot on the exhaust (left in the picture) cam gear points about 1 tooth higher than the intake one (right). As mentioned by Willie, the purpose of those dots is explained at page 196 (or H.40) of the workshop manual. The white painting marks on mine look even different to yours. I don't understand what they are supposed to allign to but my timing gears were last reassembled by a mechanic who (I hope ) knew what he was doing, so I'm pretty convinced this is how it's supposed to be.
