aussiechris

Hi Andy, This reply might be a bit late but the bearing you need is HK1520-2RS. This is the text of a post I answered a few months back... Virtually all of the kits sold by dealers include bearings with separate seals. In my opinion these are rubbish. And yes, I know that's what comes from the factory. The original bearings are HN1516 which is a full compliment needle roller with a 15mm ID, 21mm OD, and it's 16mm wide. The supplied seals are the same dimensions but 2mm wide. That makes for an overall width of 2+16+2= 20mm. There are a number of reasons why they fail early. Firstly, the needle rollers have little tits on each end to locate them in the housing as there is no cage. For some reason, in our application, those little tits break off and get in amongst the bearings causing failure. But the main reason is water ingress. Those 2mm seals have a steel shell and that doesn't seal too well in the dog bone as it is so thin. Furthermore, sometimes the seals just plain fall out of the dog bone. The reason is quite simple. The overall width of the bearing and seals is 20mm, but if you measure the dog bones you'll find they are only about 18.8mm wide. This means (assuming the bearing is perfectly centered) that the 2mm seals have just 1.4mm to seat in. And since the seals have a bit of a radius on the inside, there's bugger all holding them in place. The bearing you want is a HK1520-2RS (contact a local bearing supplier with that number). That bearing is a caged roller with in-built nitrile seals. It is 20mm wide but even though it is slightly wider than the dog bone, it is all one piece. I've been running these bearings for about 10 years now in various bikes. You can expect 5 to 10 years life out of them compared to less than a year from the standard ones. Price is about the same. Even though the original bearings have more rollers that doesn't help if they're full of rust and mud. This only applies to the four dog bone bearings. There's another two in the underside of the swing arm with two 3mm wide seals. You can't use the HK1520-2RS in there as the total width will be too wide (40mm vs 38mm total). But those bearings a well protected and don't give as much trouble. Also, you may have to get the inner rings (bushes, sleeves) off your dealer as the bearing shops seem reluctant to hold them. Gas Gas part numbers are BT27712014 (20x15x8mm) 2 required and BT27712005 (20x15x10) 2 required. I've just replaced the bearings in my 2011 Raga. The originals lasted 11 months and we don't do much mud and water here. I hope that helps. Chris Brisbane Australia.

Hi Jeff, There's no thermostat as such. It sounds like your thermo switch is working if the fan is turning on and off. Is it possible you got an air leak somewhere when you installed the reeds? I also installed Boysen reeds in my 321 and really like them. I did change the jetting slightly and it runs pretty fat (rich). I never had the pipe turn blue. If you just leave the bike idling, does the fan cycle on and off, or does it keep running? It should cycle and if it doesn't while idling for a long time, then it is probably a cooling system issue - radiator, pump or something. I've never heard of the pump stripping, the usual issue is the seal failing causing water in the gearbox oil. Chris.

Hi Farmer Jeff, I can't help a specific compression reading but a few fine scratches on the piston is normal. Usually the rings wear to the point that the end gap becomes excessive. However, if you are considering pulling the cylinder I suggest you check if you can still purchase the original type piston. I decided that after 10 years that I would treat my 321 to a new piston and rings. The dealer couldn't supply the original Mahle piston because they are no longer made and sent the S3 replacement. Unfortunately, the S3 piston is 60 grams heavier the the Mahle piston (40gms in the piston and 20gms heavier in the pin). When I questioned this issue I was assured there would be no problem and copped a lecture about how I should appreciate the fact that S3 went to the trouble to make suitable pistons. So I used the S3 piston and it's ok at low revs. However, when blasting up hill climbs at higher revs, the vibration is really quite bad. Clearly 60 grams is a huge difference on a piston the only weighs around a couple of hundred and the crank is not balanced for that. I regretted ever changing it because it ruined a great bike. I would suggest that if you can't get the Mahle piston then just replace the rings and give the piston a bit of a clean up. The original rings are probably still available. Chris.

Thanks lowbrow, they look great. Pity they weren't available a year ago - would have saved many hours designing and machining my own. Regards, Chris.

Looks good. Why couldn't they have done that two years ago?

Does your 2007 Raga have a Keihin flatslide or the same Del Orto as your old bike? I find my new Raga with the Keihin needs plenty of throttle to start. But it runs great and starts 1st kick hot or cold (as long as I don't forget the throttle). Like you, I've had years of old habit learned on my old 2001 TXT321. Chris.

I think there are two types out there. The Hebo one uses a ball bearing race and is part of a bar end. You have to.cut about 10 to 12mm off the end of the handlebar. I am more familiar with the Gas Gas or S3 one as fitted to the 2011/2012 Raga models. It uses a small roller bearing that runs in an insert that goes inside the handlebar. Only problem is that you can't really run bar ends with this one but it is nice and smooth. It also keeps dirt from getting between the throttle sleeve and bar. If you have access to a lathe it is possible to make the S3 type work with homemade bar ends :-) Chris.

If you want to remove the whole spring and cartridge then you also have to remove the large allen bolt at the bottom. Of course all the oil will fall out if you do that. If you just want to re-fill the oil then you just remove the cap and slide the lower part of the fork up. Be sure to loosen the top fork clamp screws before trying to undo the caps. But yes, you can just loosen all the clamp screws and slide the forks down without removing the caps. It is easier to do one at a time by removing the wheel and mudguard. Chris.

Hi Bondy, I use a spray-on oil called FAB-1 and it works really well. I simply wash the element in kerosene first then rinse it in water. Then towel it dry and give it an hour to fully dry before a light spray with FAB-1 and re-fit. Too easy. Chris.

Someone mentioned mineral oil. I just wanted to point out that is only for the clutch. Brakes use brake fluid (DOT4).

The other trick to removing the bearing races from the frame is to use a stick or mig welder. Just run a short bead of weld around the inside of the bearing cup and when it shrinks it will be loose. I just did some on a road bike that has a small ledge inside the steerer tube that prevents you getting a punch or drift onto the back of the bearing. When I did the lower one, it just fell out as I was taking my welding helmet off. Too easy. The bearing on the bottom triple clamp usually needs cutting or grinding. Cut almost through and hit it with a cold chisel. Chris Brisbane Australia.

Oh, I forgot to mention... You can use a couple of appropriate sized sockets and a bench vice to press the old bearings out and push the new one's in. They are tight but not that hard.

Hi Paul, Virtually all of the kits sold by dealers include bearings with separate seals. In my opinion these are rubbish. And yes, I know that's what comes from the factory. The original bearings are HN1516 which is a full compliment needle roller with a 15mm ID, 21mm OD, and it's 16mm wide. The supplied seals are the same dimensions but 2mm wide. That makes for an overall width of 2+16+2= 20mm. There are a number of reasons why they fail early. Firstly, the needle rollers have little tits on each end to locate them in the housing as there is no cage. For some reason, in our application, those little tits break off and get in amongst the bearings causing failure. But the main reason is water ingress. Those 2mm seals have a steel shell and that doesn't seal too well in the dog bone as it is so thin. Furthermore, sometimes the seals just plain fall out of the dog bone. The reason is quite simple. The overall width of the bearing and seals is 20mm, but if you measure the dog bones you'll find they are only about 18.8mm wide. This means (assuming the bearing is perfectly centered) that the 2mm seals have just 1.4mm to seat in. And since the seals have a bit of a radius on the inside, there's bugger all holding them in place. The bearing you want is a HK1520-2RS (contact a local bearing supplier with that number). That bearing is a caged roller with in-built nitrile seals. It is 20mm wide but even though it is slightly wider than the dog bone, it is all one piece. I've been running these bearings for about 10 years now in various bikes. You can expect 5 to 10 years life out of them compared to less than a year from the standard ones. Price is about the same. Even though the original bearings have more rollers that doesn't help if they're full of rust and mud. This only applies to the four dog bone bearings. There's another two in the underside of the swing arm with two 3mm wide seals. You can't use the HK1520-2RS in there as the total width will be too wide (40mm vs 38mm total). But those bearings a well protected and don't give as much trouble. Also, you may have to get the inner rings (bushes, sleeves) off your dealer as the bearing shops seem reluctant to hold them. Gas Gas part numbers are BT27712014 (20x15x8mm) 2 required and BT27712005 (20x15x10) 2 required. I've just replaced the bearings in my 2011 Raga. The originals lasted 11 months and we don't do much mud and water here. I hope that helps. Chris Brisbane Australia,

Yes, I think we all have to reach over and put the side stand down by hand. When I said the clutch was progressive, I meant that it engages nice and gradual rather than coming on all of a sudden like it did when new. You should be able to find neutral using your foot. Have fun at the trial, don't try too hard, just relax and enjoy riding on a new property. I also have a trial this weekend. Chris.

Hi Razorback, I'm glad you've got it all back together and running well. Don't be too concerned about it being difficult to find neutral while the engine is running. Mine was like that too. The clutch was draggy and not progressive from the start but it's great now. I've had my Raga for 10 months now and the clutch has just started to come good. I was trying it a lot on the weekend and I can now find neutral easily (with the clutch lever pulled in to the grip, not one fingering it). It's also really progressive now. In the meantime, you can try jiggling the bike back a forth while moving the gearshift and also giving the throttle a rev and shifting neutral as the revs drop down. I hadn't started my bike since a trial two weeks ago. On Saturday, it started 1st kick (choke and plenty of throttle). We made some massive new hill climb sections. My 300 Raga just ate them up in 4th gear including the lines with no run-up. And that's with the tallest gearing (11 front, 41 rear). I reckon these bikes take 6 to 12 months to come good, so stick with it and you will be rewarded. All the best, Chris.

Hi Jon, I probably got my post in while you were typing yours. Just to clarify, I bought my Raga 300 brand new and the settings I listed were how it was supplied. Like I said, this is the best carburated (if that's a word) bike I've ever had. But I disagree on giving it throttle while kicking though. It took me a while to figure it out as I used to start my 2001 TXT321 with little or no throttle. In any case, it costs nothing to try both techniques. Having said that, I have nothing but respect for your opinions. I've followed all your Gas Gas Guru technical articles for the past 10 years or more and you've helped me heaps. This is my chance to say thank you for all your hard work. Regards and thanks, Chris.

Hi Razorback, The standard settings for the PWK28 on your Raga should be: Main Jet: 122 Idle Jet: 45 Needle: JJH with clip in the middle groove Slide: 3.5 cutaway Idle Mixture Screw: 1.5 turns out Float height: 19mm from bottom of float to gasket surface (with carb inverted). I have moved my needle clip to one position richer to smooth out the sharpness that I had when rolling off the throttle. It runs absolutely perfect now. However, I find the bike likes plenty of throttle when starting (unlike the older models with the Dell Orto carbs). Probably about half throttle hot or cold. For cold starts, I pull the choke on and give it a quick kick. It will usually start first kick if I remember to give it throttle. No more than two kicks from cold. It will fast idle perfectly with the choke on and I do that for five or ten seconds then flick the choke off. It runs fine straight away whereas the older bikes would take a fair while to warm up before they ran any good. By the way, I'm at about sea level - but our winters are no where as cold as yours. Chris.

Hi Razorback, Don't be running 50:1 or even 70:1 fuel mix. It's not a lawn mower or motocross bike. At worst 80:1 but I've been running 100:1 in my gassers for years. That's using good fully synthetic oil such as Motul 800. Some people will argue this point but I ran 100:1 in my 2001 TXT321 for ten years before putting a set of rings in it. And that was riding a full day virtually every weekend. I'm running the same mix in my 2011 Raga. If you ever pull the head, or the exhaust header (or even the plug), you'll find there's plenty of oil in the cylinder. And the main bearings are lubed from the transmission oil. Any more oil than 100:1 and you're just clogging the exhaust. Regards, Chris.

I have the same bike (since new) and I love it. But the power is wicked. Your bike will have a black outer head. The insert you can see with 30T on it should be silver. That is standard compression. A high compression insert is red and the low compression one is black. S3 is fine - I understand the original head is an S3 Stars item anyway A low compression head and flywheel weight should make it into a smooth running torque monster. Be sure to let us know how you go. Chris Brisbane Australia.