[Pyro_]

Hey all, this post relates to my '07 bike.

So, a while back I blew my bottom end when my crank snapped, and ended up doing a full bottom/top/transmission rebuild. When rebuilding I decided that putting an aftermarket cam in would be a better option that going with a stock cam, and a stroker crank better than a standard crank.

So, I went with a HotCams Stage 2 Gold Series camshaft, with stiffer springs and all was fine and dandy. Until recently when the cam spun and put the timing out. Several of my mates have had various HotCams camshafts, and all bar one of them have had issues with them. Looks like I'm not putting a HotCam back in it.

Instead I was looking at the camshafts offered by Tokyomods, Pro Circuit and Wiseco. But unlike HotCams, they don't seem to grade their camshafts into stages. (Stage 1 is emphasis on low end power, 2 mid/high, 3 high and so on).

Does anyone have experience with any of these cams? Can you tell me what their benefits and downfalls are?

Thanks

[crfsonly]

This is very interesting to me as the Hot Cams are the most popular cam we offer and not a single customer has had any issues with them (at least not reported to us). We too have used them with great success and not a single issue. The CRF250 cams have a press-fitted cam gear not bolted or welded. So, an engine failure that would cause a running motor to stop suddenly would have the potential to rotate the cam gear relative to the cam resulting in changing the timing. So, if this is what has happened it's not the fault of the Hot Cams cam. The stock cams will do this as well.

We use the PC cams and they are outstanding cams. They are designed for motocross and so have a broad range of power. They are top shelf and come with a top shelf price. In addition, they MUST be used with the PC spring kit. These too come with a PC price. PC will not release to us or anyone else their cam specs so we can not recommend a less expensive spring package without doing some expensive cam spec work.

On the CRF250 cams, what engine builders will do to assure the cam gear does not move, or when altering the cam gear timing (read rotate it relative to the cam), is weld it in place. This provides more assurance it won't move under power.

Ken

[Pyro_]

Thanks for your reply.

I can understand how that would alter the cam timing, but my bike suffered no such event. I was riding my bike down a dirt track, when I started, there was no faults with the engine, however, about a kilometer up the track, I paused to talk to my brother, and that's when I first noticed the fault. The symptoms were: "Ticking" in low RPM range, won't idle (stalls), very hard to kick over, works pretty fine in high RPM range.

I never suspected the camshaft to be at fault, as I was not stressing the bike in any unusual way. Nevertheless, I took it to my local Honda shop to get the repairs done, as I was leaving town for a few months, they called and notified me that the camshaft had either spun the sprocket, or twisted the shaft.

I don't doubt the quality of performance of the cams, it was brilliant while it worked. But unfortunately, now it doesn't work.

I should also note that I did indeed have the stiffer valve springs fitted (HotCams springs), and when I replace my cam with another, I do not mind spending $400-500 or more for a better quality one...

[crfsonly]

the ticking sound could have been several things. the most common is the automatic decompression mechanism. the only way to know if the cam gear has indeed moved is to physically line up all of the time marks. if it has moved it won't be possible to do this. right now you are taking your shops word for it. some shops are qualified to do this work and others are not. for example, checking the time whilst the cam chain tension is off will give you a faulting reading. some know this and others don't. however, if the shop is correct and it has spun without the engine coming to a sudden mechanical failure stop this would be VERY unusual and unlikely. nothing like this has ever been reported to us and as mentioned the HC cams are the most popular we offer.

to the PC cam, the springs you have would need to be replaced if you installed the PC cam. the PC cam requires the use of the PC springs. it's not just about lift but the lift rates also. and since PC doesn't provide any cam specs we can only recommend the springs they have qualified as correct. we do offer both the springs and the cam.

let me know if i can help further.

[Pyro_]

Hey,

Thanks for all of your help. The guy at the shop I took my bike to may just be telling me it's the cam that's jacked, because when i did the major rebuild, I bought all of my parts online, and did the rebuild myself, because every time I've taken my bike to him, his mechanics have stuffed something up.

He has a brilliant honda mechanic, but the issue is that he gets so busy that he palms most of the work off onto apprentices and junior mechanics.

I've had my bike come back with bolts loose, or missing, parts installed incorrectly... When I first bought my bike from him he ensured me that they had done a full service and that all fluids were replaced and mechanics checked. When I got home and after several rides, I noticed that the coolant drain bung was missing, and my bike had been running with no coolant since the shop.

Long story short(er), I'm going to get the old cam back off of him and hopefully check it myself, do you have any idea how I could measure it to see if it has spun or twisted while its not in the bike?

Cheers for your help.

[crfsonly]

he's not a brilliant mechanic if he's having others work on his customer's bikes who are not qualified to do the work. allowing a bike to leave without coolant is major professional negligence. just my opinion.

to the cam, the best way is to install it and see if the timing marks line up. if they do install it and start it. if the cam was running well before you swapped nothing should have changed to the cam.

good luck.