primary gears

nsman · Dec 20, 2005

Without going into a lot of explanation we are building the prototype 03 450 engine as a 470.We are using a new crankshaft from an 02 fc470 complete with new piston kit and cylinder liner.There have been a few issues to overcome but they seem to be resolved at this point.One last problem is that the primary gear and clutch basket are binding together excessively resulting in a disconcerting whining noise.The fit between these two straight cut gears is simply too tight as it is difficult to even install the parts on their respective shafts.
The problem appears to be the primary gear as everything slides on and has a normal backlash feel.The primary drive gear from the 02 engine is a different part # than the 03 engine.We are attempting to use the 03 primary drive gear with an 03 clutch basket.We have tested a cracked 02 primary drive gear that fits the shaft and has the correct gear backlash.
The gears look identical does anyone know the difference between these primary gears or why the 03 gear will not work with this clutch basket and crank combination?

Taffy · Dec 20, 2005

it will be in the cut and depth of the cut. it's a shame that it's been so much hassle. to use the '02 running gear will be a pain i'm sure!

regards

Taffy

nsman · Dec 20, 2005

This primary gear and clutch basket match are the original parts and worked well before,only change is the crankshaft.

Taffy · Dec 20, 2005

then i can only think that the two centres are closer together. try opening the jaws on a vernier and going into the bottom of the cut between two teeth on opposite sides of the gear. bet there's a difference!

regards

taffy

husabutt · Dec 20, 2005

Might this apply:

Transmission

The transmission was modified with a different tooth profile between 2001 and 2002. The easiest way to determine how the engine was built is to look at the counter balancers' drive shaft. The early shaft has a straight surface and the later one has a diameter change between the position for the timing sprocket and the drive gear (tapered).

The following gears are not interchangeable between 2001 and 2002/2003: Counter balancer, balance drive shaft, drive gears on balancer drive shaft and crank shaft and also the outer clutch basket.

LINEAWEAVER · Dec 20, 2005

"This primary gear and clutch basket match are the original parts and worked well before,only change is the crankshaft."

Hi Nsman,
I believe you to have hit a tolerance "stack" limit. Most likely the result of recently installed main and transmission input shaft bearings.

You may increase said bearing radial clearance using a C4 specification as opposed to that of C3.

Such is not uncommon.

Hope this helps.

Sincerely,
Dale

nsman · Dec 20, 2005

Would it be a bad idea to attempt to lap the two gears together with fine valve grinding compound?
First, I may just order the 02 primary drive gear part # to see if it fits better.
Dale.... We did replace the main brgs and trans bearings with c3 fit,but we previously built this engine using a complete set of 02 470 cases with the original bearings and had the same issue and assumed it was a set the 03 parts just not fitting the 02 cases.

LINEAWEAVER · Dec 20, 2005

Hi Nsman,
According to my data the 02 part numbers supersede to that of 03.

I often run across manufacturing tolerance issues with these engines. Such is fairly common.

Dale

PS
If you reference an 03 parts manual you will see the "Husaberg" 02 and 03 part numbers to be the same. Using the later parts manual will note 03 and later. 01 is unique unto itself.

nsman · Dec 20, 2005

now I am confused....the primary gear that was standard on the 03 450 was #230 45 but the one that goes with the crankshaft (the 470) was #230 30.(the part #'s are on the gears)..these parts look identical but fit different....

LINEAWEAVER · Dec 20, 2005

nsman said:
now I am confused....the primary gear that was standard on the 03 450 was #230 45 but the one that goes with the crankshaft (the 470) was #230 30.(the part #'s are on the gears)..these parts look identical but fit different....

Hi Nsman,
Same specification / different manufacturer.
Unfortunately I have encountered such many times hence my reference to tolerance stacking.

Sincerely,
Dale

berger · Dec 20, 2005

There was an 03 450???

nsman · Dec 21, 2005

Hi Berger,
This was a prototype 450 engine built in 03.It used non standard crank parts that are not available.This engine has SEM ign but a FCR carb,470 style crank but with a short stroke,same bore....nsman

SFO · Dec 21, 2005

If you look in your machinists handbook there will be a pin size to use when gauging the gear profile diameter.
Utilizing the proper diameter pins placed in the gear tooth will allow you to find the true diameter of the gear, not the root depth.

nsman · Dec 21, 2005

Thanks SFO,I am now aware gear depth is not the critical issue. We have taken this gear to our machine shop guy for some professional help.

LINEAWEAVER · Dec 21, 2005

nsman said:
Hi Berger,
This was a prototype 450 engine built in 03.It used non standard crank parts that are not available.This engine has SEM ign but a FCR carb,470 style crank but with a short stroke,same bore....nsman

I built a couple similar units with Husaberg.

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