Need Help For Alan!!!

[viclioce]

Help guys! Alan bought what was supposed to be a Super Combat from a guy named Ben, in California. The frame Number is F 27057 which would indicate a mid production Super Combat frame. The bad news is the number on the cases is H01041, which indicates a Model 94 Wombat bottom end, correct? From what I look up on the charts, the SC trannies have numbers which start with K.

Here is a photo which was sent to Alan before he bought it, showing the reed valve mount between the carb & cylinder, but we can’t see inside the cylinder. This was Ben’s photo, sent to Alan.

So a couple of questions.

1. Will a Super Combat top end fit on a Model 94 bottom end? If they don’t, then he did a bait & switch!!!

2. Are the crank/rods the same for both the 94 & 97 models? I know the pistons are very different. Could this guy Mount a 97 piston on a 94 crank and make it work with a 97 top end mounted on a 94 bottom end?

3. Are the 94 Wombat gears straight cut and the 97 Super Combat gears helical cut?

4. How different are the gear ratios between the Model 94 tranny and the Model 97 tranny?

Alan wanted the Super Combat to vintage MX race with. My understanding, limited though it may be, is the 94 tranny was more like an enduro tranny with taller gears, while the 97 had a close ratio MX tranny.

Your input and guidance is humbly requested. Thanks in advance! Victor

[Bullfrog]

Vic,

1. Will a Super Combat top end fit on a Model 94 bottom end? If they don’t, then he did a bait & switch!!!
Yes, the SC top end fits on the 94 bottom end. If you received the top end shown in the photo, then odds are you got what the seller advertised. If the measurement from the head gasket surface down to the top of the exhaust port is 26mm, (and the exhaust port is stock/not ported) - then it is a Super Combat cylinder.

2. Are the crank/rods the same for both the 94 & 97 models? I know the pistons are very different. Could this guy Mount a 97 piston on a 94 crank and make it work with a 97 top end mounted on a 94 bottom end?
Yes.

3. Are the 94 Wombat gears straight cut and the 97 Super Combat gears helical cut?
I assume you are asking about the primary and pinion gears. You have it reversed. Wombat primaries are helical cut (for noise control). SC primaries are straight cut for slightly higher power transfer efficiency and strength.

4. How different are the gear ratios between the Model 94 tranny and the Model 97 tranny?
You can look this up in the Owner's Manuals online.

Alan wanted the Super Combat to vintage MX race with. My understanding, limited though it may be, is the 94 tranny was more like an enduro tranny with taller gears, while the 97 had a close ratio MX tranny.
Your understanding is correct.

Ed

[mac]

Maybe only the cases are Wombat with SC internals ?

[viclioce]

Another discovery. This tranny Alan received, has a points stator and Not a CDI Ignition. Looks like Alan got sold a 97 Super Combat top end mounted on a H numbered 94 Wombat tranny. I can’t imagine someone moving the tranny of a Super Combat over to a set of H series cases and NOT changing out the CDI. Why go through all that and then settle for a down graded ignition. Bummer too! He really wants the MX transmission. Victor

[BrianZ]

The earlier Super Combats had a problem with transmission failures. This was fixed with a cushioned primary gear P/N 974502Z. The trouble was that the transmission failure could ruin the engine cases. This may have been the case with the bike in question. Paul used to sell a transmission upgrade kit with hardened gears and a cushioned primary gear. I looked on Terry's site but I could not find it. You may want to give him a call and see what he has. Warning: It is not cheap.

The entire model 97 transmission will fit in the 94 cases, but you will need all the gears (including the kick start gear). Another difference between the 94 and 97 is that the 97 runs a needle bearing on the RH counter shaft. This can be made to fit the 94 cases but requires machining. It is not required, but should be done for reliability.

Brian

[dirty_rat]

If it is a Model 94 bottom end, it should have helical cut primary gears and a 4 plate clutch. A Combat Wombat and a Super Combat bottom end will have straight cut primary gears and a 5 plate clutch. And, as you noted, the Super Combat came with a CDI ignition, while the Wombat and Combat Wombat both used points and magneto ignitions. All three bottom ends will work with the top end shown. The biggest difference between the three transmissions are: the Super Combat has a very close ratio transmission, the Combat Wombat and Wombat had a wider ratio transmission (the only difference in the ratios is in fifth gear, where the Combat Wombat has a 1 tooth smaller countershaft gear). The other difference between the Wombat and Combat Wombat will be in final gearing because of the difference in the primary gear ratios (and your sprocket choices). I know a lot of people that run a 97 top end on a Combat Wombat bottom end (transmission, etc.) and like it.

[TimCC001]

Hello Victor,

I was browsing through the posts and found this one. I have a Model 97 Super Combat bottom end, case no. K-08539. I bought it several years ago as a bottom end only, I never had a top end for it. If Alan is interested, I could take a few pics and perhaps we could hammer out a deal.

Sincerely,
Tim

[viclioce]

I can tell Slan to read this post and he can contact you! Victor

[viclioce]

Tim. Check your PM. I replied to your email! Victor