pre 75 options

[Sammundo]

so after an excellent weekend at harrisville i think im hooked. the only bad thing was i wasnt in enough races. well, that and the ones i was in i lost but no matter. So i figure i need to enter another class. and as i liked the look of the pre 75 125 i thought that might be the place to go. Problem is i know just about nothing about dirt bike of any generation never mind ones that are older than me. So the question is what kind of bikes are you guys running?
I do have a sl125 rolling frame in the garage waiting for me to do someting with it but havnt been able to trake down an engine. would a 100 bottom end fit a 125 barrel on? or a xl combination maybe? or am i better of finding a 2 stroke motor to put in and if so what from. Any tips or hints much appreciated.
Oh and this is going to be on a bit of a budget as most of my funds have to go on a pram and cot and such things.on the bright side in a few years i will have a side car companion as i quite liked the look of that too  !!!

[mainline]

I'd be looking for an mx125, I reckon it'd be cheaper and easier to fix up than what you've got and definately faster.

[Nathan S]

SL100 motor fits into a 125 frame.
The 125 top end fits onto a 100 bottom end, but I think the cases need to be machined out to fit the bottom of the barrel in.

Could be a fun little bike, but is not a good start to a serious race bike...

If you're on a tiny budget, a twin shock DT125 is a good starting point - same basic bike as the MX125 and YZ125, and are worth even less than a SL125... You can make the little DT a lot better than stock for sod-all money, and can be made faster than a stock YZ-A for not too much more.

[Sammundo]

ok sounds good. i currently run a dt in evo which is obviously a bit down on power. i assume upgrades on this would be the same as a 74 bike? What parts should i look at replacing with yz bits? i assume head, barrel and expansion chamber form the same year bike?

[Nathan S]

My DT125 originally had:
26mm carb from a DT250;
Pod filter on the back of the carb;
No silencer (still not very loud);
electronic ignition from a YZ125E;
DT250 forks in MX250A triples;
Front wheel and brake from a YZ125E;
330mm long Mulholland shocks.

It was otherwise stock.
It wasn't fast, but it was so easy to ride that it was reasonably competitive at club days - a real asset at my skill level.
I also think it owed me about $500 all-up at that point, including new grips, new chain & sprockets etc.

It subsequently got a YZ125A gearset (in hindsight, an MX gearbox would be better), a 32mm carb from the same YZ125E. This made it fast enough to keep me comfortably in the front half of the field of Heaven's Classic 125 class (pre-75 & pre-78 combined). It was also considerably faster than my stock YZ125A.

Whenever it makes it back out the shed again, it will have a Lozza barrel, cut & shut IT125 pipe, and a MX125 airbox mated up to the 125E carby. And a RM125B(?) seat, YZ-A tank and some decent shocks.
I think it will be at least as good as the Elsinores - although obviously with different strengths and weaknesses between the two bikes.

[Sammundo]

thanks for the info. whats a lozza barrel?

[Nathan S]

A barrel ported by Uncle Lozza from the Two-Stroke Instituite.

[Lozza]

There's a few upgrades available since that was done...................

[Barronvmx]

I was racing my XL100 at Harrisville against Greg and his son on the other honda four strokes. I have spent a total of $500.00 so far and was able to pass most people and be mid pack. I can find you an engine and help with all the mods that have worked for me. Just contact me through the club and I can help you get that pre75 racer going.

Glenn W
BMCC club president